来自：http://blog.csdn.net/pjk1129/article/details/6665603
这里介绍一下网友开源的MBProgressHUD类，实现等待框，
一、网上下载 MBProgessHUD 类文件，直接导入到工程即可
二、示例分析
在我的工程中示例如下：
1）在ShowImageViewController.h头文件代码如下：
#import <UIKit/UIKit.h> #import "MBProgressHUD.h" @interface ShowImageViewController : UIViewController<MBProgressHUDDelegate> { NSString *_picUrlString; UIImageView *_imageView; MBProgressHUD *_progressHUD; } @property (nonatomic, copy) NSString *picUrlString; @property (nonatomic, retain) IBOutlet UIImageView *imageView; @property (nonatomic, retain) MBProgressHUD *progressHUD; //请求图片资源 -(void)imageResourceRequest; //显示图片信息 -(void)displayImage:(UIImage *)image; - (IBAction)dismissModealView:(id)sender; -(void)removeModalView; @end 2）在ShowImageViewController.m实现文件代码如下： #import "ShowImageViewController.h" #import <QuartzCore/QuartzCore.h> @implementation ShowImageViewController @synthesize picUrlString = _picUrlString; @synthesize imageView = _imageView; @synthesize progressHUD = _progressHUD; - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view from its nib. self.view.backgroundColor = [UIColor grayColor]; self.view.alpha = 0.8; //设置图片为圆角 self.imageView.backgroundColor = [UIColor clearColor]; self.imageView.layer.borderColor = [UIColor lightGrayColor].CGColor; self.imageView.layer.borderWidth = 5.0; self.imageView.layer.masksToBounds = YES; self.imageView.layer.cornerRadius = 10.0; } -(void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; //当进入视图时，重新设置imageView [self.imageView setImage:nil]; [self.imageView setFrame:CGRectMake(160, 200, 0, 0)]; //显示加载等待框 self.progressHUD = [[MBProgressHUD alloc] initWithView:self.view]; [self.view addSubview:self.progressHUD]; [self.view bringSubviewToFront:self.progressHUD]; self.progressHUD.delegate = self; self.progressHUD.labelText = @"加载中..."; [self.progressHUD show:YES]; //开启线程，请求图片资源 [NSThread detachNewThreadSelector:@selector(imageResourceRequest) toTarget:self withObject:nil]; } //请求图片资源 -(void)imageResourceRequest { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; //根据网络数据，获得到image资源 NSData *data = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:self.picUrlString]]; UIImage *image = [[UIImage alloc] initWithData:data]; [data release]; //回到主线程，显示图片信息 [self performSelectorOnMainThread:@selector(displayImage:) withObject:image waitUntilDone:NO]; [image release]; [pool release]; } //显示图片信息 -(void)displayImage:(UIImage *)image { //若self.progressHUD为真，则将self.progressHUD移除，设为nil if (self.progressHUD){ [self.progressHUD removeFromSuperview]; [self.progressHUD release]; self.progressHUD = nil; } //图片慢慢放大动画效果 [self.imageView setImage:image]; [UIView beginAnimations:nil context:nil]; [UIView setAnimationDuration:0.5]; [self.imageView setFrame:CGRectMake(40, 100, 240, 160)]; [UIView commitAnimations]; } - (void)viewDidUnload { [self setImageView:nil]; [super viewDidUnload]; // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { // Return YES for supported orientations return (interfaceOrientation == UIInterfaceOrientationPortrait); } - (IBAction)dismissModealView:(id)sender { //设置定时器，当动画结束时，子视图从父视图中移除 [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(removeModalView) userInfo:nil repeats:NO]; [UIView beginAnimations:nil context:nil]; [UIView setAnimationDuration:0.5]; [self.imageView setFrame:CGRectMake(160, 200, 0, 0)]; [UIView commitAnimations]; } -(void)removeModalView { [self.view removeFromSuperview]; } #pragma mark - #pragma mark MBProgressHUDDelegate methods - (void)hudWasHidden:(MBProgressHUD *)hud { NSLog(@"Hud: %@", hud); // Remove HUD from screen when the HUD was hidded [self.progressHUD removeFromSuperview]; [self.progressHUD release]; self.progressHUD = nil; } - (void)dealloc { [_picUrlString release]; [_imageView release]; [super dealloc]; } @end 三、效果展示
四、总结
利用MBProgressHUD实现加载等待框，视觉效果大大提高
