這里介紹一下網友開源的MBProgressHUD類，實現等待框，
一、網上下載 MBProgessHUD 類文件，直接導入到工程即可
二、示例分析
在我的工程中示例如下：
1）在ShowImageViewController.h頭文件代碼如下：
#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;
//請求圖片資源
-(void)imageResourceRequest;
//顯示圖片信息
-(void)displayImage:(UIImage *)image;
- (IBAction)dismissModealView:(id)sender;
-(void)removeModalView;
@end
2）在ShowImageViewController.m實現文件代碼如下：
#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;
//設置圖片為圓角
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];
//當進入視圖時，重新設置imageView
[self.imageView setImage:nil];
[self.imageView setFrame:CGRectMake(160, 200, 0, 0)];
//顯示加載等待框
self.progressHUD = [[MBProgressHUD alloc] initWithView:self.view];
[self.view addSubview:self.progressHUD];
[self.view bringSubviewToFront:self.progressHUD];
self.progressHUD.delegate = self;
self.progressHUD.labelText = @"加載中...";
[self.progressHUD show:YES];
//開啟線程，請求圖片資源
[NSThread detachNewThreadSelector:@selector(imageResourceRequest) toTarget:self withObject:nil];
}
//請求圖片資源
-(void)imageResourceRequest
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
//根據網絡數據，獲得到image資源
NSData *data = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:self.picUrlString]];
UIImage *image = [[UIImage alloc] initWithData:data];
[data release];
//回到主線程，顯示圖片信息
[self performSelectorOnMainThread:@selector(displayImage:) withObject:image waitUntilDone:NO];
[image release];
[pool release];
}
//顯示圖片信息
-(void)displayImage:(UIImage *)image
{
//若self.progressHUD為真，則將self.progressHUD移除，設為nil
if (self.progressHUD){
[self.progressHUD removeFromSuperview];
[self.progressHUD release];
self.progressHUD = nil;
}
//圖片慢慢放大動畫效果
[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 {
//設置定時器，當動畫結束時，子視圖從父視圖中移除
[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、總結
利用MBProgressHUD實現加載等待框，視覺效果大大提高