iOS實戰技巧
2016年01月27日 
79 
Yimouleng 分類：開發資訊
這是我在網上搜索到的iOS高級開發實戰講解，由于原文不是很方便瀏覽，所以我在這里整理一部分出來，方便查閱，同時謝謝原作者。
這里我不是每一個都收錄進來，這里只是放出一部分，有些用的太多，我就沒整理了，大家如果想看可以去看原文。
根據顏色生成一張尺寸為1*1的相同顏色圖片
| + (UIImage *)imageWithColor:(UIColor *)color
{
// 描述矩形
CGRect rect=CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
// 開啟位圖上下文
UIGraphicsBeginImageContext(rect.size);
// 獲取位圖上下文
CGContextRef context = UIGraphicsGetCurrentContext();
// 使用color演示填充上下文
CGContextSetFillColorWithColor(context, [color CGColor]);
// 渲染上下文
CGContextFillRect(context, rect);
// 從上下文中獲取圖片
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
// 結束上下文
UIGraphicsEndImageContext();
return theImage;
} |
返回輸入鍵盤
| - (BOOL)textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];
return YES;
} |
點擊屏幕收回鍵盤
| - (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent *)event
{
[self.view endEditing:YES];
} |
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//高度和寬度為零的，位于（0，0）的矩形常量 |
隱藏狀態欄
| [UIApplication sharedApplication] setStatusBarHidden:<#(BOOL)#> withAnimation:<#(UIStatusBarAnimation)#>//隱藏狀態欄 |
自動適應父視圖大小
| self.view.autoresizesSubviews = YES;
self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; |
UITableView的一些方法
| 這里我自己做了個測試，縮進級別設置為行號，row越大，縮進越多- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger row = indexPath.row;
return row;
} |
把plist文件中的數據賦給數組
| NSString *path = [[NSBundle mainBundle] pathForResource:@"States" ofType:@"plist"];
NSArray *array = [NSArray arrayWithContentsOfFile:path]; |
獲取觸摸的點
| - (CGPoint)locationInView:(UIView *)view;
- (CGPoint)previousLocationInView:(UIView *)view; |
獲取觸摸的屬性
| @property(nonatomic,readonly) NSTimeInterval timestamp;
@property(nonatomic,readonly) UITouchPhase phase;
@property(nonatomic,readonly) NSUInteger tapCount; |
從plist中獲取數據賦給字典
| NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"plist"];
NSDictionary *dictionary = [NSDictionary dictionaryWithContentsOfFile:plistPath]; |
NSUserDefaults注意事項
| 設置完了以后如果存儲的東西比較重要的話，一定要同步一下
[[NSUserDefaults standardUserDefaults] synchronize]; |
獲取Documents目錄
| NSString *documentsDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0]; |
獲取tmp目錄
| NSString *tmpPath = NSTemporaryDirectory(); |
利用Safari打開一個鏈接
| NSURL *url = [NSURL URLWithString:@"http://baidu.com"];
[[UIApplication sharedApplication] openURL:url]; |
利用UIWebView顯示pdf文件，網頁等等
| 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];
[webView loadRequest:request]; |
UIWebView和html的簡單交互
| myWebView = [[UIWebView alloc]initWithFrame:self.view.bounds];
[myWebView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]]];
NSError *error;
NSString *errorString = [NSString stringWithFormat:@"",error];
[myWebView loadHTMLString:errorString baseURL:nil];
//頁面跳轉了以后，停止載入
-(void)viewWillDisappear:(BOOL)animated {
if (myWebView.isLoading) {
[myWebView stopLoading];
}
myWebView.delegate = nil;
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
} |
漢字轉碼
| NSString *oriString = @"\u67aa\u738b";
NSString *escapedString = [oriString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; |
處理鍵盤通知
| 先注冊通知，然后實現具體當鍵盤彈出來要做什么，鍵盤收起來要做什么
- (void)registerForKeyboardNotifications {
keyboardShown = NO;//標記當前鍵盤是沒有顯示的
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasShown:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasHidden:) name:UIKeyboardDidHideNotification object:nil];
}
//鍵盤顯示要做什么
- (void)keyboardWasShown:(NSNotification *)notification {
if (keyboardShown) {
return;
}
NSDictionary *info = [notification userInfo];
NSValue *aValue = [info objectForKey:UIKeyboardFrameBeginUserInfoKey];
CGSize keyboardSize = [aValue CGRectValue].size;
CGRect viewFrame = scrollView.frame;
viewFrame.size.height = keyboardSize.height;
CGRect textFieldRect = activeField.frame;
[scrollView scrollRectToVisible:textFieldRect animated:YES];
keyboardShown = YES;
}
- (void)keyboardWasHidden:(NSNotification *)notification {
NSDictionary *info = [notification userInfo];
NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
CGSize keyboardSize = [aValue CGRectValue].size;
CGRect viewFrame = scrollView.frame;
viewFrame.size.height += keyboardSize.height;
scrollView.frame = viewFrame;
keyboardShown = NO;
} |
點擊鍵盤的next按鈕，在不同的textField之間換行
| - (BOOL)textFieldShouldReturn:(UITextField *)textField {
if ([textField returnKeyType] != UIReturnKeyDone) {
NSInteger nextTag = [textField tag] + 1;
UIView *nextTextField = [self.tableView viewWithTag:nextTag];
[nextTextField becomeFirstResponder];
}else {
[textField resignFirstResponder];
}
return YES;
} |
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]]); |
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]; |
有時候在iPhone游戲中，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 |
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"];
while ([scanner isAtEnd] == NO) {
NSString *buffer;
if ([scanner scanCharactersFromSet:numbers intoString:&buffer]) {
[strippedString appendString:buffer];
}else {
scanner.scanLocation = [scanner scanLocation] + 1;
}
}
NSLog(@"%@",strippedString); |
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];
if ([predicate evaluateWithObject:myString]) {
//implement
} |
設置UITableView的滾動條顏色
| self.tableView.indicatorStyle = UIScrollViewIndicatorStyleWhite; |
網絡編程
開發web等網絡應用程序的時候，需要確認網絡環境，連接情況等信息。如果沒有處理它們，是不會通過apple的審查的。
系統自帶的網絡檢查是原生的，AFNetworking也為我們添加了相關檢測機制，所以這個直接在介紹AFNetworking的時候詳解吧。
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 委托方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
}
3. 實現委托方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
self.receiveData.length = 0;//先清空數據
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[self.receiveData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
//錯誤處理
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
NSString *returnString = [[NSString alloc]initWithData:self.receiveData encoding:NSUTF8StringEncoding];
firstTimeDownloaded = YES;
} |
iOS的動畫以及自定義圖形，開個專欄總結。
隱藏狀態欄
| [UIApplication sharedApplication].statusBarHidden = YES; |
.m文件與.mm文件的區別
| .m文件是objective-c文件
.mm文件相當于c++或者c文件 |
Safari其實沒有把內存的緩存寫到存儲卡上
讀取一般性文件
| - (void)readFromTXT {
NSString *tmp;
NSArray *lines;//將文件轉化為一行一行的
lines = [[NSString stringWithContentsOfFile:@"testFileReadLines.txt"] componentsSeparatedByString:@"\n"];
NSEnumerator *nse = [lines objectEnumerator];
//讀取<>里的內容
while (tmp == [nse nextObject]) {
NSString *stringBetweenBrackets = nil;
NSScanner *scanner = [NSScanner scannerWithString:tmp];
[scanner scanUpToString:@"<" intoString:nil];
[scanner scanString:@"<" intoString:nil];
[scanner scanUpToString:@">" intoString:&stringBetweenBrackets];
NSLog(@"%@",[stringBetweenBrackets description]);
}
} |
| [self.navigationController setNavigationBarHidden:YES animated:YES]; |
調用電話，短信，郵件
| [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"mailto:apple@mac.com?Subject=hello"]];
sms://調用短信
tel://調用電話
itms://打開MobileStore.app |
獲取版本信息
| UIDevice *myDevice = [UIDevice currentDevice];
NSString *systemVersion = myDevice.systemVersion; |
UIWebView的使用
| webView.delegate = self;
(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSURL *url = request.URL;
NSString *urlStirng = url.absoluteString;
NSLog(@"%@",urlStirng);
return YES;
} |
UIButton的title和image不能同時顯示
UINavigationItem也是
不要再語言包里面設置空格
NSNotificationCenter帶參數發送
| 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 {
MPMoviePlayerController *theMovie = [aNotification object];
[[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackDidFinishNotification object:theMovie];
} |
延遲一段時間執行某個函數
| [self performSelector:@selector(dismissModal) withObject:self afterDelay:1.0]; |
| NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSString *currentDateStr = [dateFormatter stringFromDate:[NSDate date]]; |
UIView設置成圓角的方法
| mainView.layer.cornerRadius = 6;
mainView.layer.masksToBounds = YES; |
Objective-C 內存管理
一個對象可以有一個或多個擁有者
當它一個擁有者都沒有的時候，它就會被回收
如果想保留一個對象不被回收，你就必須成為它的擁有者
關鍵字
alloc
為對象分配內存，計數設為1，并返回此對象。
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。
iPhone 更改鍵盤右下角按鍵的 type
| 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; |
