iPhone开发动画效果之最简单的动画——动态加载图片 .

从本篇开始不再详细介绍每一步操作，而只介绍一些关键操作及展示核心代码和代码解释。


实现的功能：1）演示一个简单的动画效果，动态加载图片。2）点击屏幕时重新加载动画。

关键词：Animation 动画 动态加载图片


1、新建视图控制器ImageViewController（不带xib），作为根视图控制器，ImageViewController.h如下：

#import <UIKit/UIKit.h>

@interface ImageViewController : UIViewController

@property(strong,nonatomic)UIImageView *imageView;
@property(strong,nonatomic)UIImage *desktop;
-(void)loadImage;
@end

ImageViewController.m如下：

#import "ImageViewController.h"
@implementation ImageViewController
@synthesize imageView;
@synthesize desktop;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)loadView
{
    // If you create your views manually, you MUST override this method and use it to create your views.
    // If you use Interface Builder to create your views, then you must NOT override this method.
    NSLog(@"loadView");
    UIView *view = [[ UIView alloc] initWithFrame:[ UIScreen
                                                   mainScreen].applicationFrame] ;
    UIColor *bgColor = [UIColor colorWithRed:1 green:1 blue:1 alpha:1.0];
    [view setBackgroundColor:(bgColor)];
    self.view = view;
    desktop = [UIImage imageNamed:@"desktop.png"];
    
    [self performSelector:@selector(loadImage) withObject:nil afterDelay:0.1];
}

-(void)loadImage{
    if(imageView!=nil){
        [imageView removeFromSuperview];
    }
    //初始时，将imageView的宽度设置为0，这样就隐藏起来了
    imageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 0, desktop.size.height)];
    [imageView setImage:desktop];
    
    [self.view addSubview:imageView];
    //设置动画效果
    CGContextRef context = UIGraphicsGetCurrentContext();
    //开始播放动画
    [UIView beginAnimations:nil context:context];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    //[UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
    //[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
    //[UIView setAnimationCurve:UIViewAnimationCurveLinear];
    [UIView setAnimationDuration:1.5];
    //imageView最终的宽度为desktop.size.width
    [imageView setFrame:CGRectMake(0, 0, desktop.size.width, desktop.size.height)];   
    [UIView commitAnimations];
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    [self loadImage];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    imageView = nil;
    desktop = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

@end

2、运行效果是图片从左至右慢慢显示出来，如下，
[img]

[/img]