>>内容提供者
一。数据库操作器：
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// 这是一个新创建的类 public class PersonSqliteOpenHelper extends SQLiteOpenHelper { public PersonSqliteOpenHelper(Context context) { // 上下文，数据库文件，工厂，版本 super(context, "SqliteDB.db", null, 1); } @Override public void onCreate(SQLiteDatabase db) { String sql = "create table person(id integer primary key, name varchar(20), age integer);"; db.execSQL(sql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { if(oldVersion ==1 && newVersion ==2){ db.execSQL("alter table person add balance integer;"); System.err.println("升级啦----------------------------"); } } } |
二。创建内容提供者：
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// 新创建的类 public class MyProvider extends ContentProvider { private static final String AUTHORITY = "com.cuiweiyou.sqlitetest.provider.MyProvider"; // 对外提供的总机号，第三方拨打此号码 private static final int PRESON_INSERT_CODE = 0; // 操作person表添加的操作的uri匹配码。分机号 private static final int PERSON_DELETE_CODE = 1; private static final int PERSON_UPDATE_CODE = 2; private static final int PERSON_QUERY_ALL_CODE = 3; private static final int PERSON_QUERY_ITEM_CODE = 4; private static UriMatcher uriMatcher; // uri匹配器 private PersonSqliteOpenHelper mOpenHelper; // person表的数据库帮助对象 static { uriMatcher = new UriMatcher(UriMatcher.NO_MATCH); // 初始.无匹配 // 添加一些uri(分机号) // content://com.cuiweiyou.sqlitetest.provider.MyProvider/person/insert uriMatcher.addURI(AUTHORITY, "person/insert", PRESON_INSERT_CODE); // 0 // content://com.cuiweiyou.sqlitetest.provider.MyProvider/person/delete uriMatcher.addURI(AUTHORITY, "person/delete", PERSON_DELETE_CODE); // 1 // content://com.cuiweiyou.sqlitetest.provider.MyProvider/person/update uriMatcher.addURI(AUTHORITY, "person/update", PERSON_UPDATE_CODE); // 2 // content://com.cuiweiyou.sqlitetest.provider.MyProvider/person/queryAll uriMatcher.addURI(AUTHORITY, "person/queryAll", PERSON_QUERY_ALL_CODE); // 3 // content://com.cuiweiyou.sqlitetest.provider.MyProvider/person/query/# uriMatcher.addURI(AUTHORITY, "person/query/#", PERSON_QUERY_ITEM_CODE); // 4 } @Override public boolean onCreate() { mOpenHelper = new PersonSqliteOpenHelper(getContext()); return true; } @Override public Uri insert(Uri uri, ContentValues values) { switch (uriMatcher.match(uri)) { case PRESON_INSERT_CODE: // 添加人到person表中 SQLiteDatabase db = mOpenHelper.getWritableDatabase(); if(db.isOpen()) { long id = db.insert("person", null, values); db.close(); return ContentUris.withAppendedId(uri, id); } break; default: throw new IllegalArgumentException("uri不匹配: " + uri); } return null; } @Override public int delete(Uri uri, String selection, String[] selectionArgs) { switch (uriMatcher.match(uri)) { case PERSON_DELETE_CODE: // 在person表中删除数据的操作 SQLiteDatabase db = mOpenHelper.getWritableDatabase(); if(db.isOpen()) { int count = db.delete("person", selection, selectionArgs); db.close(); return count; } break; default: throw new IllegalArgumentException("uri不匹配: " + uri); } return 0; } @Override public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { switch (uriMatcher.match(uri)) { case PERSON_UPDATE_CODE: // 更新person表的操作 SQLiteDatabase db = mOpenHelper.getWritableDatabase(); if(db.isOpen()) { int count = db.update("person", values, selection, selectionArgs); db.close(); return count; } break; default: throw new IllegalArgumentException("uri不匹配: " + uri); } return 0; } @Override public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { SQLiteDatabase db = mOpenHelper.getReadableDatabase(); switch (uriMatcher.match(uri)) { case PERSON_QUERY_ALL_CODE: // 查询所有人的uri if(db.isOpen()) { Cursor cursor = db.query("person", projection, selection, selectionArgs, null, null, sortOrder); return cursor; // db.close(); 返回cursor结果集时, 不可以关闭数据库 } break; case PERSON_QUERY_ITEM_CODE: // 查询的是单条数据, uri末尾出有一个id if(db.isOpen()) { long id = ContentUris.parseId(uri); Cursor cursor = db.query("person", projection, "_id = ?", new String[]{id + ""}, null, null, sortOrder); return cursor; } break; default: throw new IllegalArgumentException("uri不匹配: " + uri); } return null; } @Override public String getType(Uri uri) { switch (uriMatcher.match(uri)) { case PERSON_QUERY_ALL_CODE: // 返回多条的MIME-type return "vnd.android.cursor.dir/person"; case PERSON_QUERY_ITEM_CODE: // 返回单条的MIME-TYPE return "vnd.android.cursor.item/person"; default: break; } return null; } } |
三。注册内容提供者：
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<?xml version="1.0" encoding="utf-8"?> <manifest... > <uses-sdk.../> <application...> <activity...> <intent-filter>...</intent-filter> </activity> <!-- name="内容提供者类" authorities="自定义的对外主机号" --> <provider android:name="com.cuiweiyou.sqlitetest.provider.MyProvider" android:authorities="com.cuiweiyou.sqlitetest.provider.MyProvider"/> </application> </manifest> |
>>内容观察者
一。创建内容观察者：
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// 这是程序入口类 public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // 解析器 ContentResolver resolver = getContentResolver(); // 监视自己的 对外公开的总机 Uri uri = Uri.parse("content://com.cuiweiyou.sqlitetest.provider.MyProvider"); // 一旦发生变化，就是有其他人使用了 resolver.registerContentObserver(Uri.parse("content://sms/"), true, new ContentObserver(new Handler()) { @Override public void onChange(boolean selfChange) { System.err.println("警示：有第三方调用"); } }); } } |
二。分派观察者：
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public class MyProvider extends ContentProvider { private static final String AUTHORITY = "com.cuiweiyou.sqlitetest.provider.MyProvider"; // 对外提供的总机号，第三方拨打此号码 private ... static { ... } @Override public boolean onCreate() { ... } @Override public Uri insert(Uri uri, ContentValues values) { switch (uriMatcher.match(uri)) { case PRESON_INSERT_CODE: // 添加人到person表中 SQLiteDatabase db = mOpenHelper.getWritableDatabase(); if(db.isOpen()) { long id = db.insert("person", null, values); db.close(); // 当此分机号的功能被第三方调用时，即向监听器发送通知（监听目标，监听器）。监听器的onChange方法会响应 // 发送到自身的监听器 getContext().getContentResolver().notifyChange(Uri.parse(AUTHORITY), null); return ContentUris.withAppendedId(uri, id); } break; default: throw new IllegalArgumentException("uri不匹配: " + uri); } return null; } @Override public int delete(Uri uri, String selection, String[] selectionArgs) { ... getContext().getContentResolver().notifyChange(Uri.parse(AUTHORITY), null); return count; } ... } @Override public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { ... getContext().getContentResolver().notifyChange(Uri.parse(AUTHORITY), null); return count; } ... } @Override public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { ... } @Override public String getType(Uri uri) { ... } } |
>>第三方内容使用者
一。JUnit测试注册：
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<?xml version="1.0" encoding="utf-8"?> <manifest... > <instrumentation android:name="android.test.InstrumentationTestRunner" android:targetPackage="com.cuiweiyou.myprovider"/> <uses-sdk.../> <application...> <uses-library android:name="android.test.runner"/> <activity...> <intent-filter>...</intent-filter> </activity> </application> </manifest> |
二。测试类：
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public class ProviderTest extends AndroidTestCase { private String TAG = "TextCase"; // 内容提供者的电话总机 private String uriProvider = "content://com.cuiweiyou.sqlitetest.provider.MyProvider"; public void testInsert() { Uri uri = Uri.parse(uriProvider + "/person/insert"); // 内容提供者访问对象 ContentResolver resolver = getContext().getContentResolver(); ContentValues values = new ContentValues(); values.put("name", "哈拉哈拉"); values.put("age", 30); uri = resolver.insert(uri, values); Log.i(TAG, "uri: " + uri); long id = ContentUris.parseId(uri); Log.i(TAG, "添加到: " + id); } public void testDelete() { Uri uri = Uri.parse(uriProvider + "/person/delete"); // 内容提供者访问对象 ContentResolver resolver = getContext().getContentResolver(); String where = "_id = ?"; String[] selectionArgs = {"21"}; int count = resolver.delete(uri, where, selectionArgs); Log.i(TAG, "删除行: " + count); } public void testUpdate() { Uri uri = Uri.parse(uriProvider + "/person/update"); // 内容提供者访问对象 ContentResolver resolver = getContext().getContentResolver(); ContentValues values = new ContentValues(); values.put("name", "lisi"); int count = resolver.update(uri, values, "_id = ?", new String[]{"20"}); Log.i(TAG, "更新行: " + count); } public void testQueryAll() { Uri uri = Uri.parse(uriProvider + "/person/queryAll"); // 内容提供者访问对象 ContentResolver resolver = getContext().getContentResolver(); Cursor cursor = resolver.query(uri, new String[]{"_id", "name", "age"}, null, null, "_id desc"); if(cursor != null && cursor.getCount() > 0) { int id; String name; int age; while(cursor.moveToNext()) { id = cursor.getInt(0); name = cursor.getString(1); age = cursor.getInt(2); Log.i(TAG, "id: " + id + ", name: " + name + ", age: " + age); } cursor.close(); } } public void testQuerySingleItem() { Uri uri = Uri.parse(uriProvider + "/person/query/#"); // 在uri的末尾添加一个id content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/query/20 uri = ContentUris.withAppendedId(uri, 20); // 内容提供者访问对象 ContentResolver resolver = getContext().getContentResolver(); Cursor cursor = resolver.query(uri, new String[]{"_id", "name", "age"}, null, null, null); if(cursor != null && cursor.moveToFirst()) { int id = cursor.getInt(0); String name = cursor.getString(1); int age = cursor.getInt(2); cursor.close(); Log.i(TAG, "id: " + id + ", name: " + name + ", age: " + age); } } } |
声明
本文由崔维友 威格灵 cuiweiyou vigiles cuiweiyou 原创，转载请注明出处：http://www.gaohaiyan.com/151.html
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