android揭露动画

1. 在MainActivity中修改

   public class MainActivity extends Activity {     
    private static final int MODE_IN = 0x1;
       private static final int MODE_OUT = 0x2;
       private LinearLayout mCircularRevealView;//用于展示圆形揭示层的布局
       @Override
       protected void onCreate(final Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
           initView();
           Button button = findViewById(R.id.button);
           //点击按钮开启动画
           button.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View v) {
                   createCircularRevealAnim(MODE_IN);
               }
           });
   
       }
       /**
        * 创建圆形揭示层动画
        */
       private void createCircularRevealAnim(int mode) {
           //设置圆心坐标和半径
           int mCx = (mCircularRevealView.getLeft() + mCircularRevealView.getRight()) / 2;//获取x坐标
           int mCy = (mCircularRevealView.getTop() + mCircularRevealView.getBottom()) / 2;//获取y坐标
           //设置圆角半径
           int mRadius = Math.max(mCircularRevealView.getWidth() / 2, mCircularRevealView.getHeight() / 2);
           Animator anim;//声明一个动画
           if (mode == MODE_IN) {
               //揭露动画创建，五个参数
               //param1:执行动画的视图；param2:动画开始的x坐标；param3:动画开始的y坐标；param4:动画开始的圆角半径；param5：动画结束的圆角半径
               anim = ViewAnimationUtils.createCircularReveal(mCircularRevealView, mCx, mCy, 0, mRadius);
           } else {
               anim = ViewAnimationUtils.createCircularReveal(mCircularRevealView, mCx, mCy, mRadius, 0);
           }
           //添加监听器来保证开始动画之前，布局不会显示，也可以添加动画退出监听，让布局隐藏
           anim.addListener(new AnimatorListenerAdapter() {
               @Override
               public void onAnimationStart(Animator animation) {
                   super.onAnimationStart(animation);
                   Log.d(TAG , "动画开始");
                   mCircularRevealView.setVisibility(View.VISIBLE);
               }
           });
           anim.setDuration(500);//设置动画时长
           anim.start();//开启动画
   
       }
    //初始化视图实例
       private void initView() {
           mCircularRevealView = findViewById(R.id.circular_reveal_view);
       }
   }
   

2. 修改布局文件activity_main.xml

   <?xml version="1.0" encoding="utf-8"?>
   <LinearLayout
       xmlns:android="http://schemas.android.com/apk/res/android"
       android:orientation="vertical"
       android:layout_width="match_parent"
       android:layout_height="match_parent">
       
    <!--揭露布局-->
       <LinearLayout
           android:id="@+id/circular_reveal_view"
           android:layout_width="match_parent"
           android:layout_height="100dp"
           android:background="#333"
           android:visibility="invisible"
           android:orientation="vertical">
       </LinearLayout>
       
       <!--触发按钮-->
       <Button
           android:id="@+id/button"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:text="button"
           />
   </LinearLayout>
   

总结：

主要方法：

创建揭露动画：

ViewAnimationUtils.createCircularReveal(
     View view, int centerX,  int centerY, float startRadius, float endRadius
);

监听动画：

Animator anim;

 anim.addListener(new AnimatorListenerAdapter() {
            //动画开始时调用
            @Override
            public void onAnimationStart(Animator animation) {
                super.onAnimationStart(animation);
            }
            
            //动画结束时调用
            @Override
            public void onAnimationEnd(Animator animation) {
                super.onAnimationEnd(animation);
            }
        });

主要方法就一个

private void createCircularRevealAnim(int mode) {
        //设置圆心坐标和半径
        int mCx = (mCircularRevealView.getLeft() + mCircularRevealView.getRight()) / 2;
        int mCy = (mCircularRevealView.getTop() + mCircularRevealView.getBottom()) / 2;
        int mRadius = Math.max(mCircularRevealView.getWidth() / 2, mCircularRevealView.getHeight() / 2);
        
        Animator anim;
        if (mode == MODE_IN) {
            anim = ViewAnimationUtils.createCircularReveal(mCircularRevealView, mCx, mCy, 0, mRadius);
        } else {
            anim = ViewAnimationUtils.createCircularReveal(mCircularRevealView, mCx, mCy, mRadius, 0);
        }
        
        anim.addListener(new AnimatorListenerAdapter() {
            //动画开始时调用
            @Override
            public void onAnimationStart(Animator animation) {
                super.onAnimationStart(animation);
                mCircularRevealView.setVisibility(View.VISIBLE);
            }

            //动画结束时调用
            @Override
            public void onAnimationEnd(Animator animation) {
                super.onAnimationEnd(animation);
            }
        });
        
        anim.setDuration(500);
        anim.start();
}