SurfaceView in Layout

Question

So I've done a lot of searching but still can't seem to find the exact reason as to why my SurfaceView won't display. Here's a little background as to what I'm doing:

I have a Linear Layout that is set Horizontally. It contains an ImageView, then a vertical Linear Layout, and finally another ImageView. In the vertical Linear Layout, there are essential three things: another ImageView at the top, an extended SurfaceView (called MagnetView) and an ImageView below that.

Here's the xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >

 <!-- Left Magnetrak -->

 <ImageView
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:src="@drawable/vectorparts_01"
    android:adjustViewBounds="true" />

<!-- Middle Linear Layout -->        
<LinearLayout 
    android:layout_width="0dip"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:layout_weight="1">

    <!-- Top Bar with Lifes and Score counter -->
    <RelativeLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true">

    <ImageView
    android:adjustViewBounds="true"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:src="@drawable/vectorparts_22"/>

    <!-- Score counter -->
    <TextView
    android:id="@+id/myImageViewText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_marginRight="10dp"
    android:layout_marginTop="5dp"
    android:gravity="center"
    android:text="000000000000"
    android:textColor="#000000" />

    <!-- Life1 -->
     <ImageView
        android:id = "@+id/life1"
        android:adjustViewBounds="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/vectorparts_13" 
        android:layout_alignParentLeft="true"
        android:layout_marginLeft="5dp"
        android:layout_marginTop="1dp"
        android:gravity="center" />

     <!-- Life2 -->
     <ImageView
        android:id = "@+id/life2"
        android:adjustViewBounds="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/vectorparts_13" 
        android:layout_toRightOf="@id/life1"
        android:layout_marginTop="1dp"
        android:layout_marginLeft="1dp"
        android:gravity="center" />

     <!-- Life3 -->
     <ImageView
        android:id = "@+id/life3"
        android:adjustViewBounds="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/vectorparts_13" 
        android:layout_toRightOf="@id/life2"
        android:layout_marginTop="1dp"
        android:layout_marginLeft="1dp"
        android:gravity="center" />

    </RelativeLayout>

    <!-- SurfaceView -->
    <LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/middlesurface">

    </LinearLayout>

     <!-- Bottom Bar -->   
    <RelativeLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true"> 

    <ImageView
    android:adjustViewBounds="true"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:src="@drawable/vectorparts_02"/>


    </RelativeLayout>


</LinearLayout>

<!-- Right Magnetrak -->
   <ImageView
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:src="@drawable/vectorparts_01"
android:adjustViewBounds="true" />

Essentially, I want the MagnetView to show through (or punch a hole) where I put it in the Layout. But it does not display. In fact, the only time my SurfaceView displays is when I set the activity's setContentView() to the SurfaceView explicitly, canceling out everything else.

Here is the actually Activity:

public class Magnetraks extends Activity {

MagnetView midSurf;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    midSurf = new MagnetView(this);
    LinearLayout midLL = new LinearLayout(this);

    midLL.findViewById(R.id.middlesurface);
    midLL.addView(midSurf);

    setContentView(R.layout.main);

    //Debugging purposes: run to see if middleSurface view is showing up when on its own.
    //setContentView(midSurf);


}

@Override
protected void onResume() {
 // TODO Auto-generated method stub
 super.onResume();
 midSurf.resume();
}

@Override
protected void onPause() {
 // TODO Auto-generated method stub
 super.onPause();
 midSurf.pause();
}

Should I place the SurfaceView at the top of my layout xml? Are there more attributes I must set? Can I just overlay the SurfaceView over everything else, make it translucent and draw what I need? Any help would be greatly appreciated, as I cannot seem to grasp how SurfaceViews work. It seems they are apart of my View hierarchy, but then documentation tells me they are something different entirely.

Thank you.

EDIT 04/17/2012

To offer a little more info: My xml UI Designer shows a big box in the middle for my extended SurfaceView class, called MagnetView. I've outlined it in red. (Stackoverflow won't allow me to post images yet)

UI Designer view(http://24.media.tumblr.com/tumblr_m2mmqvBNwW1qcreoco1_500.jpg) http://24.media.tumblr.com/tumblr_m2mmqvBNwW1qcreoco1_500.jpg

Here's the MagnetView (SurfaceView) class:

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.PixelFormat;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MagnetView extends SurfaceView implements Runnable, SurfaceHolder.Callback{
Thread mThread;
SurfaceHolder mSurfaceHolder;
volatile boolean running = false;

//Creates new surface view as well as a new surfaceholder, which allows access to the surface
public MagnetView (Context context){
    super(context);

    mSurfaceHolder = getHolder();
            mSurfaceHolder.addCallback(this);
    //this.setZOrderOnTop(true);
    //getHolder().setFormat(PixelFormat.TRANSLUCENT);


}

public void resume(){
    running = true;
    mThread = new Thread(this);
    mThread.start();
}

public void pause(){
       boolean retry = true;
       running = false;
       while(retry){
        try {
         mThread.join();
         retry = false;
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
       }
}

@Override
public void run() {
  // TODO Auto-generated method stub
    while(running){
        if(mSurfaceHolder.getSurface().isValid()){
            Canvas canvas = mSurfaceHolder.lockCanvas();
            //... actual drawing on canvas

            canvas.drawARGB(100, 255, 255, 80);

            mSurfaceHolder.unlockCanvasAndPost(canvas);
        }
    }
}


@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    // TODO Auto-generated method stub

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    this.resume();

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // TODO Auto-generated method stub

}

}

Answer 1

I am just putting down the changes.

1. Replace surface view in the xml with LinearLayout.

       <LinearLayout 
          android:id="@+id/middleSurface"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
       />
   

2. Get an instance of linear layout

   LinearLayout surface = (LinearLayout)findViewById(R.id.surface);

3. Add the surface view's instance to LinearLayout

   surface.addView(new MagnetView(this));

2,3 steps should be performed after setContentView(R.layout.main);