【iphone应用开发】iPhone应用开发之四：UIImageView和UIWebView的详细讲解

Andy-清风原创，转载请注明，谢谢。

1.UIImageView的讲解

（1）初始化

UIImageView  *imageView =[[UIImageView alloc] initWithFrame:CGRectMake(0.0,45.0,300,300)];  
  
imageView.image = [UIImage imageNamed:@"a.png"];//加载入图片  
  
[self.view addSubView:image];  

也可以这样声明：

UIImage *image =[[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURLURLWithString:@"http://farm4.static.flickr.com/3092/2915896504_a88b69c9de.jpg"]]];  
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];   

在加载入图片的时候有两种加载UIImage的方法：如下：

[UIImage imageNamed:@"a.png"];  

NSString *path = [[NSBundle mainBundle] pathForResource:@”icon”  
ofType:@”png”];  
myImage = [UIImage imageWithContentsOfFile:path]; 

如果找到图片，装载到iPhone系统缓存图象。那意味图片是(理论上)放在内存里作为cache的。因此如果图片资源多了或大了，此方式容易引起发生内存警告从而导致自动退出的问题。

最好是通过直接读取文件路径[UIImage imageWithContentsOfFile]解决掉这个问题.

NSImage *image = [[NSImage alloc]initWithContentsOfURL:(NSURL *)];  
NSImage *image = [[NSImage alloc]initWithContentsOfFile:(NSString *)]; 

最后要记得释放掉image。

 

 

（2）利用UIImageView实现幻灯片效果

 

利用UIImageView和UISider来制作幻灯片。

ImagesViewController.h  
 
#import<UIKit/UIKit.h>  
  
   
  
@interfaceImagesViewController : UIViewController  
  
{  
  
         UIImageView *imageView;  
  
         UISlider *slider;  
  
}  
  
   
  
@property (nonatomic,retain) IBOutlet UIImageView *imageView;  
  
@property (nonatomic,retain) IBOutlet UISlider *slider;  
  
   
  
-(IBAction)sliderAction:(id)sender;  
  
   
  
@end  
  

ImagesViewController.m  
 
  
 
#import"ImagesViewController.h"  
 
#import"Constants.h"  
 
  
 
#define kMinDuration 0.0  
 
#define kMaxDuration 10.0  
  
   
  
@implementationImagesViewController  
  
   
  
@synthesize imageView,slider;  
  
   
  
- (void)dealloc  
  
{  
  
         [imageView release];  
  
         [slider release];  
  
          
  
         [super dealloc];  
  
}  
  
   
  
- (void)viewDidLoad  
  
{         
  
         [super viewDidLoad];  
  
          
  
         self.title = NSLocalizedString(@"ImagesTitle",@"");  
  
         self.imageView.animationImages = [NSArray arrayWithObjects:  
  
          [UIImageimageNamed:@"scene1.jpg"],  
  
          [UIImageimageNamed:@"scene2.jpg"],  
  
          [UIImageimageNamed:@"scene3.jpg"],  
  
          [UIImageimageNamed:@"scene4.jpg"],  
  
          [UIImageimageNamed:@"scene5.jpg"],nil];  
  
         imageView.animationDuration = 5.0;  
  
         [self.imageView stopAnimating];  
  
         imageView.image= [UIImage imageNamed:@"a.png"];  
  
         [self.imageView setIsAccessibilityElement:YES];  
  
         [self.imageView setAccessibilityLabel:self.title];  
  
         [self.slidersetAccessibilityLabel:NSLocalizedString(@"DurationSlider",@"")];  
  
}  
  
- (void)viewDidUnload  
  
{  
  
         [super viewDidUnload];  
  
          
  
         self.imageView = nil;  
  
         self.slider = nil;  
  
}  
  
-(IBAction)sliderAction:(id)sender  
  
{  
  
         UISlider* durationSlider = sender;  
  
         self.imageView.animationDuration = [durationSlider value];  
  
         if (!self.imageView.isAnimating)  
  
                 [self.imageView startAnimating];  
  
}  
 
  
 
  
 
#pragma mark -  
 
#pragma markUIViewController delegate methods  
  
   
  
   
  
-(void)viewWillDisappear:(BOOL)animated  
  
{         
  
         [self.imageView stopAnimating];  
  
   
  
         self.navigationController.navigationBar.barStyle =UIBarStyleDefault;  
  
         [UIApplication sharedApplication].statusBarStyle =UIStatusBarStyleDefault;  
  
}  
  
   
  
-(void)viewWillAppear:(BOOL)animated  
  
{         
  
         [self.imageView startAnimating];  
  
         self.navigationController.navigationBar.barStyle =UIBarStyleBlackOpaque;  
  
          
  
         [UIApplication sharedApplication].statusBarStyle =UIStatusBarStyleBlackOpaque;  
  
}  
  
   
  
@end  

首先通过加载多张图片进入imageView的animationImages里面。再设置动画的时间间隔animationDuration，并设置UISider控制幻灯片播放的速度，让图片像幻灯片那么播放。

 

2.UIWebView的讲解

(1)初始化

在.h文件中声明UIWebView。

@interface WebViewController :UIViewController {  
  
IBOutlet UIWebView *webView;  
}  
  
@property (nonatomic,retain) UIWebView *webView;  
  
@end  

在.m文件中初始化UIWebView并载入要读取的URL，如下：

- (void)viewDidLoad {  
  
NSString *urlAddress =@”http://www.google.com”;  
  
//Create a URL object.  
NSURL *url = [NSURL URLWithString:urlAddress];  
  
//URL Requst Object  
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];  
  
//Load the request in theUIWebView.  
[webView loadRequest:requestObj];  
}  

并在你的delegate里面载入跟IB一起的XIB文件，如下：

-(void)applicationDidFinishLaunching:(UIApplication *)application {  
  
self.wvTutorial =[[WebViewController alloc] initWithNibName:@”WebView” bundle:[NSBundlemainBundle]];  
  
[windowaddSubview:[wvTutorial view]];  
  
// Override point forcustomization after app launch  
[window makeKeyAndVisible];  
}  

今天就讲UIImageView和UIWebView的利用，这两个都是比较有用的，在以后的开发中布局会经常用到，最后，谢谢大家支持。欢迎大家拍砖。