常用問題（三）

1、設置UILabel行間距

NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:label.text];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
[style setLineSpacing:20];
[attrString addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, label.text.length)];
label.attributedText = attrString;

// 或者使用xib，看下gif圖

2、當使用-performSelector:withObject:withObject:afterDelay:方法時，需要傳入多參數問題

// 方法一、
// 把參數放進一個數組／字典，直接把數組／字典當成一個參數傳過去，具體方法實現的地方再解析這個數組／字典
NSArray * array =
[NSArray arrayWithObjects: @”first”, @”second”, nil];
[self performSelector:@selector(fooFirstInput:) withObject: array afterDelay:15.0];

// 方法二、
// 使用NSInvocation
SEL aSelector = NSSelectorFromString(@”doSoming:argument2:”);
NSInteger argument1 = 10;
NSString *argument2 = @”argument2”;
if([self respondsToSelector:aSelector]) {
NSInvocation *inv = [NSInvocation invocationWithMethodSignature:[self methodSignatureForSelector:aSelector]];
[inv setSelector:aSelector];
[inv setTarget:self];
[inv setArgument:&(argument1) atIndex:2];
[inv setArgument:&(argument2) atIndex:3];
[inv performSelector:@selector(invoke) withObject:nil afterDelay:15.0];
}
3、UILabel顯示不同顏色字體

NSMutableAttributedString * string = [[NSMutableAttributedString alloc] initWithString:label.text];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(5,6)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(11,5)];
label.attributedText = string;
4、比較兩個CGRect/CGSize/CGPoint是否相等

if (CGRectEqualToRect(rect1, rect2)) { // 兩個區域相等
// do some
}
if (CGPointEqualToPoint(point1, point2)) { // 兩個點相等
// do some
}
if (CGSizeEqualToSize(size1, size2)) { // 兩個size相等
// do some
}
5、比較兩個NSDate相差多少小時

NSDate* date1 = someDate;
NSDate* date2 = someOtherDate;
NSTimeInterval distanceBetweenDates = [date1 timeIntervalSinceDate:date2];
double secondsInAnHour = 3600;
// 除以3600是把秒化成小時，除以60得到結果爲相差的分鐘數
NSInteger hoursBetweenDates = distanceBetweenDates / secondsInAnHour;

6、每個cell之間增加間距

// 方法一，每個分區只顯示一行cell，分區頭當作你想要的間距(注意，從數據源數組中取值的時候需要用indexPath.section而不是indexPath.row)
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return yourArry.count;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 1;
}
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
return cellSpacingHeight;
}

// 方法二，在cell的contentView上加個稍微低一點的view，cell上原本的內容放在你的view上，而不是contentView上，這樣能僞造出一個間距來。

// 方法三，自定義cell，重寫setFrame：方法
- (void)setFrame:(CGRect)frame
{
frame.size.height -= 20;
[super setFrame:frame];
}
7、播放一張張連續的圖片

// 加入現在有三張圖片分別爲animate_1、animate_2、animate_3
// 方法一
imageView.animationImages = @[[UIImage imageNamed:@”animate_1”], [UIImage imageNamed:@”animate_2”], [UIImage imageNamed:@”animate_3”]];
imageView.animationDuration = 1.0;
// 方法二
imageView.image = [UIImage animatedImageNamed:@”animate_” duration:1.0];
// 方法二解釋下，這個方法會加載animate_爲前綴的，後邊0-1024，也就是animate_0、animate_1一直到animate_1024
8、加載gif圖片

推薦使用這個框架 FLAnimatedImage
9、防止離屏渲染爲image添加圓角

// image分類
- (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;
}
10、查看系統所有字體

// 打印字體
for (id familyName in [UIFont familyNames]) {
NSLog(@”%@”, familyName);
for (id fontName in [UIFont fontNamesForFamilyName:familyName]) NSLog(@” %@”, fontName);
}
// 也可以進入這個網址查看 http://iosfonts.com/
11、獲取隨機數

NSInteger i = arc4random();
12、獲取隨機數小數(0-1之間)

define ARC4RANDOM_MAX 0x100000000

double val = ((double)arc4random() / ARC4RANDOM_MAX);
13、AVPlayer視頻播放完成的通知監聽

[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(videoPlayEnd)
name:AVPlayerItemDidPlayToEndTimeNotification
object:nil];
14、判斷兩個rect是否有交叉

if (CGRectIntersectsRect(rect1, rect2)) {
}
15、判斷一個字符串是否爲數字

NSCharacterSet *notDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
if ([str rangeOfCharacterFromSet:notDigits].location == NSNotFound)
{
// 是數字
} else
{
// 不是數字
}
16、將一個view保存爲pdf格式

• (void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
  {
  NSMutableData *pdfData = [NSMutableData data];
  UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
  UIGraphicsBeginPDFPage();
  CGContextRef pdfContext = UIGraphicsGetCurrentContext();
  [aView.layer renderInContext:pdfContext];
  UIGraphicsEndPDFContext();

  NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
  NSString* documentDirectory = [documentDirectories objectAtIndex:0];
  NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
  [pdfData writeToFile:documentDirectoryFilename atomically:YES];
  NSLog(@”documentDirectoryFileName: %@”,documentDirectoryFilename);
  }
  17、讓一個view在父視圖中心

child.center = [parent convertPoint:parent.center fromView:parent.superview];
18、獲取當前導航控制器下前一個控制器

• (UIViewController *)backViewController
  {
  NSInteger myIndex = [self.navigationController.viewControllers indexOfObject:self];

  if ( myIndex != 0 && myIndex != NSNotFound ) {
  return [self.navigationController.viewControllers objectAtIndex:myIndex-1];
  } else {
  return nil;
  }
  }
  19、保存UIImage到本地

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@”Image.png”];

[UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];
20、鍵盤上方增加工具欄

UIToolbar *keyboardDoneButtonView = [[UIToolbar alloc] init];
[keyboardDoneButtonView sizeToFit];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@”Done”
style:UIBarButtonItemStyleBordered target:self
action:@selector(doneClicked:)];
[keyboardDoneButtonView setItems:[NSArray arrayWithObjects:doneButton, nil]];
txtField.inputAccessoryView = keyboardDoneButtonView;
21、copy一個view

因爲UIView沒有實現copy協議，因此找不到copyWithZone方法，使用copy的時候導致崩潰
但是我們可以通過歸檔再解檔實現copy，這相當於對視圖進行了一次深拷貝，代碼如下
id copyOfView =
[NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:originalView]];
22、在image上繪製文字並生成新的image

UIFont *font = [UIFont boldSystemFontOfSize:12];
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
[[UIColor whiteColor] set];
[text drawInRect:CGRectIntegral(rect) withFont:font];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
23、判斷一個view是否爲另一個view的子視圖

// 如果myView是self.view本身，也會返回yes
BOOL isSubView = [myView isDescendantOfView:self.view];
24、判斷一個字符串是否包含另一個字符串

// 方法一、這種方法只適用於iOS8之後，如果是配iOS8之前用方法二
if ([str containsString:otherStr]) NSLog(@”包含”);

// 方法二
NSRange range = [str rangeOfString:otherStr];
if (range.location != NSNotFound) NSLog(@”包含”);
25、UICollectionView自動滾動到某行

// 重寫viewDidLayoutSubviews方法
-(void)viewDidLayoutSubviews {
[super viewDidLayoutSubviews];
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:NO];
}
26、修改系統UIAlertController

// 但是據說這種方法會被App Store拒絕(慎用！)
UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:@”” message:@”” preferredStyle:UIAlertControllerStyleActionSheet];
NSMutableAttributedString *hogan = [[NSMutableAttributedString alloc] initWithString:@”我是一個大文本”];
[hogan addAttribute:NSFontAttributeName
value:[UIFont systemFontOfSize:30]
range:NSMakeRange(4, 1)];
[hogan addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:NSMakeRange(4, 1)];
[alertVC setValue:hogan forKey:@”attributedTitle”];

UIAlertAction *button = [UIAlertAction actionWithTitle:@"Label text" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){ }];
UIImage *accessoryImage = [UIImage imageNamed:@"1"];
[button setValue:accessoryImage forKey:@"image"];
[alertVC addAction:button];
[self presentViewController:alertVC animated:YES completion:nil];

27、判斷某一行的cell是否已經顯示

CGRect cellRect = [tableView rectForRowAtIndexPath:indexPath];
BOOL completelyVisible = CGRectContainsRect(tableView.bounds, cellRect);
28、讓導航控制器pop回指定的控制器

NSMutableArray *allViewControllers = [NSMutableArray arrayWithArray:[self.navigationController viewControllers]];
for (UIViewController *aViewController in allViewControllers) {
if ([aViewController isKindOfClass:[RequiredViewController class]]) {
[self.navigationController popToViewController:aViewController animated:NO];
}
}
29、動畫修改label上的文字

// 方法一
CATransition *animation = [CATransition animation];
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation.type = kCATransitionFade;
animation.duration = 0.75;
[self.label.layer addAnimation:animation forKey:@”kCATransitionFade”];
self.label.text = @”New”;

// 方法二
[UIView transitionWithView:self.label
duration:0.25f
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^{

                    self.label.text = @"Well done!";

                } completion:nil];

// 方法三
[UIView animateWithDuration:1.0
animations:^{
self.label.alpha = 0.0f;
self.label.text = @”newText”;
self.label.alpha = 1.0f;
}];
30、判斷字典中是否包含某個key值

if ([dic objectForKey:@”yourKey”]) {
NSLog(@”有這個值”);
} else {
NSLog(@”沒有這個值”);
}
31、獲取屏幕方向

UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;

if(orientation == 0) //Default orientation
//默認
else if(orientation == UIInterfaceOrientationPortrait)
//豎屏
else if(orientation == UIInterfaceOrientationLandscapeLeft)
// 左橫屏
else if(orientation == UIInterfaceOrientationLandscapeRight)
//右橫屏
32、設置UIImage的透明度

// 方法一、添加UIImage分類
- (UIImage *)imageByApplyingAlpha:(CGFloat) alpha {
UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0f);

CGContextRef ctx = UIGraphicsGetCurrentContext();
CGRect area = CGRectMake(0, 0, self.size.width, self.size.height);

CGContextScaleCTM(ctx, 1, -1);
CGContextTranslateCTM(ctx, 0, -area.size.height);

CGContextSetBlendMode(ctx, kCGBlendModeMultiply);

CGContextSetAlpha(ctx, alpha);

CGContextDrawImage(ctx, area, self.CGImage);

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return newImage;

}

// 方法二、如果沒有奇葩需求，乾脆用UIImageView設置透明度
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageWithName:@”yourImage”]];
imageView.alpha = 0.5;
33、Attempt to mutate immutable object with insertString:atIndex:

這個錯是因爲你拿字符串調用insertString:atIndex:方法的時候，調用對象不是NSMutableString，應該先轉成這個類型再調用
34、UIWebView添加單擊手勢不響應

UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(webViewClick)];
tap.delegate = self;
[_webView addGestureRecognizer:tap];

// 因爲webView本身有一個單擊手勢，所以再添加會造成手勢衝突，從而不響應。需要綁定手勢代理，並實現下邊的代理方法
- (BOOL)gestureRecognizer:(UIGestureRecognizer )gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer )otherGestureRecognizer{
return YES;
}
35、獲取手機RAM容量

// 需要導入#import

define RADIANS(degrees) (((degrees) * M_PI) / 180.0)

• (void)startAnimate {
  view.transform = CGAffineTransformRotate(CGAffineTransformIdentity, RADIANS(-5));

  [UIView animateWithDuration:0.25 delay:0.0 options:(UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionRepeat | UIViewAnimationOptionAutoreverse) animations:^ {
  view.transform = CGAffineTransformRotate(CGAffineTransformIdentity, RADIANS(5));
  } completion:nil];
  }

• (void)stopAnimate {
  [UIView animateWithDuration:0.25 delay:0.0 options:(UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveLinear) animations:^ {
  view.transform = CGAffineTransformIdentity;
  } completion:nil];
  }
  49、修改UISearBar內部背景顏色

UITextField *textField = [_searchBar valueForKey:@”_searchField”];
textField.backgroundColor = [UIColor redColor];
50、UITextView滾動到頂部

// 方法一
[self.textView scrollRangeToVisible:NSMakeRange(0, 0)];
// 方法二
[self.textView setContentOffset:CGPointZero animated:YES];

51、通知監聽APP生命週期

UIApplicationDidEnterBackgroundNotification 應用程序進入後臺
UIApplicationWillEnterForegroundNotification 應用程序將要進入前臺
UIApplicationDidFinishLaunchingNotification 應用程序完成啓動
UIApplicationDidFinishLaunchingNotification 應用程序由掛起變的活躍
UIApplicationWillResignActiveNotification 應用程序掛起(有電話進來或者鎖屏)
UIApplicationDidReceiveMemoryWarningNotification 應用程序收到內存警告
UIApplicationDidReceiveMemoryWarningNotification 應用程序終止(後臺殺死、手機關機等)
UIApplicationSignificantTimeChangeNotification 當有重大時間改變(凌晨0點，設備時間被修改，時區改變等)
UIApplicationWillChangeStatusBarOrientationNotification 設備方向將要改變
UIApplicationDidChangeStatusBarOrientationNotification 設備方向改變
UIApplicationWillChangeStatusBarFrameNotification 設備狀態欄frame將要改變
UIApplicationDidChangeStatusBarFrameNotification 設備狀態欄frame改變
UIApplicationBackgroundRefreshStatusDidChangeNotification 應用程序在後臺下載內容的狀態發生變化
UIApplicationProtectedDataWillBecomeUnavailable 本地受保護的文件被鎖定,無法訪問
UIApplicationProtectedDataWillBecomeUnavailable 本地受保護的文件可用了
52、觸摸事件類型

UIControlEventTouchCancel 取消控件當前觸發的事件
UIControlEventTouchDown 點按下去的事件
UIControlEventTouchDownRepeat 重複的觸動事件
UIControlEventTouchDragEnter 手指被拖動到控件的邊界的事件
UIControlEventTouchDragExit 一個手指從控件內拖到外界的事件
UIControlEventTouchDragInside 手指在控件的邊界內拖動的事件
UIControlEventTouchDragOutside 手指在控件邊界之外被拖動的事件
UIControlEventTouchUpInside 手指處於控制範圍內的觸摸事件
UIControlEventTouchUpOutside 手指超出控制範圍的控制中的觸摸事件
53、UITextField文字周圍增加邊距

// 子類化UITextField，增加insert屬性

@interface WZBTextField : UITextField
@property (nonatomic, assign) UIEdgeInsets insets;
@end

// 在.m文件重寫下列方法
- (CGRect)textRectForBounds:(CGRect)bounds {
CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeUnlessEditing) {
return [self adjustRectWithWidthRightView:paddedRect];
}
return paddedRect;
}

• (CGRect)placeholderRectForBounds:(CGRect)bounds {
  CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);

  if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeUnlessEditing) {
  return [self adjustRectWithWidthRightView:paddedRect];
  }
  return paddedRect;
  }

• (CGRect)editingRectForBounds:(CGRect)bounds {
  CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
  if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeWhileEditing) {
  return [self adjustRectWithWidthRightView:paddedRect];
  }
  return paddedRect;
  }

• (CGRect)adjustRectWithWidthRightView:(CGRect)bounds {
  CGRect paddedRect = bounds;
  paddedRect.size.width -= CGRectGetWidth(self.rightView.frame);

  return paddedRect;
  }
  54、監聽UISlider拖動狀態

// 添加事件
[slider addTarget:self action:@selector(sliderValurChanged:forEvent:) forControlEvents:UIControlEventValueChanged];

// 實現方法
- (void)sliderValurChanged:(UISlider*)slider forEvent:(UIEvent*)event {
UITouch *touchEvent = [[event allTouches] anyObject];
switch (touchEvent.phase) {
case UITouchPhaseBegan:
NSLog(@”開始拖動”);
break;
case UITouchPhaseMoved:
NSLog(@”正在拖動”);
break;
case UITouchPhaseEnded:
NSLog(@”結束拖動”);
break;
default:
break;
}
}
55、設置UITextField光標位置

// textField需要設置的textField，index要設置的光標位置
- (void)cursorLocation:(UITextField *)textField index:(NSInteger)index
{
NSRange range = NSMakeRange(index, 0);
UITextPosition *start = [textField positionFromPosition:[textField beginningOfDocument] offset:range.location];
UITextPosition *end = [textField positionFromPosition:start offset:range.length];
[textField setSelectedTextRange:[textField textRangeFromPosition:start toPosition:end]];
}
56、去除webView底部黑色

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

for (UIView *v1 in [webView subviews])
{
    if ([v1 isKindOfClass:[UIScrollView class]])
    {
        for (UIView *v2 in v1.subviews)
        {
            if ([v2 isKindOfClass:[UIImageView class]])
            {
                v2.hidden = YES;
            }
        }
    }
}

57、獲取collectionViewCell在屏幕中的frame

UICollectionViewLayoutAttributes *attributes = [collectionView layoutAttributesForItemAtIndexPath:indexPath];
CGRect cellRect = attributes.frame;
CGRect cellFrameInSuperview = [collectionView convertRect:cellRect toView:[cv superview]];
58、比較兩個UIImage是否相等

• (BOOL)image:(UIImage )image1 isEqualTo:(UIImage )image2
  {
  NSData *data1 = UIImagePNGRepresentation(image1);
  NSData *data2 = UIImagePNGRepresentation(image2);

  return [data1 isEqual:data2];
  }
  59、解決當UIScrollView上有UIButton的時候，觸摸到button滑動不了的問題

// 子類化UIScrollView，並重寫以下方法
- (instancetype)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
self.delaysContentTouches = NO;
}

return self;

}

• (BOOL)touchesShouldCancelInContentView:(UIView *)view {
  if ([view isKindOfClass:UIButton.class]) {
  return YES;
  }

  return [super touchesShouldCancelInContentView:view];
  }
  60、UITextView中的文字添加陰影效果

• (void)setTextLayer:(UITextView )textView color:(UIColor )color
  {
  CALayer textLayer = ((CALayer )[textView.layer.sublayers objectAtIndex:0]);
  textLayer.shadowColor = color.CGColor;
  textLayer.shadowOffset = CGSizeMake(0.0f, 1.0f);
  textLayer.shadowOpacity = 1.0f;
  textLayer.shadowRadius = 1.0f;
  }
  61、MD5加密

• (NSString )md5:(NSString )str
  {
  const char *concat_str = [str UTF8String];
  unsigned char result[CC_MD5_DIGEST_LENGTH];
  CC_MD5(concat_str, (unsigned int)strlen(concat_str), result);
  NSMutableString *hash = [NSMutableString string];
  for (int i =0; i <16; i++){
  [hash appendFormat:@”%02X”, result[i]];
  }
  return [hash uppercaseString];
  }
  62、base64加密

@interface NSData (Base64)
/**
* @brief 字符串base64後轉data
*/
+ (NSData )dataWithBase64EncodedString:(NSString )string
{
if (![string length]) return nil;
NSData *decoded = nil;

if __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_9 || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_7_0

if (![NSData instancesRespondToSelector:@selector(initWithBase64EncodedString:options:)])
{

pragma clang diagnostic push

pragma clang diagnostic ignored “-Wdeprecated-declarations”

    decoded = [[self alloc] initWithBase64Encoding:[string stringByReplacingOccurrencesOfString:@"[^A-Za-z0-9+/=]" withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, [string length])]];

pragma clang diagnostic pop

}
else

endif

{
    decoded = [[self alloc] initWithBase64EncodedString:string options:NSDataBase64DecodingIgnoreUnknownCharacters];
}
return [decoded length]? decoded: nil;

}
/**
* @brief NSData轉string
* @param wrapWidth 換行長度 76 64
*/
- (NSString *)base64EncodedStringWithWrapWidth:(NSUInteger)wrapWidth
{
if (![self length]) return nil;
NSString *encoded = nil;

if __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_9 || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_7_0

if (![NSData instancesRespondToSelector:@selector(base64EncodedStringWithOptions:)])
{

pragma clang diagnostic push

pragma clang diagnostic ignored “-Wdeprecated-declarations”

    encoded = [self base64Encoding];

pragma clang diagnostic pop

}
else

endif

{
    switch (wrapWidth)
    {
        case 64:
        {
            return [self base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
        }
        case 76:
        {
            return [self base64EncodedStringWithOptions:NSDataBase64Encoding76CharacterLineLength];
        }
        default:
        {
            encoded = [self base64EncodedStringWithOptions:(NSDataBase64EncodingOptions)0];
        }
    }
}
if (!wrapWidth || wrapWidth >= [encoded length])
{
    return encoded;
}
wrapWidth = (wrapWidth / 4) * 4;
NSMutableString *result = [NSMutableString string];
for (NSUInteger i = 0; i < [encoded length]; i+= wrapWidth)
{
    if (i + wrapWidth >= [encoded length])
    {
        [result appendString:[encoded substringFromIndex:i]];
        break;
    }
    [result appendString:[encoded substringWithRange:NSMakeRange(i, wrapWidth)]];
    [result appendString:@"\r\n"];
}
return result;

}
/**
* @brief NSData轉string 換行長度默認64
*/
- (NSString *)base64EncodedString
{
return [self base64EncodedStringWithWrapWidth:0];
}
63、AES加密

import

import

import “CALayer+BorderColor.h”

@implementation CALayer (BorderColor)

• (void)setBorderUIColor:(UIColor *)color
  {
  self.borderColor = color.CGColor;
  }
  76、根據經緯度獲取城市等信息

// 創建經緯度
CLLocation *location = [[CLLocation alloc] initWithLatitude:latitude longitude:longitude];
//創建一個譯碼器
CLGeocoder *cLGeocoder = [[CLGeocoder alloc] init];
[cLGeocoder reverseGeocodeLocation:userLocation completionHandler:^(NSArray *placemarks, NSError *error) {
CLPlacemark *place = [placemarks objectAtIndex:0];
// 位置名
　　NSLog(@”name,%@”,place.name);
　　// 街道
　　NSLog(@”thoroughfare,%@”,place.thoroughfare);
　　// 子街道
　　NSLog(@”subThoroughfare,%@”,place.subThoroughfare);
　　// 市
　　NSLog(@”locality,%@”,place.locality);
　　// 區
　　NSLog(@”subLocality,%@”,place.subLocality);
　　// 國家
　　NSLog(@”country,%@”,place.country);
}
}];

/* CLPlacemark中屬性含義
name 地名

thoroughfare 街道

subThoroughfare 街道相關信息，例如門牌等

locality 城市

subLocality 城市相關信息，例如標誌性建築

administrativeArea 直轄市

subAdministrativeArea 其他行政區域信息（自治區等）

postalCode 郵編

ISOcountryCode 國家編碼

country 國家

inlandWater 水源，湖泊

ocean 海洋

areasOfInterest 關聯的或利益相關的地標
*/
77、如何防止添加多個NSNotification觀察者？

// 解決方案就是添加觀察者之前先移除下這個觀察者
[[NSNotificationCenter defaultCenter] removeObserver:observer name:name object:object];
[[NSNotificationCenter defaultCenter] addObserver:observer selector:selector name:name object:object];
78、將一個xib添加到另外一個xib上

// 假設你的自定義view名字爲CustomView，你需要在CustomView.m中重寫 - (instancetype)initWithCoder:(NSCoder *)aDecoder 方法，代碼如下：
- (instancetype)initWithCoder:(NSCoder *)aDecoder {
if ((self = [super initWithCoder:aDecoder])) {
[self addSubview:[[[NSBundle mainBundle] loadNibNamed:@”CustomView” owner:self options:nil] objectAtIndex:0]];
}
return self;
}

將一個xib添加到另外一個xib上.png
79、處理字符串，使其首字母大寫

NSString *str = @"abcdefghijklmn";
NSString *resultStr;
if (str && str.length > 0) {
    resultStr = [str stringByReplacingCharactersInRange:NSMakeRange(0,1) withString:[[str substringToIndex:1] capitalizedString]];
}
NSLog(@"%@", resultStr);

80、判斷一個UIAlertView/UIAlertController是否顯示

// UIAlertView自帶屬性
if (alert.visible)
{
NSLog(@”顯示了”);
} else {
NSLog(@”未顯示”);
}

// UIAlertController沒有visible屬性，需要自己判斷，添加一個全局變量 BOOL visible
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@”Title” message:@”message” preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction alertAction = [UIAlertAction actionWithTitle:@”ActionTitle” style:UIAlertActionStyleDefault handler:^(UIAlertAction _Nonnull action) {
self.visible = NO;
}];
UIAlertAction calcelAction = [UIAlertAction actionWithTitle:@”calcelTitle” style:UIAlertActionStyleCancel handler:^(UIAlertAction _Nonnull action) {
self.visible = NO;
}];
[alertController addAction:alertAction];
[alertController addAction:calcelAction];
[self presentViewController:alertController animated:YES completion:^{
self.visible = YES;
}];
81、獲取字符串中的數字

• (NSString )getNumberFromStr:(NSString )str
  {
  NSCharacterSet *nonDigitCharacterSet = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
  return [[str componentsSeparatedByCharactersInSet:nonDigitCharacterSet] componentsJoinedByString:@”“];
  }

  NSLog(@”%@”, [self getNumberFromStr:@”a0b0c1d2e3f4fda8fa8fad9fsad23”]); // 00123488923
  82、爲UIView的某個方向添加邊框

// 添加UIView分類

// UIView+WZB.h

import

import “UIView+WZB.h”

@implementation UIView (WZB)

• (void)wzb_addBorder:(WZBBorderDirectionType)direction color:(UIColor *)color width:(CGFloat)width
  {
  CALayer *border = [CALayer layer];
  border.backgroundColor = color.CGColor;
  switch (direction) {
  case WZBBorderDirectionTop:
  {
  border.frame = CGRectMake(0.0f, 0.0f, self.bounds.size.width, width);
  }
  break;
  case WZBBorderDirectionLeft:
  {
  border.frame = CGRectMake(0.0f, 0.0f, width, self.bounds.size.height);
  }
  break;
  case WZBBorderDirectionBottom:
  {
  border.frame = CGRectMake(0.0f, self.bounds.size.height - width, self.bounds.size.width, width);
  }
  break;
  case WZBBorderDirectionRight:
  {
  border.frame = CGRectMake(self.bounds.size.width - width, 0, width, self.bounds.size.height);
  }
  break;

  default:
      break;
  

  }
  [self.layer addSublayer:border];
  }
  83、通過屬性設置UISwitch、UIProgressView等控件的寬高

mySwitch.transform = CGAffineTransformMakeScale(5.0f, 5.0f);

progressView.transform = CGAffineTransformMakeScale(5.0f, 5.0f);
84、自動搜索功能，用戶連續輸入的時候不搜索，用戶停止輸入的時候自動搜索(我這裏設置的是0.5s，可根據需求更改)

// 輸入框文字改變的時候調用
-(void)searchBar:(UISearchBar )searchBar textDidChange:(NSString )searchText{
// 先取消調用搜索方法
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(searchNewResult) object:nil];
// 0.5秒後調用搜索方法
[self performSelector:@selector(searchNewResult) withObject:nil afterDelay:0.5];
}
85、修改UISearchBar的佔位文字顏色

// 方法一（推薦使用）
UITextField *searchField = [searchBar valueForKey:@"_searchField"];
[searchField setValue:[UIColor blueColor] forKeyPath:@"_placeholderLabel.textColor"];

// 方法二（已過期）
[[UILabel appearanceWhenContainedIn:[UISearchBar class], nil] setTextColor:[UIColor redColor]];

// 方法三（已過期）
NSDictionary *placeholderAttributes = @{NSForegroundColorAttributeName : [UIColor redColor], NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue" size:15],};
NSAttributedString *attributedPlaceholder = [[NSAttributedString alloc] initWithString:searchBar.placeholder attributes:placeholderAttributes];
[[UITextField appearanceWhenContainedIn:[UISearchBar class], nil] setAttributedPlaceholder:attributedPlaceholder];

86、某個界面多個事件同時響應引起的問題(比如，兩個button同時按push到新界面，兩個都會響應，可能導致push重疊)

// UIView有個屬性叫做exclusiveTouch，設置爲YES後，其響應事件會和其他view互斥(有其他view事件響應的時候點擊它不起作用)
view.exclusiveTouch = YES;

// 一個一個設置太麻煩了，可以全局設置
[[UIView appearance] setExclusiveTouch:YES];

// 或者只設置button
[[UIButton appearance] setExclusiveTouch:YES];
87、修改tabBar的frame

// 子類化UITabBarViewController，我這裏以修改tabBar高度爲例，重寫viewWillLayoutSubviews方法

import “WZBTabBarViewController.h”

@interface WZBTabBarViewController ()

@end

@implementation WZBTabBarViewController
- (void)viewWillLayoutSubviews {

CGRect tabFrame = self.tabBar.frame;
tabFrame.size.height = 100;
tabFrame.origin.y = self.view.frame.size.height - 100;
self.tabBar.frame = tabFrame;

}
@end
88、修改鍵盤背景顏色

// 設置某個鍵盤顏色
textField.keyboardAppearance = UIKeyboardAppearanceAlert;

// 設置工程中所有鍵盤顏色
[[UITextField appearance] setKeyboardAppearance:UIKeyboardAppearanceAlert];
89、修改image顏色

UIImage *image = [UIImage imageNamed:@”test”];
imageView.image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClipToMask(context, rect, image.CGImage);
CGContextSetFillColorWithColor(context, [[UIColor redColor] CGColor]);
CGContextFillRect(context, rect);
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

UIImage *flippedImage = [UIImage imageWithCGImage:img.CGImage scale:1.0 orientation: UIImageOrientationDownMirrored];
imageView.image = flippedImage;

90、動畫執行removeFromSuperview

[UIView animateWithDuration:0.2
                 animations:^{
                     view.alpha = 0.0f;
                 } completion:^(BOOL finished){
                     [view removeFromSuperview];
                 }];

91、啓動頁顯示延時

• (BOOL)application:(UIApplication )application didFinishLaunchingWithOptions:(NSDictionary )launchOptions
  {
  // 延時10s
  sleep(10);
  return YES;
  }
  92、設置UIButton高亮時的背景顏色

// 方法一、子類化UIButton，重寫setHighlighted:方法，代碼如下

import “WZBButton.h”

@implementation WZBButton

• (void)setHighlighted:(BOOL)highlighted {
  [super setHighlighted:highlighted];

  UIColor *normalColor = [UIColor greenColor];
  UIColor *highlightedColor = [UIColor redColor];
  self.backgroundColor = highlighted ? highlightedColor : normalColor;

}

// 方法二、利用setBackgroundImage:forState:方法
[button setBackgroundImage:[self imageWithColor:[UIColor blueColor]] forState:UIControlStateHighlighted];

• (UIImage )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;
  }
  93、關於圖片拉伸

推薦看這個博客，講的很詳細http://blog.csdn.net/q199109106q/article/details/8615661
94、利用runtime獲取一個類所有屬性

• (NSArray *)allPropertyNames:(Class)aClass
  {
  unsigned count;
  objc_property_t *properties = class_copyPropertyList(aClass, &count);

  NSMutableArray *rv = [NSMutableArray array];

  unsigned i;
  for (i = 0; i < count; i++)
  {
  objc_property_t property = properties[i];
  NSString *name = [NSString stringWithUTF8String:property_getName(property)];
  [rv addObject:name];
  }

  free(properties);

  return rv;
  }
  95、設置textView的某段文字變成其他顏色

• (void)setupTextView:(UITextView )textView text:(NSString )text color:(UIColor *)color {
  NSMutableAttributedString *string = [[NSMutableAttributedString alloc]initWithString:textView.text];
  [string addAttribute:NSForegroundColorAttributeName value:color range:[textView.text rangeOfString:text]];
  [textView setAttributedText:string];
  }
  96、讓push跳轉動畫像modal跳轉動畫那樣效果(從下往上推上來)

• (void)push
  {
  TestViewController *vc = [[TestViewController alloc] init];
  vc.view.backgroundColor = [UIColor redColor];
  CATransition* transition = [CATransition animation];
  transition.duration = 0.4f;
  transition.type = kCATransitionMoveIn;
  transition.subtype = kCATransitionFromTop;
  [self.navigationController.view.layer addAnimation:transition forKey:kCATransition];
  [self.navigationController pushViewController:vc animated:NO];
  }

• (void)pop
  {
  CATransition* transition = [CATransition animation];
  transition.duration = 0.4f;
  transition.type = kCATransitionReveal;
  transition.subtype = kCATransitionFromBottom;
  [self.navigationController.view.layer addAnimation:transition forKey:kCATransition];
  [self.navigationController popViewControllerAnimated:NO];
  }
  97、上傳圖片太大，壓縮圖片

-(UIImage )resizeImage:(UIImage )image
{
float actualHeight = image.size.height;
float actualWidth = image.size.width;
float maxHeight = 300.0;
float maxWidth = 400.0;
float imgRatio = actualWidth/actualHeight;
float maxRatio = maxWidth/maxHeight;
float compressionQuality = 0.5;//50 percent compression

if (actualHeight > maxHeight || actualWidth > maxWidth)
{
    if(imgRatio < maxRatio)
    {
        //adjust width according to maxHeight
        imgRatio = maxHeight / actualHeight;
        actualWidth = imgRatio * actualWidth;
        actualHeight = maxHeight;
    }
    else if(imgRatio > maxRatio)
    {
        //adjust height according to maxWidth
        imgRatio = maxWidth / actualWidth;
        actualHeight = imgRatio * actualHeight;
        actualWidth = maxWidth;
    }
    else
    {
        actualHeight = maxHeight;
        actualWidth = maxWidth;
    }
}

CGRect rect = CGRectMake(0.0, 0.0, actualWidth, actualHeight);
UIGraphicsBeginImageContext(rect.size);
[image drawInRect:rect];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
NSData *imageData = UIImageJPEGRepresentation(img, compressionQuality);
UIGraphicsEndImageContext();

return [UIImage imageWithData:imageData];

}

鏈接：http://www.jianshu.com/p/9fcd37c0ea05
來源：簡書

著作權歸作者所有。商業轉載請聯繫作者獲得授權，非商業轉載請註明出處。