Saturday, January 23, 2021

How to download and save an image from a given URL in android

This example demonstrates how do I download and save an image from a given URL in android.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.CoordinatorLayout

   xmlns:android="http://schemas.android.com/apk/res/android"

   xmlns:app="http://schemas.android.com/apk/res-auto"

   android:id="@+id/coordinatorLayout"

   android:layout_width="match_parent"

   android:layout_height="match_parent">

   <Button

      android:id="@+id/btnDownload"

      android:layout_width="wrap_content"

      android:layout_height="wrap_content"

      android:text="Download Image"

      android:layout_margin="25dp"

      android:layout_gravity="top|center_horizontal" />

   <ImageView

      android:id="@+id/imageView"

      android:layout_width="match_parent"

      android:layout_height="200dp"

      android:scaleType="centerCrop"

      app:layout_anchor="@id/btnDownload"

      android:layout_gravity="bottom"

      app:layout_anchorGravity="bottom"

      android:layout_margin="10dp" />

</android.support.design.widget.CoordinatorLayout>

Step 3 − Add the following code to src/MainActivity.java

public class MainActivity extends AppCompatActivity {

   Context context;

   Activity activity;

   CoordinatorLayout coordinatorLayout;

   Button button;

   ProgressDialog mProgressDialog;

   ImageView mImageView;

   URL url;

   AsyncTask mMyTask;

   @Override

   protected void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

      setContentView(R.layout.activity_main);

      context = getApplicationContext();

      activity = MainActivity.this;

      coordinatorLayout = findViewById(R.id.coordinatorLayout);

      button = findViewById(R.id.btnDownload);

      mImageView = findViewById(R.id.imageView);

      mProgressDialog = new ProgressDialog(activity);

      mProgressDialog.setIndeterminate(true);

      mProgressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);

      mProgressDialog.setTitle("AsyncTask");

      mProgressDialog.setMessage("Please wait, we are downloading your image file...");

      button.setOnClickListener(new View.OnClickListener() {

         @Override

         public void onClick(View view) {

            mMyTask = new DownloadTask().execute(stringToURL());

         }

      });

   }

   private class DownloadTask extends AsyncTask<URL,Void,Bitmap>{

      protected void onPreExecute(){

         mProgressDialog.show();

      }

      protected Bitmap doInBackground(URL...urls){

         URL url = urls[0];

         HttpURLConnection connection = null;

         try{

            connection = (HttpURLConnection) url.openConnection();

            connection.connect();

            InputStream inputStream = connection.getInputStream();

            BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);

            return BitmapFactory.decodeStream(bufferedInputStream);

         }catch(IOException e){

            e.printStackTrace();

         }

         return null;

      }

      // When all async task done

      protected void onPostExecute(Bitmap result){

         // Hide the progress dialog

         mProgressDialog.dismiss();

         if(result!=null){

            mImageView.setImageBitmap(result);

         } else {

            // Notify user that an error occurred while downloading image

            Toast.makeText(MainActivity.this, "Error", Toast.LENGTH_SHORT).show();

         }

      }

   }

   protected URL stringToURL() {

      try {

         url = new URL("https://wallpapersite.com/images/pages/pic_w/6408.jpg");

         return url;

      } catch (MalformedURLException e) {

         e.printStackTrace();

      }

      return null;

   }

}

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.sample">

   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

   <uses-permission android:name="android.permission.INTERNET"/>

   <application

      android:allowBackup="true"

      android:icon="@mipmap/ic_launcher"

      android:label="@string/app_name"

      android:roundIcon="@mipmap/ic_launcher_round"

      android:supportsRtl="true"

      android:theme="@style/AppTheme">

      <activity android:name=".MainActivity">

         <intent-filter>

            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />

         </intent-filter>

      </activity>

   </application>

</manifest>

Let's try to run your application. I assume you have connected your actual Android example device with your computer. To run the app from android studio, open one of your project's activity files and click Run Play Icon icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen 

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