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);

  }
}