Falling leaf animation

some_activity.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorPrimary"
    tools:context="SomeActivity">
  
    <!--A simple layout is a full screen relative layout so we can put the image in the middle
    I use a relative, cause I can not triggered the animation, thoose conditions are not includede
    in the previous file, but you could check something and see if the animation start or just skip it-->

    <!--and this is the leaf-->
    <ImageView
        android:id="@+id/loadingLeaf"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/leaf"
        android:layout_centerInParent="true"/>
        
        <!--You can download the leaf from here-->
        <!--http://cutiko.cl/wp-content/uploads/2016/02/leaf.zip-->

</RelativeLayout>

SomeActivity.java

//This code is highly summarized

private int height;
private Timer timer;
private int leafFallDuration = 6000;
private int leafRotationDuration = 900;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.some_activity);
    
    //We are going to use the height so we have to get it first
    DisplayMetrics displaymetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
    height = displaymetrics.heightPixels;
    
    //this method is in charge to make the leaf fall from the top over and over again
    leafFalling();
    //we call the first rotation, and the first will call the second and the secon will call the first, recursively, then leaf is always moving
    firstLeafRotation();
    }
}

private void leafFalling() {
  //The trick here is, the animation is triggered, so the leaf start to fall
  //then, the timer is also set, to the exact same duration than the animation
  //So, when the animation is over, the timer will run out, calling the animation again
  //and setting the timer, recursivety
  TranslateAnimation animation = new TranslateAnimation(0, 0, -height/2, 0);
  animation.setDuration(leafFallDuration);
  loadingLeaf.startAnimation(animation);

  TimerTask reloadLeaf = new TimerTask() {
      @Override
      public void run() {
          leafFalling();
      }
  };

  timer.schedule(reloadLeaf, leafFallDuration);
}

void firstLeafRotation() {
    //The trick here is the same than above, but insted of calling it self when the timer run out
    //the second animation will be triggered, and the secon will cal the first
    loadingLeaf.animate().rotationBy(75).setDuration(leafRotationDuration).setInterpolator(new LinearInterpolator()).start();

    TimerTask reloadLeaf = new TimerTask() {
        @Override
        public void run() {
            secondLeafRotation();
        }
    };

    timer.schedule(reloadLeaf, leafRotationDuration);
}

    
private void secondLeafRotation() {
    loadingLeaf.animate().rotationBy(-75).setDuration(leafRotationDuration).setInterpolator(new LinearInterpolator()).start();

    //So when this timer is executed, the first rotation will be called, and will restart the movement
    TimerTask reloadLeaf = new TimerTask() {
        @Override
        public void run() {
            firstLeafRotation();
        }
    };

    timer.schedule(reloadLeaf, leafRotationDuration);
}

//NOTE: if you want to stop the animation, just use a broadcast receiver listening to some other something running in background