iOS实战技巧
2016年01月27日 
79 
Yimouleng 分类：开发资讯
这是我在网上搜索到的iOS高级开发实战讲解，由于原文不是很方便浏览，所以我在这里整理一部分出来，方便查阅，同时谢谢原作者。
这里我不是每一个都收录进来，这里只是放出一部分，有些用的太多，我就没整理了，大家如果想看可以去看原文。
根据颜色生成一张尺寸为1*1的相同颜色图片
| + (UIImage *)imageWithColor:(UIColor *)color
{
// 描述矩形
CGRect rect=CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
// 开启位图上下文
UIGraphicsBeginImageContext(rect.size);
// 获取位图上下文
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);
// 从上下文中获取图片
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
// 结束上下文
UIGraphicsEndImageContext();
return theImage;
} |
返回输入键盘
| - (BOOL)textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];
return YES;
} |
点击屏幕收回键盘
| - (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent *)event
{
[self.view endEditing:YES];
} |
CGRect
| CGRectFromString(<#NSString *string#>)//有字符串恢复出矩形
CGRectInset(<#CGRect rect#>, <#CGFloat dx#>, <#CGFloat dy#>)//创建较小或者较大的矩形
CGRectIntersectsRect(<#CGRect rect1#>, <#CGRect rect2#>)//判断两巨星是否交叉，是否重叠
CGRectZero//高度和宽度为零的，位于（0，0）的矩形常量 |
隐藏状态栏
| [UIApplication sharedApplication] setStatusBarHidden:<#(BOOL)#> withAnimation:<#(UIStatusBarAnimation)#>//隐藏状态栏 |
自动适应父视图大小
| self.view.autoresizesSubviews = YES;
self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; |
UITableView的一些方法
| 这里我自己做了个测试，缩进级别设置为行号，row越大，缩进越多- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger row = indexPath.row;
return row;
} |
把plist文件中的数据赋给数组
| NSString *path = [[NSBundle mainBundle] pathForResource:@"States" ofType:@"plist"];
NSArray *array = [NSArray arrayWithContentsOfFile:path]; |
获取触摸的点
| - (CGPoint)locationInView:(UIView *)view;
- (CGPoint)previousLocationInView:(UIView *)view; |
获取触摸的属性
| @property(nonatomic,readonly) NSTimeInterval timestamp;
@property(nonatomic,readonly) UITouchPhase phase;
@property(nonatomic,readonly) NSUInteger tapCount; |
从plist中获取数据赋给字典
| NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"plist"];
NSDictionary *dictionary = [NSDictionary dictionaryWithContentsOfFile:plistPath]; |
NSUserDefaults注意事项
| 设置完了以后如果存储的东西比较重要的话，一定要同步一下
[[NSUserDefaults standardUserDefaults] synchronize]; |
获取Documents目录
| NSString *documentsDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0]; |
获取tmp目录
| NSString *tmpPath = NSTemporaryDirectory(); |
利用Safari打开一个链接
| NSURL *url = [NSURL URLWithString:@"http://baidu.com"];
[[UIApplication sharedApplication] openURL:url]; |
利用UIWebView显示pdf文件，网页等等
| 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的简单交互
| 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];
//页面跳转了以后，停止载入
-(void)viewWillDisappear:(BOOL)animated {
if (myWebView.isLoading) {
[myWebView stopLoading];
}
myWebView.delegate = nil;
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
} |
汉字转码
| NSString *oriString = @"\u67aa\u738b";
NSString *escapedString = [oriString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; |
处理键盘通知
| 先注册通知，然后实现具体当键盘弹出来要做什么，键盘收起来要做什么
- (void)registerForKeyboardNotifications {
keyboardShown = NO;//标记当前键盘是没有显示的
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasShown:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasHidden:) name:UIKeyboardDidHideNotification object:nil];
}
//键盘显示要做什么
- (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;
} |
点击键盘的next按钮，在不同的textField之间换行
| - (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;
} |
设置日期格式
| dateFormatter = [[NSDateFormatter alloc]init];
dateFormatter.locale = [NSLocale currentLocale];
dateFormatter.calendar = [NSCalendar autoupdatingCurrentCalendar];
dateFormatter.timeZone = [NSTimeZone defaultTimeZone];
dateFormatter.dateStyle = NSDateFormatterShortStyle;
NSLog(@"%@",[dateFormatter stringFromDate:[NSDate date]]); |
加载大量图片的时候，可以使用
| NSString *imagePath = [[NSBundle mainBundle] pathForResource:@"icon" ofType:@"png"];
UIImage *myImage = [UIImage imageWithContentsOfFile:imagePath]; |
有时候在iPhone游戏中，既要播放背景音乐，同时又要播放比如枪的开火音效。
| 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表示一直循环 |
从通讯录中读取电话号码，去掉数字之间的-
| 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); |
正则判断：字符串只包含字母和数字
| NSString *myString = @"Letter1234";
NSString *regex = @"[a-z][A-Z][0-9]";
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex];
if ([predicate evaluateWithObject:myString]) {
//implement
} |
设置UITableView的滚动条颜色
| self.tableView.indicatorStyle = UIScrollViewIndicatorStyleWhite; |
网络编程
开发web等网络应用程序的时候，需要确认网络环境，连接情况等信息。如果没有处理它们，是不会通过apple的审查的。
系统自带的网络检查是原生的，AFNetworking也为我们添加了相关检测机制，所以这个直接在介绍AFNetworking的时候详解吧。
使用NSURLConnection下载数据
| 1. 创建对象
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. 实现委托方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
self.receiveData.length = 0;//先清空数据
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[self.receiveData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
//错误处理
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
NSString *returnString = [[NSString alloc]initWithData:self.receiveData encoding:NSUTF8StringEncoding];
firstTimeDownloaded = YES;
} |
iOS的动画以及自定义图形，开个专栏总结。
隐藏状态栏
| [UIApplication sharedApplication].statusBarHidden = YES; |
.m文件与.mm文件的区别
| .m文件是objective-c文件
.mm文件相当于c++或者c文件 |
Safari其实没有把内存的缓存写到存储卡上
读取一般性文件
| - (void)readFromTXT {
NSString *tmp;
NSArray *lines;//将文件转化为一行一行的
lines = [[NSString stringWithContentsOfFile:@"testFileReadLines.txt"] componentsSeparatedByString:@"\n"];
NSEnumerator *nse = [lines objectEnumerator];
//读取<>里的内容
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]; |
调用电话，短信，邮件
| [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"mailto:apple@mac.com?Subject=hello"]];
sms://调用短信
tel://调用电话
itms://打开MobileStore.app |
获取版本信息
| 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不能同时显示
UINavigationItem也是
不要再语言包里面设置空格
NSNotificationCenter带参数发送
| 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];
} |
延迟一段时间执行某个函数
| [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设置成圆角的方法
| mainView.layer.cornerRadius = 6;
mainView.layer.masksToBounds = YES; |
Objective-C 内存管理
一个对象可以有一个或多个拥有者
当它一个拥有者都没有的时候，它就会被回收
如果想保留一个对象不被回收，你就必须成为它的拥有者
关键字
alloc
为对象分配内存，计数设为1，并返回此对象。
一个代码块内要确保copy，alloc 和 retain 的使用数量与 release 和 autorelease 的数量相等。
iPhone 更改键盘右下角按键的 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; |
