使用多个翻译和持续时间偏移重复 Android 动画

Question

我想要一个可以无限上下移动图像的动画。但是，当我运行代码时，动画仅发生一次。这是动画 xml：

<?xml version="1.0" encoding="utf-8"?>
<set
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/linear_interpolator"
    android:repeatCount="3"
    android:repeatMode="restart">
   <!-- move down -->
   <translate
       android:fromYDelta="0%"
       android:toYDelta="50%"
       android:duration="1500"
       android:fillAfter="true"/>

   <!-- move up -->
   <translate
       android:fromYDelta="0%"
       android:startOffset="1500"
       android:toYDelta="-50%"
       android:duration="1500"
       android:fillAfter="true"/>

   <!-- continue to move up -->
   <translate
       android:fromYDelta="0%"
       android:startOffset="3000"
       android:toYDelta="-20%"
       android:duration="600"
       android:fillAfter="true"/>

   <!-- down to original pos -->
   <translate
       android:fromYDelta="0%"
       android:startOffset="3600"
       android:toYDelta="20%"
       android:duration="600"
       android:fillAfter="true"/>

</set>

这是我的java代码：

public class MainActivity extends AppCompatActivity {

    Animation move1, move2, move3, move4, move5;
    Button login;
    ImageView bar1, bar2, bar3, bar4, bar5;
    int delay1 = 500;
    int delay2 = 1560;
    int delay3 = 2300;
    int delay4 = 3065;

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

        login = findViewById(R.id.btLogin);
        bar1 =  findViewById(R.id.ivBar1);
        bar2 =  findViewById(R.id.ivBar2);
        bar3 =  findViewById(R.id.ivBar3);
        bar4 =  findViewById(R.id.ivBar4);
        bar5 =  findViewById(R.id.ivBar5);

        move1= AnimationUtils.loadAnimation(getApplicationContext(),R.anim.move);
        move2= AnimationUtils.loadAnimation(getApplicationContext(),R.anim.move);
        move3= AnimationUtils.loadAnimation(getApplicationContext(),R.anim.move);
        move4= AnimationUtils.loadAnimation(getApplicationContext(),R.anim.move);
        move5= AnimationUtils.loadAnimation(getApplicationContext(),R.anim.move);

        bar1.startAnimation(move1);

        Handler handler = new Handler();
        handler.postDelayed(() -> bar2.startAnimation(move2), delay1);
        handler.postDelayed(() -> bar3.startAnimation(move3), delay2);
        handler.postDelayed(() -> bar4.startAnimation(move4), delay3);
        handler.postDelayed(() -> bar5.startAnimation(move5), delay4);


        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            return insets;
        });
    }
}

为什么它不无限重复？和xml中的fill-after属性有关系吗？非常感谢您的帮助，这是一个班级项目。

Answer 1

从动画 XML 中删除

android:fillAfter="true"

，并在父

android:repeatCount="infinite"

标记中设置

<set>

，而不是

repeatCount="3"

。

fillAfter

使每个动画保持其最终状态，防止正确循环。

<?xml version="1.0" encoding="utf-8"?>
<set
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:interpolator="@android:anim/linear_interpolator"
   android:repeatCount="infinite"
   android:repeatMode="restart">
  <!-- move down -->
  <translate
      android:fromYDelta="0%"
      android:toYDelta="50%"
      android:duration="1500"/>

  <!-- move up -->
  <translate
      android:fromYDelta="50%"
      android:startOffset="1500"
      android:toYDelta="-50%"
      android:duration="1500"/>

  <!-- continue to move up -->
  <translate
      android:fromYDelta="-50%"
      android:startOffset="3000"
      android:toYDelta="-20%"
      android:duration="600"/>

  <!-- down to original pos -->
  <translate
      android:fromYDelta="-20%"
      android:startOffset="3600"
      android:toYDelta="0%"
      android:duration="600"/>

</set>

这就是让它无限循环所需的全部。