Using Bitmap class object to draw an image

2

This is a sample program to draw an image using Bitmap class object.

Underlying Algorithm:

Basic description of algorithm in step by step form:

1.) Create a Project DrawBitmap.
2.) To draw an image we will create a inner class BitmapView which will extends View :

class BitmapView extends View 
{
    public BitmapView(Context context) {
            super(context);
    }
    @Override
    public void onDraw(Canvas canvas) {
	Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.five);
        canvas.drawColor(Color.BLACK);
        canvas.drawBitmap(bmp, 10, 10, null);
    }
}

3.) Put an image in res/drawable
4.) Run the application.

Steps to Create:

1.) Open Eclipse. Use the New Project Wizard and select Android Project Give the respective project name i.e. DrawBitmap. Enter following information:
Project name: DrawBitmap
Build Target: Android 2.3
Application name: DrawBitmap
Package name: com.sample.DrawBitmap
Create Activity: DrawBitmap

On Clicking Finish DrawBitmap code structure is generated with the necessary Android Packages being imported along with DrawBitmap.java. DrawBitmap class will look like following:

package com.sample.DrawBitmap;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
 
public class DrawBitmap extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new BitmapView(this));
    }
 
    class BitmapView extends View {
        public BitmapView(Context context) {
            super(context);
        }
 
        @Override
        public void onDraw(Canvas canvas) {
            Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.five);
            canvas.drawColor(Color.BLACK);
            canvas.drawBitmap(bmp, 10, 10, null);
        }
    }
}

Output –The final output:

2 Responses

  1. Jason says:

    Thanks so much for this tutorial. I’m very much a noob and am piecing my app together. I wasted several hours over this past weekend trying to find a clear basic tutorial explaining displaying a bitmap. Thanks again

  2. Jason says:

    Thanks so much for this tutorial. I\’m very much a noob and am piecing my app together. I wasted several hours over this past weekend trying to find a clear basic tutorial explaining displaying a bitmap. Thanks again

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