16、程序启动画面大小  iOS设备现在有三种不同的分辨率：iPhone 320x480、iPhone 4 640x960、iPad 768x1024。以前程序的启动画面(图片)只要准备一个 Default.png 就可以了，但是现在变得复杂多了。下面就是 CocoaChina 会员做得总结   如果一个程序，既支持iPhone又支持iPad，那么它需要包含下面几个图片： Default-Portrait.png iPad专用竖向启动画面 768x1024或者768x1004 Default-Landscape.png iPad专用横向启动画面 1024x768或者1024x748 Default-PortraitUpsideDown.png iPad专用竖向启动画面(Home按钮在屏幕上面)，可省略 768x1024或者768x1004 Default-LandscapeLeft.png iPad专用横向启动画面，可省略 1024x768或者1024x748 Default-LandscapeRight.png iPad专用横向启动画面，可省略 1024x768或者1024x748 Default.png iPhone默认启动图片，如果没有提供上面几个iPad专用启动图片，则在iPad上运行时也使用Default.png（不推荐） 320x480或者320x460 Default@2x.png iPhone4启动图片640x960或者640x920   为了在iPad上使用上述的启动画面，你还需要在info.plist中加入key: UISupportedInterfaceOrientations。同时，加入值UIInterfaceOrientationPortrait, UIInterfacOrientationPortraitUpsideDown, UIInterfaceOrientationLandscapeLeft, UIInterfaceOrientationLandscapeRight 17、ASIHTTPRequest实现断点下载 - (IBAction)URLFetchWithProgress:(id)sender { [startButton setTitle:@"Stop" forState:UIControlStateNormal]; [startButton addTarget:self action:@selector(stopURLFetchWithProgress:)forControlEvents:UIControlEventTouchUpInside]; NSString*tempFile = [[[[NSBundle mainBundle] bundlePath]stringByDeletingLastPathComponent]stringByAppendingPathComponent:@"MemexTrails_1.0b1.zip.download"]; if ([[NSFileManager defaultManager] fileExistsAtPath:tempFile]) { [[NSFileManager defaultManager] removeItemAtPath:tempFile error:nil]; } [self resumeURLFetchWithProgress:self]; } - (IBAction)stopURLFetchWithProgress:(id)sender { networkQueue = [[ASINetworkQueue alloc] init]; timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:selfselector:@selector(updateBandwidthUsageIndicator) userInfo:nil repeats:YES]; timer = nil; [startButton setTitle:@"Stop" forState:UIControlStateNormal]; [startButton addTarget:self action:@selector(URLFetchWithProgress:)forControlEvents:UIControlEventTouchUpInside]; [networkQueue cancelAllOperations]; [resumeButton setEnabled:YES]; } - (IBAction)resumeURLFetchWithProgress:(id)sender  { [resumeButton setEnabled:NO]; [startButton setTitle:@"Start" forState:UIControlStateNormal];  [startButton addTarget:self action:@selector(stopURLFetchWithProgress:)forControlEvents:UIControlEventTouchUpInside]; [networkQueue cancelAllOperations]; [networkQueue setShowAccurateProgress:YES]; [networkQueue setDownloadProgressDelegate:progressIndicator]; [networkQueue setDelegate:self]; [networkQueue setRequestDidFinishSelector:@selector(URLFetchWithProgressComplete:)]; ASIHTTPRequest*request=[[[ASIHTTPRequest alloc] initWithURL:[NSURLURLWithString:@"http://9991.net/blog/mp3/2.mp3"]] autorelease]; [request setDownloadDestinationPath:[[[[NSBundle mainBundle] bundlePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"MemexTrails_1.0b1.mp3"]]; [request setTemporaryFileDownloadPath:[[[[NSBundle mainBundle] bundlePath]stringByDeletingLastPathComponent]stringByAppendingPathComponent:@"MemexTrails_1.0b1.zip.down"]]; [request setAllowResumeForFileDownloads:YES]; [networkQueue addOperation:request]; [networkQueue go]; } - (void)URLFetchWithProgressComplete:(ASIHTTPRequest *)request { if ([request error]) { fileLocation.text=[NSString stringWithFormat:@"An error occurred:%@",[[[requesterror] userInfo] objectForKey:@"Title"]]; } else { fileLocation.text=[NSString stringWithFormat:@"File downloaded to %@",[requestdownloadDestinationPath]]; } [startButton setTitle:@"Start" forState:UIControlStateNormal]; [startButton addTarget:self action:@selector(URLFetchWithProgress:)forControlEvents:UIControlEventTouchUpInside]; } - (IBAction)throttleBandwidth:(id)sender { if ([(UIButton *)sender state] ==YES) { [ASIHTTPRequest setMaxBandwidthPerSecond:ASIWWANBandwidthThrottleAmount]; } else { [ASIHTTPRequest setMaxBandwidthPerSecond:]; } } 18、Safari 启动本地app 在plist文件中加入URL types 结构如下图，在Safari中地址栏输入 设置的字符串，比如设置的是 QQ，地址栏输入 QQ:// 就可以起点本地应用。     19、拖到视频进度与滑动手势冲突解决办法 #pragma mark -#pragma mark UIGestureRecognizerDelegate - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{    UIView *touchView = touch.view;         if ([touchView isKindOfClass:[UISlider class]])     {        return NO;    }    else    {        return YES;    }} 20、创建并保存Cookie的方法          NSString *cookieString = [NSString stringWithString:[headers objectForKey:@"Cookie"]];                 NSMutableDictionary *cookieProperties = [[NSMutableDictionary alloc] init];        [cookieProperties setValue:cookieString forKey:NSHTTPCookieValue];        [cookieProperties setValue:@"QQCookie" forKey:NSHTTPCookieName];        [cookieProperties setValue:@".QQ.com" forKey:NSHTTPCookieDomain];        [cookieProperties setValue:[NSDate dateWithTimeIntervalSinceNow:60*60] forKey:NSHTTPCookieExpires];        [cookieProperties setValue:@"/" forKey:NSHTTPCookiePath];        NSHTTPCookie *newcookie = [[NSHTTPCookie alloc] initWithProperties:cookieProperties];                 [[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookie:newcookie];  21、popover横竖屏位置改变解决办法 1、 delegate中 处理 - (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController{    userImageShow = NO;         if ([popoverController isEqual:myPopover])     {        [myPopover release];        myPopover = nil;    }} 2、屏幕旋转时重新弹出Popover if (myPopover)   {      if ((self.interfaceOrientation ==        UIInterfaceOrientationLandscapeLeft) || (self.interfaceOrientation ==        UIInterfaceOrientationLandscapeRight))      {            [myPopover presentPopoverFromRect:CGRectMake(10,180, 1, 1)                                                inView:self.view                              permittedArrowDirections:UIPopoverArrowDirectionRight                                              animated:YES];     }     else     {           [myPopover presentPopoverFromRect:CGRectMake(20,180, 1, 1)                                                inView:self.view                              permittedArrowDirections:UIPopoverArrowDirectionRight                                              animated:YES];      } } 22、plist各种key值含义 原文：http://www.minroad.com/?p=434   UIRequiresPersistentWiFi 在程序中弹出wifi选择的key（系统设置中需要将wifi提示打开）UIAppFonts 内嵌字体（http://www.minroad.com/?p=412 有详细介绍）UIApplicationExitsOnSuspend 程序是否在后台运行，自己在进入后台的时候exit(0)是很傻的办法UIBackgroundModes 后台运行时的服务，具体看iOS4的后台介绍UIDeviceFamily array类型（1为iPhone和iPod touch设备，2为iPad)UIFileSharingEnabled 开启itunes共享document文件夹UILaunchImageFile 相当于Default.png（更名而已）UIPrerenderedIcon icon上是否有高光UIRequiredDeviceCapabilities 设备需要的功能（具体点击这里查看）UIStatusBarHidden 状态栏隐藏（和程序内的区别是在于显示Default.png已经生效）UIStatusBarStyle 状态栏类型UIViewEdgeAntialiasing 是否开启抗锯齿CFBundleDisplayName app显示名CFBundleIconFile、CFBundleIconFiles 图标CFBundleName 与CFBundleDisplayName的区别在于这个是短名，16字符之内CFBundleVersion 版本CFBundleURLTypes 自定义url，用于利用url弹回程序CFBundleLocalizations 本地资源的本地化语言，用于itunes页面左下角显示本地话语种CFBundleDevelopmentRegion 也是本地化相关，如果用户所在地没有相应的语言资源，则用这个key的value来作为默认最后附上官方文档，所有的key都有，看英文原版才是正路：）点我进入