iPhone代码片段收集(2)

   1. 随机数：

srandom(time(NULL)); //随机数种子

id d = random(); // 随机数

  2. 视频播放：

    MPMoviePlayerController *moviePlayer;
    moviePlayer = [[MPMoviePlayerController alloc]
                   initWithContentURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"Movie" ofType:@"m4v"]]];
    //初始化视频播放器对象，并传入被播放文件的地址
    moviePlayer.movieControlMode = MPMovieControlModeDefault;
    [moviePlayer play];
    //此处有内存溢出

   3.  启动界面显示：

iPhone软件启动后的第一屏图片是非常重要的往往就是loading载入中的意思。设置它说来也简单，但是却无比重要

只需要在resource里面将你希望设置的图片更名为Default.png，这个图片就可以成为iPhone载入的缺省图片

    4. iPhone的系统目录:

//得到Document目录：
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

//得到temp临时目录：
NSString *tempPath = NSTemporaryDirectory();

//得到目录上的文件地址：
NSString *文件地址 = [目录地址 stringByAppendingPathComponent:@"文件名.扩展名"];

    5. 状态栏显示Indicator：

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES; 

  6.app Icon显示数字：

- (void)applicationDidEnterBackground:(UIApplication *)application{
    [[UIApplication sharedApplication] setApplicationIconBadgeNumber:5];
}

   7.sqlite保存地址：

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *thePath = [paths objectAtIndex:0];
    NSString *filePath = [thePath stringByAppendingPathComponent:@"kilonet1.sqlite"];
    
    NSString *dbPath = [[[NSBundle mainBundle] resourcePath]
                        stringByAppendingPathComponent:@"kilonet2.sqlite"];  

   8.Application退出：exit(0);

      9. AlertView，ActionSheet的cancelButton点击事件：

-(void) actionSheet :(UIActionSheet *) actionSheet didDismissWithButtonIndex:(NSInteger) buttonIndex {
    NSLog(@"cancel actionSheet........");
    //当用户按下cancel按钮
    if( buttonIndex == [actionSheet cancelButtonIndex]) {
        exit(0);
    }
//    //当用户按下destructive按钮
//    if( buttonIndex == [actionSheet destructiveButtonIndex]) {
//        // DoSomething here.
//    }
}

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex {
     NSLog(@"cancel alertView........");
    if (buttonIndex == [alertView cancelButtonIndex]) {
        exit(0);
    }
}

    10.给Window设置全局的背景图片：

window.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"coolblack.png"]];

    11. UITextField文本框显示及对键盘的控制:

#pragma mark -
#pragma mark UITextFieldDelegate 
//控制键盘跳转
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
   
    if (textField == _txtAccount) {
        if ([_txtAccount.text length]==0) {
            return NO;
        }
        [_txtPassword becomeFirstResponder];
    } else if (textField == _txtPassword) {
        [_txtPassword resignFirstResponder];
    }
    
    return YES;
}

//输入框背景更换
-(BOOL) textFieldShouldBeginEditing:(UITextField *)textField{
    
    [textField setBackground:[UIImage imageNamed:@"ctext_field_02.png"]];
    
    return YES;
}

-(void) textFieldDidEndEditing:(UITextField *)textField{
    [textField setBackground:[UIImage imageNamed:@"ctext_field_01.png"]];
}

    12.UITextField文本框前面空白宽度设置以及后面组合按钮设置：

    //给文本输入框后面加入空白
    _txtAccount.rightView = _btnDropDown;
    _txtAccount.rightViewMode =  UITextFieldViewModeAlways;
    
    //给文本输入框前面加入空白
    CGRect frame = [_txtAccount frame];
    frame.size.width = 5;
    UIView *leftview = [[UIView alloc] initWithFrame:frame];
    _txtAccount.leftViewMode = UITextFieldViewModeAlways;
    _txtAccount.leftView = leftview;

    13. UIScrollView 设置滑动不超出本身范围：

 [fcScrollViewsetBounces:NO]; 

     14. 遍历View里面所有的Subview：

    NSLog(@"subviews count=%d",[self.view.subviews count]);
    if ([self.view.subviews count] > 0) {
        for (UIView *curView in self.view.subviews) {
                       NSLog(@"view.subviews=%@", [NSString stringWithUTF8String:object_getClassName(curView)]);
        }
    }

    14. 在drawRect里画文字：

     UIFont * f = [UIFont systemFontOfSize:20]; 

    [[UIColordarkGrayColor] set]; 

    NSString * text = @"hi \nKiloNet"; 

    [text drawAtPoint:CGPointMake(center.x,center.y) withFont:f];

    15. NSArray查找是否存在对象时用indexOfObject,如果不存在则返回为NSNotFound.

     16. NString与NSArray之间相互转换：

array = [string componentsSeparatedByString:@","];
string = [[array valueForKey:@"description"] componentsJoinedByString:@","];

     17. TabController随意切换tab bar：

[self.tabBarController setSelectedIndex:tabIndex];

或者 self.tabBarController.selectedIndex = tabIndex;

或者实现下面的delegate来扑捉tab bar的事件：

 

-(BOOL) tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController {
    
    if ([viewController.tabBarItem.title isEqualToString: NSLocalizedString(@"Logout",nil)]) {
        [self showLogout];
        return NO;
    }
    return YES;
}

    18. 自定义View之间切换动画：

- (void) pushController: (UIViewController*) controller
         withTransition: (UIViewAnimationTransition) transition
{
    [UIView beginAnimations:nil context:NULL];
    [self pushViewController:controller animated:NO];
    [UIView setAnimationDuration:.5];
    [UIView setAnimationBeginsFromCurrentState:YES];        
    [UIView setAnimationTransition:transition forView:self.view cache:YES];
    [UIView commitAnimations];
}

    或者：

CATransition *transition = [CATransition animation];
transition.duration = kAnimationDuration;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionPush;
transition.subtype = kCATransitionFromTop;
transitioning = YES;
transition.delegate = self;
[self.navigationController.view.layer addAnimation:transition forKey:nil];
    
self.navigationController.navigationBarHidden = NO;
[self.navigationController pushViewController:tableViewController animated:YES];

      19. UIWebView加载时白色显示问题解决以及字体统一设置：

    uiWebView.opaque = NO; 

 

     20.计算字符串长度：

CGFloat w = [title sizeWithFont:[UIFontfontWithName:@"Arial"size:18]].width; 

    21. iTunesLink should be your applications link

NSString *iTunesLink = @"http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=xxxxxx&mt=8";

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:iTunesLink]];

 

    22.时间转换NSString & NSDate：

 -(NSDate *)NSStringDateToNSDate:(NSString *)string {    

    NSDateFormatter *formatter = [[NSDateFormatteralloc] init];

    [formatter setTimeZone:[NSTimeZonetimeZoneWithAbbreviation:@"UTC"]];

    [formatter setDateFormat:@"yyyy-MM-dd"];

    NSDate *date = [formatter dateFromString:string];

    [formatter release];

    return date;

}

 NSString*year =[myDate descriptionWithCalendarFormat:@"%Y" timeZone:nil locale:nil];

or

NSDateFormatter*formatter =[[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy"];

//Optionally for time zone converstions
[formatter setTimeZone:[NSTimeZone timeZoneWithName:@"..."]];

NSString*stringFromDate =[formatter stringFromDate:myNSDateInstance];

 22。 模拟器的文件位置

其中#username#表示当前用户名:
/Users/#username#/Library/Application Support/iPhone Simulator/User/Applications/

  23.在使用UISearchBar时，将背景色设定为clearColor，或者将translucent设为YES，都不能使背景透明，经过一番研究，发现了一种超级简单和实用的方法：

1	[[searchbar.subviews objectAtIndex:0]removeFromSuperview];

背景完全消除了，只剩下搜索框本身了。 

   24.  图像与缓存 :

UIImageView *wallpaper = [[UIImageView alloc] initWithImage:

        [UIImage imageNamed:@"icon.png"]]; // 会缓存图片

UIImageView *wallpaper = [[UIImageView alloc] initWithImage:

        [UIImage imageWithContentsOfFile:@"icon.png"]]; // 不会缓存图片 

  25. iphone-常用的对视图图层(layer)的操作

对图层的操作：

(1.给图层添加背景图片：
myView.layer.contents = (id)[UIImage imageNamed:@"view_BG.png"].CGImage;

(2.将图层的边框设置为圆脚
myWebView.layer.cornerRadius = 8;
myWebView.layer.masksToBounds = YES;

(3.给图层添加一个有色边框
myWebView.layer.borderWidth = 5;
myWebView.layer.borderColor = [[UIColor colorWithRed:0.52 green:0.09 blue:0.07 alpha:1] CGColor];

 26. UIPopoverController 使用

-(void) onSetting:(id) sender {

 

    SplitBaseController *detail = [[SettingServerControlleralloc] init];

 

    

    CGRect frame = [(UIView *)sender frame];

    frame.origin.y = 0;

    

    UIPopoverController *popwin = [[UIPopoverControlleralloc] initWithContentViewController:detail];

    [popwin setPopoverContentSize:CGSizeMake(400, 300) animated:YES];

    popwin.delegate = self;

    [popwin presentPopoverFromRect: frame inView:self.viewpermittedArrowDirections:UIPopoverArrowDirectionAnyanimated:YES];

 

    [detail release];

} 

 27.在UINavigationBar中添加左箭头返回按钮

 

在iPhone里面最讨厌的控件之一就是 UINavigationBar了。这个控件样式修改不方便，连添加按钮也特别麻烦。下面的例子是如何手动添加带箭头的按钮：

 

UINavigationItem *item = [navBar.items objectAtIndex:0];

UINavigationItem *back = [[UINavigationItem alloc] initWithTitle:@"Back"];

NSArray *items = [[NSArray alloc] initWithObjects:back,item,nil];

[navBar setItems:items];

 

- (BOOL)navigationBar:(UINavigationBar *)navigationBar

shouldPopItem:(UINavigationItem *)item{

//在此处添加点击back按钮之后的操作代码 

return NO;

}