Android开发之Activity全透明渐变切换方法

 <style name="AppTheme2" parent="Theme.AppCompat.Light">  <!-- Customize your theme here. -->  <item name="windowNoTitle">true</item>  <item name="colorPrimary">@color/colorPrimary</item>  <item name="colorPrimaryDark">@color/tabbackground</item>  <item name="colorAccent">@color/colorAccent</item> 　　<item name="android:windowBackground">@color/transparent</item>//这个之时全透明  <item name="android:windowIsTranslucent">true</item>  <item name="android:windowAnimationStyle">@style/activityanimation</item> </style> <style name="activityanimation" >  <item name="android:activityOpenEnterAnimation">@null</item>  <item name="android:activityOpenExitAnimation">@null</item>  <item name="android:activityCloseEnterAnimation">@null</item>  <item name="android:activityCloseExitAnimation">@null</item> </style>

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/ll" android:orientation="vertical" android:layout_width="match_parent" android:background="#000" android:layout_height="match_parent"> <MyImageView  android:layout_width="match_parent"  android:layout_height="300dp"  android:layout_centerInParent="true"  android:clickable="true"  android:background="@mipmap/meinv"/></RelativeLayout>

public class Activitytwo extends AppCompatActivity{ private int tran=0x00000000; private int end=0x88000000; private RelativeLayout ll; @Override protected void onCreate(@Nullable Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);  setContentView(R.layout.ativity);  ll = (RelativeLayout) findViewById(R.id.ll);  returnposition();  ll.setOnClickListener(new View.OnClickListener() {   @Override   public void onClick(View v) {    finish();   }  }); } public void returnposition() {  ValueAnimator colorAnim = ObjectAnimator.ofInt(ll, "backgroundColor", tran, end);  colorAnim.setDuration(300);  colorAnim.setEvaluator(new ArgbEvaluator());  colorAnim.start(); } @Override public void finish() {  ValueAnimator colorAnim = ObjectAnimator.ofInt(ll, "backgroundColor", end, tran);  colorAnim.setDuration(300);  colorAnim.setEvaluator(new ArgbEvaluator());  colorAnim.start();  super.finish(); }}