Passing data to two different classes from click

Question

In my app i have a ListActivity that pulls data from a Database using LoaderManager. What i want to do is when an item is clicked, i want to start another activity (that pulls data from a database and displays a grid) and also pass the id to my content provider to perform the database query via the content provider. How can do this?

I have searched for answers but i just can't seem to find one that solves this problem.

I tried to use getIntent() in the ContentProvider but i found out that getIntent() doesn't work like in this question How do I pass data between Activities in Android application?

This is the onListItemClick

   protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id); 
    startActivity(i);

}

For me to create the next activty, i need to know which item was clicked (hence id). This id i what will be passed to Content Provider

    public Cursor query(Uri uri, String[] projection, String selection,
        String[] selectionArgs, String sortOrder) {

    switch (mUriMatcher.match(uri)) {
    case QUESTIONS:
        Log.d(DBHelper.TAG, "fetching categories");
        return  myDH.fetchCatgories();

    case GRID:
        //row here is the id from my list activity
        //myDH is an instance of my DB helper class
        return myDH.fetchQuestions(row);

    default:
        throw new IllegalArgumentException("Unsupported URI: " + uri);
    }
}

I have set up a urimatcher. My question is how do i get that id from my list to become the argument for this query. I am using LoaderManager so i have to make the query from the content provider.

This is the ContentProvider class

    private static final int QUESTIONS = 1;
private static final int GRID = 2;
TestAdapter myTestAdapter;
DBHelper myDH;
private static final UriMatcher mUriMatcher;

static {
    mUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    mUriMatcher.addURI(AUTHORITY, BASE_PATH_CATEGORY, QUESTIONS);
    mUriMatcher.addURI(AUTHORITY, BASE_PATH_GRID, GRID);
}

@Override
public boolean onCreate() {
    myDH = new DBHelper(getContext());
    try {
        myDH.createDatabase();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    myDH.openDatabase();
    return true;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
        String[] selectionArgs, String sortOrder) {

    switch (mUriMatcher.match(uri)) {
    case QUESTIONS:
        Log.d(DBHelper.TAG, "fetching categories");
        return  myDH.fetchCatgories();
    case GRID:
                   //this is where i need the position that was clicked
                   //so that i can use this value in the DBHelper.
        return myDH.fetchQuestions(row);

    default:
        throw new IllegalArgumentException("Unsupported URI: " + uri);
    }
}

I am using the ContentProvider to communicate with my DBHelper. This is the relevant part of the code

  //DBHelper Code
  public Cursor fetchQuestions(long row) throws SQLException{
    Cursor cursor = myDataBase.rawQuery("select _id, used, question_level from questions_en where category" + " = " + row, null);
    return cursor;
}

The cursor returned will be used in another activity to populate a grid.

Without using LoaderManager, (this method is working but it uses the deprecated startManagingCursor) this is the relevant code for the listActivity

    @Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id); 
    Intent i = new Intent(this, QuestionSelection.class);
    i.putExtra(DBHelper.KEY_ID, id);
    startActivity(i);

}

Now in the next Activity's onCreate:

        protected void onCreate(Bundle savedInstanceState) {
    Bundle extras = getIntent().getExtras();
    rowId = extras.getLong(DBHelper.KEY_ID);
    mDbHelper = new DBHelper(this);
    try {
        mDbHelper.createDatabase();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    mDbHelper.openDatabase();
    Cursor cursor = mDbHelper.fetchQuestions(rowId);
    startManagingCursor(cursor);
    String[] from = {DBHelper.KEY_ID, "question_level", "used"};
    int[] to = {R.id.grid_text, R.id.grid_image_right, R.id.grid_image_left};
    GridView grid = (GridView)findViewById(R.id.question_grid);
    mAdapter = new SimpleCursorAdapter(this, R.layout.grid_item, cursor, from, to);
    grid.setAdapter(mAdapter);
}

Answer 1

You can pass the item position from the ListView to your activity when you start it like this:

protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id); 
    i.putExtra("itemPosition", position);
    startActivity(i);
}

Then, in the other activity, you can get the item position like this:

int itemPosition = getIntent().getIntExtra("itemPosition", -1);
if (itemPosition != -1) {
    // itemPosition is the position in the ListView where the user clicked...