新浪微博樣式的ActionSheet

實現此功能的關鍵是在view里面生成一個UIWindow（該window會自動被加入到已有的window上面），然后設置windowlevel和hidden屬性就可以顯示或者隱藏。

//懶加載window，新建window之后會被自動添加到已有window上，只要設置windowLevel和hidden屬性即可顯示
-(UIWindow *)actionWindow{

    if (!_actionWindow) {
        _actionWindow = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];
        _actionWindow.windowLevel = UIWindowLevelAlert;
        _actionWindow.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:.3];
    }
    return _actionWindow;
}

//顯示
-(void)show{
    //設置self初始位置
    self.frame = CGRectMake(0, ZDHEIGHT, ZDWIDTH, ZDHEIGHT);

    //添加本身到新建window
    [self.actionWindow addSubview:self];

    self.actionWindow.hidden = NO;
    [UIView animateWithDuration:ZDANIMATIONTIME animations:^{
        self.frame = CGRectMake(0, 0, ZDWIDTH, ZDHEIGHT);
    }];
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    [self dismissFromeSuperView];

}

//移除
-(void)dismissFromeSuperView {

    [UIView animateWithDuration:ZDANIMATIONTIME animations:^{
        self.frame = CGRectMake(0, ZDHEIGHT, ZDWIDTH, ZDHEIGHT);

    } completion:^(BOOL finished) {

        [self removeFromSuperview];
        self.actionWindow.hidden = YES;
        self.actionWindow = nil;

    }];
}

項目地址： https://github.com/newbbydong/SinaWeiboActionSheet