安卓 View设置VISIBLE、GONE时,添加执行动画
我们在开发中经常要实现view的可见性的设置,但是如果view面积较大时可见性如果变化,在视觉效果上会比较生硬,因此我们需要加上动画,在可见不可见之间增加一个过渡
直接上代码:
1、VISIBLE动画
TranslateAnimation showAnim = new TranslateAnimation(Animation.RELATIVE_TO_SELF, 1.0f,
Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 0.0f);
showAnim.setDuration(500);
view.startAnimation(showAnim);
view.setVisibility(View.VISIBLE);
2、GONE动画TranslateAnimation hideAnim = new TranslateAnimation(Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 1.0f,
Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 0.0f);
hideAnim.setDuration(500);
view.startAnimation(hideAnim);
view.setVisibility(View.GONE);
这里,最重要的是TranslateAnimation,进入这个构造函数:
/** * Constructor to use when building a TranslateAnimation from code * * @param fromXType Specifies how fromXValue should be interpreted. One of * Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or * Animation.RELATIVE_TO_PARENT. * @param fromXValue Change in X coordinate to apply at the start of the * animation. This value can either be an absolute number if fromXType * is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise. * @param toXType Specifies how toXValue should be interpreted. One of * Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or * Animation.RELATIVE_TO_PARENT. * @param toXValue Change in X coordinate to apply at the end of the * animation. This value can either be an absolute number if toXType * is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise. * @param fromYType Specifies how fromYValue should be interpreted. One of * Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or * Animation.RELATIVE_TO_PARENT. * @param fromYValue Change in Y coordinate to apply at the start of the * animation. This value can either be an absolute number if fromYType * is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise. * @param toYType Specifies how toYValue should be interpreted. One of * Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or * Animation.RELATIVE_TO_PARENT. * @param toYValue Change in Y coordinate to apply at the end of the * animation. This value can either be an absolute number if toYType * is ABSOLUTE, or a percentage (where 1.0 is 100%) otherwise. */ public TranslateAnimation(int fromXType, float fromXValue, int toXType, float toXValue, int fromYType, float fromYValue, int toYType, float toYValue) { mFromXValue = fromXValue; mToXValue = toXValue; mFromYValue = fromYValue; mToYValue = toYValue; mFromXType = fromXType; mToXType = toXType; mFromYType = fromYType; mToYType = toYType; }
可以看到,这个构造函数主要是传入设置起始点坐标(x,y)、终点坐标(x,y),每个坐标值对应一个类型type。
Animation.RELATIVE_TO_SELF代表着坐标以当前view为基准。
0.0f即0%,代表view初始位置坐标;
1.0f即100%,代表以view初始位置为原点,相应x坐标/y坐标增加父宽度/父高度的100%;
TranslateAnimation showAnim = new TranslateAnimation(Animation.RELATIVE_TO_SELF, 1.0f,
Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 0.0f);
表示从(1.0f,0.0f)移动到(0.0f,0.0f),即view从屏幕右侧不可见区域移动到初始位置,符合VISIBLE效果。new TranslateAnimation(Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 1.0f,
Animation.RELATIVE_TO_SELF, 0.0f,
Animation.RELATIVE_TO_SELF, 0.0f);
表示从(0.0f,0.0f)移动到(1.0f,0.0f),即view从初始位置移动到屏幕右侧不可见区域,符合GONE效果。