1 /*
2  * Copyright (C) 2011 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.newsreader;
18 
19 import android.os.Bundle;
20 import android.support.v4.app.ListFragment;
21 import android.view.View;
22 import android.widget.AdapterView;
23 import android.widget.AdapterView.OnItemClickListener;
24 import android.widget.ArrayAdapter;
25 import android.widget.ListView;
26 
27 import java.util.ArrayList;
28 import java.util.List;
29 
30 /**
31  * Fragment that displays the news headlines for a particular news category.
32  *
33  * This Fragment displays a list with the news headlines for a particular news category.
34  * When an item is selected, it notifies the configured listener that a headlines was selected.
35  */
36 public class HeadlinesFragment extends ListFragment implements OnItemClickListener {
37     // The list of headlines that we are displaying
38     List<String> mHeadlinesList = new ArrayList<String>();
39 
40     // The list adapter for the list we are displaying
41     ArrayAdapter<String> mListAdapter;
42 
43     // The listener we are to notify when a headline is selected
44     OnHeadlineSelectedListener mHeadlineSelectedListener = null;
45 
46     /**
47      * Represents a listener that will be notified of headline selections.
48      */
49     public interface OnHeadlineSelectedListener {
50         /**
51          * Called when a given headline is selected.
52          * @param index the index of the selected headline.
53          */
onHeadlineSelected(int index)54         public void onHeadlineSelected(int index);
55     }
56 
57     /**
58      * Default constructor required by framework.
59      */
HeadlinesFragment()60     public HeadlinesFragment() {
61         super();
62     }
63 
64     @Override
onStart()65     public void onStart() {
66         super.onStart();
67         setListAdapter(mListAdapter);
68         getListView().setOnItemClickListener(this);
69         loadCategory(0);
70     }
71 
72     @Override
onCreate(Bundle savedInstanceState)73     public void onCreate(Bundle savedInstanceState) {
74         super.onCreate(savedInstanceState);
75         mListAdapter = new ArrayAdapter<String>(getActivity(), R.layout.headline_item,
76                 mHeadlinesList);
77     }
78 
79     /**
80      * Sets the listener that should be notified of headline selection events.
81      * @param listener the listener to notify.
82      */
setOnHeadlineSelectedListener(OnHeadlineSelectedListener listener)83     public void setOnHeadlineSelectedListener(OnHeadlineSelectedListener listener) {
84         mHeadlineSelectedListener = listener;
85     }
86 
87     /**
88      * Load and display the headlines for the given news category.
89      * @param categoryIndex the index of the news category to display.
90      */
loadCategory(int categoryIndex)91     public void loadCategory(int categoryIndex) {
92         mHeadlinesList.clear();
93         int i;
94         NewsCategory cat = NewsSource.getInstance().getCategory(categoryIndex);
95         for (i = 0; i < cat.getArticleCount(); i++) {
96             mHeadlinesList.add(cat.getArticle(i).getHeadline());
97         }
98         mListAdapter.notifyDataSetChanged();
99     }
100 
101     /**
102      * Handles a click on a headline.
103      *
104      * This causes the configured listener to be notified that a headline was selected.
105      */
106     @Override
onItemClick(AdapterView<?> parent, View view, int position, long id)107     public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
108         if (null != mHeadlineSelectedListener) {
109             mHeadlineSelectedListener.onHeadlineSelected(position);
110         }
111     }
112 
113     /** Sets choice mode for the list
114      *
115      * @param selectable whether list is to be selectable.
116      */
setSelectable(boolean selectable)117     public void setSelectable(boolean selectable) {
118         if (selectable) {
119             getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
120         }
121         else {
122             getListView().setChoiceMode(ListView.CHOICE_MODE_NONE);
123         }
124     }
125 }
126