如何设置RotateAnimation的半径

Question

I am able to rate an image pointing to center of the screen. But it rotates in big radius, partially keeps off the screen. How to set radius like say 100 px.

    DisplayMetrics displaymetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);

    screenWidthPixel = displaymetrics.widthPixels;
    screenHeightPixel = displaymetrics.heightPixels;

    center_x = screenWidthPixel/2;
    center_y = screenHeightPixel/2;

    //RotateAnimation rotate = new RotateAnimation(0, 360, Animation.ABSOLUTE, center_x, Animation.ABSOLUTE, center_y);
    RotateAnimation rotate = new RotateAnimation(0, 360, center_x, center_y);
    rotate.setDuration(2000);
    rotate.setRepeatCount(Animation.INFINITE);
    rotate.setInterpolator(new LinearInterpolator());

    ImageView image= (ImageView) findViewById(R.id.test_img);

    image.setAnimation(rotate);

I am looking something like rotate.setRadius(100)

Answer 1

Try this:

Remove center_x, center_y parameters from RotateAnimation() and instead set ImageView in center of the screen in layout.xml .

Activity.java

 RotateAnimation rotate = new RotateAnimation(0, 360);
 rotate.setDuration(2000);
 rotate.setRepeatCount(Animation.INFINITE);
 rotate.setInterpolator(new LinearInterpolator());
 ImageView image= (ImageView) findViewById(R.id.test_img);
 image.setAnimation(rotate);

layout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/test_img"
        android:src="@mipmap/ic_launcher"
        android:layout_centerInParent="true"
        />
</RelativeLayout>