Android AsyncQueryHandler を使う

UI スレッド上で getContentResolver().query() とかをすると、処理が重たい場合にスレッドをブロックしてしまって ANR になることもあるので、別スレッドで非同期に query() するための AsyncQueryHandler というクラスがあります。

AsyncQueryHandler は abstract クラスなので、継承したクラスを作って、onQueryComplete() や onQueryInsertComplete() を Override し、ここで Adapter に Cursor をセットします。
こんな感じで使います。

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1. public class AsyncQueryHandlerSampleActivity extends ListActivity {  
2.   
3.     private static final String[] PHONE_PROJECTION = new String[] {  
4.         Phone._ID,  
5.         Phone.TYPE,  
6.         Phone.NUMBER  
7.     };  
8.   
9.     private static final int COLUMN_TYPE = 1;  
10.   
11.     private static final int[] COLOR_LIST = new int[] {  
12.         Color.parseColor("#002A42"),  
13.         Color.parseColor("#3DC3EA"),  
14.         Color.parseColor("#99417B"),  
15.         Color.parseColor("#F2AE30"),  
16.         Color.parseColor("#F2D338"),  
17.     };  
18.       
19.     public class CustomAsyncQueryHandler extends AsyncQueryHandler {  
20.   
21.         public CustomAsyncQueryHandler(ContentResolver cr) {  
22.             super(cr);  
23.         }  
24.           
25.         @Override  
26.         protected void onQueryComplete(int token, Object cookie, Cursor cursor) {  
27.             super.onQueryComplete(token, cookie, cursor);  
28.               
29.             SimpleCursorAdapter adapter = new SimpleCursorAdapter(  
30.                     AsyncQueryHandlerSampleActivity.this,  
31.                     android.R.layout.simple_list_item_2,   
32.                     cursor,  
33.                     new String[] { Phone.TYPE, Phone.NUMBER },  
34.                     new int[] { android.R.id.text1, android.R.id.text2 });  
35.               
36.             adapter.setViewBinder(new SimpleCursorAdapter.ViewBinder() {  
37.                   
38.                 public boolean setViewValue(View view, Cursor cursor, int columnIndex) {  
39.                     if (columnIndex == COLUMN_TYPE) {  
40.                         int type = cursor.getInt(COLUMN_TYPE);  
41.                         String text = (String) Phone.getTypeLabel(getResources(), type, null);  
42.                           
43.                         ((TextView) view).setText(text);  
44.                         ((TextView) view).setTextColor(COLOR_LIST[type % 5]);  
45.                         return true;  
46.                     }  
47.                     return false;  
48.                 }  
49.             });  
50.             setListAdapter(adapter);  
51.         }  
52.           
53.     }  
54.       
55.     @Override  
56.     protected void onCreate(Bundle savedInstanceState) {  
57.         super.onCreate(savedInstanceState);  
58.           
59.         CustomAsyncQueryHandler asyncQueryHandler = new CustomAsyncQueryHandler(getContentResolver());  
60.         asyncQueryHandler.startQuery(  
61.                 0, // token  
62.                 null, // cookie  
63.                 Phone.CONTENT_URI,  
64.                 PHONE_PROJECTION,   // projection  
65.                 null,   // selection  
66.                 null,   // selectionArgs  
67.                 null    // orderBy  
68.                 );  
69.     }  
70. }  

public class AsyncQueryHandlerSampleActivity extends ListActivity { private static final String[] PHONE_PROJECTION = new String[] { Phone._ID, Phone.TYPE, Phone.NUMBER }; private static final int COLUMN_TYPE = 1; private static final int[] COLOR_LIST = new int[] { Color.parseColor("#002A42"), Color.parseColor("#3DC3EA"), Color.parseColor("#99417B"), Color.parseColor("#F2AE30"), Color.parseColor("#F2D338"), }; public class CustomAsyncQueryHandler extends AsyncQueryHandler { public CustomAsyncQueryHandler(ContentResolver cr) { super(cr); } @Override protected void onQueryComplete(int token, Object cookie, Cursor cursor) { super.onQueryComplete(token, cookie, cursor); SimpleCursorAdapter adapter = new SimpleCursorAdapter( AsyncQueryHandlerSampleActivity.this, android.R.layout.simple_list_item_2, cursor, new String[] { Phone.TYPE, Phone.NUMBER }, new int[] { android.R.id.text1, android.R.id.text2 }); adapter.setViewBinder(new SimpleCursorAdapter.ViewBinder() { public boolean setViewValue(View view, Cursor cursor, int columnIndex) { if (columnIndex == COLUMN_TYPE) { int type = cursor.getInt(COLUMN_TYPE); String text = (String) Phone.getTypeLabel(getResources(), type, null); ((TextView) view).setText(text); ((TextView) view).setTextColor(COLOR_LIST[type % 5]); return true; } return false; } }); setListAdapter(adapter); } } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); CustomAsyncQueryHandler asyncQueryHandler = new CustomAsyncQueryHandler(getContentResolver()); asyncQueryHandler.startQuery( 0, // token null, // cookie Phone.CONTENT_URI, PHONE_PROJECTION, // projection null, // selection null, // selectionArgs null // orderBy ); } }