iphone用Animation實現動畫效果

1、寫了一個小Demo，實現上下移動的：         主要代碼如下：[cpp]- (IBAction)upChange:(id)sender {      if (typeView == down) {          [self.downBtn setHidden:NO];          [self.upBtn setHidden:NO];          [UIView animateWithDuration:0.5 animations:^{              self.upView.center = CGPointMake(self.upView.center.x, 0);               self.downView.center = CGPointMake(self.downView.center.x, (self.upView.frame.size.height+self.downView.frame.size.height)/2);          }];                    typeView = middle;      }else if(typeView == middle){          [self.downBtn setHidden:NO];          [self.upBtn setHidden:YES];          [UIView animateWithDuration:0.5 animations:^{              self.upView.center = CGPointMake(self.upView.center.x, -(self.upView.frame.size.height/2));              self.downView.center = CGPointMake(self.downView.center.x, self.downView.frame.size.height/2);          }];                    typeView = up;      }    }    - (IBAction)downChange:(id)sender {      if (typeView == middle) {          [self.downBtn setHidden:YES];          [self.upBtn setHidden:NO];          [UIView animateWithDuration:0.5 animations:^{              self.upView.center = CGPointMake(self.upView.center.x, self.upView.frame.size.height/2);               self.downView.center = CGPointMake(self.downView.center.x, self.upView.frame.size.height+self.downView.frame.size.height/2);          }];            typeView = down;      }else if(typeView == up)      {          [self.downBtn setHidden:NO];          [self.upBtn setHidden:NO];          [UIView animateWithDuration:0.5 animations:^{              self.upView.center = CGPointMake(self.upView.center.x, 0);              self.downView.center = CGPointMake(self.downView.center.x, (self.upView.frame.size.height+self.downView.frame.size.height)/2);          }];                    typeView = middle;      }    }   - (IBAction)upChange:(id)sender {    if (typeView == down) {        [self.downBtn setHidden:NO];        [self.upBtn setHidden:NO];        [UIView animateWithDuration:0.5 animations:^{            self.upView.center = CGPointMake(self.upView.center.x, 0);             self.downView.center = CGPointMake(self.downView.center.x, (self.upView.frame.size.height+self.downView.frame.size.height)/2);        }];                typeView = middle;    }else if(typeView == middle){        [self.downBtn setHidden:NO];        [self.upBtn setHidden:YES];        [UIView animateWithDuration:0.5 animations:^{            self.upView.center = CGPointMake(self.upView.center.x, -(self.upView.frame.size.height/2));            self.downView.center = CGPointMake(self.downView.center.x, self.downView.frame.size.height/2);        }];                typeView = up;    } } - (IBAction)downChange:(id)sender {    if (typeView == middle) {        [self.downBtn setHidden:YES];        [self.upBtn setHidden:NO];        [UIView animateWithDuration:0.5 animations:^{            self.upView.center = CGPointMake(self.upView.center.x, self.upView.frame.size.height/2);             self.downView.center = CGPointMake(self.downView.center.x, self.upView.frame.size.height+self.downView.frame.size.height/2);        }];         typeView = down;    }else if(typeView == up)    {        [self.downBtn setHidden:NO];        [self.upBtn setHidden:NO];        [UIView animateWithDuration:0.5 animations:^{            self.upView.center = CGPointMake(self.upView.center.x, 0);            self.downView.center = CGPointMake(self.downView.center.x, (self.upView.frame.size.height+self.downView.frame.size.height)/2);        }];                typeView = middle;    } }   這是主要的代碼，另外還有一些需要注意的一些小細，如你的兩個view的大小，需要計算出精確位置。  下面開始學習[UIView animateWithDuration]方法的使用：函數原型：+ (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_4_0); // delay = 0.0, options = 0, completion = NULL duration：動畫期間animations：該代碼兒塊中是所有view要完成的動畫的所有屬性的定義；還有另外兩個函數：+ (void)animateWithDuration:(NSTimeInterval)duration delay:(NSTimeInterval)delay options:(UIViewAnimationOptions)options animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_4_0);   + (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion__OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_4_0);// delay = 0.0, options = 0   options:是動畫執行的選項completion：是動畫完成以後所要執行的代碼塊兒。