多年iOS開發經驗總結(一)

總結了幾個月的東西終於能和大家分享了，不多說，直接看東西！

1、禁止手機睡眠

1	[UIApplication sharedApplication].idleTimerDisabled = YES;

2、隱藏某行cell

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

{

// 如果是你需要隱藏的那一行，返回高度爲0

if(indexPath.row == YouWantToHideRow)

return 0;

return 44;

}

// 然後再你需要隱藏cell的時候調用

[self.tableView beginUpdates];

[self.tableView endUpdates];

3、禁用button高亮

button.adjustsImageWhenHighlighted = NO;

或者在創建的時候

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

4、tableview遇到這種報錯failed to obtain a cell from its dataSource

是因爲你的cell被調用的早了。先循環使用了cell，後又創建cell。順序錯了

可能原因：1、xib的cell沒有註冊 2、內存中已經有這個cell的緩存了(也就是說通過你的cellId找到的cell並不是你想要的類型)，這時候需要改下cell的標識

5、cocoa pods報這個錯誤：unable to access ‘https://github.com/facebook/pop.git/': Operation timed out after 0 milliseconds with 0 out of 0 bytes received

解決辦法：原因可能是網絡問題，網絡請求超時了，只需要重試就行了

6、cocoa pods 出現ERROR: While executing gem ... (Errno::EPERM)

解決辦法：

https://segmentfault.com/q/1010000002926243

7、動畫切換window的根控制器

// options是動畫選項

[UIView transitionWithView:[UIApplication sharedApplication].keyWindow duration:0.5f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{

BOOL oldState = [UIView areAnimationsEnabled];

[UIView setAnimationsEnabled:NO];

[UIApplication sharedApplication].keyWindow.rootViewController = [RootViewController new];

[UIView setAnimationsEnabled:oldState];

} completion:^(BOOL finished) {

}];

8、去除數組中重複的對象

1	NSArray *newArr = [oldArr valueForKeyPath:@“@distinctUnionOfObjects.self"];

9、編譯的時候遇到 no such file or directory: ／users／apple／XXX

是因爲編譯的時候，在此路徑下找不到這個文件，解決這個問題，首先是是要檢查缺少的文件是不是在工程中，如果不在工程中，需要從本地拖進去，如果發現已經存在工程中了，或者拖進去還是報錯，這時候需要去build phases中搜索這個文件，這時候很可能會搜出現兩個相同的文件，這時候，有一個路徑是正確的，刪除另外一個即可。如果刪除了還是不行，需要把兩個都刪掉，然後重新往工程裏拖進這個文件即可

10、iOS8系統中，tableView最好實現下-tableView: heightForRowAtIndexPath:這個代理方法，要不然在iOS8中可能就會出現顯示不全或者無法響應事件的問題

11、iOS8中實現側滑功能的時候這個方法必須實現，要不然在iOS8中無法側滑

// 必須寫的方法，和editActionsForRowAtIndexPath配對使用，裏面什麼不寫也行

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

}

12、三個通知

NSSystemTimeZoneDidChangeNotification監聽修改時間界面的兩個按鈕狀態變化

UIApplicationSignificantTimeChangeNotification 監聽用戶改變時間（只要點擊自動設置按鈕就會調用） NSSystemClockDidChangeNotification 監聽用戶修改時間（時間不同纔會調用）

13、SDWebImage本地緩存有時候會害人。如果之前緩存過一張圖片，即使下次服務器換了這張圖片，但是圖片url沒換，用sdwebimage下載下來的還是以前那張,所以遇到這種問題，不要先去懟服務器，清空下緩存再試就好了。

14、上線前注意：

1）、刪掉代碼中所有的測試代碼
2）、如果後臺有審覈模式，提醒後臺開啓此模式
3）、主流程再跑一跑
4）、全局搜索waring，檢查所有標記waring的地方

15、跳進app權限設置

// 跳進app設置

if (UIApplicationOpenSettingsURLString != NULL) {

NSURL *url = [NSURL URLWithString:UIApplicationOpenSettingsURLString];

[[UIApplication sharedApplication] openURL:url];

}

16、給一個view截圖

UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);

[view.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *img = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

17、開發中如果要動態修改tableView的tableHeaderView或者tableFooterView的高度，需要給tableView重新設置，而不是直接更改高度。正確的做法是重新設置一下tableView.tableFooterView = 更改過高度的view。爲什麼？其實在iOS8以上直接改高度是沒有問題的，在iOS8中出現了contentSize不準確的問題，這是解決辦法。

18、注意對象爲nil的時候，調用此對象分類的方法不會執行

19、collectionView的內容小於其寬高的時候是不能滾動的，設置可以滾動：

1 2	collectionView.alwaysBounceHorizontal = YES; collectionView.alwaysBounceVertical = YES;

20、設置navigationBar上的title顏色和大小

1	[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor youColor], NSFontAttributeName : [UIFont systemFontOfSize:15]}]

21、顏色轉圖片

+ (UIImage *)cl_imageWithColor:(UIColor *)color {

CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);

UIGraphicsBeginImageContext(rect.size);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetFillColorWithColor(context, [color CGColor]);

CGContextFillRect(context, rect);

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

22、view設置圓角

#define ViewBorderRadius(View, Radius, Width, Color)\

[View.layer setCornerRadius:(Radius)];\

[View.layer setMasksToBounds:YES];\

[View.layer setBorderWidth:(Width)];\

[View.layer setBorderColor:[Color CGColor]] // view圓角

23、強／弱引用

1 2	#define WeakSelf(type) __weak typeof(type) weak##type = type; // weak #define StrongSelf(type) __strong typeof(type) type = weak##type; // strong

24、由角度轉換弧度

1	#define DegreesToRadian(x) (M_PI * (x) / 180.0)

25、由弧度轉換角度

1	#define RadianToDegrees(radian) (radian*180.0)/(M_PI)

26、獲取圖片資源

1	#define GetImage(imageName) [UIImage imageNamed:[NSString stringWithFormat:@"%@",imageName]]

27、獲取temp

1	#define PathTemp NSTemporaryDirectory()

28、獲取沙盒 Document

1	#define PathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]

29、獲取沙盒 Cache

1	#define PathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]

30、GCD代碼只執行一次

1	#define kDISPATCH_ONCE_BLOCK(onceBlock) static dispatch_once_t onceToken; dispatch_once(&onceToken, onceBlock);

31、自定義NSLog

#ifdef DEBUG

#define NSLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)

#else

#define NSLog(...)

#endif

32、Font

#define FontL(s) [UIFont systemFontOfSize:s weight:UIFontWeightLight]

#define FontR(s) [UIFont systemFontOfSize:s weight:UIFontWeightRegular]

#define FontB(s) [UIFont systemFontOfSize:s weight:UIFontWeightBold]

#define FontT(s) [UIFont systemFontOfSize:s weight:UIFontWeightThin]

#define Font(s) FontL(s)

33、FORMAT

1	#define FORMAT(f, ...) [NSString stringWithFormat:f, ## __VA_ARGS__]

34、在主線程上運行

1	#define kDISPATCH_MAIN_THREAD(mainQueueBlock) dispatch_async(dispatch_get_main_queue(), mainQueueBlock);

35、開啓異步線程

1	#define kDISPATCH_GLOBAL_QUEUE_DEFAULT(globalQueueBlock) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), globalQueueBlocl);

36、通知

#define NOTIF_ADD(n, f) [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(f) name:n object:nil]

#define NOTIF_POST(n, o) [[NSNotificationCenter defaultCenter] postNotificationName:n object:o]

#define NOTIF_REMV() [[NSNotificationCenter defaultCenter] removeObserver:self]

37、隨機顏色

+ (UIColor *)RandomColor {

NSInteger aRedValue = arc4random() % 255;

NSInteger aGreenValue = arc4random() % 255;

NSInteger aBlueValue = arc4random() % 255;

UIColor *randColor = [UIColor colorWithRed:aRedValue / 255.0f green:aGreenValue / 255.0f blue:aBlueValue / 255.0f alpha:1.0f];

return randColor;

}

38、獲取window

+(UIWindow*)getWindow {

UIWindow* win = nil; //[UIApplication sharedApplication].keyWindow;

for (id item in [UIApplication sharedApplication].windows) {

if ([item class] == [UIWindow class]) {

if (!((UIWindow*)item).hidden) {

win = item;

break;

}

return win;

}

39、修改textField的placeholder的字體顏色、大小

1 2	[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"]; [textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];

40、統一收起鍵盤

1	[[[UIApplication sharedApplication] keyWindow] endEditing:YES];

41、控制屏幕旋轉，在控制器中寫

/** 是否支持自動轉屏 */

- (BOOL)shouldAutorotate {

return YES;

}

/** 支持哪些屏幕方向 */

- (UIInterfaceOrientationMask)supportedInterfaceOrientations {

return UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight;

}

/** 默認的屏幕方向（當前ViewController必須是通過模態出來的UIViewController（模態帶導航的無效）方式展現出來的，纔會調用這個方法） */

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {

return UIInterfaceOrientationLandscapeLeft | UIInterfaceOrientationLandscapeRight;

}

42、獲取app緩存大小

- (CGFloat)getCachSize {

NSUInteger imageCacheSize = [[SDImageCache sharedImageCache] getSize];

//獲取自定義緩存大小

//用枚舉器遍歷一個文件夾的內容

//1.獲取文件夾枚舉器

NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];

NSDirectoryEnumerator *enumerator = [[NSFileManager defaultManager] enumeratorAtPath:myCachePath];

__block NSUInteger count = 0;

//2.遍歷

for (NSString *fileName in enumerator) {

NSString *path = [myCachePath stringByAppendingPathComponent:fileName];

NSDictionary *fileDict = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil];

count += fileDict.fileSize;//自定義所有緩存大小

}

// 得到是字節轉化爲M

CGFloat totalSize = ((CGFloat)imageCacheSize+count)/1024/1024;

return totalSize;

}

43、清理app緩存

- (void)handleClearView {

//刪除兩部分

//1.刪除 sd 圖片緩存

//先清除內存中的圖片緩存

[[SDImageCache sharedImageCache] clearMemory];

//清除磁盤的緩存

[[SDImageCache sharedImageCache] clearDisk];

//2.刪除自己緩存

NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];

[[NSFileManager defaultManager] removeItemAtPath:myCachePath error:nil];

}

44、模型轉字典

static NSSet *classes;

- (NSMutableDictionary *)getParameterDictionary {

NSMutableDictionary *dict = [NSMutableDictionary dictionary];

Class c = self.class;

while (c) {

unsigned count;

objc_property_t *properties = class_copyPropertyList([c class], &count);

for (int i = 0; i < count; i++) {

NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];

dict[key] = [self valueForKey:key];

}

free(properties);

// 獲得父類

c = class_getSuperclass(c);

if ([self isClassFromFoundation:c]) break;

}

return dict;

}

- (BOOL)isClassFromFoundation:(Class)c

{

if (c == [NSObject class] || c == [NSManagedObject class]) return YES;

__block BOOL result = NO;

[[self foundationClasses] enumerateObjectsUsingBlock:^(Class foundationClass, BOOL *stop) {

if ([c isSubclassOfClass:foundationClass]) {

result = YES;

*stop = YES;

}

}];

return result;

}

- (NSSet *)foundationClasses

{

if (classes == nil) {

// 集合中沒有NSObject，因爲幾乎所有的類都是繼承自NSObject，具體是不是NSObject需要特殊判斷

classes = [NSSet setWithObjects:

[NSURL class],

[NSDate class],

[NSValue class],

[NSData class],

[NSError class],

[NSArray class],

[NSDictionary class],

[NSString class],

[NSAttributedString class], nil];

}

return classes;

}

45、交換兩個方法實現

Class aClass = [self class];

SEL originalSelector = @selector(viewWillAppear:);

SEL swizzledSelector = @selector(xxx_viewWillAppear:);

Method originalMethod = class_getInstanceMethod(aClass, originalSelector);

Method swizzledMethod = class_getInstanceMethod(aClass, swizzledSelector);

BOOL didAddMethod =

class_addMethod(aClass,

originalSelector,

method_getImplementation(swizzledMethod),

method_getTypeEncoding(swizzledMethod));

if (didAddMethod) {

class_replaceMethod(aClass,

swizzledSelector,

method_getImplementation(originalMethod),

method_getTypeEncoding(originalMethod));

} else {

method_exchangeImplementations(originalMethod, swizzledMethod);

}

46、打印百分號和引號

1 2	NSLog(@"%%"); NSLog(@"\"");

47、幾個常用權限判斷

if ([CLLocationManager authorizationStatus] ==kCLAuthorizationStatusDenied) {

NSLog(@"沒有定位權限");

}

AVAuthorizationStatus statusVideo = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

if (statusVideo == AVAuthorizationStatusDenied) {

NSLog(@"沒有攝像頭權限");

}

//是否有麥克風權限

AVAuthorizationStatus statusAudio = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeAudio];

if (statusAudio == AVAuthorizationStatusDenied) {

NSLog(@"沒有錄音權限");

}

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {

if (status == PHAuthorizationStatusDenied) {

NSLog(@"沒有相冊權限");

}

}];

48、獲取手機型號

+ (NSString *)getDeviceInfo {

struct utsname systemInfo;

uname(&systemInfo);

NSString *platform = [NSString stringWithCString:systemInfo.machine encoding:NSASCIIStringEncoding];

if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 2G";

if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";

if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";

if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";

if ([platform isEqualToString:@"iPhone3,2"]) return @"iPhone 4";

if ([platform isEqualToString:@"iPhone3,3"]) return @"iPhone 4";

if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4S";

if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5";

if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5";

if ([platform isEqualToString:@"iPhone5,3"]) return @"iPhone 5c";

if ([platform isEqualToString:@"iPhone5,4"]) return @"iPhone 5c";

if ([platform isEqualToString:@"iPhone6,1"]) return @"iPhone 5s";

if ([platform isEqualToString:@"iPhone6,2"]) return @"iPhone 5s";

if ([platform isEqualToString:@"iPhone7,1"]) return @"iPhone 6 Plus";

if ([platform isEqualToString:@"iPhone7,2"]) return @"iPhone 6";

if ([platform isEqualToString:@"iPhone8,1"]) return @"iPhone 6s";

if ([platform isEqualToString:@"iPhone8,2"]) return @"iPhone 6s Plus";

// 日行兩款手機型號均爲日本獨佔，可能使用索尼FeliCa支付方案而不是蘋果支付

if ([platform isEqualToString:@"iPhone9,1"]) return @"國行、日版、港行iPhone 7";

if ([platform isEqualToString:@"iPhone9,2"]) return @"港行、國行iPhone 7 Plus";

if ([platform isEqualToString:@"iPhone9,3"]) return @"美版、臺版iPhone 7";

if ([platform isEqualToString:@"iPhone9,4"]) return @"美版、臺版iPhone 7 Plus";

if ([platform isEqualToString:@"iPhone8,4"]) return @"iPhone SE";

if ([platform isEqualToString:@"iPod1,1"]) return @"iPod Touch 1G";

if ([platform isEqualToString:@"iPod2,1"]) return @"iPod Touch 2G";

if ([platform isEqualToString:@"iPod3,1"]) return @"iPod Touch 3G";

if ([platform isEqualToString:@"iPod4,1"]) return @"iPod Touch 4G";

if ([platform isEqualToString:@"iPod5,1"]) return @"iPod Touch 5G";

if ([platform isEqualToString:@"iPad1,1"]) return @"iPad 1G";

if ([platform isEqualToString:@"iPad2,1"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,2"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,3"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,4"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,5"]) return @"iPad Mini 1G";

if ([platform isEqualToString:@"iPad2,6"]) return @"iPad Mini 1G";

if ([platform isEqualToString:@"iPad2,7"]) return @"iPad Mini 1G";

if ([platform isEqualToString:@"iPad3,1"]) return @"iPad 3";

if ([platform isEqualToString:@"iPad3,2"]) return @"iPad 3";

if ([platform isEqualToString:@"iPad3,3"]) return @"iPad 3";

if ([platform isEqualToString:@"iPad3,4"]) return @"iPad 4";

if ([platform isEqualToString:@"iPad3,5"]) return @"iPad 4";

if ([platform isEqualToString:@"iPad3,6"]) return @"iPad 4";

if ([platform isEqualToString:@"iPad4,1"]) return @"iPad Air";

if ([platform isEqualToString:@"iPad4,2"]) return @"iPad Air";

if ([platform isEqualToString:@"iPad4,3"]) return @"iPad Air";

if ([platform isEqualToString:@"iPad4,4"]) return @"iPad Mini 2G";

if ([platform isEqualToString:@"iPad4,5"]) return @"iPad Mini 2G";

if ([platform isEqualToString:@"iPad4,6"]) return @"iPad Mini 2G";

if ([platform isEqualToString:@"i386"]) return @"iPhone Simulator";

if ([platform isEqualToString:@"x86_64"]) return @"iPhone Simulator";

return platform;

}

49、長按複製功能

- (void)viewDidLoad

{

[self.view addGestureRecognizer:[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(pasteBoard:)]];

}

- (void)pasteBoard:(UILongPressGestureRecognizer *)longPress {

if (longPress.state == UIGestureRecognizerStateBegan) {

UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];

pasteboard.string = @"需要複製的文本";

}

50、cocoapods升級

在終端執行 sudo gem install -n / usr / local / bin cocoapods --pre

51、設置啓動頁後，依然顯示之前的

刪除app，手機重啓，重新安裝

52、判斷圖片類型

//通過圖片Data數據第一個字節來獲取圖片擴展名

- (NSString *)contentTypeForImageData:(NSData *)data

{

uint8_t c;

[data getBytes:&c length:1];

switch (c)

{

case 0xFF:

return @"jpeg";

case 0x89:

return @"png";

case 0x47:

return @"gif";

case 0x49:

case 0x4D:

return @"tiff";

case 0x52:

if ([data length] < 12) {

return nil;

}

NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding];

if ([testString hasPrefix:@"RIFF"]

&& [testString hasSuffix:@"WEBP"])

{

return @"webp";

}

return nil;

}

return nil;

}

53、獲取手機和app信息

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];

CFShow(infoDictionary);

// app名稱

NSString *app_Name = [infoDictionary objectForKey:@"CFBundleDisplayName"];

// app版本

NSString *app_Version = [infoDictionary objectForKey:@"CFBundleShortVersionString"];

// app build版本

NSString *app_build = [infoDictionary objectForKey:@"CFBundleVersion"];

//手機序列號

NSString* identifierNumber = [[UIDevice currentDevice] uniqueIdentifier];

NSLog(@"手機序列號: %@",identifierNumber);

//手機別名：用戶定義的名稱

NSString* userPhoneName = [[UIDevice currentDevice] name];

NSLog(@"手機別名: %@", userPhoneName);

//設備名稱

NSString* deviceName = [[UIDevice currentDevice] systemName];

NSLog(@"設備名稱: %@",deviceName );

//手機系統版本

NSString* phoneVersion = [[UIDevice currentDevice] systemVersion];

NSLog(@"手機系統版本: %@", phoneVersion);

//手機型號

NSString* phoneModel = [[UIDevice currentDevice] model];

NSLog(@"手機型號: %@",phoneModel );

//地方型號（國際化區域名稱）

NSString* localPhoneModel = [[UIDevice currentDevice] localizedModel];

NSLog(@"國際化區域名稱: %@",localPhoneModel );

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];

// 當前應用名稱

NSString *appCurName = [infoDictionary objectForKey:@"CFBundleDisplayName"];

NSLog(@"當前應用名稱：%@",appCurName);

// 當前應用軟件版本比如：1.0.1

NSString *appCurVersion = [infoDictionary objectForKey:@"CFBundleShortVersionString"];

NSLog(@"當前應用軟件版本:%@",appCurVersion);

// 當前應用版本號碼 int類型

NSString *appCurVersionNum = [infoDictionary objectForKey:@"CFBundleVersion"];

NSLog(@"當前應用版本號碼：%@",appCurVersionNum);

54、獲取一個類的所有屬性

id LenderClass = objc_getClass("Lender");

unsigned int outCount, i;

objc_property_t *properties = class_copyPropertyList(LenderClass, &outCount);

for (i = 0; i < outCount; i++) {

objc_property_t property = properties[i];

fprintf(stdout, "%s %s\n", property_getName(property), property_getAttributes(property));

}

55、image圓角

- (UIImage *)circleImage

{

// NO代表透明

UIGraphicsBeginImageContextWithOptions(self.size, NO, 1);

// 獲得上下文

CGContextRef ctx = UIGraphicsGetCurrentContext();

// 添加一個圓

CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);

// 方形變圓形

CGContextAddEllipseInRect(ctx, rect);

// 裁剪

CGContextClip(ctx);

// 將圖片畫上去

[self drawInRect:rect];

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

56、image拉伸

+ (UIImage *)resizableImage:(NSString *)imageName

{

UIImage *image = [UIImage imageNamed:imageName];

CGFloat imageW = image.size.width;

CGFloat imageH = image.size.height;

return [image resizableImageWithCapInsets:UIEdgeInsetsMake(imageH * 0.5, imageW * 0.5, imageH * 0.5, imageW * 0.5) resizingMode:UIImageResizingModeStretch];

}

57、JSON字符串轉字典

+ (NSDictionary *)parseJSONStringToNSDictionary:(NSString *)JSONString {

NSData *JSONData = [JSONString dataUsingEncoding:NSUTF8StringEncoding];

NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:JSONData options:NSJSONReadingMutableLeaves error:nil];

return responseJSON;

}

58、身份證號驗證

- (BOOL)validateIdentityCard {

BOOL flag;

if (self.length <= 0) {

flag = NO;

return flag;

}

NSString *regex2 = @"^(\\d{14}|\\d{17})(\\d|[xX])$";

NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];

return [identityCardPredicate evaluateWithObject:self];

}

59、獲取設備mac地址

+ (NSString *)macAddress {

int mib[6];

size_t len;

char *buf;

unsigned char *ptr;

struct if_msghdr *ifm;

struct sockaddr_dl *sdl;

mib[0] = CTL_NET;

mib[1] = AF_ROUTE;

mib[2] = 0;

mib[3] = AF_LINK;

mib[4] = NET_RT_IFLIST;

if((mib[5] = if_nametoindex("en0")) == 0) {

printf("Error: if_nametoindex error\n");

return NULL;

}

if(sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {

printf("Error: sysctl, take 1\n");

return NULL;

}

if((buf = malloc(len)) == NULL) {

printf("Could not allocate memory. Rrror!\n");

return NULL;

}

if(sysctl(mib, 6, buf, &len, NULL, 0) < 0) {

printf("Error: sysctl, take 2");

return NULL;

}

ifm = (struct if_msghdr *)buf;

sdl = (struct sockaddr_dl *)(ifm + 1);

ptr = (unsigned char *)LLADDR(sdl);

NSString *outstring = [NSString stringWithFormat:@"X:X:X:X:X:X",

*ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];

free(buf);

return outstring;

}

60、導入自定義字體庫

1、找到你想用的字體的 ttf 格式，拖入工程
2、在工程的plist中增加一行數組，“Fonts provided by application”
3、爲這個key添加一個item，value爲你剛纔導入的ttf文件名
4、直接使用即可：label.font = [UIFont fontWithName:@"你剛纔導入的ttf文件名" size:20.0]；

61、拿到當前正在顯示的控制器，不管是push進去的，還是present進去的都能拿到

- (UIViewController *)getVisibleViewControllerFrom:(UIViewController*)vc {

if ([vc isKindOfClass:[UINavigationController class]]) {

return [self getVisibleViewControllerFrom:[((UINavigationController*) vc) visibleViewController]];

}else if ([vc isKindOfClass:[UITabBarController class]]){

return [self getVisibleViewControllerFrom:[((UITabBarController*) vc) selectedViewController]];

} else {

if (vc.presentedViewController) {

return [self getVisibleViewControllerFrom:vc.presentedViewController];

} else {

return vc;

}

62、runtime爲一個類動態添加屬性

1 2	// 動態添加屬性的本質是: 讓對象的某個屬性與值產生關聯 objc_setAssociatedObject(self, WZBPlaceholderViewKey, placeholderView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

63、獲取runtime爲一個類動態添加的屬性

1	objc_getAssociatedObject(self, WZBPlaceholderViewKey);

64、KVO監聽某個對象的屬性

// 添加監聽者

[self addObserver:self forKeyPath:property options:NSKeyValueObservingOptionNew context:nil];

// 當監聽的屬性值變化的時候會來到這個方法

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

if ([keyPath isEqualToString:@"property"]) {

[self textViewTextChange];

} else {

}

65、Reachability判斷網絡狀態

NetworkStatus status = [[Reachability reachabilityForInternetConnection] currentReachabilityStatus];

if (status == NotReachable) {

NSLog(@"當前設備無網絡");

}

if (status == ReachableViaWiFi) {

NSLog(@"當前wifi網絡");

}

if (status == NotReachable) {

NSLog(@"當前蜂窩移動網絡");

}

66、AFNetworking監聽網絡狀態

// 監聽網絡狀況

AFNetworkReachabilityManager *mgr = [AFNetworkReachabilityManager sharedManager];

[mgr setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {

switch (status) {

case AFNetworkReachabilityStatusUnknown:

break;

case AFNetworkReachabilityStatusNotReachable: {

[SVProgressHUD showInfoWithStatus:@"當前設備無網絡"];

}

break;

case AFNetworkReachabilityStatusReachableViaWiFi:

[SVProgressHUD showInfoWithStatus:@"當前Wi-Fi網絡"];

break;

case AFNetworkReachabilityStatusReachableViaWWAN:

[SVProgressHUD showInfoWithStatus:@"當前蜂窩移動網絡"];

break;

default:

break;

}

}];

[mgr startMonitoring];

67、透明顏色不影響子視圖透明度

1	[UIColor colorWithRed: green: blue: alpha:];

68、取圖片某一點的顏色

if (point.x < 0 || point.y < 0) return nil;

CGImageRef imageRef = self.CGImage;

NSUInteger width = CGImageGetWidth(imageRef);

NSUInteger height = CGImageGetHeight(imageRef);

if (point.x >= width || point.y >= height) return nil;

unsigned char *rawData = malloc(height * width * 4);

if (!rawData) return nil;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

NSUInteger bytesPerPixel = 4;

NSUInteger bytesPerRow = bytesPerPixel * width;

NSUInteger bitsPerComponent = 8;

CGContextRef context = CGBitmapContextCreate(rawData,

width,

height,

bitsPerComponent,

bytesPerRow,

colorSpace,

kCGImageAlphaPremultipliedLast

| kCGBitmapByteOrder32Big);

if (!context) {

free(rawData);

return nil;

}

CGColorSpaceRelease(colorSpace);

CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);

CGContextRelease(context);

int byteIndex = (bytesPerRow * point.y) + point.x * bytesPerPixel;

CGFloat red = (rawData[byteIndex] * 1.0) / 255.0;

CGFloat green = (rawData[byteIndex + 1] * 1.0) / 255.0;

CGFloat blue = (rawData[byteIndex + 2] * 1.0) / 255.0;

CGFloat alpha = (rawData[byteIndex + 3] * 1.0) / 255.0;

UIColor *result = nil;

result = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];

free(rawData);

return result;

69、判斷該圖片是否有透明度通道

- (BOOL)hasAlphaChannel

{

CGImageAlphaInfo alpha = CGImageGetAlphaInfo(self.CGImage);

return (alpha == kCGImageAlphaFirst ||

alpha == kCGImageAlphaLast ||

alpha == kCGImageAlphaPremultipliedFirst ||

alpha == kCGImageAlphaPremultipliedLast);

}

70、獲得灰度圖

+ (UIImage*)covertToGrayImageFromImage:(UIImage*)sourceImage

{

int width = sourceImage.size.width;

int height = sourceImage.size.height;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

CGContextRef context = CGBitmapContextCreate (nil,width,height,8,0,colorSpace,kCGImageAlphaNone);

CGColorSpaceRelease(colorSpace);

if (context == NULL) {

return nil;

}

CGContextDrawImage(context,CGRectMake(0, 0, width, height), sourceImage.CGImage);

CGImageRef contextRef = CGBitmapContextCreateImage(context);

UIImage *grayImage = [UIImage imageWithCGImage:contextRef];

CGContextRelease(context);

CGImageRelease(contextRef);

return grayImage;

}

71、根據bundle中的文件名讀取圖片

+ (UIImage *)imageWithFileName:(NSString *)name {

NSString *extension = @"png";

NSArray *components = [name componentsSeparatedByString:@"."];

if ([components count] >= 2) {

NSUInteger lastIndex = components.count - 1;

extension = [components objectAtIndex:lastIndex];

name = [name substringToIndex:(name.length-(extension.length+1))];

}

// 如果爲Retina屏幕且存在對應圖片，則返回Retina圖片，否則查找普通圖片

if ([UIScreen mainScreen].scale == 2.0) {

name = [name stringByAppendingString:@"@2x"];

NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];

if (path != nil) {

return [UIImage imageWithContentsOfFile:path];

}

if ([UIScreen mainScreen].scale == 3.0) {

name = [name stringByAppendingString:@"@3x"];

NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];

if (path != nil) {

return [UIImage imageWithContentsOfFile:path];

}

NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];

if (path) {

return [UIImage imageWithContentsOfFile:path];

}

return nil;

}

72、合併兩個圖片

+ (UIImage*)mergeImage:(UIImage*)firstImage withImage:(UIImage*)secondImage {

CGImageRef firstImageRef = firstImage.CGImage;

CGFloat firstWidth = CGImageGetWidth(firstImageRef);

CGFloat firstHeight = CGImageGetHeight(firstImageRef);

CGImageRef secondImageRef = secondImage.CGImage;

CGFloat secondWidth = CGImageGetWidth(secondImageRef);

CGFloat secondHeight = CGImageGetHeight(secondImageRef);

CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));

UIGraphicsBeginImageContext(mergedSize);

[firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];

[secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

73、根據bundle中的圖片名創建imageview

+ (id)imageViewWithImageNamed:(NSString*)imageName

{

return [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];

}

74、爲imageView添加倒影

CGRect frame = self.frame;

frame.origin.y += (frame.size.height + 1);

UIImageView *reflectionImageView = [[UIImageView alloc] initWithFrame:frame];

self.clipsToBounds = TRUE;

reflectionImageView.contentMode = self.contentMode;

[reflectionImageView setImage:self.image];

reflectionImageView.transform = CGAffineTransformMakeScale(1.0, -1.0);

CALayer *reflectionLayer = [reflectionImageView layer];

CAGradientLayer *gradientLayer = [CAGradientLayer layer];

gradientLayer.bounds = reflectionLayer.bounds;

gradientLayer.position = CGPointMake(reflectionLayer.bounds.size.width / 2, reflectionLayer.bounds.size.height * 0.5);

gradientLayer.colors = [NSArray arrayWithObjects:

(id)[[UIColor clearColor] CGColor],

(id)[[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.3] CGColor], nil];

gradientLayer.startPoint = CGPointMake(0.5,0.5);

gradientLayer.endPoint = CGPointMake(0.5,1.0);

reflectionLayer.mask = gradientLayer;

[self.superview addSubview:reflectionImageView];

75、畫水印

// 畫水印

- (void) setImage:(UIImage *)image withWaterMark:(UIImage *)mark inRect:(CGRect)rect

{

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)

{

UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0.0);

}

//原圖

[image drawInRect:self.bounds];

//水印圖

[mark drawInRect:rect];

UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

self.image = newPic;

}

76、讓label的文字內容顯示在左上／右上／左下／右下／中心頂／中心底部

自定義UILabel

// 重寫label的textRectForBounds方法

- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {

CGRect rect = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];

switch (self.textAlignmentType) {

case WZBTextAlignmentTypeLeftTop: {

rect.origin = bounds.origin;

}

break;

case WZBTextAlignmentTypeRightTop: {

rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, bounds.origin.y);

}

break;

case WZBTextAlignmentTypeLeftBottom: {

rect.origin = CGPointMake(bounds.origin.x, CGRectGetMaxY(bounds) - rect.size.height);

}

break;

case WZBTextAlignmentTypeRightBottom: {

rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, CGRectGetMaxY(bounds) - rect.size.height);

}

break;

case WZBTextAlignmentTypeTopCenter: {

rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - rect.origin.y);

}

break;

case WZBTextAlignmentTypeBottomCenter: {

rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - CGRectGetMaxY(bounds) - rect.size.height);

}

break;

case WZBTextAlignmentTypeLeft: {

rect.origin = CGPointMake(0, rect.origin.y);

}

break;

case WZBTextAlignmentTypeRight: {

rect.origin = CGPointMake(rect.origin.x, 0);

}

break;

case WZBTextAlignmentTypeCenter: {

rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, (CGRectGetHeight(bounds) - CGRectGetHeight(rect)) / 2);

}

break;

default:

break;

}

return rect;

}

- (void)drawTextInRect:(CGRect)rect {

CGRect textRect = [self textRectForBounds:rect limitedToNumberOfLines:self.numberOfLines];

[super drawTextInRect:textRect];

}

77、scrollView上的輸入框，鍵盤擋住的問題

推薦用IQKeyboardManager這個框架！

手動解決如下

1、監聽鍵盤彈出／消失的通知

2、在通知中加入代碼：

NSDictionary* info = [aNotification userInfo];

CGRect keyPadFrame=[[UIApplication sharedApplication].keyWindow convertRect:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] fromView:self.view];

CGSize kbSize =keyPadFrame.size;

CGRect activeRect=[self.view convertRect:activeField.frame fromView:activeField.superview];

CGRect aRect = self.view.bounds;

aRect.size.height -= (kbSize.height);

CGPoint origin = activeRect.origin;

origin.y -= backScrollView.contentOffset.y;

if (!CGRectContainsPoint(aRect, origin)) {

CGPoint scrollPoint = CGPointMake(0.0,CGRectGetMaxY(activeRect)-(aRect.size.height));

[backScrollView setContentOffset:scrollPoint animated:YES];

}

78、frame佈局的cell動態高度

這種通常在你的模型中添加一個輔助屬性cellHeight，在模型中重寫這個屬性的get方法，根據你的佈局和模型中的其他屬性值計算出總高度。最後在tableView：heightForRow方法中，根據indexPath找出對應的模型，返回這個高度即可。

79、AutoLayout佈局的cell動態高度

// 1、設置tableView的屬性

self.tableView.rowHeight = UITableViewAutomaticDimension;

self.tableView.estimatedRowHeight = 44.0; // 這個屬性非0，估計cell高度

// 2、至上而下設置cell的約束，注意，上下左右最好都要頂到cell的四周

cell

80、使用performSelector:調用函數，內存泄漏問題

當我們在開發中使用[obj performSelector:NSSelectorFromString(@"aMethod")];這類方法時可能會收到一個警告"performSelector may cause a leak because its selector is unknown".

是因爲編譯器不清楚這個對象能不能相應這個方法，如果不能，則是不安全的，而且編譯器也不清楚該怎麼處理這個方法的返回值！

使用以下代碼調用即可：

if (! obj) { return; }

SEL selector = NSSelectorFromString(@"aMethod");

IMP imp = [obj methodForSelector:selector];

void (*func)(id, SEL) = (void *)imp;

func(obj, selector);

或者：

SEL selector = NSSelectorFromString(@"aMethod");

((void (*)(id, SEL))[obj methodForSelector:selector])(obj, selector);

81、一個字符串是否包含另一個字符串

// 方法1

if ([str1 containsString:str2]) {

NSLog(@"str1包含str2");

} else {

NSLog(@"str1不包含str2");

}

// 方法2

if ([str1 rangeOfString: str2].location == NSNotFound) {

NSLog(@"str1包含str2");

} else {

NSLog(@"str1不包含str2");

}

82、cell去除選中效果

1	cell.selectionStyle = UITableViewCellSelectionStyleNone;

83、cell點按效果

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

[tableView deselectRowAtIndexPath:indexPath animated:YES];

}

84、當刪除一個從xib拖出來的屬性時，一定記得把xib中對應的線也刪掉，不然會報類似[setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key的crash

點擊這個叉號刪除

85、真機測試的時候報錯：Could not launch "你的 App"，process launch failed: Security

因爲你的app沒有上線，iOS9開始，需要手動信任Xcode生成的描述文件，打開手機設置->通用->描述文件->點擊你的app的描述文件->點擊信任

86、真機測試的時候報錯：Could not find Developer Disk Image

這是因爲你的設備系統版本大於Xcode能兼容的系統版本，比如你的設備是iOS10.3，而Xcode版本是8.2（Xcode8.2最大兼容iOS10.2），就會報這個錯誤。解決辦法就是升級Xcode！

87、UITextView沒有placeholder的問題？

網上有很多此類自定義控件，也可以參考下我寫的一個UITextView分類 UITextView-WZB

88、移除字符串中的空格和換行

+ (NSString *)removeSpaceAndNewline:(NSString *)str {

NSString *temp = [str stringByReplacingOccurrencesOfString:@" " withString:@""];

temp = [temp stringByReplacingOccurrencesOfString:@"\r" withString:@""];

temp = [temp stringByReplacingOccurrencesOfString:@"\n" withString:@""];

return temp;

}

89、判斷字符串中是否有空格

+ (BOOL)isBlank:(NSString *)str {

NSRange _range = [str rangeOfString:@" "];

if (_range.location != NSNotFound) {

//有空格

return YES;

} else {

//沒有空格

return NO;

}

90、獲取一個視頻的第一幀圖片

NSURL *url = [NSURL URLWithString:filepath];

AVURLAsset *asset1 = [[AVURLAsset alloc] initWithURL:url options:nil];

AVAssetImageGenerator *generate1 = [[AVAssetImageGenerator alloc] initWithAsset:asset1];

generate1.appliesPreferredTrackTransform = YES;

NSError *err = NULL;

CMTime time = CMTimeMake(1, 2);

CGImageRef oneRef = [generate1 copyCGImageAtTime:time actualTime:NULL error:&err];

UIImage *one = [[UIImage alloc] initWithCGImage:oneRef];

return one;

91、獲取視頻的時長

+ (NSInteger)getVideoTimeByUrlString:(NSString *)urlString {

NSURL *videoUrl = [NSURL URLWithString:urlString];

AVURLAsset *avUrl = [AVURLAsset assetWithURL:videoUrl];

CMTime time = [avUrl duration];

int seconds = ceil(time.value/time.timescale);

return seconds;

}

92、字符串是否爲空

+ (BOOL)isEqualToNil:(NSString *)str {

return str.length <= 0 || [str isEqualToString:@""] || !str;

}

93、將app上傳到App Store的時候通常會遇到這個問題

try again

很多人說這事蘋果爸爸服務器問題，重複嘗試幾次，總會成功的！

但是經過嘗試發現如果使用Application Loader上傳成功率就非常高，所以還是推薦把ipa文件導出直接用Application Loader上傳。

如果Application Loader也不行，需要檢查下自己的網絡，有時候vpn也會提高速度。

94、當tableView佔不滿一屏時，去除下邊多餘的單元格

1 2	self.tableView.tableHeaderView = [UIView new]; self.tableView.tableFooterView = [UIView new];

95、isKindOfClass和isMemberOfClass的區別

1 2	isKindOfClass可以判斷某個對象是否屬於某個類，或者這個類的子類。 isMemberOfClass更加精準，它只能判斷這個對象類型是否爲這個類(不能判斷子類)

96、__block

當一個局部變量需要在block裏改變時，需要在定義時加上__block修飾，具體請看官方文檔 http://developer.apple.com/library/ios/documentation/cocoa/Conceptual/Blocks/Articles/bxVariables.html#//apple_ref/doc/uid/TP40007502-CH6-SW6

97、-[ViewController aMethod:]: unrecognized selector sent to instance 0x7fe91e607fb0

這是一個經典錯誤，ViewController不能響應aMethod這個方法，錯誤原因可能viewController文件中沒有實現aMethod這個方法

98、UITableView () failed to obtain a cell from its dataSource ()

這個錯誤原因是tableView的代理方法-tableView:cellForRowAtIndexPath:需要返回一個UITableViewCell,而你返回了一個nil。另外這個地方返回值不是UITableViewCell類型也會導致崩潰

99、約束如何做UIView動畫？

1、把需要改的約束Constraint拖條線出來，成爲屬性
2、在需要動畫的地方加入代碼，改變此屬性的constant屬性
3、開始做UIView動畫，動畫裏邊調用layoutIfNeeded方法

@property (weak, nonatomic) IBOutlet NSLayoutConstraint *buttonTopConstraint;

self.buttonTopConstraint.constant = 100;

[UIView animateWithDuration:.5 animations:^{

[self.view layoutIfNeeded];

}];

100、從NSURL中拿到鏈接字符串

1	NSString *urlString = myURL.absoluteString;

101、將tableView滾動到頂部

[tableView setContentOffset:CGPointZero animated:YES];

或者

[tableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];

102、如果用addTarget:action:forControlEvents:方法爲一個button添加了很多點擊事件，在某個時刻想一次刪除怎麼辦？只需要調用下邊這句代碼

1	[youButton removeTarget:nil action:nil forControlEvents:UIControlEventAllEvents];

103、某個字體的高度

1	font.lineHeight;

104、刪除某個view所有的子視圖

1 2	[[someView subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];

105、刪除NSUserDefaults所有記錄

//方法一

NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];

[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];

//方法二

- (void)resetDefaults {

NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];

NSDictionary * dict = [defs dictionaryRepresentation];

for (id key in dict) {

[defs removeObjectForKey:key];

}

[defs synchronize];

}

// 方法三

[[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary] forName:[[NSBundle mainBundle] bundleIdentifier]];

106、禁用系統滑動返回功能

- (void)viewDidAppear:(BOOL)animated

{

[super viewDidAppear:animated];

if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = self;

}

- (void)viewWillDisappear:(BOOL)animated {

[super viewWillDisappear:animated];

if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = nil;

}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer

{

return NO;

}

107、模擬器報錯

模擬器報錯

解決辦法：

打開模擬器->Simulator->Reset Content and Settings...

如果不行，就重啓試試！

108、自定義cell選中背景顏色

UIView *bgColorView = [[UIView alloc] init];

bgColorView.backgroundColor = [UIColor redColor];

[cell setSelectedBackgroundView:bgColorView];

109、UILabel設置內邊距

子類化UILabel，重寫drawTextInRect方法

- (void)drawTextInRect:(CGRect)rect {

// 邊距，上左下右

UIEdgeInsets insets = {0, 5, 0, 5};

[super drawTextInRect:UIEdgeInsetsInsetRect(rect, insets)];

}

110、UILabel設置文字描邊

子類化UILabel，重寫drawTextInRect方法

- (void)drawTextInRect:(CGRect)rect

{

CGContextRef c = UIGraphicsGetCurrentContext();

// 設置描邊寬度

CGContextSetLineWidth(c, 1);

CGContextSetLineJoin(c, kCGLineJoinRound);

CGContextSetTextDrawingMode(c, kCGTextStroke);

// 描邊顏色

self.textColor = [UIColor redColor];

[super drawTextInRect:rect];

// 文本顏色

self.textColor = [UIColor yellowColor];

CGContextSetTextDrawingMode(c, kCGTextFill);

[super drawTextInRect:rect];

}

111、使用模擬器截圖

1 2	快捷鍵command + s 或者File->Save Screen Shot

112、scrollView滾動到最下邊

1 2	CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.bounds.size.height); [scrollView setContentOffset:bottomOffset animated:YES];

113、UIView背景顏色漸變

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];

[self.view addSubview:view];

CAGradientLayer *gradient = [CAGradientLayer layer];

gradient.frame = view.bounds;

gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor blackColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil];

[view.layer insertSublayer:gradient atIndex:0];

114、停止UIView動畫

1	[yourView.layer removeAllAnimations]

115、爲UIView某個角添加圓角

// 左上角和右下角添加圓角

UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerBottomRight) cornerRadii:CGSizeMake(20, 20)];

CAShapeLayer *maskLayer = [CAShapeLayer layer];

maskLayer.frame = view.bounds;

maskLayer.path = maskPath.CGPath;

view.layer.mask = maskLayer;

116、刪除Xcode Derived data緩存數據

依次點擊Xcode -> Preferences -> location，然後點擊 Derived data路徑後到小箭頭，刪除這個文件夾下的數據就可以了，如圖

Xcode Derived data

117、將一個view放置在其兄弟視圖的最上面

1	[parentView bringSubviewToFront:yourView]

118、將一個view放置在其兄弟視圖的最下面

1	[parentView sendSubviewToBack:yourView]

119、讓手機震動一下

倒入框架

#import

AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);

或者

AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

120、layoutSubviews方法什麼時候調用？

1、init方法不會調用
2、addSubview方法等時候會調用
3、bounds改變的時候調用
4、scrollView滾動的時候會調用scrollView的layoutSubviews方法(所以不建議在scrollView的layoutSubviews方法中做複雜邏輯)
5、旋轉設備的時候調用
6、子視圖被移除的時候調用

參考請看：http://blog.logichigh.com/2011/03/16/when-does-layoutsubviews-get-called/

121、讓UILabel在指定的地方換行

// 換行符爲\n,在需要換行的地方加上這個符號即可，如

label.numberOfLines = 0;

label.text = @"此處\n換行";

122、搖一搖功能

1、打開搖一搖功能

[UIApplication sharedApplication].applicationSupportsShakeToEdit = YES;

2、讓需要搖動的控制器成爲第一響應者

[self becomeFirstResponder];

3、實現以下方法

// 開始搖動

- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event

// 取消搖動

- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event

// 搖動結束

- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event

123、獲取圖片大小

1 2	CGFloat imageWidth = image.size.width; CGFloat imageHeight = imageWidth * image.scale;

124、獲取view的座標在整個window上的位置

// v上的(0, 0)點在toView上的位置

CGPoint point = [v convertPoint:CGPointMake(0, 0) toView:[UIApplication sharedApplication].windows.lastObject];

或者

CGPoint point = [v.superview convertPoint:v.frame.origin toView:[UIApplication sharedApplication].windows.lastObject];

125、提交App Store審覈程序限制

您的應用程序的未壓縮大小必須小於4GB。每個Mach-O可執行文件（例如app_name.app/app_name）不能超過這些限制：

對於MinimumOSVersion小於7.0的應用程序：TEXT二進制文件中所有部分的總數最多爲80 MB 。

對於MinimumOSVersion7.x到8.x的應用程序：TEXT對於二進制文件中每個體系結構片段的每個片段，最大爲60 MB 。

對於MinimumOSVersion9.0或更高版本的應用程序：__TEXT二進制文件中所有部分的總數最多爲500 MB 。參閱：iTunes Connect開發者指南

126、修改UISegmentedControl的字體大小

1	[segment setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:15.0f]} forState:UIControlStateNormal];

127、在非ViewController的地方彈出UIAlertController對話框

// 最好抽成一個分類

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"message" preferredStyle:UIAlertControllerStyleAlert];

//...

id rootViewController = [UIApplication sharedApplication].delegate.window.rootViewController;

if([rootViewController isKindOfClass:[UINavigationController class]])

{

rootViewController = ((UINavigationController *)rootViewController).viewControllers.firstObject;

}

if([rootViewController isKindOfClass:[UITabBarController class]])

{

rootViewController = ((UITabBarController *)rootViewController).selectedViewController;

}

[rootViewController presentViewController:alertController animated:YES completion:nil];

128、獲取一個view所屬的控制器

// view分類方法

- (UIViewController *)belongViewController {

for (UIView *next = [self superview]; next; next = next.superview) {

UIResponder* nextResponder = [next nextResponder];

if ([nextResponder isKindOfClass:[UIViewController class]]) {

return (UIViewController *)nextResponder;

}

return nil;

}

129、UIImage和base64互轉

// view分類方法

- (NSString *)encodeToBase64String:(UIImage *)image {

return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];

}

- (UIImage *)decodeBase64ToImage:(NSString *)strEncodeData {

NSData *data = [[NSData alloc]initWithBase64EncodedString:strEncodeData options:NSDataBase64DecodingIgnoreUnknownCharacters];

return [UIImage imageWithData:data];

}

130、UIWebView設置背景透明

1 2	[webView setBackgroundColor:[UIColor clearColor]]; [webView setOpaque:NO];

131、判斷NSDate是不是今天

NSDateComponents *otherDay = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:aDate];

NSDateComponents *today = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:[NSDate date]];

if([today day] == [otherDay day] &&

[today month] == [otherDay month] &&

[today year] == [otherDay year] &&

[today era] == [otherDay era]) {

// 是今天

}

132、設置tableView分割線顏色

1	[self.tableView setSeparatorColor:[UIColor myColor]];

133、設置屏幕方向

1	[[UIDevice currentDevice] setValue:@(UIInterfaceOrientationLandscapeLeft) forKey:@"orientation"];

134、比較兩個顏色是否相等

- (BOOL)isEqualToColor:(UIColor *)otherColor {

CGColorSpaceRef colorSpaceRGB = CGColorSpaceCreateDeviceRGB();

UIColor *(^convertColorToRGBSpace)(UIColor*) = ^(UIColor *color) {

if (CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor)) == kCGColorSpaceModelMonochrome) {

const CGFloat *oldComponents = CGColorGetComponents(color.CGColor);

CGFloat components[4] = {oldComponents[0], oldComponents[0], oldComponents[0], oldComponents[1]};

CGColorRef colorRef = CGColorCreate( colorSpaceRGB, components );

UIColor *color = [UIColor colorWithCGColor:colorRef];

CGColorRelease(colorRef);

return color;

} else

return color;

};

UIColor *selfColor = convertColorToRGBSpace(self);

otherColor = convertColorToRGBSpace(otherColor);

CGColorSpaceRelease(colorSpaceRGB);

return [selfColor isEqual:otherColor];

}

135、tableViewCell分割線頂到頭

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {

[cell setSeparatorInset:UIEdgeInsetsZero];

[cell setLayoutMargins:UIEdgeInsetsZero];

cell.preservesSuperviewLayoutMargins = NO;

}

- (void)viewDidLayoutSubviews {

[self.tableView setSeparatorInset:UIEdgeInsetsZero];

[self.tableView setLayoutMargins:UIEdgeInsetsZero];

}

136、不讓控制器的view隨着控制器的xib拉伸或壓縮

1	self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth \| UIViewAutoresizingFlexibleHeight;

137、cocoaPods報錯 : [!] Unable to add a source with url https://github.com/CocoaPods/Specs.git named master-1.

You can try adding it manually in ~/.cocoapods/repos or via pod repo add.

解決方法：這是因爲電腦裏安裝了另外一個Xcode導致cocoapods找不到路徑了

在終端執行 sudo xcode-select -switch /Applications/Xcode.app 即可

138、安裝cocoapods的時候出現 ERROR: While executing gem ... (Errno::EPERM)

1	Operation not permitted - /usr/bin/pod

解決辦法：直接在終端執行 sudo gem install -n /usr/local/bin cocoapods

139、在狀態欄增加網絡請求的菊花，類似safari加載網頁的時候狀態欄菊花

1	[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

140、檢查一個rect是否包含一個point

1 2	// point是否在rect內 BOOL isContains = CGRectContainsPoint(rect, point);

141、在指定的寬度下，讓UILabel自動設置最佳font

1	label.adjustsFontSizeToFitWidth = YES;

142、將一個image保存在相冊中

UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);

或者

#import

[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{

PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];

changeRequest.creationDate = [NSDate date];

} completionHandler:^(BOOL success, NSError *error) {

if (success) {

NSLog(@"successfully saved");

}

else {

NSLog(@"error saving to photos: %@", error);

}

}];

143、修改cell.imageView的大小

UIImage *icon = [UIImage imageNamed:@""];

CGSize itemSize = CGSizeMake(30, 30);

UIGraphicsBeginImageContextWithOptions(itemSize, NO ,0.0);

CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);

[icon drawInRect:imageRect];

cell.imageView.image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

144、爲一個view添加虛線邊框

CAShapeLayer *border = [CAShapeLayer layer];

border.strokeColor = [UIColor colorWithRed:67/255.0f green:37/255.0f blue:83/255.0f alpha:1].CGColor;

border.fillColor = nil;

border.lineDashPattern = @[@4, @2];

border.path = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;

border.frame = view.bounds;

[view.layer addSublayer:border];

145、UITextView中打開或禁用複製，剪切，選擇，全選等功能

// 繼承UITextView重寫這個方法

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender

{

// 返回NO爲禁用，YES爲開啓

// 粘貼

if (action == @selector(paste:)) return NO;

// 剪切

if (action == @selector(cut:)) return NO;

// 複製

if (action == @selector(copy:)) return NO;

// 選擇

if (action == @selector(select:)) return NO;

// 選中全部

if (action == @selector(selectAll:)) return NO;

// 刪除

if (action == @selector(delete:)) return NO;

// 分享

if (action == @selector(share)) return NO;

return [super canPerformAction:action withSender:sender];

}

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