title: Wallpaper app crashing on clicking set button
body: <p>I have been trying to make a wallpaper app. When we click on a specific image from the gallery, it opens a new activity as below, where the image is displayed in full size and there is a button to set it as the wallpaper. I am using Glide library to load the pictures from the url. Please tell me how to set it as the wallpaper from the url as thee app loads the full size picture but crashes every time I click on the button. Maybe it is a problem with ether loading from the url or with setting it as the wallpaper.</p>
  
  <pre><code>import android.app.WallpaperManager;
  import android.content.Context;
  import android.content.Intent;
  import android.graphics.Bitmap;
  import android.graphics.BitmapFactory;
  import android.support.v7.app.AppCompatActivity;
  import android.os.Bundle;
  import android.view.KeyEvent;
  import android.view.View;
  import android.widget.Button;
  import android.widget.ImageView;
  import android.widget.Toast;
  
  import com.bumptech.glide.Glide;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.HttpURLConnection;
  import java.net.URL;
  
  public class Main2Activity extends AppCompatActivity {
      ImageView img;
  private Bitmap theBitmap;
  Button b;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      final Context c= getApplicationContext();
      setContentView(R.layout.activity_main2);
      b= (Button) findViewById(R.id.button);
      Intent i=getIntent();
      final String url=i.getStringExtra("picture");
  
      img= (ImageView) findViewById(R.id.imageView4);
      Glide.with(this).load(url).fitCenter()  .into(img);
      b.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
               theBitmap=getBitmapFromURL(url);
              WallpaperManager wallpaperManager = WallpaperManager.getInstance(getBaseContext());
              try {
                  wallpaperManager.setBitmap(theBitmap);
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      });
  
  
  }
  public static Bitmap getBitmapFromURL(String src) {
      try {
          URL url = new URL(src);
          HttpURLConnection connection = (HttpURLConnection) url.openConnection();
          connection.setDoInput(true);
          connection.connect();
          InputStream input = connection.getInputStream();
          Bitmap myBitmap = BitmapFactory.decodeStream(input);
          return myBitmap;
      } catch (IOException e) {
          e.printStackTrace();
          return null;
      }
    }
  }
  </code></pre>
  
  <p>I have set the permission in AndroidManifest as </p>
  
  <pre><code>&lt;uses-permission android:name="android.permission.INTERNET" /&gt;
  &lt;uses-permission android:name="android.permission.SET_WALLPAPER" /&gt;
  </code></pre>
  
  <p>This is the error that I get on pressing the 'set as wallpaper' button:-</p>
  
  <pre><code>07-20 09:33:43.127 3024-3024/com.android.backgroundchooser E/AndroidRuntime: FATAL EXCEPTION: main
                                                                           Process: com.android.backgroundchooser, PID: 3024
                                                                           android.os.NetworkOnMainThreadException
                                                                               at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
                                                                               at com.android.org.conscrypt.OpenSSLSocketImpl$SSLOutputStream.write(OpenSSLSocketImpl.java:755)
                                                                               at com.android.okhttp.okio.Okio$1.write(Okio.java:76)
                                                                               at com.android.okhttp.okio.AsyncTimeout$1.write(AsyncTimeout.java:155)
                                                                               at com.android.okhttp.okio.RealBufferedSink.flush(RealBufferedSink.java:221)
                                                                               at com.android.okhttp.internal.http.HttpConnection.flush(HttpConnection.java:141)
                                                                               at com.android.okhttp.internal.http.HttpTransport.finishRequest(HttpTransport.java:52)
                                                                               at com.android.okhttp.internal.http.HttpEngine.readNetworkResponse(HttpEngine.java:902)
                                                                               at com.android.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:788)
                                                                               at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:443)
                                                                               at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:388)
                                                                               at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:231)
                                                                               at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)
                                                                               at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java)
                                                                               at com.android.backgroundchooser.Main2Activity.getBitmapFromURL(Main2Activity.java:60)
                                                                               at com.android.backgroundchooser.Main2Activity$1.onClick(Main2Activity.java:42)
                                                                               at android.view.View.performClick(View.java:5204)
                                                                               at android.view.View$PerformClick.run(View.java:21156)
                                                                               at android.os.Handler.handleCallback(Handler.java:739)
                                                                               at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                               at android.os.Looper.loop(Looper.java:148)
                                                                               at android.app.ActivityThread.main(ActivityThread.java:5466)
                                                                               at java.lang.reflect.Method.invoke(Native Method)
                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  </code></pre>
  
  <p>Please also if someone could suggest if it is a problem with the permission as I am using a marshmallow device.</p>
  
  <p>Thanks a lot, in advance.</p>