android-jamendo源码学习（三）——SearchActivity

精彩继续~~~前面介绍了android-jamendo源码学习（二）——HomeActivity ，到了主页面后面我们按照主页面中从上到下的顺序来接着介绍，在这里就来看SearchActivity的实现。

（一）首先我们先根据布局文件来分析下整个页面的布局：布局文件search.xml

search.xml

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:orientation="vertical" android:layout_width="fill_parent"
 3     android:layout_height="fill_parent" android:background="#000000">
 4 
 5     <LinearLayout android:layout_width="fill_parent"
 6         android:layout_height="wrap_content" android:background="@drawable/gradient_dark_purple"
 7         android:orientation="horizontal" android:gravity="center"
 8         android:minHeight="75dip">
 9         <EditText android:id="@+id/SearchEditText"
10             android:layout_height="wrap_content" android:layout_width="fill_parent"
11             android:layout_weight="1" android:layout_marginLeft="10dip"
12             android:layout_marginRight="10dip" android:singleLine="true"
13             android:hint="@string/search_hint"></EditText>
14         <Button android:id="@+id/SearchButton" android:layout_width="wrap_content"
15             android:layout_height="wrap_content" android:text="@string/search"
16             android:layout_marginRight="10dip"></Button>
17     </LinearLayout>
18     <android.gesture.GestureOverlayView
19         xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gestures"
20         android:layout_width="fill_parent" android:layout_height="fill_parent"
21         android:layout_weight="1" android:gestureStrokeType="multiple"
22         android:eventsInterceptionEnabled="false" android:orientation="vertical">
23         <com.teleca.jamendo.util.FixedViewFlipper
24             android:id="@+id/SearchViewFlipper" android:background="#fff"
25             android:layout_weight="1" android:layout_width="fill_parent"
26             android:layout_height="fill_parent">
27             <ListView android:layout_width="fill_parent" android:id="@+id/SearchListView"
28                 android:divider="#000" android:layout_height="fill_parent" />
29             <TextView android:layout_width="wrap_content"
30                 android:layout_height="wrap_content" android:text="@string/no_results"
31                 android:layout_gravity="center"></TextView>
32             <TextView android:layout_width="wrap_content"
33                 android:layout_height="wrap_content" android:text="@string/search_list_hint"
34                 android:layout_gravity="center"></TextView>
35         </com.teleca.jamendo.util.FixedViewFlipper>
36     </android.gesture.GestureOverlayView>
37     <LinearLayout android:id="@+id/LinearLayout"
38         android:background="@drawable/gradient_orange" android:layout_height="60dip"
39         android:layout_width="fill_parent" android:gravity="center">
40         <Spinner android:id="@+id/SearchSpinner"
41             android:layout_height="wrap_content" android:layout_width="fill_parent"
42             android:layout_marginLeft="10dip" android:layout_marginRight="10dip"></Spinner>
43     </LinearLayout>
44 
45 </LinearLayout>

 第一个LinearLayout是页面最上面的search输入框search按钮。紧接着是一个手势视图内嵌套了一个FixedViewFlipper用来显示查询之前的提示、查询成功后的结果（ListView）和查询不到结果的文字提示。最后一个还是一个LinearLayout中的一个Spinner用来显示查询方式的下拉列表。

（二）SearchActivity

首先给出源码方便大家学习：

SearchActivity

  1 /**
  2  * Allows content searching on Jamendo services
  3  * 
  4  * @author Lukasz Wisniewski
  5  */
  6 public class SearchActivity extends Activity {
  7 
  8     enum SearchMode{
  9         Artist,
 10         Tag,
 11         UserPlaylist,
 12         UserStarredAlbums
 13     };
 14 
 15     private Spinner mSearchSpinner;
 16     private ListView mSearchListView;
 17     private EditText mSearchEditText;
 18     private Button mSearchButton;
 19     private ViewFlipper mViewFlipper;
 20     private GestureOverlayView mGestureOverlayView;
 21 
 22     private PlaylistRemote[] mPlaylistRemotes = null;
 23 
 24     private SearchMode mSearchMode;
 25 
 26     /**
 27      * Launch this Activity from the outside
 28      *
 29      * @param c context from which Activity should be started
 30      */
 31     public static void launch(Context c){
 32         Intent intent = new Intent(c, SearchActivity.class);
 33         c.startActivity(intent);
 34     }
 35 
 36     /** Called when the activity is first created. */
 37     @Override
 38     public void onCreate(Bundle savedInstanceState) {
 39         super.onCreate(savedInstanceState);
 40         requestWindowFeature(Window.FEATURE_NO_TITLE);
 41         setContentView(R.layout.search);
 42 
 43         mSearchSpinner = (Spinner)findViewById(R.id.SearchSpinner);
 44         ArrayAdapter adapter = ArrayAdapter.createFromResource(
 45                 this, R.array.search_modes, android.R.layout.simple_spinner_item);
 46         adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
 47         mSearchSpinner.setAdapter(adapter);
 48 
 49         mSearchButton = (Button)findViewById(R.id.SearchButton);
 50         mSearchButton.setOnClickListener(mSearchButtonListener);
 51 
 52         mSearchEditText = (EditText)findViewById(R.id.SearchEditText);
 53         mSearchListView = (ListView)findViewById(R.id.SearchListView);
 54 
 55         mViewFlipper = (ViewFlipper)findViewById(R.id.SearchViewFlipper);
 56         if(mSearchListView.getCount() == 0){
 57             mViewFlipper.setDisplayedChild(2); // search list hint
 58         }
 59 
 60         mGestureOverlayView = (GestureOverlayView) findViewById(R.id.gestures);
 61         mGestureOverlayView.addOnGesturePerformedListener(JamendoApplication
 62                 .getInstance().getPlayerGestureHandler());
 63     }
 64 
 65     @Override
 66     protected void onResume() {
 67         super.onResume();
 68         boolean gesturesEnabled = PreferenceManager.getDefaultSharedPreferences(this).getBoolean("gestures", true);
 69         mGestureOverlayView.setEnabled(gesturesEnabled);
 70     }
 71 
 72     @SuppressWarnings("unchecked")
 73     @Override
 74     protected void onRestoreInstanceState(Bundle savedInstanceState) {
 75         mSearchMode = (SearchMode) savedInstanceState.getSerializable("mode");
 76         if(mSearchMode != null){
 77             if(mSearchMode.equals(SearchMode.Artist) 
 78                     || mSearchMode.equals(SearchMode.Tag)
 79                     || mSearchMode.equals(SearchMode.UserStarredAlbums)){
 80                 AlbumAdapter adapter = new AlbumAdapter(this);
 81                 adapter.setList((ArrayList<Album>) savedInstanceState.get("values"));
 82                 mSearchListView.setAdapter(adapter);
 83                 mSearchListView.setOnItemClickListener(mAlbumClickListener);
 84             }
 85             
 86             if(mSearchMode.equals(SearchMode.UserPlaylist)) {
 87                 PlaylistRemoteAdapter adapter = new PlaylistRemoteAdapter(this); 
 88                 adapter.setList((ArrayList<PlaylistRemote>) savedInstanceState.get("values"));
 89                 mSearchListView.setAdapter(adapter);
 90                 mSearchListView.setOnItemClickListener(mPlaylistClickListener);
 91             }
 92             
 93             mViewFlipper.setDisplayedChild(savedInstanceState.getInt("flipper_page"));
 94         }
 95         super.onRestoreInstanceState(savedInstanceState);
 96     }
 97 
 98     @Override
 99     protected void onSaveInstanceState(Bundle outState) {
100         if(mSearchMode != null){
101             outState.putSerializable("mode", mSearchMode);
102             if(mSearchMode.equals(SearchMode.Artist) 
103                     || mSearchMode.equals(SearchMode.Tag) 
104                     || mSearchMode.equals(SearchMode.UserStarredAlbums)){
105                 AlbumAdapter adapter = (AlbumAdapter)mSearchListView.getAdapter();
106                 outState.putSerializable("values", adapter.getList());
107             }
108 
109             if(mSearchMode.equals(SearchMode.UserPlaylist)) {
110                 PlaylistRemoteAdapter adapter = (PlaylistRemoteAdapter)mSearchListView.getAdapter();
111                 outState.putSerializable("values", adapter.getList());
112             }
113             
114             outState.putInt("flipper_page", mViewFlipper.getDisplayedChild());
115         }
116         super.onSaveInstanceState(outState);
117     }
118 
119     private OnClickListener mSearchButtonListener = new OnClickListener(){
120 
121         @Override
122         public void onClick(View v) {
123             new SearchingDialog(SearchActivity.this,
124                     R.string.searching,
125                     R.string.search_fail)
126             .execute(mSearchSpinner.getSelectedItemPosition());    
127         }
128 
129     };
130 
131     private OnItemClickListener mAlbumClickListener = new OnItemClickListener(){
132 
133         @Override
134         public void onItemClick(AdapterView<?> adapterView, View view, int position,
135                 long time) {
136             Album album = (Album)adapterView.getItemAtPosition(position);
137             PlayerActivity.launch(SearchActivity.this, album);
138         }
139 
140     };
141 
142     private OnItemClickListener mPlaylistClickListener = new OnItemClickListener(){
143 
144         @Override
145         public void onItemClick(AdapterView<?> adapterView, View arg1, int position,
146                 long arg3) {
147             PlaylistRemote playlistRemote = (PlaylistRemote) adapterView.getItemAtPosition(position);
148             PlayerActivity.launch(SearchActivity.this, playlistRemote);
149         }
150 
151     };
152 
153     /**
154      * Allows cancelling search query
155      * 
156      * @author Lukasz Wisniewski
157      */
158     private class SearchingDialog extends LoadingDialog<Integer, Integer>{
159 
160         private Integer mSearchMode;
161         private BaseAdapter mAdapter;
162 
163         public SearchingDialog(Activity activity, int loadingMsg, int failMsg) {
164             super(activity, loadingMsg, failMsg);
165         }
166 
167         @Override
168         public Integer doInBackground(Integer... params) {
169             mSearchMode = params[0];
170             switch(mSearchMode){
171             case 0:
172                 // artist search
173                 albumSearch(0); 
174                 break;
175             case 1:
176                 // tag search
177                 albumSearch(1); 
178                 break;
179             case 2:
180                 // playlist search
181                 playlistSearch(); 
182                 break;
183             case 3:
184                 // starred album search
185                 albumSearch(3); 
186                 break;
187             default:
188             }
189             return mSearchMode;
190         }
191 
192         @Override
193         public void doStuffWithResult(Integer result) {
194             mSearchListView.setAdapter(mAdapter);
195 
196             if(mSearchListView.getCount() > 0){
197                 mViewFlipper.setDisplayedChild(0); // display results
198             } else {
199                 mViewFlipper.setDisplayedChild(1); // display no results message
200             }
201 
202             // results are albums
203             if(mSearchMode.equals(0) || mSearchMode.equals(1) ||  mSearchMode.equals(3)){
204                 mSearchListView.setOnItemClickListener(mAlbumClickListener);
205             }
206 
207             // results are playlists
208             if(mSearchMode.equals(2)){
209                 mSearchListView.setOnItemClickListener(mPlaylistClickListener);
210             }
211         }
212 
213         private void albumSearch(int id){
214             JamendoGet2Api service = new JamendoGet2ApiImpl();
215             String query = mSearchEditText.getText().toString();
216             Album[] albums = null;
217             try {
218                 switch (id) {
219                 case 0:
220                     albums = service.searchForAlbumsByArtist(query);
221                     SearchActivity.this.mSearchMode = SearchMode.Artist;
222                     break;
223                 case 1:
224                     albums = service.searchForAlbumsByTag(query);
225                     SearchActivity.this.mSearchMode = SearchMode.Tag;
226                     break;
227                 case 3:
228                     albums = service.getUserStarredAlbums(query);
229                     SearchActivity.this.mSearchMode = SearchMode.UserStarredAlbums;
230                     break;
231 
232                 default:
233                     return;
234                 }
235 
236                 AlbumAdapter albumAdapter = new AlbumAdapter(SearchActivity.this); 
237                 albumAdapter.setList(albums);
238                 albumAdapter.setListView(mSearchListView);
239                 mAdapter = albumAdapter;
240 
241             } catch (JSONException e) {
242                 e.printStackTrace();
243             } catch (WSError e) {
244                 publishProgress(e);
245                 this.cancel(true);
246             }
247         }
248 
249         private void playlistSearch(){
250             JamendoGet2Api service = new JamendoGet2ApiImpl();
251             String user = mSearchEditText.getText().toString();
252             try {
253                 mPlaylistRemotes = service.getUserPlaylist(user);
254                 if(mPlaylistRemotes != null){
255                     PlaylistRemoteAdapter purpleAdapter = new PlaylistRemoteAdapter(SearchActivity.this);                
256                     purpleAdapter.setList(mPlaylistRemotes);
257                     mAdapter = purpleAdapter;
258                     SearchActivity.this.mSearchMode = SearchMode.UserPlaylist;
259                 }
260 
261             } catch (JSONException e) {
262                 e.printStackTrace();
263             } catch (WSError e) {
264                 publishProgress(e);
265                 this.cancel(true);
266             }
267         }
268 
269     }
270 
271 }

一、首先还是看onCreate方法：

 1 /** Called when the activity is first created. */
 2     @Override
 3     public void onCreate(Bundle savedInstanceState) {
 4         super.onCreate(savedInstanceState);
 5         requestWindowFeature(Window.FEATURE_NO_TITLE);
 6         setContentView(R.layout.search);
 7 
 8         mSearchSpinner = (Spinner)findViewById(R.id.SearchSpinner);
 9         ArrayAdapter adapter = ArrayAdapter.createFromResource(
10                 this, R.array.search_modes, android.R.layout.simple_spinner_item);
11         adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
12         mSearchSpinner.setAdapter(adapter);
13 
14         mSearchButton = (Button)findViewById(R.id.SearchButton);
15         mSearchButton.setOnClickListener(mSearchButtonListener);
16 
17         mSearchEditText = (EditText)findViewById(R.id.SearchEditText);
18         mSearchListView = (ListView)findViewById(R.id.SearchListView);
19 
20         mViewFlipper = (ViewFlipper)findViewById(R.id.SearchViewFlipper);
21         if(mSearchListView.getCount() == 0){
22             mViewFlipper.setDisplayedChild(2); // search list hint
23         }
24 
25         mGestureOverlayView = (GestureOverlayView) findViewById(R.id.gestures);
26         mGestureOverlayView.addOnGesturePerformedListener(JamendoApplication
27                 .getInstance().getPlayerGestureHandler());
28     }

oncreate中先是给SearchSpinner设置适配器，然后给SearchButton添加监听事件，最后设置GestureOverlayView的监听事件。有关gesture的请介绍移步android-jamendo源码学习——Gesture(手势)

整个方法都很简单明了，这是SearchActiviy主要功能肯定是search所以重点就落在了SearchButton的onclick事件上。下面我们来看mSearchButtonListener：

 1 private OnClickListener mSearchButtonListener = new OnClickListener(){
 2 
 3         @Override
 4         public void onClick(View v) {
 5             new SearchingDialog(SearchActivity.this,
 6                     R.string.searching,
 7                     R.string.search_fail)
 8             .execute(mSearchSpinner.getSelectedItemPosition());    
 9         }
10 
11     };

到这还没有看到真正的实现代码，onClick中只有一个SearchingDialog，继续看：

  1 /**
  2      * Allows cancelling search query
  3      * 
  4      * @author Lukasz Wisniewski
  5      */
  6     private class SearchingDialog extends LoadingDialog<Integer, Integer>{
  7 
  8         private Integer mSearchMode;
  9         private BaseAdapter mAdapter;
 10 
 11         public SearchingDialog(Activity activity, int loadingMsg, int failMsg) {
 12             super(activity, loadingMsg, failMsg);
 13         }
 14 
 15         @Override
 16         public Integer doInBackground(Integer... params) {
 17             mSearchMode = params[0];
 18             switch(mSearchMode){
 19             case 0:
 20                 // artist search
 21                 albumSearch(0); 
 22                 break;
 23             case 1:
 24                 // tag search
 25                 albumSearch(1); 
 26                 break;
 27             case 2:
 28                 // playlist search
 29                 playlistSearch(); 
 30                 break;
 31             case 3:
 32                 // starred album search
 33                 albumSearch(3); 
 34                 break;
 35             default:
 36             }
 37             return mSearchMode;
 38         }
 39 
 40         @Override
 41         public void doStuffWithResult(Integer result) {
 42             mSearchListView.setAdapter(mAdapter);
 43 
 44             if(mSearchListView.getCount() > 0){
 45                 mViewFlipper.setDisplayedChild(0); // display results
 46             } else {
 47                 mViewFlipper.setDisplayedChild(1); // display no results message
 48             }
 49 
 50             // results are albums
 51             if(mSearchMode.equals(0) || mSearchMode.equals(1) ||  mSearchMode.equals(3)){
 52                 mSearchListView.setOnItemClickListener(mAlbumClickListener);
 53             }
 54 
 55             // results are playlists
 56             if(mSearchMode.equals(2)){
 57                 mSearchListView.setOnItemClickListener(mPlaylistClickListener);
 58             }
 59         }
 60 
 61         private void albumSearch(int id){
 62             JamendoGet2Api service = new JamendoGet2ApiImpl();
 63             String query = mSearchEditText.getText().toString();
 64             Album[] albums = null;
 65             try {
 66                 switch (id) {
 67                 case 0:
 68                     albums = service.searchForAlbumsByArtist(query);
 69                     SearchActivity.this.mSearchMode = SearchMode.Artist;
 70                     break;
 71                 case 1:
 72                     albums = service.searchForAlbumsByTag(query);
 73                     SearchActivity.this.mSearchMode = SearchMode.Tag;
 74                     break;
 75                 case 3:
 76                     albums = service.getUserStarredAlbums(query);
 77                     SearchActivity.this.mSearchMode = SearchMode.UserStarredAlbums;
 78                     break;
 79 
 80                 default:
 81                     return;
 82                 }
 83 
 84                 AlbumAdapter albumAdapter = new AlbumAdapter(SearchActivity.this); 
 85                 albumAdapter.setList(albums);
 86                 albumAdapter.setListView(mSearchListView);
 87                 mAdapter = albumAdapter;
 88 
 89             } catch (JSONException e) {
 90                 e.printStackTrace();
 91             } catch (WSError e) {
 92                 publishProgress(e);
 93                 this.cancel(true);
 94             }
 95         }
 96 
 97         private void playlistSearch(){
 98             JamendoGet2Api service = new JamendoGet2ApiImpl();
 99             String user = mSearchEditText.getText().toString();
100             try {
101                 mPlaylistRemotes = service.getUserPlaylist(user);
102                 if(mPlaylistRemotes != null){
103                     PlaylistRemoteAdapter purpleAdapter = new PlaylistRemoteAdapter(SearchActivity.this);                
104                     purpleAdapter.setList(mPlaylistRemotes);
105                     mAdapter = purpleAdapter;
106                     SearchActivity.this.mSearchMode = SearchMode.UserPlaylist;
107                 }
108 
109             } catch (JSONException e) {
110                 e.printStackTrace();
111             } catch (WSError e) {
112                 publishProgress(e);
113                 this.cancel(true);
114             }
115         }
116 
117     }

好长一段代码。。。。看来是顺藤摸到瓜了，这就是整个SearchActivity中真正实现search过程的地方。

SearchingDialog这个内部类继承了LoadingDialog<Integer, Integer>，关于LoadingDialog在上一篇博客中涉及到了这里就不赘述了，想看的可以移步android-jamendo源码学习（二）——HomeActivity 。

1. 首先看doInBackground(Integer... params)，主要是根据获取searchSpinner选中的searchMode来调用不同search方法，mSearchMode = params[0];中的params[0]是调用在这个内部类的execute方法传进来的mSearchSpinner.getSelectedItemPosition()。其中涉及到了两个方法，albumSearch()和playlistSearch()。两个方法实现方法大体一样在这就以albumSearch为例分析下：

首先看albumSearch()：

 1 private void albumSearch(int id){
 2             JamendoGet2Api service = new JamendoGet2ApiImpl();
 3             String query = mSearchEditText.getText().toString();
 4             Album[] albums = null;
 5             try {
 6                 switch (id) {
 7                 case 0:
 8                     albums = service.searchForAlbumsByArtist(query);
 9                     SearchActivity.this.mSearchMode = SearchMode.Artist;
10                     break;
11                 case 1:
12                     albums = service.searchForAlbumsByTag(query);
13                     SearchActivity.this.mSearchMode = SearchMode.Tag;
14                     break;
15                 case 3:
16                     albums = service.getUserStarredAlbums(query);
17                     SearchActivity.this.mSearchMode = SearchMode.UserStarredAlbums;
18                     break;
19 
20                 default:
21                     return;
22                 }
23 
24                 AlbumAdapter albumAdapter = new AlbumAdapter(SearchActivity.this); 
25                 albumAdapter.setList(albums);
26                 albumAdapter.setListView(mSearchListView);
27                 mAdapter = albumAdapter;
28 
29             } catch (JSONException e) {
30                 e.printStackTrace();
31             } catch (WSError e) {
32                 publishProgress(e);
33                 this.cancel(true);
34             }
35         }

首先是JamendoGet2Api service = new JamendoGet2ApiImpl();获得从读取服务器的封装api，这里先不讨论api。然后根据传入的id值调用不同的方法来获取相应的内容，以id=0为例albums = service.searchForAlbumsByArtist(query); SearchActivity.this.mSearchMode = SearchMode.Artist;调用api的searchForAlbumsByArtist方法根据用户输入的mSearchEditText.getText()的查询内容来从服务器读取相应的ablum。然后设置mSearchMode。最后将获得的ablum传递给适配器albumAdapter。如果数据读取过程中捕获到WSError就调用publishProgress显示在也面上并结束线程。 这里我们要看一下这个适配器AlbumAdapter的具体内容：

AlbumAdapter

 1 /**
 2  * Adapter representing albums
 3  * 
 4  * @author Lukasz Wisniewski
 5  */
 6 public class AlbumAdapter extends ArrayListAdapter<Album> {
 7     
 8     public AlbumAdapter(Activity context) {
 9         super(context);
10     }
11 
12     @Override
13     public View getView(int position, View convertView, ViewGroup parent) {
14         View row=convertView;
15 
16         ViewHolder holder;
17 
18         if (row==null) {
19             LayoutInflater inflater = mContext.getLayoutInflater();
20             row=inflater.inflate(R.layout.album_row, null);
21 
22             holder = new ViewHolder();
23             holder.image = (RemoteImageView)row.findViewById(R.id.AlbumRowImageView);
24             holder.albumText = (TextView)row.findViewById(R.id.AlbumRowAlbumTextView);
25             holder.artistText = (TextView)row.findViewById(R.id.AlbumRowArtistTextView);
26             holder.progressBar = (ProgressBar)row.findViewById(R.id.AlbumRowRatingBar);
27 
28             row.setTag(holder);
29         }
30         else{
31             holder = (ViewHolder) row.getTag();
32         }
33         
34         holder.image.setDefaultImage(R.drawable.no_cd);
35         holder.image.setImageUrl(mList.get(position).getImage(),position, getListView());
36         holder.albumText.setText(mList.get(position).getName());
37         holder.artistText.setText(mList.get(position).getArtistName());
38         holder.progressBar.setMax(10);
39         holder.progressBar.setProgress((int) (mList.get(position).getRating()*10));
40 
41         return row;
42     }
43     
44     /**
45      * Class implementing holder pattern,
46      * performance boost
47      * 
48      * @author Lukasz Wisniewski
49      */
50     static class ViewHolder {
51         RemoteImageView image;
52         TextView albumText;
53         TextView artistText;
54         ProgressBar progressBar;
55     }
56 }

AlbumAdapter继承了ArrayListAdapter（之前介绍过），主要就是实现了ArrayListAdapter中的抽象方法getView，jamendo通过基类ArrayListAdapter提供的抽象方法分离了适配器的具体实现。AlbumAdapter没什么特别的就是把获得数据显示在相应的view上。为了避免每次调用重复创建convertView，使用了ViewHolder进行缓存配合setTag提高效率，ViewHolder是listview常用的优化方法。另外其中用到了RemoteImageView，一个ImageView的扩展类具体移步android-jamendo源码学习之ImageView扩展类——RemoteImageView 。

2. 关注doStuffWithResult(Integer result)方法，这是实现的LoadingDialog的一个抽象方法，当doInBackground方法返回值不为null时调用。

 1 @Override
 2         public void doStuffWithResult(Integer result) {
 3             mSearchListView.setAdapter(mAdapter);
 4 
 5             if(mSearchListView.getCount() > 0){
 6                 mViewFlipper.setDisplayedChild(0); // display results
 7             } else {
 8                 mViewFlipper.setDisplayedChild(1); // display no results message
 9             }
10 
11             // results are albums
12             if(mSearchMode.equals(0) || mSearchMode.equals(1) ||  mSearchMode.equals(3)){
13                 mSearchListView.setOnItemClickListener(mAlbumClickListener);
14             }
15 
16             // results are playlists
17             if(mSearchMode.equals(2)){
18                 mSearchListView.setOnItemClickListener(mPlaylistClickListener);
19             }
20         }

首先是给listview设置刚刚获取到数据的Adapter，判断listview中是否有数据，如果有mViewFlipper就显示第一个view-SearchListView，如果没有就显示第二个view-no_results。然后根据search类型不同设置相应的item点击事件。如果search的结果是albums 就设置mAlbumClickListener，如果是playlists就设置mPlaylistClickListener。简单说就是当检索结果是专辑（ablum）就设置点击事件：点击后播放该ablum，如果是播放list就设置点击事件：显示playlist的具体内容。两个监听器源码给出：

mAlbumClickListener mPlaylistClickListener

 1 private OnItemClickListener mAlbumClickListener = new OnItemClickListener(){
 2 
 3         @Override
 4         public void onItemClick(AdapterView<?> adapterView, View view, int position,
 5                 long time) {
 6             Album album = (Album)adapterView.getItemAtPosition(position);
 7             PlayerActivity.launch(SearchActivity.this, album);
 8         }
 9 
10     };
11 
12     private OnItemClickListener mPlaylistClickListener = new OnItemClickListener(){
13 
14         @Override
15         public void onItemClick(AdapterView<?> adapterView, View arg1, int position,
16                 long arg3) {
17             PlaylistRemote playlistRemote = (PlaylistRemote) adapterView.getItemAtPosition(position);
18             PlayerActivity.launch(SearchActivity.this, playlistRemote);
19         }

二、 Search状态的保存。由于search页面是基于本search页面的activity的跳转，也就是说从search跳转后有可能会再返回search页面，为了避免在返回时因为searchActivity被kill掉而没有数据，所以有必要保存。主要实现如下：

 1     @SuppressWarnings("unchecked")
 2     @Override
 3     protected void onRestoreInstanceState(Bundle savedInstanceState) {
 4         mSearchMode = (SearchMode) savedInstanceState.getSerializable("mode");
 5         if(mSearchMode != null){
 6             if(mSearchMode.equals(SearchMode.Artist) 
 7                     || mSearchMode.equals(SearchMode.Tag)
 8                     || mSearchMode.equals(SearchMode.UserStarredAlbums)){
 9                 AlbumAdapter adapter = new AlbumAdapter(this);
10                 adapter.setList((ArrayList<Album>) savedInstanceState.get("values"));
11                 mSearchListView.setAdapter(adapter);
12                 mSearchListView.setOnItemClickListener(mAlbumClickListener);
13             }
14             
15             if(mSearchMode.equals(SearchMode.UserPlaylist)) {
16                 PlaylistRemoteAdapter adapter = new PlaylistRemoteAdapter(this); 
17                 adapter.setList((ArrayList<PlaylistRemote>) savedInstanceState.get("values"));
18                 mSearchListView.setAdapter(adapter);
19                 mSearchListView.setOnItemClickListener(mPlaylistClickListener);
20             }
21             
22             mViewFlipper.setDisplayedChild(savedInstanceState.getInt("flipper_page"));
23         }
24         super.onRestoreInstanceState(savedInstanceState);
25     }
26 
27     @Override
28     protected void onSaveInstanceState(Bundle outState) {
29         if(mSearchMode != null){
30             outState.putSerializable("mode", mSearchMode);
31             if(mSearchMode.equals(SearchMode.Artist) 
32                     || mSearchMode.equals(SearchMode.Tag) 
33                     || mSearchMode.equals(SearchMode.UserStarredAlbums)){
34                 AlbumAdapter adapter = (AlbumAdapter)mSearchListView.getAdapter();
35                 outState.putSerializable("values", adapter.getList());
36             }
37 
38             if(mSearchMode.equals(SearchMode.UserPlaylist)) {
39                 PlaylistRemoteAdapter adapter = (PlaylistRemoteAdapter)mSearchListView.getAdapter();
40                 outState.putSerializable("values", adapter.getList());
41             }
42             
43             outState.putInt("flipper_page", mViewFlipper.getDisplayedChild());
44         }
45         super.onSaveInstanceState(outState);
46     }

不做太多解释了，onSaveInstanceState(Bundle outState) 保存状态，onRestoreInstanceState(Bundle savedInstanceState)回复状态。

到这里SearchActivity就介绍完了，SearchActivity相对比较简单，有些内容在之前介绍过这里就没有赘述，大家可以看看以前的博客。

今天头脑有点晕，写的可能有点乱，将就这看吧。

休息~休息一下~~~

posted @ 2013-01-18 18:58 若水恋冰阅读(1566) 评论(0) 编辑收藏举报

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android-jamendo源码学习（三）——SearchActivity

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