CODEWITHSUNDEEP
android
hrskrs
hrskrs

Reputation: 4480

NullPointerException while trying to bind at SimpleCursorAdapter

I have asked a question before where i found my mistake. However now i am facing with another problem. I have checked all the similar errors asked on StackOverflow but without success.Any help is appriciated.

The idea here is that i am getting image names from DB so depending on those names images from Drawable folder will be shown in a listView together with a description but im getting an error of NullPointException at setViewValue.

Here is the code snippet:

private void populateListView() {
    ListView customListView = (ListView)findViewById(R.id.lvCustom);

    Cursor cursor = DBhelper.getAllimages();

    startManagingCursor(cursor);

    String[] from = { DBhelper.COLUMN_PIC_URL, DBhelper.COLUMN_PIC_DESC};
    int[] to = {R.id.ivImg, R.id.tvTitle};
    SimpleCursorAdapter cursorAdapter = new SimpleCursorAdapter(this, R.layout.custom_listview_row, cursor, from, to, 0);

    cursorAdapter.setViewBinder(new ViewBinder() {
        @Override
        public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
            ImageView imageImageView = (ImageView)findViewById(R.id.ivImg);
            String[] imgNames = new String[cursor.getCount()];
            int[] imgResourceIds = new int[cursor.getCount()]; 
            for(int i=0; i<cursor.getCount(); i++){
                imgNames[i] = cursor.getString(cursor.getColumnIndex(DBhelper.COLUMN_PIC_URL));
                imgResourceIds[i] = getResources().getIdentifier(imgNames[i], "drawable", getPackageName());
                imageImageView.setImageResource(imgResourceIds[i]);
                cursor.moveToNext();
            }

            return true;
        }
    });

    customListView.setAdapter(cursorAdapter);

}

Here is the Error from LogCat:

enter image description here

I have tried to log the output of imgNames[i] where it returns the url pic from the DB correctly and imgResourceIds[i] where it return the image resource id correctly also(it does not return NULL but something like: 295731). But it stops at imageImageView.setImageResource(imgResourceIds[i]);

To see from where that NullPointerException is coming, i commented out imageImageView.setImageResource(imgResourceIds[i]);. This time imageNames(those with a TAG) and imgResourceIds(those system printed out) came correctly but doubled, when i removed cursor.MoveToNext() last row were doubled. Here is the screen shot of that: enter image description here

I have tried all the suggestions on stack about gettin a NullException but without success. Any idea where i am doing mistake?

Upvotes: 0

Views: 134

Answers (3)

hrskrs
hrskrs

Reputation: 4480

Ok guys the problem was at return statement. One thing that i was ignoring was that setViewValue requires a validation about return statement.

Before starting any action in setViewValue initialise a boolean value to falseand if the action is successful assign the value totrue` and return that value:

boolean binded = false;

if(view instanceof ImageView){
//your actions
binded = true;
}

return binded;

Upvotes: 0

Simas
Simas

Reputation: 44118

It is unclear where the ImageView is actually located. But judging from this line

int[] to = {R.id.ivImg, R.id.tvTitle};

It looks like it's a part of each ListViews item. So you should be finding the view inside of the item.

Try this line and see how it goes:

ImageView imageImageView = (ImageView) view.findViewById(R.id.ivImg);

Also, I find it weird that you are looping setImageResource on the ImageView.

This is what your ViewBinder should look like:

cursorAdapter.setViewBinder(new SimpleCursorAdapter.ViewBinder() {
    @Override
    public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
        ImageView imageImageView = (ImageView) view.findViewById(R.id.ivImg);
        String name = cursor.getString(cursor.getColumnIndex(DBhelper.COLUMN_PIC_URL));
        int resourceId = getResources().getIdentifier(name, "drawable",
                getPackageName());
        imageImageView.setImageResource(resourceId);

        return true;
    }
});

Then again I don't understand why you are using a ViewBinder when the CursorAdapter can handle setting an ImageView by itself.

Upvotes: 1

user3806339
user3806339

Reputation: 144

It maybe you did not initialize the ImageView in ivImg in layout file. Check if you have defined ImageView R.id.ivImg in custom_listview_row

Upvotes: 0

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