java.lang.NullPointerException OnClickListener

Question

I am having an issue with a click listener for a choose file button.

This is the error.

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener

I understand what a null pointer exception is and I have search thoroughly for an issue similar to mine. I tried a lot of solution for issue similar to mine but I get always an error and this is my code :

public class Main2Activity extends AppCompatActivity {

Button btnChoiseFile;
ImageView imgView;
private static final int SELECT_PICTURE = 0;
String filePath = "";

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    if((Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED ) {
            ActivityCompat.requestPermissions((Activity) this, new String[]{ Manifest.permission.WRITE_EXTERNAL_STORAGE}, 300);
        }
    }

    btnChoiseFile = (Button) findViewById(R.id.button2);
    btnChoiseFile.setOnClickListener(listenerChoiceFile);
    ImageView imgView = (ImageView) findViewById(R.id.img_view);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case SELECT_PICTURE:
            if (data != null) {


                Uri selectedImage = data.getData();
                filePath = getPath(selectedImage);
                Log.d("path", filePath);

                imgView.setImageBitmap(BitmapFactory.decodeFile(filePath));

            }
            break;
    }
    super.onActivityResult(requestCode, resultCode, data);
}

public String getPath(Uri uri) {
    String[] projection = {MediaStore.Images.Media.DATA};
    Cursor cursor = managedQuery(uri, projection, null, null, null);
    int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
    cursor.moveToFirst();
    return cursor.getString(column_index);
}

View.OnClickListener listenerChoiceFile = new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        Intent intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        startActivityForResult(intent, SELECT_PICTURE);
        intent.setType("*/*");
        startActivityForResult(intent, SELECT_PICTURE);
    }
};

}

`btnChoiseFile.setOnClickListener(new View.OnClickListener() ...` Try this version. The error maybe could be, to the error reference id `button2` or many other things. i recommmned that you should put more code... — R. García, May 18 '18 at 11:26
smple issue, check id of button given is correct by checking xml — dev, May 18 '18 at 11:31
@R.García it is ... since the ID of the button is probably incorrect, there is a NPE during the call of `setOnClickListener`. By the way, the instance `listenerChoiceFile` is initialiazed below, as a class member, it exist and isn't null — AxelH, May 18 '18 at 11:32
@R.GarcíaI have never seen compiler lie to me. Just take it as a funny manner — Shubham AgaRwal, May 18 '18 at 11:32

score 0 · Answer 1 · answered May 18 '18 at 11:31

0

Make sure you have a button with id = button2 in your activity_main layout(or that you are using the layout you intended). The button will usually only be null here if you don't have it defined in your layout.

answered May 18 '18 at 11:31

Cody W.

376
2
6

score 0 · Answer 2 · answered May 18 '18 at 11:34

0

check if u have Button with id button2 in activity_main. Post stack trace or more details

answered May 18 '18 at 11:34

Er. Pratik Chatterjee

698
7
11

Thank you , Now it works – Yassine May 18 '18 at 11:44
Welcome. Try to click the stack trace on logcat where u see the class name it will take u to the error code directly most of the times or post the stack trace from next time as it helps to identify the exact problem. – Er. Pratik Chatterjee May 18 '18 at 11:52

java.lang.NullPointerException OnClickListener

2 Answers2