Android example source code file (List8.java)

This example Android source code file (List8.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, arraylist, baseadapter, button, content, context, imageview, integer, list8, listactivity, object, os, override, photoadapter, ui, view, viewgroup, widget

The List8.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.apis.view;

import com.example.android.apis.R;

import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.AbsListView;

import java.util.ArrayList;


/**
 * A list view that demonstrates the use of setEmptyView. This example alos uses
 * a custom layout file that adds some extra buttons to the screen.
 */
public class List8 extends ListActivity {

    PhotoAdapter mAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Use a custom layout file
        setContentView(R.layout.list_8);
        
        // Tell the list view which view to display when the list is empty
        getListView().setEmptyView(findViewById(R.id.empty));
        
        // Set up our adapter
        mAdapter = new PhotoAdapter(this);
        setListAdapter(mAdapter);
        
        // Wire up the clear button to remove all photos
        Button clear = (Button) findViewById(R.id.clear);
        clear.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                mAdapter.clearPhotos();
            } });
        
        // Wire up the add button to add a new photo
        Button add = (Button) findViewById(R.id.add);
        add.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                mAdapter.addPhotos();
            } });
    }

    /**
     * A simple adapter which maintains an ArrayList of photo resource Ids. 
     * Each photo is displayed as an image. This adapter supports clearing the
     * list of photos and adding a new photo.
     *
     */
    public class PhotoAdapter extends BaseAdapter {

        private Integer[] mPhotoPool = {
                R.drawable.sample_thumb_0, R.drawable.sample_thumb_1, R.drawable.sample_thumb_2,
                R.drawable.sample_thumb_3, R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
                R.drawable.sample_thumb_6, R.drawable.sample_thumb_7};

        private ArrayList<Integer> mPhotos = new ArrayList();
        
        public PhotoAdapter(Context c) {
            mContext = c;
        }

        public int getCount() {
            return mPhotos.size();
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            // Make an ImageView to show a photo
            ImageView i = new ImageView(mContext);

            i.setImageResource(mPhotos.get(position));
            i.setAdjustViewBounds(true);
            i.setLayoutParams(new AbsListView.LayoutParams(LayoutParams.WRAP_CONTENT,
                    LayoutParams.WRAP_CONTENT));
            // Give it a nice background
            i.setBackgroundResource(R.drawable.picture_frame);
            return i;
        }

        private Context mContext;

        public void clearPhotos() {
            mPhotos.clear();
            notifyDataSetChanged();
        }
        
        public void addPhotos() {
            int whichPhoto = (int)Math.round(Math.random() * (mPhotoPool.length - 1));
            int newPhoto = mPhotoPool[whichPhoto];
            mPhotos.add(newPhoto);
            notifyDataSetChanged();
        }

    }
}