前言
iOS开发过程中,总有那么一些个小问题让人纠结,它们不会让程序崩溃,但是会让人崩溃。除此之外,还将分享一些细节现在我通过自己的总结以及从其他地方的引用,来总结一下一些常见小问题。
本篇长期更新,多积累,多奉献,同时感谢其中一些文章的作者的整理,感谢!
iOS高级开发实战讲解
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。
1.返回输入键盘
<UITextFieldDelegate>
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];
return YES;
}
2.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
3.隐藏状态栏
[UIApplication sharedApplication] setStatusBarHidden:<#(BOOL)#> withAnimation:<#(UIStatusBarAnimation)#>//隐藏状态栏
4.自动适应父视图大小
self.view.autoresizesSubviews = YES;
self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
5.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
<UITableViewDelegate>
- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger row = indexPath.row;
return row;
}
6.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];
7.获取触摸的点
- (CGPoint)locationInView:(UIView *)view;
- (CGPoint)previousLocationInView:(UIView *)view;
8.获取触摸的属性
@property(nonatomic,readonly) NSTimeInterval timestamp;
@property(nonatomic,readonly) UITouchPhase phase;
@property(nonatomic,readonly) NSUInteger tapCount;
9.从plist中获取数据赋给字典
NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"plist"];
NSDictionary *dictionary = [NSDictionary dictionaryWithContentsOfFile:plistPath];
10.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];
11.获取Documents目录
NSString *documentsDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
12.获取tmp目录
NSString *tmpPath = NSTemporaryDirectory();
13.利用Safari打开一个链接
NSURL *url = [NSURL URLWithString:@"http://baidu.com"];
[[UIApplication sharedApplication] openURL:url];
14.利用UIWebView显示pdf文件,网页等等
<UIWebViewDelegate>
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];
15.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:@"<html><center><font size=+5 color='red'>AnError Occurred;<br>%@</font></center></html>",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;
}
16.汉字转码
NSString *oriString = @"\u67aa\u738b";
NSString *escapedString = [oriString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
17.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;
}
18.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;
}
19.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]]);
20.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];
21.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
22.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);
23.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
}
24.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。
25.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。
26.隐藏状态栏
[UIApplication sharedApplication].statusBarHidden = YES;
27..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
28.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]);
}
}
29.隐藏UINavigationBar
[self.navigationController setNavigationBarHidden:YES animated:YES];
30.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
31.获取版本信息
UIDevice *myDevice = [UIDevice currentDevice];
NSString *systemVersion = myDevice.systemVersion;
32.UIWebView
的使用
<UIWebViewDelegate>
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
33.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];
}
34.延迟一段时间执行某个函数
[self performSelector:@selector(dismissModal) withObject:self afterDelay:1.0];
35.用NSDateFormatter
调整时间格式代码
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSString *currentDateStr = [dateFormatter stringFromDate:[NSDate date]];
36.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。
- copy 复制一个对象,此对象计数为1,返回此对象。你将成为此克隆对象的拥有者。
- retain 对象计数+1,并成为次对象的拥有者。
- release 对象计数-1,并丢掉此对象。
- autorelease 在未来的某一个时刻,对象计数-1。并在未来的某个时间放弃此对象。
原则
- 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。
- 在使用以 alloc 或 new 开头或包含 copy 的方法,或 retain 一个对象时,你将会编程它的拥有者。
- 实现 dealloc 方法,这是系统当 retain -> 0 的时候,自动调用的。手动调用会引起 retain count 计数错误(多一次的 release)。
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;
总结
不积跬步无以至千里,不积小流无以成江海。