Android_資料庫_非同步作業封裝

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/** * A particular {@link AsyncQueryHandler} allowing clients to be notified via a * listener. The {@link NotifyingAsyncQueryHandler} also make sure no strong * reference is kept on the given listener (as it is often a Context). *  */public class DBAsyncHandler extends AsyncQueryHandler {private WeakReference<DBAsyncListener> mListener;/** * Client may use this to listen to completed query operations. run on UI * Thread */public static class DBAsyncListener {public DBAsyncListener() {}/** * run on UI Thread <br /> * <b>cursor close() method needn't be called</b> */protected void onQueryComplete(int token, Object cookie, Cursor cursor) {}protected void onInsertComplete(int token, Object cookie, Uri uri) {}protected void onUpdateComplete(int token, Object cookie, int result) {}protected void onDeleteComplete(int token, Object cookie, int result) {}}/**instance in UI Thread*/public DBAsyncHandler(ContentResolver resolver, DBAsyncListener listener) {super(resolver);setDBListener(listener);}/** * Assign the given {@link DBAsyncListener}. */public void setDBListener(DBAsyncListener listener) {mListener = (listener != null) ? new WeakReference<DBAsyncListener>(listener) : null;}private DBAsyncListener getDBListener() {return (mListener == null) ? null : mListener.get();}/** such as Activity-onDestory(), this method is called */public void clearDBListener() {mListener = null;}public void startQuery(int token, Object cookie, Uri uri, String[] projection, String selection, String[] selectionArgs, String orderBy) {super.startQuery(token, cookie, uri, projection, selection, selectionArgs, orderBy);}@Overrideprotected void onQueryComplete(int token, Object cookie, Cursor cursor) {DBAsyncListener listener = getDBListener();if (listener != null) {listener.onQueryComplete(token, cookie, cursor);if (cursor != null && !cursor.isClosed())cursor.close();} else if (cursor != null) {cursor.close();}}@Overrideprotected void onDeleteComplete(int token, Object cookie, int result) {DBAsyncListener listener = getDBListener();if (listener != null) {listener.onDeleteComplete(token, cookie, result);}}@Overrideprotected void onInsertComplete(int token, Object cookie, Uri uri) {DBAsyncListener listener = getDBListener();if (listener != null) {listener.onInsertComplete(token, cookie, uri);}}@Overrideprotected void onUpdateComplete(int token, Object cookie, int result) {DBAsyncListener listener = getDBListener();if (listener != null) {listener.onUpdateComplete(token, cookie, result);}}}

public class MyProvider extends ContentProvider {private final static String TAG = MyProvider.class.getSimpleName();private final static int Person = 1;public final static String BASE = "com.baidu.my.provider";public final static Uri URI_Person = Uri.parse("content://com.baidu.my.provider/Person");private final static UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH); // 如果都匹配不成功，則返回建構函式中指定的參數值，預設為-1private SQLiteDatabase db;static {MATCHER.addURI(BASE, "Person", Person);}@Overridepublic boolean onCreate() {MyDBHelper dbHelper = new MyDBHelper(this.getContext());db = dbHelper.getWritableDatabase();return true;}@Overridepublic Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {Cursor c = null;switch (MATCHER.match(uri)) {case Person:c = db.query(DBPerson.TableName, projection, selection, selectionArgs, null, null, sortOrder);c.setNotificationUri(getContext().getContentResolver(), URI_Person);break;default:break;}return c;}@Overridepublic String getType(Uri uri) {switch (MATCHER.match(uri)) {case Person:return "vnd.android.cursor.dir/vnd." + BASE + ".request";default:break;}return null;}@Overridepublic Uri insert(Uri uri, ContentValues values) {long id = 0;switch (MATCHER.match(uri)) {case Person:id = db.insert(DBPerson.TableName, null, values);if (id > 0) {// 資料發生改變，發出通知getContext().getContentResolver().notifyChange(URI_Person, null);}return ContentUris.withAppendedId(uri, id);}return null;}@Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {// TODO Auto-generated method stubreturn 0;}@Overridepublic int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {// TODO Auto-generated method stubreturn 0;}}

public class MyDBHelper extends SQLiteOpenHelper {private static final String TAG = "DBHelper";private static final String DB_NAME = "my.db";private static final int DB_VERSION = /**/ 57 /**/;/****謹慎修改，否則將導致使用者曆史資料被刪除****/public MyDBHelper(Context context) {super(context, DB_NAME, null, DB_VERSION);}@Overridepublic void onCreate(SQLiteDatabase db) {db.execSQL(getRequestCreateStr());}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {db.execSQL("DROP TABLE IF EXISTS " + DBPerson.TableName);onCreate(db);}private String getRequestCreateStr() {StringBuffer sb = new StringBuffer();sb.append("CREATE TABLE ").append(DBPerson.TableName);sb.append(" (");sb.append(BaseColumns._ID).append(" INTEGER PRIMARY KEY,");sb.append(DBPerson.MetaDate.Name).append(" TEXT,");sb.append(DBPerson.MetaDate.Age).append(" TEXT)");return sb.toString();}}

public interface DBPerson extends BaseDB{public interface MetaDate {String Name = "Name";String Age = "Age";}public String TableName = "Person";public String[] PROJECTION = { MetaDate.Name, MetaDate.Age};public String SORT_ORDER = MetaDate.Age + " ASC";}

public class MainActivity extends Activity {private DBAsyncHandler dbAsyncHandler;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//dbAsyncHandler = new DBAsyncHandler(getContentResolver(), dbListener);}private DBAsyncHandler.DBAsyncListener dbListener = new DBAsyncListener() {protected void onQueryComplete(int token, Object cookie, Cursor cursor) {Toast.makeText(getApplicationContext(), "ok = " + cursor.getCount(), 1).show();}protected void onInsertComplete(int token, Object cookie, android.net.Uri uri) {Toast.makeText(getApplicationContext(), "插入ok！", 1).show();}};public void query(View view) {//querydbAsyncHandler.startQuery(100, null, MyProvider.URI_Person, DBPerson.PROJECTION, null, null, DBPerson.SORT_ORDER);}public void insert(View view) {//insertContentValues initialValues = new ContentValues();initialValues.put(DBPerson.MetaDate.Name, "baidu");initialValues.put(DBPerson.MetaDate.Age, System.currentTimeMillis());dbAsyncHandler.startInsert(100, null, MyProvider.URI_Person, initialValues);}@Overrideprotected void onDestroy() {//cleardbAsyncHandler.clearDBListener();super.onDestroy();}}

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Android_資料庫_非同步作業封裝