创建游标适配器时崩溃

Question

我正在构建一个由游标适配器操作的列表框。创建游标适配器的调用崩溃。我已经写了下面的代码。RoomShare是保存列表的活动。MessDatabase是从SQLiteOpenHelper扩展而来的类。TempDataFromDB是保存从DB派生的ecord的临时类。DB2CursorAdapter是游标适配器。logcat-java.lang.IollegalArgumentException：列"_id"不存在。可用列：[id，参与者，Mess_NameTEXT]

public class RoomShare extends AppCompatActivity {
DB2CursorAdapter DBAdapter;
MessDatabase mdb;
Cursor cursor;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_room_share);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "text u", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
String selectQuery = "SELECT  * FROM " + TempDataFromDB.TABLE_NAME /*+ " ORDER BY " +
TempDataFromDB.COLUMN_MESS_NAME + " DESC"*/;
mdb = new MessDatabase(this);
SQLiteDatabase db = mdb.getWritableDatabase();
cursor = db.rawQuery(selectQuery, null);
DBAdapter = new DB2CursorAdapter(this, cursor, false);//---------crash here
//final ListView listview = (ListView) findViewById(R.id.listview);
//listview.setAdapter(DBAdapter);
}
---------------------------------------------------------------------------  
public class DB2CursorAdapter extends CursorAdapter {
private LayoutInflater cursorInflater;
public DB2CursorAdapter(Context context, Cursor cursor, boolean flags) {
super(context,cursor);
cursorInflater = (LayoutInflater) context.getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
// R.layout.list_row is your xml layout for each row
return cursorInflater.inflate(R.layout.db_cursor_room_share, parent, false);
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
TextView tvBody = (TextView) view.findViewById(R.id.tvBody);
TextView tvPriority = (TextView) view.findViewById(R.id.tvPriority);
// Extract properties from cursor
String id = cursor.getString(cursor.getInt(cursor.getColumnIndex(TempDataFromDB.COLUMN_ID)));
String mess_name = cursor.getString(cursor.getColumnIndex(TempDataFromDB.COLUMN_MESS_NAME));
// Populate fields with extracted properties
tvBody.setText(id);
tvPriority.setText(mess_name);
}
}
---------------------------------------------------------
public class MessDatabase extends SQLiteOpenHelper {
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "ShareRoom_db";
public MessDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(TempDataFromDB.CREATE_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//this.getWritableDatabase();
}
--------------------------------------------------------------------------------
public class TempDataFromDB {
public static final String TABLE_NAME = "Share_room";
public static final String COLUMN_ID = "id";
public static final String COLUMN_PARTICIPANTS = "Participants";
public static final String COLUMN_MESS_NAME = "Mess_Name";

private int id;
private String Participants;
String[] arrayParticipants;
private String Mess_Name;

// Create table SQL query
public static final String CREATE_TABLE =
"CREATE TABLE " + TABLE_NAME + "("
+ COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ COLUMN_PARTICIPANTS+ " TEXT,"
+ COLUMN_MESS_NAME+"TEXT"
+ ")";
public TempDataFromDB() {
}
public TempDataFromDB(int id, String Participants,String Mess) {
this.id = id;
this.Participants = Participants;
this.Mess_Name = Mess;
}
public int getId() {
return id;
}
public String getParticipants() {
//arrayParticipants = convertStringToArray(Participants);
return this.Participants;
}
public void setParticipant(String Participants) {
this.arrayParticipants = convertStringToArray(Participants);
//this.arrayParticipants = Participants;
//this.Participants = convertArrayToString(this.arrayParticipants);
}
public String getMess_Name() {
return Mess_Name;
}
public void setId(int id) {
this.id = id;
}
public void setMess_Name(String Mess_Name) {
this.Mess_Name = Mess_Name;
}
}

Answer 1

这可以通过更改来解决

public static final String COLUMN_ID = "id";
to
public static final String COLUMN_ID = "_id";

我在一篇帖子中读到，你应该使用"_id"而不是"id">