//添加慢動(dòng)畫
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.2];
Loading *loading = [[Loading alloc]initWithFrame:[UIScreen mainScreen].bounds];
[self.view insertSubview:loading aboveSubview:self.view];
//提交動(dòng)畫
[UIView commitAnimations];
