Set alpha of AnimationDrawable

Alpha of a AnimationDrawable can be changed using setAlpha(int alpha), Specify an alpha value for the AnimationDrawable. 0 means fully transparent, and 255 means fully opaque.



Modify from last exercise "Start and Stop frame animation with AnimationDrawable", add a SeekBar to set alpha of the animation.

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:orientation="vertical" >

 <TextView
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="@string/hello" />
 <TextView
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="Set Alpha" />
 <SeekBar
     android:id="@+id/setalpha"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:progress="255"
     android:max="255" />
 <Button
     android:id="@+id/startanimation"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="Start Animation" />
 <Button
     android:id="@+id/stopanimation"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="Stop Animation" />
 <ImageView
     android:id="@+id/myanimation"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:src="@anim/anim_android"
     />

</LinearLayout>

Modify the code of the actiity

package com.exercise.AndroidAnimation;

import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.SeekBar;

public class AndroidAnimationActivity extends Activity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main);
  
     ImageView myAnimation = (ImageView)findViewById(R.id.myanimation);
     final AnimationDrawable myAnimationDrawable
      = (AnimationDrawable)myAnimation.getDrawable();
  
     SeekBar setAnimationAlpha = (SeekBar)findViewById(R.id.setalpha);
     Button startAnimation = (Button)findViewById(R.id.startanimation);
     Button stopAnimation = (Button)findViewById(R.id.stopanimation);
  
     startAnimation.setOnClickListener(new Button.OnClickListener(){

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   if(!myAnimationDrawable.isRunning()){
    myAnimationDrawable.start();
   }
  }});
  
     stopAnimation.setOnClickListener(new Button.OnClickListener(){

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   if(myAnimationDrawable.isRunning()){
    myAnimationDrawable.stop();
   }
  }});
  
     setAnimationAlpha.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener(){

  @Override
  public void onProgressChanged(SeekBar seekBar, int progress,
    boolean fromUser) {
   myAnimationDrawable.setAlpha(progress);
  
  }

  @Override
  public void onStartTrackingTouch(SeekBar seekBar) {
   // TODO Auto-generated method stub
  
  }

  @Override
  public void onStopTrackingTouch(SeekBar seekBar) {
   // TODO Auto-generated method stub
  
  }});

 }
}

Download the files.


Next:
- Creaete AnimationDrawable and copy frames from another AnimationDrawable