在ImageView中图像未更改

Question

I want to change image after some animation to first image. I am trying with this code but only the second image is getting animated. First image is not displaying.

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);      
        anim(); 


    }



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

   public void anim() {
        Animation animfadein =AnimationUtils.loadAnimation(this,R.anim.fadein);
        Animation animfadeout =AnimationUtils.loadAnimation(this,R.anim.fadeout);
        findViewById(R.id.imageView1).startAnimation(animfadein);
        findViewById(R.id.imageView1).startAnimation(animfadeout);
        Context myActivity =getApplicationContext();
        Toast.makeText(myActivity, "Please wait", Toast.LENGTH_SHORT).show();
        button();
       }

    public void button() {
        ImageView imgView1 = (ImageView)findViewById(R.id.imageView1);          
        Drawable myDrawable = getResources().getDrawable(R.drawable.start);
        imgView1.setImageDrawable(myDrawable);
    }

}    

My xml file is like this

<LinearLayout 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="@drawable/background"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

   <ImageView

        android:id="@+id/imageView1"
        android:contentDescription="@string/description"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"    
        android:src="@drawable/ic_logo"/>



</LinearLayout>

I tried using setImageresource still same first image is not displaying. Please let me know what mistake i have done.Thanks in advance :)

Answer 1

You will need to use animation listener for achieving this:

animFadeIn.setAnimationListener(new AnimationListener() {

    @Override
    public void onAnimationStart(Animation animation) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onAnimationRepeat(Animation animation) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onAnimationEnd(Animation animation) {
        //start animFadeOut Here
    }
});

Hope this helps.

Answer 2

You are running everything in onCreate which is done before the user is even able to see any of the UI. It is until onStart that the user will see the UI. even so, the change will be almost immediate, so you might want to wait a few secs. Try this:

@Override
protected void onStart() {
    super.onStart();
    new Thread(new Runnable() {

        @Override
        public void run() {
            try {
                Thread.sleep(5000);
                runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        anim();
                    }
                });
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }).start();
}

In general you are making a thread wait 5 secs then do the animation. I am not going to go over what's the best way to do this, but you certainly need to modify this on the UI thread, so I included it in the snippet.
For more information about threading go here:
http://www.vogella.com/tutorials/AndroidBackgroundProcessing/article.html