Save file to SD Card

In the previous exercises "Load ImageView with bitmap from internet" and "Generate QR code using Google Chart API", images were downloaded from internet for display only. Here, we are going to save the download image to SD Card.



The path to SD Card can be retrieved using
Environment.getExternalStorageDirectory();

Then compress and write to SD Card by:
outStream = new FileOutputStream(file);
bm.compress(Bitmap.CompressFormat.PNG, 100, outStream);
outStream.flush();
outStream.close();

In order to premit the App to access internet and write to SD Card, we need "android.permission.INTERNET" and "android.permission.WRITE_EXTERNAL_STORAGE".
Modify AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.exercise.AndroidWebImage"
    android:versionCode="1"
    android:versionName="1.0">
  <application android:icon="@drawable/icon" android:label="@string/app_name">
      <activity android:name=".AndroidWebImage"
                android:label="@string/app_name">
          <intent-filter>
              <action android:name="android.intent.action.MAIN" />
              <category android:name="android.intent.category.LAUNCHER" />
          </intent-filter>
      </activity>

  </application>
  <uses-sdk android:minSdkVersion="4" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
</manifest>

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
<Button
  android:id="@+id/save"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Save"
  />
<ImageView
  android:id="@+id/image"
  android:scaleType="center"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
/>
</LinearLayout>

AndroidWebImage.java

package com.exercise.AndroidWebImage;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class AndroidWebImage extends Activity {

String image_URL=
 "http://chart.apis.google.com/chart?chs=200x200&cht=qr&chl=http%3A%2F%2Fcomputer-help-tips.blogspot.com%2F";

String extStorageDirectory;

Bitmap bm;

  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
    
      Button buttonSave = (Button)findViewById(R.id.save);

      ImageView bmImage = (ImageView)findViewById(R.id.image);
   BitmapFactory.Options bmOptions;
   bmOptions = new BitmapFactory.Options();
   bmOptions.inSampleSize = 1;
   bm = LoadImage(image_URL, bmOptions);
   bmImage.setImageBitmap(bm);
  
   extStorageDirectory = Environment.getExternalStorageDirectory().toString();
 
   buttonSave.setText("Save to " + extStorageDirectory + "/qr.PNG");
   buttonSave.setOnClickListener(buttonSaveOnClickListener);
  }

  private Bitmap LoadImage(String URL, BitmapFactory.Options options)
  {      
   Bitmap bitmap = null;
   InputStream in = null;      
      try {
          in = OpenHttpConnection(URL);
          bitmap = BitmapFactory.decodeStream(in, null, options);
          in.close();
      } catch (IOException e1) {
      }
      return bitmap;              
  }

private InputStream OpenHttpConnection(String strURL) throws IOException{
 InputStream inputStream = null;
 URL url = new URL(strURL);
 URLConnection conn = url.openConnection();

 try{
  HttpURLConnection httpConn = (HttpURLConnection)conn;
  httpConn.setRequestMethod("GET");
  httpConn.connect();

  if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
   inputStream = httpConn.getInputStream();
  }
 }
 catch (Exception ex)
 {
 }
 return inputStream;
}

Button.OnClickListener buttonSaveOnClickListener
 = new Button.OnClickListener(){

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   OutputStream outStream = null;
   File file = new File(extStorageDirectory, "er.PNG");
   try {
    outStream = new FileOutputStream(file);
    bm.compress(Bitmap.CompressFormat.PNG, 100, outStream);
    outStream.flush();
    outStream.close();
   
    Toast.makeText(AndroidWebImage.this, "Saved", Toast.LENGTH_LONG).show();
   
   } catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    Toast.makeText(AndroidWebImage.this, e.toString(), Toast.LENGTH_LONG).show();
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    Toast.makeText(AndroidWebImage.this, e.toString(), Toast.LENGTH_LONG).show();
   }

  }

};

}

Download the files.

next: Load bitmap file from SD Card

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