android - 无论如何以编程方式动画线性布局的布局权重属性

Question

我在线性布局中有两个 View ，我以编程方式更改了它们的 layout_weight 属性。有没有一种方法可以为这种重量变化设置动画，所以当重量改变时， View 会滑向新的尺寸？

Answer 1

您可以简单地使用 ObjectAnimator。

ObjectAnimator anim = ObjectAnimator.ofFloat(
                viewToAnimate,
                "weight",
                startValue,
                endValue);
        anim.setDuration(2500);
        anim.start();

一个问题是 View 类没有 setWeight() 方法(ObjectAnimator 需要它)。为了解决这个问题，我编写了简单的包装器来帮助归档 View 权重动画。

public class ViewWeightAnimationWrapper {
    private View view;

    public ViewWeightAnimationWrapper(View view) {
        if (view.getLayoutParams() instanceof LinearLayout.LayoutParams) {
            this.view = view;
        } else {
            throw new IllegalArgumentException("The view should have LinearLayout as parent");
        }
    }

    public void setWeight(float weight) {
        LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) view.getLayoutParams();
        params.weight = weight;
        view.getParent().requestLayout();
    }

    public float getWeight() {
        return ((LinearLayout.LayoutParams) view.getLayoutParams()).weight;
    }
}

这样使用:

    ViewWeightAnimationWrapper animationWrapper = new ViewWeightAnimationWrapper(view);
    ObjectAnimator anim = ObjectAnimator.ofFloat(animationWrapper,
                    "weight",
                    animationWrapper.getWeight(),
                    weight);
            anim.setDuration(2500);
            anim.start();