【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：

-》1

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

-》2

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 ObjectNSURLRequest *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。