Unable to add custom view in linear layout - Android

Question

I am adding myCustomView in a linear layout multiple times, it is working fine for first instance of customView, but unable to add it multiple times.

Here is the Custom View class:

public class MultiTouchView extends View {

      private float x, y;
      Bitmap image;

      public MultiTouchView(Context context, Bitmap image) {
       super(context);
       this.image = image;

       // TODO Auto-generated constructor stub
      }

      public MultiTouchView(Context context, AttributeSet attrs) {
            super(context, attrs);
          }

          public MultiTouchView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
          }

      @Override
      protected void onDraw(Canvas canvas) {
       // TODO Auto-generated method stub       
        canvas.drawBitmap(image, x, y, null);
      }

      @Override
      protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
       // TODO Auto-generated method stub

          super.onMeasure(widthMeasureSpec, heightMeasureSpec);
          setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec),
             MeasureSpec.getSize(heightMeasureSpec));   
      }

      @Override
      public boolean onTouchEvent(MotionEvent event) {
       // TODO Auto-generated method stub

       int action = event.getAction();
       switch(action){
       case MotionEvent.ACTION_MOVE:
        x = event.getX();
        y = event.getY();

        break;
       case MotionEvent.ACTION_DOWN:

        x = event.getX();
        y = event.getY();

        break;
       case MotionEvent.ACTION_UP:
        break;

       }

       invalidate();
       return true;
      } 
     }

This is the class where i am adding custom view:

public class AndroidTouch extends Activity {

    LinearLayout linear;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

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

          Bitmap backgroundCard = BitmapFactory.decodeResource(
                    getResources(), R.drawable.ic_launcher);

        MultiTouchView mt1 = new MultiTouchView(this, backgroundCard);
        linear.addView(mt1);

         Bitmap backgroundCard2 = BitmapFactory.decodeResource(
        getResources(), R.drawable.icon);
         MultiTouchView mt2 = new MultiTouchView(this, backgroundCard2);
         linear.addView(mt2);
    }
}

Answer 1

If you set a background color to the MultiTouchView views, then you will find that the color of the entire screen is same as the color of the 2nd view which was added.

I specified layout params for the child views and i was able to get the views to draw on screen. the modified code:

public class AndroidTouch extends Activity {

    LinearLayout linear;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_c);

        linear = (LinearLayout)findViewById(R.id.main);

        Bitmap backgroundCard = BitmapFactory.decodeResource(getResources(), R.drawable.image1);
        int w = backgroundCard.getWidth();
        int h = backgroundCard.getHeight();
        LayoutParams params = new LayoutParams(w, h);
        MultiTouchView mt1 = new MultiTouchView(getApplicationContext(), backgroundCard);
        //mt1.setBackgroundColor(Color.RED);//try uncommenting this wihtout layout params change
        linear.addView(mt1, params);


        Bitmap backgroundCard2 = BitmapFactory.decodeResource(getResources(), R.drawable.image2);
        params = new LayoutParams(backgroundCard2.getWidth(), backgroundCard2.getHeight());
        MultiTouchView mt2 = new MultiTouchView(getApplicationContext(), backgroundCard2);
        //mt1.setBackgroundColor(Color.BLUE);<-- Entire screen turns blue
        linear.addView(mt2, params);
    }
}

But i believe you will face another problem after this. From the code it is evident that you are trying to draw the views at the touched positions. I would suggest using one single custom view and adding multiple images to the same view. Only in this case you have to determine which view needs to be drawn in a different co-ordinate and which view remains same.

Hope this helps