Get the canvas bitmap of custom View

I have a series of previous articles to draw something on custom view's canvas. All these code lose everythng after the app exit. Now I want to save the drawing in a file. In this article, I will demonstrate how to get the canvas bitmap of custom view.

package com.sunil;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
 
public class MyView extends View {
  
 boolean freeTouched = false;
 Path freePath;
  
 Bitmap myCanvasBitmap = null;
 Canvas myCanvas = null;
  
 Matrix identityMatrix;
 
 public MyView(Context context) {
  super(context);
 }
 
 public MyView(Context context, AttributeSet attrs) {
  super(context, attrs);
 }
 
 public MyView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
 }
  
 @Override
 protected void onDraw(Canvas canvas) {
     
  if(freeTouched){
   Paint paint = new Paint();
   paint.setStyle(Paint.Style.STROKE);
   paint.setColor(Color.RED);
   paint.setStrokeWidth(10);
    
   myCanvas.drawPath(freePath, paint);
   canvas.drawBitmap(myCanvasBitmap, identityMatrix, null);
    
  }
 }
 
 @Override
 public boolean onTouchEvent(MotionEvent event) {
   
  switch(event.getAction()){
  case MotionEvent.ACTION_UP:
   freeTouched = false;
   break;
  case MotionEvent.ACTION_DOWN:
   freeTouched = true;
   freePath = new Path();
   freePath.moveTo(event.getX(), event.getY());
    
   myCanvasBitmap.eraseColor(Color.BLACK);
    
   break;
  case MotionEvent.ACTION_MOVE:
   freePath.lineTo(event.getX(), event.getY());
   invalidate();
   break;
  }
   
  return true;
 }
  
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 
  int w = MeasureSpec.getSize(widthMeasureSpec);
  int h = MeasureSpec.getSize(heightMeasureSpec);
 
  myCanvasBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
  myCanvas = new Canvas();
  myCanvas.setBitmap(myCanvasBitmap);
   
  identityMatrix = new Matrix();
   
  setMeasuredDimension(w, h);
 }
 
 public Bitmap getCanvasBitmap(){
   
  return myCanvasBitmap;
   
 }
 
}

Create /res/menu/menu.xml to define our option menu.

The main code, AndroidMyCanvasActivity.java.

package com.sunil;

import android.app.Activity;
import android.app.AlertDialog;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
import android.widget.LinearLayout;
 
public class AndroidMyCanvasActivity extends Activity {
  
 MyView myView;
  
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
         
        myView = new MyView(this);
 
        setContentView(myView);
         
    }
 
 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  MenuInflater menuInflater = getMenuInflater();
  menuInflater.inflate(R.menu.menu, menu);
  return true;
 }
 
 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
  switch(item.getItemId()){
  case R.id.opt_capture:
   openCaptureDialog();
   return true;
  default:
   return false;
   
  }
 }
  
 private void openCaptureDialog(){
 
  Bitmap bmMyView = myView.getCanvasBitmap();
 
  AlertDialog.Builder captureDialog = new AlertDialog.Builder(AndroidMyCanvasActivity.this);
  captureDialog.setTitle("Canvas Captured");
   
  ImageView bmImage = new ImageView(AndroidMyCanvasActivity.this);
   
     bmImage.setImageBitmap(bmMyView);
      
     LayoutParams bmImageLayoutParams = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
     bmImage.setLayoutParams(bmImageLayoutParams);
       
     LinearLayout dialogLayout = new LinearLayout(AndroidMyCanvasActivity.this);
     dialogLayout.setOrientation(LinearLayout.VERTICAL);
     dialogLayout.addView(bmImage);
     captureDialog.setView(dialogLayout);
      
  captureDialog.setPositiveButton("OK", null);
  captureDialog.show();
      
 }
 
}

Cheers Guys!