Thursday, October 13, 2011

Save and Read Bitmap in Internal Storage

Refer to the last exercise "Pass Bitmap between activities", pass Bitmap as extra is not recommended for large bitmap. Saving in Internal Storage and read in second activity is an alternative.

It's a example to save and read bitmap in Internal Storage. In AndroidBitmapActivity class, the bitmaps are saved in Internal Storage, in MODE_PRIVATE (where the created file can only be accessed by the calling application). The bitmaps will be read in SecondActivity class.

AndroidBitmapActivity.java
package com.exercise.AndroidBitmap;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class AndroidBitmapActivity extends Activity {

ImageView image1, image2, image3, image4;
Button buttonSwitch;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
image1 = (ImageView)findViewById(R.id.image1);
image2 = (ImageView)findViewById(R.id.image2);
image3 = (ImageView)findViewById(R.id.image3);
image4 = (ImageView)findViewById(R.id.image4);
buttonSwitch = (Button)findViewById(R.id.switchactivity);

Bitmap bmOriginal = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
image1.setImageBitmap(bmOriginal);

int width = bmOriginal.getWidth();
int height = bmOriginal.getHeight();

final Bitmap bmDulicated2 = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
final Bitmap bmDulicated3 = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
final Bitmap bmDulicated4 = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
int[] srcPixels = new int[width * height];
bmOriginal.getPixels(srcPixels, 0, width, 0, 0, width, height);
int[] destPixels = new int[width * height];

swapGB(srcPixels, destPixels);
bmDulicated2.setPixels(destPixels, 0, width, 0, 0, width, height);
image2.setImageBitmap(bmDulicated2);

swapRB(srcPixels, destPixels);
bmDulicated3.setPixels(destPixels, 0, width, 0, 0, width, height);
image3.setImageBitmap(bmDulicated3);

swapRG(srcPixels, destPixels);
bmDulicated4.setPixels(destPixels, 0, width, 0, 0, width, height);
image4.setImageBitmap(bmDulicated4);

buttonSwitch.setOnClickListener(new Button.OnClickListener(){

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub

FileOutputStream fos;
try {
fos = openFileOutput("BITMAP_A", Context.MODE_PRIVATE);
bmDulicated2.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();

fos = openFileOutput("BITMAP_B", Context.MODE_PRIVATE);
bmDulicated3.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();

fos = openFileOutput("BITMAP_C", Context.MODE_PRIVATE);
bmDulicated4.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Intent intent = new Intent(AndroidBitmapActivity.this, SecondActivity.class);
startActivity(intent);
}});

}

void swapGB(int[] src, int[] dest){
for(int i = 0; i < src.length; i++){
dest[i] = (src[i] & 0xffff0000)
| ((src[i] & 0x000000ff)<<8)
| ((src[i] & 0x0000ff00)>>8);
}
}

void swapRB(int[] src, int[] dest){
for(int i = 0; i < src.length; i++){
dest[i] = (src[i] & 0xff00ff00)
| ((src[i] & 0x000000ff)<<16)
| ((src[i] & 0x00ff0000)>>16);
}
}

void swapRG(int[] src, int[] dest){
for(int i = 0; i < src.length; i++){
dest[i] = (src[i] & 0xff0000ff)
| ((src[i] & 0x0000ff00)<<8)
| ((src[i] & 0x00ff0000)>>8);
}
}
}


SecondActivity.java
package com.exercise.AndroidBitmap;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.ImageView;

public class SecondActivity extends Activity {

ImageView imageA, imageB, imageC;

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
imageA = (ImageView)findViewById(R.id.imagea);
imageB = (ImageView)findViewById(R.id.imageb);
imageC = (ImageView)findViewById(R.id.imagec);

Bitmap bitmapA = null;
Bitmap bitmapB = null;
Bitmap bitmapC = null;
FileInputStream fis;

try {
fis = openFileInput("BITMAP_A");
bitmapA = BitmapFactory.decodeStream(fis);
fis.close();

fis = openFileInput("BITMAP_B");
bitmapB = BitmapFactory.decodeStream(fis);
fis.close();

fis = openFileInput("BITMAP_C");
bitmapC = BitmapFactory.decodeStream(fis);
fis.close();

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

imageA.setImageBitmap(bitmapA);
imageB.setImageBitmap(bitmapB);
imageC.setImageBitmap(bitmapC);

}

}



Download the files.

Related article:
- Share Bitmap between activities as global common resources
- Internal Storage



1 comment:

madhuri addepalli said...

Thankyou..Worked perfectly