java - Android - Set ImageView to URL

Question

I am trying to set an Imageview to a URL.

Below is my code

protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.getpic);
    ImageView i = (ImageView)findViewById(R.id.ivget);

    URL url;
    try {

        url = new URL("http://0-media-cdn.foolz.us/ffuuka/board/sp/thumb/1359/41/1359419073599s.jpg");
        Bitmap image = BitmapFactory.decodeStream(url.openConnection().getInputStream());
        i.setImageBitmap(image);
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

But whenever I try to open/run the app it crashes, why isnt it working?

06-15 00:37:20.977: E/AndroidRuntime(8579): FATAL EXCEPTION: main
06-15 00:37:20.977: E/AndroidRuntime(8579): java.lang.RuntimeException: Unable to  instantiate activity  ComponentInfo{com.OptimusApps.stayhealthy/com.OptimusApps.stayhealthy.Practice2}:  java.lang.NullPointerException
06-15 00:37:20.977: E/AndroidRuntime(8579):     at   android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1993)
 06-15 00:37:20.977: E/AndroidRuntime(8579):    at  android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2104)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.app.ActivityThread.access$600(ActivityThread.java:132)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1157)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.os.Looper.loop(Looper.java:137)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.app.ActivityThread.main(ActivityThread.java:4575)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at java.lang.reflect.Method.invokeNative(Native Method)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at  java.lang.reflect.Method.invoke(Method.java:511)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at dalvik.system.NativeStart.main(Native Method)
06-15 00:37:20.977: E/AndroidRuntime(8579): Caused by: java.lang.NullPointerException
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.app.Activity.findViewById(Activity.java:1794)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at com.OptimusApps.stayhealthy.Practice2.<init>(Practice2.java:17)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at java.lang.Class.newInstanceImpl(Native Method)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at java.lang.Class.newInstance(Class.java:1319)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
06-15 00:37:20.977: E/AndroidRuntime(8579):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1984)
06-15 00:37:20.977: E/AndroidRuntime(8579):     ... 11 more

above is the logcat, I am not sure where the error is in it specificaly though..............................................................................................................................................................

Answer 1

You should not do network related operation on the main ui thread.

You can findViewById of the current view hierachy set to the activity. check if you have imageview in ivget.xml. Also use a asynctask as below and make a http get request to get the image.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="173dp"
        android:src="@drawable/ic_launcher" />

</RelativeLayout>

MainActivity.java

    public class AndroidCustomGalleryActivity extends Activity { 
ImageView iv;
Bitmap image ;
ProgressDialog pd;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    iv = (ImageView) findViewById(R.id.imageView1);
    pd = new ProgressDialog(this);
    pd.setMessage("Loading..");
    new TheTask().execute();    
}
class TheTask extends AsyncTask<Void,Void,Void>
{

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        pd.show();
    }


    @Override
    protected Void doInBackground(Void... params) {
        // TODO Auto-generated method stub
        try
        {
        //URL url = new URL( "http://a3.twimg.com/profile_images/670625317/aam-logo-v3-twitter.png");


        image = downloadBitmap("http://a3.twimg.com/profile_images/670625317/aam-logo-v3-twitter.png");
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        pd.dismiss();
        if(image!=null)
        {
            iv.setImageBitmap(image);
        }

    }   
}
 private Bitmap downloadBitmap(String url) {
     // initilize the default HTTP client object
     final DefaultHttpClient client = new DefaultHttpClient();

     //forming a HttoGet request 
     final HttpGet getRequest = new HttpGet(url);
     try {

         HttpResponse response = client.execute(getRequest);

         //check 200 OK for success
         final int statusCode = response.getStatusLine().getStatusCode();

         if (statusCode != HttpStatus.SC_OK) {
             Log.w("ImageDownloader", "Error " + statusCode + 
                     " while retrieving bitmap from " + url);
             return null;

         }

         final HttpEntity entity = response.getEntity();
         if (entity != null) {
             InputStream inputStream = null;
             try {
                 // getting contents from the stream 
                 inputStream = entity.getContent();

                 // decoding stream data back into image Bitmap that android understands
                 image = BitmapFactory.decodeStream(inputStream);


             } finally {
                 if (inputStream != null) {
                     inputStream.close();
                 }
                 entity.consumeContent();
             }
         }
     } catch (Exception e) {
         // You Could provide a more explicit error message for IOException
         getRequest.abort();
         Log.e("ImageDownloader", "Something went wrong while" +
                 " retrieving bitmap from " + url + e.toString());
     } 

     return image;
 }
}