放大渐变消失动画，APP启动界面常用
[UIView animateWithDuration:1.5 animations:^{
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
self.window.transform=CGAffineTransformMakeScale(2.f, 2.f);
self.window.alpha = 0;
} completion:^(BOOL finished) {
[self remove];
}];
