前言
iOS開發過程中，總有那麼一些個小問題讓人糾結，它們不會讓程序崩潰，但是會讓人崩潰。除此之外，還將分享一些細節現在我通過自己的總結以及從其他地方的引用，來總結一下一些常見小問題。 本篇長期更新，多積累，多奉獻，同時感謝大家提出的寶貴更新意見！
iOS高級開發實戰講解
這是我在網上搜索到的iOS高級開發實戰講解，由於原文不是很方便瀏覽，所以我在這裏整理一部分出來，方便查閱，同時謝謝大家。 這裏我不是每一個都收錄進來，這裏只是放出一部分，有些用的太多，我就沒整理了，大家如果想看可以去查看網上文章或者官網文檔。
1.返回輸入鍵盤
- (BOOL)textFieldShouldReturn:(UITextField *)textField { <span style="white-space:pre"> </span>[textField resignFirstResponder]; return YES; }
2.CGRect
CGRectFromString(<#NSString *string#>)//有字符串恢復出矩形
CGRectInset(<#CGRect rect#>, <#CGFloat dx#>, <#CGFloat dy#>)//創建較小或者較大的矩形
CGRectIntersectsRect(<#CGRect rect1#>, <#CGRect rect2#>)//判斷兩巨星是否交叉，是否重疊 CGRectZero//高度和寬度爲零的，位於（0，0）的矩形常量
3.隱藏狀態欄
[UIApplication sharedApplication] setStatusBarHidden:<#(BOOL)#> withAnimation:<#(UIStatusBarAnimation)#>//隱藏狀態欄
4.自適應父視圖的大小
self.view.autoresizesSubviews = YES; self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
5.UITableview的一些方法
這裏我自己做了個測試，縮進級別設置爲行號，row越大，縮進越多 - (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath {<span style="white-space:pre"> </span> NSInteger row = indexPath.row; <span style="white-space:pre"> </span>return row; }NSString *path = [[NSBundle mainBundle] pathForResource:@"States" ofType:@"plist"]; NSArray *array = [NSArray arrayWithContentsOfFile:path];
- (CGPoint)locationInView:(UIView *)view; - (CGPoint)previousLocationInView:(UIView *)view;
@property(nonatomic,readonly) NSTimeInterval timestamp; @property(nonatomic,readonly) UITouchPhase phase; @property(nonatomic,readonly) NSUInteger tapCount;
NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"plist"];NSDictionary *dictionary = [NSDictionary dictionaryWithContentsOfFile:plistPath];
設置完了以後如果存儲的東西比較重要的話，一定要同步一下 [[NSUserDefaults standardUserDefaults] synchronize];
NSString *documentsDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
12.獲取tmp目錄
NSString *tmpPath = NSTemporaryDirectory();
13.利用Safari打開一個鏈接
NSURL *url = [NSURL URLWithString:@"http://baidu.com"]; [[UIApplication sharedApplication] openURL:url];
UIWebView *webView = [[UIWebView alloc]initWithFrame:self.view.bounds]; webView.delegate = self; webView.scalesPageToFit = YES;webView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; [webView setAllowsInlineMediaPlayback:YES]; [self.view addSubview:webView]; NSString *pdfPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"pdf"]; NSURL *url = [NSURL fileURLWithPath:pdfPath]; NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:(NSURLRequestUseProtocolCachePolicy) timeoutInterval:5];
myWebView = [[UIWebView alloc]initWithFrame:self.view.bounds]; [myWebView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]]]; NSError *error; <span style="font-size:18px;">NSString *errorString = [NSString stringWithFormat:@"AnError Occurred;
%@</span><span style="font-family:Microsoft Yahei, Hiragino Sans GB, Helvetica, Helvetica Neue, 微軟雅黑, Tahoma, Arial, sans-serif;color:#14191e;"><span style="font-size: 14px;">"<html><center><font size=+5 color='red'>AnError Occurred;<br>%@</font><.center><?html>"</span></span><span style="font-size:18px;">,error]; </span>[myWebView loadHTMLString:errorString baseURL:nil]; //頁面跳轉了以後，停止載入 -(void)viewWillDisappear:(BOOL)animated { <span style="white-space:pre"> </span>if (myWebView.isLoading) { <span style="white-space:pre"> </span>[myWebView stopLoading]; <span style="white-space:pre"> </span>}<span style="white-space:pre"> </span> myWebView.delegate = nil; <span style="white-space:pre"> </span>[UIApplication sharedApplication].networkActivityIndicatorVisible = NO; }
16.漢字轉碼
NSString *oriString = @"\u67aa\u738b"; NSString *escapedString = [oriString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]；
17.處理鍵盤通知
- (void)keyboardWasShown:(NSNotification *)notification { <span style="white-space:pre"> </span>if (keyboardShown) { <span style="white-space:pre"> </span>return; <span style="white-space:pre"> </span>} <span style="white-space:pre"> </span>NSDictionary *info = [notification userInfo]; <span style="white-space:pre"> </span><span style="white-space:pre"> </span>NSValue *aValue = [info objectForKey:UIKeyboardFrameBeginUserInfoKey]; <span style="white-space:pre"> </span>CGSize keyboardSize = [aValue CGRectValue].size; <span style="white-space:pre"> </span>CGRect viewFrame = scrollView.frame; <span style="white-space:pre"> </span>viewFrame.size.height = keyboardSize.height; <span style="white-space:pre"> </span><span style="white-space:pre"> </span>CGRect textFieldRect = activeField.frame; <span style="white-space:pre"> </span>[scrollView scrollRectToVisible:textFieldRect animated:YES]; keyboardShown = YES; } - (void)keyboardWasHidden:(NSNotification *)notification { <span style="white-space:pre"> </span>NSDictionary *info = [notification userInfo]; <span style="white-space:pre"> </span>NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey]; <span style="white-space:pre"> </span>CGSize keyboardSize = [aValue CGRectValue].size; <span style="white-space:pre"> </span><span style="white-space:pre"> </span>CGRect viewFrame = scrollView.frame; <span style="white-space:pre"> </span>viewFrame.size.height += keyboardSize.height; <span style="white-space:pre"> </span>scrollView.frame = viewFrame; <span style="white-space:pre"> </span><span style="white-space:pre"> </span>keyboardShown = NO; }
18.點擊鍵盤的next按鈕，在不同的textField之間換行
- (BOOL)textFieldShouldReturn:(UITextField *)textField { <span style="white-space:pre"> </span>if ([textField returnKeyType] != UIReturnKeyDone) {<span style="white-space:pre"> </span> NSInteger nextTag = [textField tag] + 1;<span style="white-space:pre"> </span> UIView *nextTextField = [self.tableView viewWithTag:nextTag]; <span style="white-space:pre"> </span>[nextTextField becomeFirstResponder]; <span style="white-space:pre"> </span>}else { <span style="white-space:pre"> </span>[textField resignFirstResponder]; <span style="white-space:pre"> </span>} <span style="white-space:pre"> </span>return YES; }
19.設置日期格式
dateFormatter = [[NSDateFormatter alloc]init]; dateFormatter.locale = [NSLocale currentLocale]; dateFormatter.calendar = [NSCalendar autoupdatingCurrentCalendar]; dateFormatter.timeZone = [NSTimeZone defaultTimeZone]; dateFormatter.dateStyle = NSDateFormatterShortStyle; NSLog(@"%@",[dateFormatter stringFromDate:[NSDate date]]);
20.加載大量圖片的時候可以使用
NSString *imagePath = [[NSBundle mainBundle] pathForResource:@"icon" ofType:@"png"]; UIImage *myImage = [UIImage imageWithContentsOfFile:imagePath];
21.有時候在iPhone遊戲中，既要播放背景音樂，同時又要播放比如槍的開火音效
NSString *musicFilePath = [[NSBundle mainBundle] pathForResource:@"xx" ofType:@"wav"];NSURL *musicURL = [NSURL fileURLWithPath:musicFilePath]; AVAudioPlayer *musicPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:musicURL error:nil]; [musicPlayer prepareToPlay]; musicPlayer.volume = 1; musicPlayer.numberOfLoops = -1;//-1表示一直循環
22.從通訊錄中讀取電話號碼，去掉數字之間的-
NSString *originalString = @"(123)123123abc"; NSMutableString *strippedString = [NSMutableString stringWithCapacity:originalString.length]; NSScanner *scanner = [NSScanner scannerWithString:originalString]; NSCharacterSet *numbers = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"]; <span style="white-space:pre"> </span>while ([scanner isAtEnd] == NO) { <span style="white-space:pre"> </span>NSString *buffer; <span style="white-space:pre"> </span>if ([scanner scanCharactersFromSet:numbers intoString:&buffer]) { <span style="white-space:pre"> </span>[strippedString appendString:buffer]; <span style="white-space:pre"> </span>}else { <span style="white-space:pre"> </span>scanner.scanLocation = [scanner scanLocation] + 1; <span style="white-space:pre"> </span>}<span style="white-space:pre"> </span> }<span style="white-space:pre"> </span> NSLog(@"%@",strippedString);
23.正則判斷：字符串只包含字母和數字
NSString *myString = @"Letter1234"; NSString *regex = @"[a-z][A-Z][0-9]"; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex];<span style="white-space:pre"> </span> if ([predicate evaluateWithObject:myString]) { <span style="white-space:pre"> </span>//implement <span style="white-space:pre"> </span>}
24.設置UITableView的滾動條顏色
self.tableView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
25.使用NSURLConnection下載數據
1. 創建對象 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]]; [NSURLConnection connectionWithRequest:request delegate:self]; 2. NSURLConnection delegate 委託方法 - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { <span style="white-space:pre"> </span>//implement<span style="font-family: Arial, Helvetica, sans-serif;">}</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;"> - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { </span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>//implement</span><span style="font-family: Arial, Helvetica, sans-serif;">} </span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;">- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>//implement</span><span style="font-family: Arial, Helvetica, sans-serif;"> }</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;"> - (void)connectionDidFinishLoading:(NSURLConnection *)connection {</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>//implement</span><span style="font-family: Arial, Helvetica, sans-serif;"> }</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;"> 3. 實現委託方法 </span><span style="font-family: Arial, Helvetica, sans-serif;">- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { </span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>self.receiveData.length = 0;//先清空數據</span><span style="font-family: Arial, Helvetica, sans-serif;"> }</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;"> - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span> [self.receiveData appendData:data]; </span><span style="font-family: Arial, Helvetica, sans-serif;">} </span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;">- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { </span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>//錯誤處理 </span><span style="font-family: Arial, Helvetica, sans-serif;">} </span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;">- (void)connectionDidFinishLoading:(NSURLConnection *)connection { </span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>[UIApplication sharedApplication].networkActivityIndicatorVisible = NO; </span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span>NSString *returnString = [[NSString alloc]initWithData:self.receiveData encoding:NSUTF8StringEncoding];</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="white-space:pre"> </span> firstTimeDownloaded = YES;</span><span style="font-family: Arial, Helvetica, sans-serif;">
</span><span style="font-family: Arial, Helvetica, sans-serif;"> } </span>26.隱藏狀態欄
[UIApplication sharedApplication].statusBarHidden = YES;
27..m和.mm文件的區別
.m文件是objective-c文件
.mm文件相當於c++或者c文件
28.讀取一般性文件
- (void)readFromTXT {<span style="white-space:pre"> </span> NSString *tmp;<span style="white-space:pre"> </span> NSArray *lines;//將文件轉化爲一行一行的 <span style="white-space:pre"> </span>lines = [[NSString stringWithContentsOfFile:@"testFileReadLines.txt"] componentsSeparatedByString:@"\n"]; <span style="white-space:pre"> </span>NSEnumerator *nse = [lines objectEnumerator]; //讀取<>裏的內容 <span style="white-space:pre"> </span>while (tmp == [nse nextObject]) { <span style="white-space:pre"> </span>NSString *stringBetweenBrackets = nil; <span style="white-space:pre"> </span>NSScanner *scanner = [NSScanner scannerWithString:tmp];<span style="white-space:pre"> </span>[scanner scanUpToString:@"<" intoString:nil]; <span style="white-space:pre"> </span>[scanner scanString:@"<" intoString:nil]; <span style="white-space:pre"> </span><span style="white-space:pre"> </span>[scanner scanUpToString:@">" intoString:&stringBetweenBrackets]; <span style="white-space:pre"> </span>NSLog(@"%@",[stringBetweenBrackets description]); <span style="white-space:pre"> </span>} }
29.隱藏UINavigationBar
[self.navigationController setNavigationBarHidden:YES animated:YES];
30.調用電話，短信，郵件
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"mailto:[email protected]?Subject=hello"]];sms://調用短信 tel://調用電話 itms://打開MobileStore.app
31.獲取版本信息
UIDevice *myDevice = [UIDevice currentDevice]; NSString *systemVersion = myDevice.systemVersion;
32.UIWebView的使用
webView.delegate = self; (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType { <span style="white-space:pre"> </span>NSURL *url = request.URL; NSString *urlStirng = url.absoluteString; <span style="white-space:pre"> </span>NSLog(@"%@",urlStirng); <span style="white-space:pre"> </span>return YES; }
MPMoviePlayerController *theMovie = [[MPMoviePlayerController alloc]initWithContentURL:[NSURL fileURLWithPath:moviePath]]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(myMovieFinishedCallback:) name:MPMoviePlayerPlaybackDidFinishNotification object:theMovie]; [theMovie play];- (void)myMovieFinishedCallback:(NSNotification *)aNotification { <span style="white-space:pre"> </span>MPMoviePlayerController *theMovie = [aNotification object]; <span style="white-space:pre"> </span>[[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackDidFinishNotification object:theMovie]; }
34.延遲一段時間執行某個方法
[self performSelector:@selector(dismissModal) withObject:self afterDelay:1.0];
35.用NSDateFormatter調整時間格式代碼
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init]; dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss"; NSString *currentDateStr = [dateFormatter stringFromDate:[NSDate date]];
36.UIView設置成爲圓角
mainView.layer.cornerRadius = 6;
mainView.layer.masksToBounds = YES;
SearchBar *mySearchBar = [[UISearchBar alloc]init];
mySearchBar.frame = CGRectMake(0, 0, self.view.bounds.size.width, 44);
mySearchBar.placeholder = @"placeholderString";
mySearchBar.delegate = self;
[self.view addSubview:mySearchBar];
UITextField *searchField = [[mySearchBar subviews] lastObject];
searchField.returnKeyType = UIReturnKeyDone;
Objective-C內存管理
1.一個對象可以有一個或多個擁有者 2.當它一個擁有者都沒有的時候，它就會被回收 3.如果想保留一個對象不被回收，你就必須成爲它的擁有者
關鍵字
1.alloc 爲對象分配內存，計數設爲1，並返回此對象。 2.copy 複製一個對象，此對象計數爲1，返回此對象。你將成爲此克隆對象的擁有者。 3.retain 對象計數+1，併成爲次對象的擁有者。 4.release 對象計數-1，並丟掉此對象。 5.autorelease 在未來的某一個時刻，對象計數-1。並在未來的某個時間放棄此對象。
原則
1.一個代碼塊內要確保copy，alloc 和 retain 的使用數量與 release 和 autorelease 的數量相等。 2.在使用以 alloc 或 new 開頭或包含 copy 的方法，或 retain 一個對象時，你將會編程它的擁有者。 3.實現 dealloc 方法，這是系統當 retain -> 0 的時候，自動調用的。手動調用會引起 retain count 計數錯誤（多一次的 release）。
總結
不積跬步無以至千里，不積小流無以成江海
——— 與君共勉！