Android自定义textview实现竖直滚动跑马灯效果

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/activity_main"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context="myandroidstituds.test3.MainActivity">

 <LinearLayout
  android:layout_centerInParent="true"
  android:layout_width="180dp"
  android:layout_height="50dp">
 <TextView
  android:padding="10dp"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="#55000000"
  />
 </LinearLayout>
 <myandroidstituds.test3.MarqueeLayout
  android:id="@+id/mar"
  android:layout_centerInParent="true"
  android:layout_width="180dp"
  android:layout_height="50dp">
  <TextView
   android:id="@+id/tv1"
   android:textSize="20sp"
   android:gravity="center"
   android:background="@android:color/transparent"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:textColor="#000000"
   android:visibility="gone"
   android:text="两个黄鹂鸣翠柳"
   />
  <TextView
   android:id="@+id/tv2"
   android:textSize="20sp"
   android:background="@android:color/transparent"
   android:gravity="center"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:textColor="#000000"
   android:visibility="gone"
   android:text="一行白鹭上青天"
   />
 </myandroidstituds.test3.MarqueeLayout>
</RelativeLayout>

public class MarqueeLayout extends FrameLayout implements ViewTreeObserver.OnGlobalLayoutListener{
 private View view1;
 private View view2;
 public int interval = 2000;
 public MarqueeLayout(Context context) {
  this(context,null);
 }
 public MarqueeLayout(Context context, AttributeSet attrs) {
  this(context, attrs,0);
 }
 public MarqueeLayout(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  getViewTreeObserver().addOnGlobalLayoutListener(this);
 }
 @Override
 protected void onFinishInflate() {
  super.onFinishInflate();
  if(getChildCount()!=2){
   throw new IllegalArgumentException("MarqueeLayout should have 2 child!");
  }
  view1 = getChildAt(0);
  view2 = getChildAt(1);
 }
 @Override
 public void onGlobalLayout() {
  getViewTreeObserver().removeGlobalOnLayoutListener(this);

  view2.setTranslationY(view2.getHeight());
 }

 private Handler handler = new Handler(){
  @Override
  public void handleMessage(Message msg) {
   super.handleMessage(msg);
   startAnim();
  }
 };
 boolean isAniming = false;
 /**
  * 开始滚动
  */
 public void start(){
  getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
   @Override
   public void onGlobalLayout() {
    getViewTreeObserver().removeGlobalOnLayoutListener(this);
    startAnim();
   }
  });
 }
 public void startAnim(){
  if(isAniming)return;

  isAniming = true;
  int targetY1 = view1.getTranslationY()==0?-view1.getHeight():0;
  int targetY2 = view2.getTranslationY()==0?-view2.getHeight():0;

  ViewCompat.animate(view1)
    .translationY(targetY1)
    .setListener(new ViewPropertyAnimatorListenerAdapter(){
     @Override
     public void onAnimationEnd(View view) {
      super.onAnimationEnd(view);
      //移动到下方
      resetView(view);
     }
    })
    .setDuration(400).start();
  ViewCompat.animate(view2)
    .translationY(targetY2)
    .setListener(new ViewPropertyAnimatorListenerAdapter(){
     @Override
     public void onAnimationEnd(View view) {
      super.onAnimationEnd(view);
      //移动到下方
      resetView(view);
      isAniming = false;
      handler.sendEmptyMessageDelayed(0,interval);
     }
    })
    .setDuration(400)
    .start();
 }
 private void resetView(View view) {
  if(view.getTranslationY()==-view.getHeight()){
   view.setTranslationY(view.getHeight()*2);
  }
 }
 public void stop(){
  handler.removeCallbacksAndMessages(null);
 }
}

public class MainActivity extends AppCompatActivity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  MarqueeLayout marqueeLayout = (MarqueeLayout) findViewById(R.id.mar);
  TextView tv1 = (TextView) findViewById(R.id.tv1);
  TextView tv2 = (TextView) findViewById(R.id.tv2);
  marqueeLayout.start();
  tv1.setVisibility(tv1.getTranslationY() == 0 ? View.VISIBLE : View.GONE);
  tv2.setVisibility(tv2.getTranslationY() == 0 ? View.VISIBLE : View.GONE);

 }
}