animateWithDuration不能褪色

Question

我想预先形成一个淡出，然后淡入我的标签，我可以让两者分开工作，但不能在一起。

    [UILabel animateWithDuration:1.0 animations:^{
        _swixValla.alpha = 0.0;
        _skigoValla.alpha = 0.0;
        _rodeValla.alpha = 0.0;
        _startValla.alpha = 0.0;
    }];


    [UILabel animateWithDuration:1.0 animations:^{
        _swixValla.alpha = 1.0;
        _skigoValla.alpha = 1.0;
        _rodeValla.alpha = 1.0;
        _startValla.alpha = 1.0;
    }];

这不管用

    [UILabel animateWithDuration:1.0 animations:^{
        _swixValla.alpha = 0.0;
        _skigoValla.alpha = 0.0;
        _rodeValla.alpha = 0.0;
        _startValla.alpha = 0.0;


    [UILabel animateWithDuration:1.0 animations:^{
        _swixValla.alpha = 1.0;
        _skigoValla.alpha = 1.0;
        _rodeValla.alpha = 1.0;
        _startValla.alpha = 1.0;
    }];
    }];

这也不起作用。

我怎么才能解决这个问题？

Answer 1

如果您想将它们组合起来，在完成第一项操作后启动第二项操作，请使用：

[UIView animateWithDuration:1.0 animations:^{
    _swixValla.alpha = 0.0;
    _skigoValla.alpha = 0.0;
    _rodeValla.alpha = 0.0;
    _startValla.alpha = 0.0;
}completion:^(BOOL finished){
    [UILabel animateWithDuration:1.0 animations:^{
        _swixValla.alpha = 1.0;
        _skigoValla.alpha = 1.0;
        _rodeValla.alpha = 1.0;
        _startValla.alpha = 1.0;
    }];
}];