Displaying Cursor Results from DB in ListView after OnItemClick

Question

I have an activity where I want it to display results from a database using ListView. The table has three columns: word, description, and category. On the activity page, I have a list of categories being read from an array. I want to set it up so that if you click on an item on the list (for example Cat1), the results returned from the cursor will be all words/descriptions with the category Cat1 in the DB. Currently I simply have a Toast with that category's name appear when clicked.

As it is right now, the activity does not run properly. I have read around on the web, and am not sure how to proceed. Here is the code I have so far. If anyone can help me, I would really appreciate it.

public class Categories extends ListActivity { DataBaseHelper db = new DataBaseHelper(this); private SQLiteDatabase data; int position;

private ListView list;
private String[] categories = {
    "C1", "C2", "C3", "C4",
    "C5", "C6", "C7", "C8",
    "C9", "C10", "C11", "C12"
};

@Override
public void onCreate(Bundle icicle){
    super.onCreate(icicle);
    setContentView(R.layout.cat_list);

    list = (ListView)findViewById(R.id.cat_listing);
    list.setAdapter(new ArrayAdapter<String>(this,
        R.layout.categories, categories));
    list.setTextFilterEnabled(true);

    Cursor cursor = data.rawQuery("SELECT term, desc FROM words WHERE cat = '" + categories[position] + "'", null);
    startManagingCursor(cursor);

    String columns[] = new String[] { "term", "desc" };
    int[] to = new int[] { R.id.cat_term, R.id.cat_desc };

    SimpleCursorAdapter myAdapter = new SimpleCursorAdapter(this, R.layout.cat_result, cursor, columns, to);
    this.setListAdapter(myAdapter);

    list.setOnItemClickListener(new OnItemClickListener(){

        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id){
            CharSequence text = categories[position];
            Toast toast = Toast.makeText(getApplicationContext(),
                    text, Toast.LENGTH_SHORT);
            toast.show();
        }
    });
}

}

Answer 1

I have a similar function in my app. You will need to create a XML file to define the layout for the list and call them in your java code.

Here is the example XML:

LIST:

<LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:orientation="vertical"  >
    <ListView 
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"   >
    </ListView>
    <TextView
        android:id="@+id/android:empty"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="@string/no_projects"
        android:padding="10dp"
        android:textSize="16sp"
        android:textStyle="bold"    >
    </TextView>
</LinearLayout>

This is the custom layout XML. I call it list_rows:

<LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:orientation="vertical"  >
    <TextView
        android:id="@+id/text1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
    </TextView>
    <TextView
        android:id="@+id/text2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
    </TextView>
    <TextView
        android:id="@+id/text3"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
    </TextView>
</LinearLayout>

And this is the JAVA code:

String[] fields = new String[]  {   db.TABLE_PRJ_NAME, db.TABLE_PRJ_TYPE, db.TABLE_PRJ_DESC };
    int[] views = new int[] {   /*android.R.id.text1*/ R.id.text1, R.id.text2, R.id.text3   };

    c = db.getAllProjects();
    startManagingCursor(c);

    // Set the ListView
    SimpleCursorAdapter prjName = new SimpleCursorAdapter(
            this,
            R.layout.project_list_rows,
            //android.R.layout.simple_list_item_1,
            c, fields, views);
    setListAdapter(prjName);

The onListItemClickListener

// This section of code is for handling the Click Event of the Projects List
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);

    Cursor o = (Cursor) this.getListAdapter().getItem(position);
    String projectName = o.getString(1);

    Intent showProjectDetails = new Intent(this, ProjectDetails.class);
    Bundle bundle = new Bundle();

    bundle.putString("sendProjectName", projectName);

    showProjectDetails.putExtras(bundle);
    startActivity(showProjectDetails);
}

What the new part of the code is doing is just sending the selected item to another activity through an intent. Then in the new activity, I am querying the DB using the selected item name from the bundle and displaying the result.

Do ask if you need further explanation.

Answer 2

I am making a very similar program. I'm having trouble with it as its my first program for android/java. What help I have got is from web and my step father who use to teach java.

When helping me setup a database he explained to setup my tables so categories is paired with items under it. So you would have a table for your categories including the title you will display for that category as well as your primary key. Then you need a table for the next level down from category, say title. This would include a text for title and primary key. Next you need to make another table to pair them up. A title key, category key, and primary key.

From there you will need to tell java to pair them up based off that last table.

I'm a noob so sorry I couldn't give more/better info. But anything I find on this issue I'll post here and good luck.