Android example source code file (NotesList.java)

This example Android source code file (NotesList.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, classcastexception, content, contextmenuinfo, cursor, intent, menu_item_delete, menu_item_insert, menuitem, network, noteslist, override, projection, simplecursoradapter, string, tag, ui, uri, view, widget

The NotesList.java Android example source code

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.notepad;

import com.example.android.notepad.NotePad.Notes;

import android.app.ListActivity;
import android.content.ComponentName;
import android.content.ContentUris;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

/**
 * Displays a list of notes. Will display notes from the {@link Uri}
 * provided in the intent if there is one, otherwise defaults to displaying the
 * contents of the {@link NotePadProvider}
 */
public class NotesList extends ListActivity {
    private static final String TAG = "NotesList";

    // Menu item ids
    public static final int MENU_ITEM_DELETE = Menu.FIRST;
    public static final int MENU_ITEM_INSERT = Menu.FIRST + 1;

    /**
     * The columns we are interested in from the database
     */
    private static final String[] PROJECTION = new String[] {
            Notes._ID, // 0
            Notes.TITLE, // 1
    };

    /** The index of the title column */
    private static final int COLUMN_INDEX_TITLE = 1;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setDefaultKeyMode(DEFAULT_KEYS_SHORTCUT);

        // If no data was given in the intent (because we were started
        // as a MAIN activity), then use our default content provider.
        Intent intent = getIntent();
        if (intent.getData() == null) {
            intent.setData(Notes.CONTENT_URI);
        }

        // Inform the list we provide context menus for items
        getListView().setOnCreateContextMenuListener(this);
        
        // Perform a managed query. The Activity will handle closing and requerying the cursor
        // when needed.
        Cursor cursor = managedQuery(getIntent().getData(), PROJECTION, null, null,
                Notes.DEFAULT_SORT_ORDER);

        // Used to map notes entries from the database to views
        SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.noteslist_item, cursor,
                new String[] { Notes.TITLE }, new int[] { android.R.id.text1 });
        setListAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);

        // This is our one standard application action -- inserting a
        // new note into the list.
        menu.add(0, MENU_ITEM_INSERT, 0, R.string.menu_insert)
                .setShortcut('3', 'a')
                .setIcon(android.R.drawable.ic_menu_add);

        // Generate any additional actions that can be performed on the
        // overall list.  In a normal install, there are no additional
        // actions found here, but this allows other applications to extend
        // our menu with their own actions.
        Intent intent = new Intent(null, getIntent().getData());
        intent.addCategory(Intent.CATEGORY_ALTERNATIVE);
        menu.addIntentOptions(Menu.CATEGORY_ALTERNATIVE, 0, 0,
                new ComponentName(this, NotesList.class), null, intent, 0, null);

        return true;
    }

    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        super.onPrepareOptionsMenu(menu);
        final boolean haveItems = getListAdapter().getCount() > 0;

        // If there are any notes in the list (which implies that one of
        // them is selected), then we need to generate the actions that
        // can be performed on the current selection.  This will be a combination
        // of our own specific actions along with any extensions that can be
        // found.
        if (haveItems) {
            // This is the selected item.
            Uri uri = ContentUris.withAppendedId(getIntent().getData(), getSelectedItemId());

            // Build menu...  always starts with the EDIT action...
            Intent[] specifics = new Intent[1];
            specifics[0] = new Intent(Intent.ACTION_EDIT, uri);
            MenuItem[] items = new MenuItem[1];

            // ... is followed by whatever other actions are available...
            Intent intent = new Intent(null, uri);
            intent.addCategory(Intent.CATEGORY_ALTERNATIVE);
            menu.addIntentOptions(Menu.CATEGORY_ALTERNATIVE, 0, 0, null, specifics, intent, 0,
                    items);

            // Give a shortcut to the edit action.
            if (items[0] != null) {
                items[0].setShortcut('1', 'e');
            }
        } else {
            menu.removeGroup(Menu.CATEGORY_ALTERNATIVE);
        }

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case MENU_ITEM_INSERT:
            // Launch activity to insert a new item
            startActivity(new Intent(Intent.ACTION_INSERT, getIntent().getData()));
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View view, ContextMenuInfo menuInfo) {
        AdapterView.AdapterContextMenuInfo info;
        try {
             info = (AdapterView.AdapterContextMenuInfo) menuInfo;
        } catch (ClassCastException e) {
            Log.e(TAG, "bad menuInfo", e);
            return;
        }

        Cursor cursor = (Cursor) getListAdapter().getItem(info.position);
        if (cursor == null) {
            // For some reason the requested item isn't available, do nothing
            return;
        }

        // Setup the menu header
        menu.setHeaderTitle(cursor.getString(COLUMN_INDEX_TITLE));

        // Add a menu item to delete the note
        menu.add(0, MENU_ITEM_DELETE, 0, R.string.menu_delete);
    }
        
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        AdapterView.AdapterContextMenuInfo info;
        try {
             info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
        } catch (ClassCastException e) {
            Log.e(TAG, "bad menuInfo", e);
            return false;
        }

        switch (item.getItemId()) {
            case MENU_ITEM_DELETE: {
                // Delete the note that the context menu is for
                Uri noteUri = ContentUris.withAppendedId(getIntent().getData(), info.id);
                getContentResolver().delete(noteUri, null, null);
                return true;
            }
        }
        return false;
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        Uri uri = ContentUris.withAppendedId(getIntent().getData(), id);
        
        String action = getIntent().getAction();
        if (Intent.ACTION_PICK.equals(action) || Intent.ACTION_GET_CONTENT.equals(action)) {
            // The caller is waiting for us to return a note selected by
            // the user.  The have clicked on one, so return it now.
            setResult(RESULT_OK, new Intent().setData(uri));
        } else {
            // Launch activity to view/edit the currently selected item
            startActivity(new Intent(Intent.ACTION_EDIT, uri));
        }
    }
}