:
* 要求personid为2且name为xiaoming1
* 所以在查询时分为两步:
* 第一步:
* 解析出personid放入where查询条件
* 第二部:
* 判断是否有其他限制(如name),若有则将其
* 组拼到where查询条件.
* 详细代码见下.
*/
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteDatabase db=dbOpenHelper.getWritableDatabase();
Cursor cursor;
switch (URI_MATCHER.match(uri)) {
//查询表
case PERSONS:
cursor=db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
break;
//按照id查询某条数据
case PERSON:
//第一步:
long id=ContentUris.parseId(uri);
String where="personid="+id;
//第二步:
if(selection!=null&&!"".equals(selection.trim())){
where=selection+" and "+where;
}
cursor=db.query("person", projection, where, selectionArgs, null, null, sortOrder);
break;
default:
throw new IllegalArgumentException("unknown uri"+uri.toString());
}
return cursor;
}
/**
* 返回当前Uri所代表的数据的MIME类型.
* 如果该Uri对应的数据可能包含多条记录,那么返回
* 字符串应该以"vnd.android.cursor.dir/"开头
* 如果该Uri对应的数据只包含一条记录,那么返回
* 字符串应该以"vnd.android.cursor.item/"开头
*/
@Override
public String getType(Uri uri) {
switch (URI_MATCHER.match(uri)) {
case PERSONS:
return "vnd.android.cursor.dir/persons";
case PERSON:
return "vnd.android.cursor.item/person";
default:
throw new IllegalArgumentException("unknown uri"+uri.toString());
}
}
}
DBOpenHelper如下:
package cn.testcontentprovider;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBOpenHelper extends SQLiteOpenHelper {
public DBOpenHelper(Context context) {
super(context, "contentprovidertest.db", null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table person(personid integer primary key autoincrement,name varchar(20),phone varchar(12),salary Integer(12))");
}
//当数据库版本号发生变化时调用该方法
@Override
public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
//db.execSQL("ALTER TABLE person ADD phone varchar(12) NULL");
//db.execSQL("ALTER TABLE person ADD salary Integer NULL");
}
}
AndroidManifest.xml如下: