Empty space appears when the image moves from left to right and right to left

When the image moves from left to right and right to left, it leaves white space. What I want to do is fill my layout completely with the image so that the animation looks better and there is no white space.

This white area is covered by this picture, so the full background moves.

MainActivity.java

package com.example.abdul.game;

import android.opengl.Matrix;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;


public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    FrameLayout img_animation = (FrameLayout) findViewById(R.id.img_animation);

    TranslateAnimation animation = new TranslateAnimation(0.0f, 400.0f,
            0.0f, 0.0f);          //  new TranslateAnimation(xFrom,xTo, yFrom,yTo)
    animation.setDuration(7000);  // animation duration
    animation.setRepeatCount(Animation.INFINITE);  // animation repeat count
    animation.setRepeatMode(2);   // repeat animation (left to right, right to left )
//      animation.setFillAfter(true);

    img_animation.startAnimation(animation);  // start animation





}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

      

        
        
        
      

    

activity_main.xml

<FrameLayout 
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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:id="@+id/img_animation"
android:background="@drawable/a"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"  
tools:context=".MainActivity">

<ImageView
android:layout_width="125dp"
android:layout_height="125dp"
android:background="#000"/>

</FrameLayout>