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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.apis.view;
     18 
     19 import com.example.android.apis.R;
     20 
     21 import android.app.ListActivity;
     22 import android.content.Context;
     23 import android.os.Bundle;
     24 import android.view.View;
     25 import android.view.ViewGroup;
     26 import android.view.ViewGroup.LayoutParams;
     27 import android.widget.BaseAdapter;
     28 import android.widget.Button;
     29 import android.widget.ImageView;
     30 import android.widget.AbsListView;
     31 
     32 import java.util.ArrayList;
     33 
     34 
     35 /**
     36  * A list view that demonstrates the use of setEmptyView. This example alos uses
     37  * a custom layout file that adds some extra buttons to the screen.
     38  */
     39 public class List8 extends ListActivity {
     40 
     41     PhotoAdapter mAdapter;
     42 
     43     @Override
     44     public void onCreate(Bundle savedInstanceState) {
     45         super.onCreate(savedInstanceState);
     46 
     47         // Use a custom layout file
     48         setContentView(R.layout.list_8);
     49 
     50         // Tell the list view which view to display when the list is empty
     51         getListView().setEmptyView(findViewById(R.id.empty));
     52 
     53         // Set up our adapter
     54         mAdapter = new PhotoAdapter(this);
     55         setListAdapter(mAdapter);
     56 
     57         // Wire up the clear button to remove all photos
     58         Button clear = (Button) findViewById(R.id.clear);
     59         clear.setOnClickListener(new View.OnClickListener() {
     60 
     61             public void onClick(View v) {
     62                 mAdapter.clearPhotos();
     63             } });
     64 
     65         // Wire up the add button to add a new photo
     66         Button add = (Button) findViewById(R.id.add);
     67         add.setOnClickListener(new View.OnClickListener() {
     68 
     69             public void onClick(View v) {
     70                 mAdapter.addPhotos();
     71             } });
     72     }
     73 
     74     /**
     75      * A simple adapter which maintains an ArrayList of photo resource Ids.
     76      * Each photo is displayed as an image. This adapter supports clearing the
     77      * list of photos and adding a new photo.
     78      *
     79      */
     80     public class PhotoAdapter extends BaseAdapter {
     81 
     82         private Integer[] mPhotoPool = {
     83                 R.drawable.sample_thumb_0, R.drawable.sample_thumb_1, R.drawable.sample_thumb_2,
     84                 R.drawable.sample_thumb_3, R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
     85                 R.drawable.sample_thumb_6, R.drawable.sample_thumb_7};
     86 
     87         private ArrayList<Integer> mPhotos = new ArrayList<Integer>();
     88 
     89         public PhotoAdapter(Context c) {
     90             mContext = c;
     91         }
     92 
     93         public int getCount() {
     94             return mPhotos.size();
     95         }
     96 
     97         public Object getItem(int position) {
     98             return position;
     99         }
    100 
    101         public long getItemId(int position) {
    102             return position;
    103         }
    104 
    105         public View getView(int position, View convertView, ViewGroup parent) {
    106             // Make an ImageView to show a photo
    107             ImageView i = new ImageView(mContext);
    108 
    109             i.setImageResource(mPhotos.get(position));
    110             i.setAdjustViewBounds(true);
    111             i.setLayoutParams(new AbsListView.LayoutParams(LayoutParams.WRAP_CONTENT,
    112                     LayoutParams.WRAP_CONTENT));
    113             // Give it a nice background
    114             i.setBackgroundResource(R.drawable.picture_frame);
    115             return i;
    116         }
    117 
    118         private Context mContext;
    119 
    120         public void clearPhotos() {
    121             mPhotos.clear();
    122             notifyDataSetChanged();
    123         }
    124 
    125         public void addPhotos() {
    126             int whichPhoto = (int)Math.round(Math.random() * (mPhotoPool.length - 1));
    127             int newPhoto = mPhotoPool[whichPhoto];
    128             mPhotos.add(newPhoto);
    129             notifyDataSetChanged();
    130         }
    131 
    132     }
    133 }
    134