ContentProvider使用

来源：互联网发布：淘宝综合排名规则编辑：程序博客网时间：2024/06/05 12:07

ContentProvider很少用到、用于暴漏数据给外部程序访问。

首先还是DBHelper,因为ContentProvider最终还是调用的DBHelper

public class DBHelper extends SQLiteOpenHelper {

private static final String DB_NAME = "database.db";

private static final int DB_VERSION = 1;

private SQLiteDatabase db ;

public DBHelper(Context context) {

super(context, DB_NAME, null, DB_VERSION);

db = getWritableDatabase();

}

@Override

public void onCreate(SQLiteDatabase db) {

StringBuffer sql = new StringBuffer();

sql.append( "CREATE TABLE table_like ( " );

sql.append( " _id INTEGER PRIMARY KEY, " );

sql.append( " brand_name TEXT, " );

sql.append( " short_title TEXT " );

sql.append( ") " );

db.execSQL(sql.toString());

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

if (oldVersion < newVersion) {

onCreate(db);

}

public void excuteSQL(String sql, Object... bindArgs) {

db.execSQL(sql, bindArgs);

}

public Cursor query(String sql, String... selectionArgs) {

return db .rawQuery(sql, selectionArgs);

}

public Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String orderBy) {

return db .query(table, columns, selection, selectionArgs, null, null , orderBy);

}

public long insert(String table, ContentValues values) {

return db .insert(table, null, values);

}

public int update(String table, ContentValues values, String whereClause, String[] whereArgs) {

return db .update(table, values, whereClause, whereArgs);

}

public int delete(String table, String whereClause, String[] whereArgs) {

return db .delete(table, whereClause, whereArgs);

}

//第二部、自定义contentProvider继承系统的ContentProvider（将DBhelper对象的方法进行封装）

public class MyContentProvider extends ContentProvider {

public static final UriMatcher URI_MATCHER= new UriMatcher(UriMatcher.NO_MATCH );

public static final int TUAN=1;

public static final String TUAN_NAME= "Tuan";

public static final String AUTHORITY="com.lb.contentprovider" ;//这个和注册的路径一致

private DBHelper db ;

static{

//向外暴漏的接口 uri,TUAN参数是用来判断根据TUAN来判断操作哪个表

URI_MATCHER.addURI(AUTHORITY, "tuan", TUAN);

}

@Override

public boolean onCreate() {

//实例化DB

db= new DBHelper(getContext());

return true ;

}

@Override

public int delete(Uri uri, String selection, String[] selectionArgs) {

int code = URI_MATCHER.match(uri); //得到这个uri的code码、进行判断

int row =0;

switch (code) {

case TUAN :

row= db.delete( TUAN_NAME, selection, selectionArgs);

break;

default:

break;

}

return row;

}

@Override

public String getType(Uri uri) {

return null ;

}

@Override

public Uri insert(Uri uri, ContentValues values) {

int code =URI_MATCHER.match(uri);

switch (code) {

case TUAN :

db.insert( TUAN_NAME, values);

break;

default:

break;

}

return null ;

}

@Override

public Cursor query(Uri uri, String[] projection, String selection,

String[] selectionArgs, String sortOrder) {

Cursor c = null;

int code=URI_MATCHER .match(uri);

switch (code) {

case TUAN :

c= db.query( TUAN_NAME, projection, selection, selectionArgs, sortOrder);

break;

default:

break;

}

return c;

}

@Override

public int update(Uri uri, ContentValues values, String selection,

String[] selectionArgs) {

int i =0;

int code =URI_MATCHER.match(uri);

switch (code) {

case TUAN :

i= db.update( TUAN_NAME, values, selection, selectionArgs);

break;

default:

break;

}

return i;

}

//第三部、在配置文件注册！！！

<provider

android:name="com.lb.contentprovider.MyContentProvider"

android:authorities="com.lb.contentprovider"

android:exported="true" //为true外部程序才能访问

tools:ignore="ExportedContentProvider" />

接着是另外一个apk程序来访问

插入

ContentResolver resolver = getContentResolver();

ContentValues values = new ContentValues();

values.put( "brand_name", text1 .getText().toString());

values.put( "short_title", text2 .getText().toString());

resolver.insert(Uri. parse(Constants.URI), values);

Constants. URI="content://com.lb.contentprovider/tuan" ;

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