Android - 如何让图像的动画以特定的时间间隔出现？

Question

我正在参加有关 Android 编程的 Coursera 类(class)。这是我正在尝试做的事情的例证...

这是我到目前为止的代码...

XML:

<Button
        android:id="@+id/startbutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/leftfoot"
        android:layout_alignRight="@+id/leftfoot"
        android:onClick="startRhythmandAnimation"
        android:text="@string/start_button" />

Java:

public class Assignment3MainActivity extends Activity {

private View mMileTimeGoal;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_assignment3_main);
    mMileTimeGoal = findViewById(R.id.miletimegoal);
}

public void startRhythmandAnimation () {
    String MileTime = mMileTimeGoal.getContext().toString();
    String[] time_array = MileTime.split(":");
    int hours = Integer.parseInt(time_array[0]);
    int minutes = Integer.parseInt(time_array[1]);
    int seconds = Integer.parseInt(time_array[2]);
    int duration = 3600 * hours + 60 * minutes + seconds;
    int steps_per_second = 3;

    int running_rate = duration * steps_per_second;

    View rightfoot = findViewById(R.id.rightfoot);
    View leftfoot = findViewById(R.id.leftfoot);

    rightfoot.setVisibility(View.VISIBLE);
    Animation anim = AnimationUtils.makeInChildBottomAnimation(this);
    rightfoot.startAnimation(anim);

    leftfoot.setVisibility(View.VISIBLE);
    leftfoot.startAnimation(anim);
}

关于如何形成我的算法以滑动和淡化我的右脚 View 和左脚 View 的任何想法？

我应该使用 while 循环并启动某种类型的计时器吗？

Answer 1

Activity

private Handler mHandler;    
private long mInterval = 1000;
private View mLeftfoot;
private Animation mFootAnim;

public void onCreate(Bundle bundle) {
   ...
   mHandler = new Handler(); //.os package class when importing
   mLeftfoot = findViewById(R.id.leftfoot);
   mFootAnim = AnimationUtils.loadAnimation(this, R.anim.foot);
   stepRecursive();
}

private void stepRecursive() {
    mHandler.postDelayed(new Runnable() {
        @Override
        public void run() {
            mLeftFoot.startAnimation(mFootAnim );
            stepRecursive();
        }
    }, mInterval);
}

/res/anim/foot.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromYDelta="0" android:toYDelta="-15" android:duration="400"/>
    <alpha android:fromAlpha="1.0" android:toAlpha="0" android:duration="400" />
</set>

这就是我的想法(因此未经测试)，但应该足以让您朝着正确的方向前进