UIView動畫簡介

開發過程當為了讓應用更絢,就加入一些動畫效果。CoreAnimation比較複雜，其實UIView的簡單動畫就可以滿足我們應用開發。UIView支援的動畫屬性有，frame, center, bounds,transform, alpha.  什麼意思呢，就是你可以修改這些屬性來完成動畫，比如設定frame，uiview就可以動了。下面看一段代碼：

    // begin the animations block:    [UIView beginAnimations:@"animationID" context:NULL];    // define how long the animation should take, in seconds. 0.5 is half a second.    [UIView setAnimationDuration:3];    // animate the view itself by changing its frame:    [theView setFrame:newFrame];    // or by changing its alpha value:    [theView setAlpha:0.5];    // or by rotating it:    theView.transform = CGAffineTransformMakeRotation(-0.7853981625); // 45 deg    // optional: to execute code after the animation has finished, set the delegate:        [UIView setAnimationDelegate:self];        // optional: set the animation curve:    //   UIViewAnimationCurveEaseIn: begins slowly, then speeds up    //   UIViewAnimationCurveEaseOut: begins fast, then slows down    //   UIViewAnimationCurveEaseInOut: begins slowly, faster in the middle, slows down at end    //   UIViewAnimationCurveLinear: same speed throughout    [UIView setAnimationCurve: UIViewAnimationCurveEaseOut];    // start animating!    [UIView commitAnimations];

這樣就完成了一個動畫效果， beginAnimatins:與commitAnimations這是必須寫的，中間設定你的屬性，這兒設定了三個屬性，分別是frame,alpha,transform. 這樣就完成了一個動畫，那個"animationID"隨便取名字。動畫的時間有多長呢， 有一個預設時間，在這兒我們設定的是3秒， 動畫有一個快慢，比如快進，setAnimationCurve就是控制什麼時候快進，什麼時候慢播。當這個動畫完了的時候，會有一個delegate方法調用：

- (void)animationDidStop:(NSString *)animID finished:(BOOL)didFinish context:(void *)context {    if ( [animID isEqualToString:@"animationID"] ) {        NSLog(@"move10 animation finished.");        [self moveBack];    }    else if ( [animID isEqualToString:@"moveBack"] ) {        NSLog(@"done moving.");    }}

在這兒你可以檢測到哪一個動畫完了，比如在這兒我們檢測到了animationID與moveBack.

是不是很簡單呀？

在iOS4以上，支援block了，所以用它使編程將更簡單，如傳統的動畫是這樣：

[UIView beginAnimations:nil context:nil];[UIView setAnimationDuration:0.5];[UIView setAnimationTransition:UIViewAnimationTransitionCurlDown                                       forView:containerView cache:YES]; [containerView addSubview:subview]; [UIView commitAnimations];

如果用block的方式將是：

[UIView transitionWithView:containerView duration:0.5options:UIViewAnimationOptionTransitionCurlDownanimations:^ { [containerView addSubview:subview]; }completion:nil];

具體參看文檔：http://developer.apple.com/library/ios/#documentation/uikit/reference/UIView_Class/UIView/UIView.html