今天在看FragmentManager源码的时候看见了一段关于优化动画性能的代码,通过真机实测,发现确实达到了不错的性能优化效果,分享给你们java
前提: 手机为真机, 魅族MX5E, 系统 5.0( api 26的模拟器下看GPU 条形图不知道为何优化代码反而不如不优化的,多是没有硬件加速致使的吧)android
优化前效果以下 canvas
优化后效果以下 api
通过对比发现,确实性能优化很多性能优化
我这边给出我扣出来的代码(kotlin版本)bash
class AnimateOnHWLayerIfNeededListener(private var mView: View?) : Animator.AnimatorListener {
private var mShouldRunOnHWLayer = false
override fun onAnimationStart(animation: Animator) {
mShouldRunOnHWLayer = shouldRunOnHWLayer(mView, animation)
if (mShouldRunOnHWLayer) {
mView!!.setLayerType(View.LAYER_TYPE_HARDWARE, null)
}
}
override fun onAnimationEnd(animation: Animator) {
if (mShouldRunOnHWLayer) {
mView!!.setLayerType(View.LAYER_TYPE_NONE, null)
}
mView = null
animation.removeListener(this)
}
override fun onAnimationCancel(animation: Animator) {
}
override fun onAnimationRepeat(animation: Animator) {
}
fun shouldRunOnHWLayer(v: View?, anim: Animator?): Boolean {
return if (v == null || anim == null) {
false
} else v.layerType == View.LAYER_TYPE_NONE
&& v.hasOverlappingRendering()
&& modifiesAlpha(anim)
}
private fun modifiesAlpha(anim: Animator?): Boolean {
if (anim == null) {
return false
}
if (anim is ValueAnimator) {
val valueAnim = anim as ValueAnimator?
val values = valueAnim!!.values
for (i in values.indices) {
if ("alpha" == values[i].propertyName) {
return true
}
}
} else if (anim is AnimatorSet) {
val animList = anim.childAnimations
for (i in animList.indices) {
if (modifiesAlpha(animList[i])) {
return true
}
}
}
return false
}
}
复制代码
java 版本以下app
static class AnimateOnHWLayerIfNeededListener implements Animator.AnimatorListener {
private boolean mShouldRunOnHWLayer = false;
private View mView;
public AnimateOnHWLayerIfNeededListener(final View v) {
if (v == null) {
return;
}
mView = v;
}
@Override
public void onAnimationStart(Animator animation) {
mShouldRunOnHWLayer = shouldRunOnHWLayer(mView, animation);
if (mShouldRunOnHWLayer) {
mView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
}
}
@Override
public void onAnimationEnd(Animator animation) {
if (mShouldRunOnHWLayer) {
mView.setLayerType(View.LAYER_TYPE_NONE, null);
}
mView = null;
animation.removeListener(this);
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
static boolean shouldRunOnHWLayer(View v, Animator anim) {
if (v == null || anim == null) {
return false;
}
return v.getLayerType() == View.LAYER_TYPE_NONE
&& v.hasOverlappingRendering()
&& modifiesAlpha(anim);
}
static boolean modifiesAlpha(Animator anim) {
if (anim == null) {
return false;
}
if (anim instanceof ValueAnimator) {
ValueAnimator valueAnim = (ValueAnimator) anim;
PropertyValuesHolder[] values = valueAnim.getValues();
for (int i = 0; i < values.length; i++) {
if (("alpha").equals(values[i].getPropertyName())) {
return true;
}
}
} else if (anim instanceof AnimatorSet) {
List<Animator> animList = ((AnimatorSet) anim).getChildAnimations();
for (int i = 0; i < animList.size(); i++) {
if (modifiesAlpha(animList.get(i))) {
return true;
}
}
}
return false;
}
}
复制代码
测试代码 xml以下 ,布局很简单5个宽高全屏幕的View,而后作alpha动画 ide
重点就是alphaAnimation.addListener(AnimateOnHWLayerIfNeededListener(v))
这句代码,就是用了FragmentManager源码中扣出来的动画优化代码。布局
上述代码解决了alpha动画的优化,那么若是是scale,x,y移动动画呢,同理啦,就是把判断alpha的代码去掉就好了,核心其实就是动画开始前启用离屏缓冲,也就是mView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
,而后动画结束的时候,关闭离屏缓冲,也就是mView.setLayerType(View.LAYER_TYPE_NONE, null);
,不少朋友搞不清楚,硬件加速和View.LAYER_TYPE_HARDWARE的关系,我这里说一下,android 4.0之后全部页面默认所有开启硬件加速,View树无特殊状况,LayerType是View.LAYER_TYPE_NONE
,LAYER_TYPE_HARDWARE这个叫作硬件层面的离屏缓冲(学过java swing的同窗应该知道一个叫双缓冲的东西,LAYER_TYPE_HARDWARE就是使用了硬件作双缓冲),LAYER_TYPE_HARDWARE和硬件加速关系是当硬件加速开启的时候才能使用硬件离屏缓冲(硬件双缓冲)LAYER_TYPE_HARDWARE,而若是你指定View的LayerType为LAYER_TYPE_SOFTWARE 这个叫作软离屏缓冲(用内存作双缓冲),使用了LAYER_TYPE_SOFTWARE等于主动放弃了硬件加速,那为何要主动放弃可以提升渲染性能的硬件加速呢?由于有一些canvas的操做不支持硬件加速,这些不支持的点你能够去android开发者文档官网找到。性能
在说一下,上述思路解决了属性(alpha,scale,x,y)动画优化,若是要使用动画改变控件的宽高的时候如何优化呢?很明显会卡死,原理就是会致使在极端的时间了全局的requestLayout 从新measure layout draw整个视图树,优化方法能够看到我以前的基于recyclerView add子view思想动态改变控件宽高 优化的文章,连接为www.imooc.com/article/219…
好了,分享到此结束。喜欢就点个推荐吧。欢迎加我QQ 819151780和我讨论android技术。