Display text on a specified location in a custom View

Last exercise "Get color on a specified location from ImageView's background bitmap" display text in a TextView on a fixed location. It's modified to display the text on a separated custom View on the touched location.

Create a new custom View, InfoView.java. It's used to display the text.

package com.exercise.AndroidDetechTouch;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class InfoView extends View {
 
 String info = "";
 float x = 0; //init value 
 float y = 0; //init value

 public InfoView(Context context) {
  super(context);
  // TODO Auto-generated constructor stub
 }

 public InfoView(Context context, AttributeSet attrs) {
  super(context, attrs);
  // TODO Auto-generated constructor stub
 }

 public InfoView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  // TODO Auto-generated constructor stub
 }
 
 @Override
 protected void onDraw(Canvas canvas) {
  // TODO Auto-generated method stub
  super.onDraw(canvas);
  
  Paint paint = new Paint();
  paint.setStyle(Paint.Style.FILL_AND_STROKE);
  paint.setColor(Color.WHITE);
  paint.setStrokeWidth(2);
  paint.setTextSize(30);
  
  canvas.drawCircle(x, y, 5, paint);
  canvas.drawText(info, x, y, paint);
  
 }

 public void updateInfo(String t_info, float t_x, float t_y){
  info = t_info;
  x = t_x;
  y = t_y;
  invalidate();
 }

}

Modify TouchView.java

package com.exercise.AndroidDetechTouch;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ImageView;

public class TouchView extends ImageView {
 
 Bitmap bitmap;
 double bmWidth, bmHeight; 
 
 String touchInfo;
 float touchX, touchY;

 public TouchView(Context context) {
  super(context);
  // TODO Auto-generated constructor stub
  init();
 }

 public TouchView(Context context, AttributeSet attrs) {
  super(context, attrs);
  // TODO Auto-generated constructor stub
  init();
 }

 public TouchView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  // TODO Auto-generated constructor stub
  init();
 }
 
 private void init(){
  bitmap = ((BitmapDrawable)getBackground()).getBitmap();
  bmWidth = (double)bitmap.getWidth();
  bmHeight = (double)bitmap.getHeight();
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  // TODO Auto-generated method stub
  setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec),
       MeasureSpec.getSize(heightMeasureSpec));
 }

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

  switch(event.getAction()){
  case MotionEvent.ACTION_DOWN:
  case MotionEvent.ACTION_MOVE:
   touchX = event.getX();
   touchY = event.getY();
   
   touchInfo = "Touched@" 
     + String.valueOf(touchX) + " : " + String.valueOf(touchY);

      ((AndroidDetechTouchActivity)getContext()).updateMsg(touchInfo, touchX, touchY);
      
   break;
  case MotionEvent.ACTION_UP:
   touchX = event.getX();
   touchY = event.getY();
   
   touchInfo = "UnTouched@\n" 
     + String.valueOf(touchX) + " : " + String.valueOf(touchY);
   
   ((AndroidDetechTouchActivity)getContext()).updateMsg(touchInfo, touchX, touchY);
   break;
  }
  
  return true;
 }
 
 /*
 private int getColor(float x, float y){

  if ( x < 0 || y < 0 || x > (float)getWidth() || y > (float)getHeight()){
   return 0; //Invalid, return 0
  }else{
   //Convert touched x, y on View to on Bitmap
   int xBm = (int)(x * (bmWidth / (double)getWidth()));
      int yBm = (int)(y * (bmHeight / (double)getHeight()));

   return bitmap.getPixel(xBm, yBm);
  }
 }
 */

}

Modify main activity, AndroidDetechTouchActivity.java.

package com.exercise.AndroidDetechTouch;

import android.app.Activity;
import android.os.Bundle;

public class AndroidDetechTouchActivity extends Activity {

 TouchView touchView;
 InfoView infoView;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        touchView = (TouchView)findViewById(R.id.touchview);
        infoView = (InfoView)findViewById(R.id.infoview);

    }

    public void updateMsg(String t_info, float t_x, float t_y){

     infoView.updateInfo(t_info, t_x, t_y);
     
    }

}

Modify main.xml, to place the InfoView over TouchView.

<?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" />
 <FrameLayout 
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
     >
     <com.exercise.AndroidDetechTouch.TouchView
         android:id="@+id/touchview"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"
         android:background="@drawable/ic_launcher"
         />
     <com.exercise.AndroidDetechTouch.InfoView
         android:id="@+id/infoview"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"
         />
 </FrameLayout>
</LinearLayout>

Download the files.

Next:
- Map the touch position with a mask