1、寫瞭一個小Demo，實現上下移動的效果圖：
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，另外還有一些需要註意的一些小細，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：動畫持續時間
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。