安卓开发怎么删除数据库中所有表数据

public class DatabaseHelper extends SQLiteOpenHelper {
private static DatabaseHelper mInstance = null;

/** 数据库名称 **/
public static final String DATABASE_NAME = "xys.db";

/** 数据库版本号 **/
private static final int DATABASE_VERSION = 1;

/**数据库SQL语句 添加一个表**/
private static final String NAME_TABLE_CREATE = "create table test("
+ "_id INTEGER PRIMARY KEY AUTOINCREMENT," + "name TEXT,"+"hp INTEGER DEFAULT 100,"+ "mp INTEGER DEFAULT 100,"
+ "number INTEGER);";

DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

/**单例模式**/
static synchronized DatabaseHelper getInstance(Context context) {
if (mInstance == null) {
mInstance = new DatabaseHelper(context);
}
return mInstance;
}

@Override
public void onCreate(SQLiteDatabase db) {
/**向数据中添加表**/
db.execSQL(NAME_TABLE_CREATE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
/**可以拿到当前数据库的版本信息 与之前数据库的版本信息 用来更新数据库**/
}

/**
* 删除数据库
* @param context
* @return
*/
public boolean deleteDatabase(Context context) {
return context.deleteDatabase(DATABASE_NAME);
}
}

执行删除语句被