SimpleCursorAdapter正在难以使用 [英] SimpleCursorAdapter is being difficult to use

问题描述

我一直停留在从长一个时间点，即与使用

I have been stuck at one point from long time, i.e with the use of

 SimpleCursorAdapter 

，因为它在返回正确的值失败。我见过很多类似的帖子在SO本身，说我应该在游标数据库查询添加_id列，而我应该做的。

as it fails while returning the correct value. I have seen similar many post in SO itself, saying that I should add _id column in the cursor database query, rather I should do

 db.rawQuery(String,String)

在OnCreate（..）我的code是

My code in the onCreate(..) is

HospitalData = new Database(this);
HospitalData.open();
Cursor c = HospitalData.getAllRows_Patient_Db();
startManagingCursor(c);
c.moveToFirst();

//HERE SOME LOOP IS NEEDED FOR TRAVERSING AND PUTTING IN THE LISTVIEW
while(c.isAfterLast() == false)
{
    String[] columns = new String[] { c.getString(1), c.getString(2) };
    int[] to = new int[] { R.id.room_number_db, R.id.pt_initial_db };
    adapter = new SimpleCursorAdapter(this,R.layout.patient_db, c,columns,to);
    c.moveToNext();
}
setListAdapter(adapter);

和previously我的数据库访问code是如下：

And previously my database accessing code was as follows

 public Cursor getAllRows_Patient_Db() 
{               
    return db.query(DATABASE_PATIENT_TABLE, new String[] {KEY_ROWID, KEY_ROOM_NUMBER,                             
                                                        KEY_PATIENT_INITIAL
            }, 
            null, 
            null, 
            null, 
            null, 
            null);
}

，其中KEY_ROWID定义如下

where KEY_ROWID is defined as follows

public static final String KEY_ROWID = "_id";

而与此误差

07-04 22:10:23.301: ERROR/AndroidRuntime(16795): Caused by: java.lang.IllegalArgumentException: column '90' does not exist
07-04 22:10:23.301: ERROR/AndroidRuntime(16795):     at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:314)
07-04 22:10:23.301: ERROR/AndroidRuntime(16795):     at android.widget.SimpleCursorAdapter.findColumns(SimpleCursorAdapter.java:312)

下面列90不是列ID但据我的数据库是存储在cursor.getString数据（1），但我认为这是试图寻找cursor.getString（0），这是该行的ID。

Here column 90 is not the column id but according to my database is the data stored in cursor.getString(1), but I think here it is trying to search cursor.getString(0) which is the row id.

后来我改变了我的code如下：

Later I changed my code as follows

public Cursor getAllRows_Patient_Db() 
{
  String db_sel = "SELECT id as _id, KEY_ROOM_NUMBER" +
    ",KEY_PATIENT_INITIAL FROM DATABASE_PATIENT_TABLE";

    return db.rawQuery(db_sel,null);
}

不过还是我收到错误，这个时间误差是不同的。

But still I am getting error, this time error is different

07-04 21:36:12.510: ERROR/global(9861): Deprecated Thread methods are not supported.

 07-04 21:36:12.950: ERROR/AndroidRuntime(9861): FATAL EXCEPTION: main
 07-04 21:36:12.950: ERROR/AndroidRuntime(9861): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pro/com.pro.CopyOfFirstScreen}: android.database.sqlite.SQLiteException: no such table: DATABASE_PATIENT_TABLE: , while compiling: SELECT id as _id, KEY_ROOM_NUMBER,KEY_PATIENT_INITIAL FROM DATABASE_PATIENT_TABLE

 07-04 21:36:12.950: ERROR/AndroidRuntime(9861): Caused by: android.database.sqlite.SQLiteException: no such table: DATABASE_PATIENT_TABLE: , while compiling: SELECT id as _id, KEY_ROOM_NUMBER,KEY_PATIENT_INITIAL FROM DATABASE_PATIENT_TABLE

我坚持了下来，从很长的时间，请大家帮忙！

I am stuck with it from very long time, please help!!

编辑：好的，现在有你们帮助我的查询语句是正确的，感谢您，我很抱歉，我不理解的数据库查询语法不错，但我想学习

EDIT : Okay now with you guys help my query statement is correct and thanks for that, I am sorry I am not good in understanding the syntax for database query but I am trying to learn

更改后的工作查询

String db_sel = "SELECT _id as _id, room_number" +",patient_initial FROM " + DATABASE_PATIENT_TABLE;

其实我不得不改变与键值声明字符串

Actually I had to change the declared String with the key values

public static final String KEY_ROWID = "_id";
public static final String KEY_ROOM_NUMBER = "room_number";
public static final String KEY_PATIENT_INITIAL = "patient_initial";

但现在我看到的另一个问题，是不是从查询语句，但我访问或使用simplecursorAdapter的方式

But now I see another problem that is not from the query statement but the way I am accessing or using the simplecursorAdapter

正如你可以看到我的表中有2行3列，现在我要来从列2和列3中的数据，并把它放在我的列表视图。
但我得到另一个错误从查询修复后

As you can see that my table has 2 rows and 3 columns, Now I want to fetch the data from column 2 and column 3 and put it in my listview. But after the fix from the query I am getting another error

这本来就是

   String[] columns = new String[] {c.getString(1), c.getString(2) };
        int[] to = new int[] {  R.id.room_number_db, R.id.pt_initial_db };
     adapter = new SimpleCursorAdapter(this,R.layout.patient_db, c,columns,to);
     c.moveToNext();
    setListAdapter(adapter);

和错误是

  07-05 21:32:29.228: ERROR/AndroidRuntime(1505): Caused by: java.lang.IllegalArgumentException: column '90' does not exist
  07-05 21:32:29.228: ERROR/AndroidRuntime(1505):     at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:314)
  07-05 21:32:29.228: ERROR/AndroidRuntime(1505):     at android.widget.SimpleCursorAdapter.findColumns(SimpleCursorAdapter.java:312)

android.widget.SimpleCursorAdapter.findColumns（SimpleCursorAdapter.java:312）

android.widget.SimpleCursorAdapter.findColumns(SimpleCursorAdapter.java:312)

正如你可以看到它正在试图访问访问行的第一列inspite的数据

As you can see it is trying to access the data of first column inspite of accessing the row

之后，我改变了我的code更改

After that I made changes in my code

     int x = 0;         
     String[] columns = new String[] { c.getString(0),c.getString(1), c.getString(2) };
        int[] to = new int[] { x, R.id.room_number_db, R.id.pt_initial_db };
     adapter = new SimpleCursorAdapter(this,R.layout.patient_db, c,columns,to);
     c.moveToNext();
    setListAdapter(adapter); 

这是仅仅是为了一个猜测，找出SimpleCursorAdapter运行方式不同与普通的光标，我得到的错误是

This was only a guess in order to find out how differently SimpleCursorAdapter works compared to a normal cursor and the error I get is

 07-05 21:34:47.947: ERROR/AndroidRuntime(1966): Caused by: java.lang.IllegalArgumentException: column '1' does not exist
 07-05 21:34:47.947: ERROR/AndroidRuntime(1966):     at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:314)

我知道这个问题正变得太长:-(做ü建议我从这里删除一些code。

I know this question is becoming too long :-( do u suggest me to remove some code from here.

推荐答案

在解决问题，更主要的是，我要确保我总是查询每个查询的数据库的_id，但如果我这样做cursor.getString（someIndex），那么这被作为的误导在我的情况适配器正在第一列的ROWID的内容，并试图寻找该行。

The problem is fixed, the main thing is that I should make sure I always query for the _id with each query to the database, but if I do it with cursor.getString(someIndex) then this gets misleaded as the adapter in my case is taking the content of first column as the rowid and is trying to search the row.

虚空做rawQuery（），或使用选择_id为_id的东西是强制性的。这些东西是因为我觉得有时候误导。

Nether doing rawQuery(),or using "Select _id as _id" stuffs are mandatory. these things are sometime misleading as I felt.

所以，让事情简单以下是code。
数据库code

So keeping things simple below is the code. Database code

 public Cursor getAllRows_Patient_Db() 
{               
    return db.query(DATABASE_PATIENT_TABLE, new String[] {
            KEY_ROWID, 
            KEY_ROOM_NUMBER,
            KEY_PATIENT_INITIAL
            }, 
            null, 
            null, 
            null, 
            null, 
            null);
}

活动code

    HospitalData = new Database(this);
    HospitalData.open();
    Cursor c = HospitalData.getAllRows_Patient_Db();


    startManagingCursor(c);

    String[] columns = new String[] {HospitalData.KEY_ROOM_NUMBER,HospitalData.KEY_PATIENT_INITIAL };
     int[] to = new int[] {  R.id.room_number_db, R.id.pt_initial_db };
     adapter = new SimpleCursorAdapter(this,R.layout.patient_db, c,columns,to);
     c.moveToNext();
     setListAdapter(adapter);

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