Android pick image from Gallery NullPointerException?-Collection of common programming errors

I am currently trying to create an App, which allows the user to pic an image from gallery and upload it to a server. But i’m still stuck in picking an image. I followed a tutorial exactly, but when launching the activity i get a NullPointer.

Do you guys see any errors?

Thanks in advance!

Heres the code;

package de.arvidg.exampleactionbartabs;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;


public class UploadPicture extends Activity {

    private static int RESULT_LOAD_IMAGE = 1;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button buttonLoadImage = (Button) findViewById(R.id.choosepic2);
        buttonLoadImage.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {

                Intent i = new Intent(
                        Intent.ACTION_PICK,
                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

                startActivityForResult(i, RESULT_LOAD_IMAGE);
            }
        });
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
            Uri selectedImage = data.getData();
            String[] filePathColumn = { MediaStore.Images.Media.DATA };

            Cursor cursor = getContentResolver().query(selectedImage,
                    filePathColumn, null, null, null);
            cursor.moveToFirst();

            int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
            String picturePath = cursor.getString(columnIndex);
            cursor.close();

            ImageView imageView = (ImageView) findViewById(R.id.chosenPicView);
            imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));

        }


    }
}

LogCat:

03-17 10:56:35.470: W/dalvikvm(12169): threadid=1: thread exiting with uncaught exception (group=0x41e64300)
03-17 10:56:35.480: E/AndroidRuntime(12169): FATAL EXCEPTION: main
03-17 10:56:35.480: E/AndroidRuntime(12169): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.arvidg.exampleactionbartabs/de.arvidg.exampleactionbartabs.UploadPicture}: java.lang.NullPointerException
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2190)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2215)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.ActivityThread.access$600(ActivityThread.java:145)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1211)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.os.Looper.loop(Looper.java:137)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.ActivityThread.main(ActivityThread.java:4978)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at java.lang.reflect.Method.invokeNative(Native Method)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at java.lang.reflect.Method.invoke(Method.java:511)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:558)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at dalvik.system.NativeStart.main(Native Method)
03-17 10:56:35.480: E/AndroidRuntime(12169): Caused by: java.lang.NullPointerException
03-17 10:56:35.480: E/AndroidRuntime(12169):    at de.arvidg.exampleactionbartabs.UploadPicture.onCreate(UploadPicture.java:34)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.Activity.performCreate(Activity.java:5008)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
03-17 10:56:35.480: E/AndroidRuntime(12169):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
03-17 10:56:35.480: E/AndroidRuntime(12169):    ... 11 more

main.xml

Line 34 is the last bracket of that statement

buttonLoadImage.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {

                Intent i = new Intent(
                        Intent.ACTION_PICK,
                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

                startActivityForResult(i, RESULT_LOAD_IMAGE);
            }
        });

1. just change

   Button buttonLoadImage = (Button) findViewById(R.id.choosepic2);
   

   to

   Button buttonLoadImage = (Button) findViewById(R.id.selectpic);
   

   at some point in your code you have changed the id of your button in the layout file and didn’t reflect that change on the activity code.

   always double check your ids.

2. Your mistake is i think in front of you. You have given wrong id of the Button and ImageView also.

   Initialize your button with the id which you have given in your layout as below: Define your button id as R.id.selectpic.

     Button buttonLoadImage = (Button) findViewById(R.id.selectpic);
   

   And your ImageView id as R.id.imageView1 besides R.id.chosenPicView as below:

    ImageView imageView = (ImageView) findViewById(R.id.imageView1); 
   

   And then try out.

Originally posted 2013-11-16 20:49:04.