Android四大组件之内容提供者
2016-07-29 本文已影响67人
kdroid
ContentProvider
是Android中提供的专门用于不同应用之间进行数据共享的方式
底层由Binder机制实现，由于系统对他做了封装，使用起来比AIDL方便许多，无需关注底层细节即可轻松进行IPC
Provider的onCreate由Server端主线程调用，所以不要做耗时任务
CRUD操作由Binder线程调用，所以可以做并发操作，不会引起堵塞
Server
// 服务端数据库
public class DbOpenHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "providers.db";
private static final int DB_VERSION = 1;
public static final String BOOK_TABLE_NAME = "book";
public static final String USER_TABLE_NAME = "user";
private static final String CREATE_BOOK_TABLE = "CREATE TABLE IF NOT EXISTS " + BOOK_TABLE_NAME + "(" +
"_id INTEGER PRIMARY KEY, " +
"name TEXT" +
")";
private static final String CREATE_USER_TABLE = "CREATE TABLE IF NOT EXISTS " + USER_TABLE_NAME + "(" +
"_id INTEGER PRIMARY KEY, " +
"name TEXT," +
"sex INTEGER" +
")";
public DbOpenHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_BOOK_TABLE);
db.execSQL(CREATE_USER_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO: 2016/7/29 ignore
}
}
// 实现内容提供者
public class CustomProvider extends ContentProvider {
public static final String TAG = "CustomProvider";
public static final String AUTHORITY = "com.rtfsc.auth.provider";
public static final Uri BOOK_CONTENT_URI = Uri.parse("content://"
+ AUTHORITY + "/book");
public static final Uri USER_CONTENT_URI = Uri.parse("content://"
+ AUTHORITY + "/user");
public static final int BOOK_URI_CODE = 0;
public static final int USER_URI_CODE = 1;
private static final UriMatcher sUriMatcher = new UriMatcher(
UriMatcher.NO_MATCH);
private Context mContext;
private SQLiteDatabase mDatabase;
static {
sUriMatcher.addURI(AUTHORITY, "book", BOOK_URI_CODE);
sUriMatcher.addURI(AUTHORITY, "user", USER_URI_CODE);
}
private String getTableName(Uri uri) {
String tableName = null;
switch (sUriMatcher.match(uri)) {
case BOOK_URI_CODE:
tableName = DbOpenHelper.BOOK_TABLE_NAME;
break;
case USER_URI_CODE:
tableName = DbOpenHelper.USER_TABLE_NAME;
break;
default:
break;
}
return tableName;
}
@Override
public boolean onCreate() {
Log.d(TAG, "onCreate, current thread: " + Thread.currentThread().getName());
mContext = getContext();
mDatabase = new DbOpenHelper(mContext).getWritableDatabase();
initData();
return true;
}
private void initData() {
mDatabase.execSQL("delete from " + DbOpenHelper.BOOK_TABLE_NAME);
mDatabase.execSQL("delete from " + DbOpenHelper.USER_TABLE_NAME);
mDatabase.execSQL("insert into " + DbOpenHelper.BOOK_TABLE_NAME + " values(1,'Android');");
mDatabase.execSQL("insert into " + DbOpenHelper.BOOK_TABLE_NAME + " values(2,'iOS');");
mDatabase.execSQL("insert into " + DbOpenHelper.BOOK_TABLE_NAME + " values(3,'Pytnon');");
mDatabase.execSQL("insert into " + DbOpenHelper.USER_TABLE_NAME + " values(1,'Wong',1);");
mDatabase.execSQL("insert into " + DbOpenHelper.USER_TABLE_NAME + " values(2,'Kim',1);");
mDatabase.execSQL("insert into " + DbOpenHelper.USER_TABLE_NAME + " values(3,'Hung',1);");
}
@Nullable
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
Log.d(TAG, "query, current thread: " + Thread.currentThread().getName());
String tableName = getTableName(uri);
if (tableName.isEmpty()) {
throw new IllegalArgumentException("Unsupport URI: " + uri);
}
return mDatabase.query(tableName, projection, selection, selectionArgs, null, null, null);
}
@Nullable
@Override
public String getType(Uri uri) {
Log.d(TAG, "getType");
return null;
}
@Nullable
@Override
public Uri insert(Uri uri, ContentValues values) {
Log.d(TAG, "insert");
String tableName = getTableName(uri);
if (tableName.isEmpty()) {
throw new IllegalArgumentException("Unsupport URI: " + uri);
}
mDatabase.insert(tableName, null, values);
mContext.getContentResolver().notifyChange(uri, null);
return uri;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
Log.d(TAG, "delete");
String tableName = getTableName(uri);
if (tableName.isEmpty()) {
throw new IllegalArgumentException("Unsupport URI: " + uri);
}
int count = mDatabase.delete(tableName, selection, selectionArgs);
if (count > 0) {
mContext.getContentResolver().notifyChange(uri, null);
}
return count;
}
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
Log.d(TAG, "update");
String tableName = getTableName(uri);
if (tableName.isEmpty()) {
throw new IllegalArgumentException("Unsupport URI: " + uri);
}
int row = mDatabase.update(tableName, values, selection, selectionArgs);
if (row > 0) {
mContext.getContentResolver().notifyChange(uri, null);
}
return row;
}
}
// 注册内容提供者
<provider
android:name="com.rtfsc.CustomProvider"
android:authorities="com.rtfsc.auth.provider"
android:permission="com.rtfsc.provider"
android:process=":provider"/>
Client
// 添加权限
<uses-permission android:name="com.rtfsc.provider"/>
public class MainActivity extends AppCompatActivity {
public static final String PROVIDER_CONTENT_PREFIX = "content://com.rtfsc.auth.provider";
private IOnChangeListener mListener = new IOnChangeListener.Stub() {
@Override
public void onChange(String aString) throws RemoteException {
System.out.println(aString);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Uri bookUri = Uri.parse(PROVIDER_CONTENT_PREFIX + "/book");
Uri userUri = Uri.parse(PROVIDER_CONTENT_PREFIX + "/user");
ContentValues contentValues = new ContentValues();
contentValues.put("_id", 4);
contentValues.put("name", "Effctive of java");
getContentResolver().insert(bookUri, contentValues);
Cursor cursor = getContentResolver().query(bookUri, new String[]{"_id", "name"}, null, null, null);
if (cursor == null) {
return;
}
while (cursor.moveToNext()) {
String id = cursor.getString(cursor.getColumnIndex("_id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
System.out.println("id = " + id + " name = " + name);
}
cursor.close();
}
}
// log
07-29 09:28:34.885 1277-1277/com.rtfsc I/System.out: id = 1 name = Android
07-29 09:28:34.885 1277-1277/com.rtfsc I/System.out: id = 2 name = iOS
07-29 09:28:34.885 1277-1277/com.rtfsc I/System.out: id = 3 name = Pytnon
07-29 09:28:34.885 1277-1277/com.rtfsc I/System.out: id = 4 name = Effctive of java
