android - 如何从右到左缩放按钮，android动画

Question

要将从左到右的比例应用于按钮，我使用了以下代码。我的按钮在布局的右侧。我希望按钮应该从它的右侧 X 位置开始并缩放到左侧 X 位置如何实现这一点？

view.startAnimation(new ScaleAnimation(0.0f, 1.0f, 1.0f, 1.0f));

Answer 1

需要设置起点在右中，还需要这样设置动画的时长:

ScaleAnimation anim = new ScaleAnimation(0.0f, 1.0f, 1.0f, 1.0f, Animation.RELATIVE_TO_SELF,1.0f, Animation.RELATIVE_TO_SELF, 0.5f);
anim.setDuration(700);
view.startAnimation(anim);

在您的情况下，Y 起始位置并不重要。

如果你不明白这个构造函数:

public ScaleAnimation (float fromX, float toX, float fromY, float toY, int pivotXType, float pivotXValue, int pivotYType, float pivotYValue)

Since: API Level 1

Constructor to use when building a ScaleAnimation from code

Parameters:

fromX: Horizontal scaling factor to apply at the start of the animation

toX: Horizontal scaling factor to apply at the end of the animation

fromY: Vertical scaling factor to apply at the start of the animation

toY: Vertical scaling factor to apply at the end of the animation

pivotXType: Specifies how pivotXValue should be interpreted. One of Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or Animation.RELATIVE_TO_PARENT.

pivotXValue: The X coordinate of the point about which the object is being scaled, specified as an absolute number where 0 is the left edge. (This point remains fixed while the object changes size.) This value can either be an absolute number if pivotXType is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise.

pivotYType: Specifies how pivotYValue should be interpreted. One of Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or Animation.RELATIVE_TO_PARENT.

pivotYValue: The Y coordinate of the point about which the object is being scaled, specified as an absolute number where 0 is the top edge. (This point remains fixed while the object changes size.) This value can either be an absolute number if pivotYType is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise.