Android 3.0 无法从光标窗口读取行号、列号
我有一个在 android 2.1 上运行良好的应用程序，但是当尝试将其转换到 3.0 时，我收到一个我不熟悉的光标错误。
Java.lang.IllegalStateException: 无法读取 row0、column -1 光标窗口。确保光标之前已正确初始化 从中访问数据。
所有数据都存储在 SQLite 数据库中，此代码在 android 2.1 中运行良好。在 android 3.0 中光标是否必须以不同的方式初始化？
下面列出的是我的代码。
private void OpenGroupData(){
SQLiteDatabase db = openOrCreateDatabase(DATABASE_NAME,Context.MODE_PRIVATE,null);
Cursor cur = db.rawQuery("SELECT groupid FROM properties GROUP BY GroupID" + ";" , null);
LinearLayout glayout = (LinearLayout) findViewById(R.id.Grouplayout);
LinearLayout gwindow = (LinearLayout) findViewById(R.id.groupwindow);
TextView data = new TextView(this);
glayout.addView(data);
data.setText("");
int ID = cur.getColumnIndex("groupid");
int idvalue;
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_USER);
try{
// Check if our result was valid.
cur.moveToFirst();
if (cur != null) {
// Loop through all Results
do {data = new TextView(this);
data.setTextSize(20);
data.setClickable(true);
data.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
GroupClick(v);
}
});
glayout.addView(data);
idvalue = cur.getInt(ID);
data.setId(idvalue);
data.setText("Group: " + idvalue);
}while(cur.moveToNext());
}
cur.close();
db.close();
} catch(Exception e) {
Toast.makeText(getApplicationContext(), "Open Group Exception: " + e.toString(), Toast.LENGTH_SHORT).show();
}
}
I have an application that runs fine on android 2.1, but when trying to transition it to 3.0 I get a cursor error that I'm not familar with.
Java.lang.IllegalStateException: Couldn't read row0, column -1 from
cursor window. Make sure cursor is initialized correctly before
accessing data from it.
All the data is storred in a SQLite database and this code works fine in android 2.1. Does a cursor have to be initialized differently in android 3.0?
Listed below is my code.
private void OpenGroupData(){
SQLiteDatabase db = openOrCreateDatabase(DATABASE_NAME,Context.MODE_PRIVATE,null);
Cursor cur = db.rawQuery("SELECT groupid FROM properties GROUP BY GroupID" + ";" , null);
LinearLayout glayout = (LinearLayout) findViewById(R.id.Grouplayout);
LinearLayout gwindow = (LinearLayout) findViewById(R.id.groupwindow);
TextView data = new TextView(this);
glayout.addView(data);
data.setText("");
int ID = cur.getColumnIndex("groupid");
int idvalue;
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_USER);
try{
// Check if our result was valid.
cur.moveToFirst();
if (cur != null) {
// Loop through all Results
do {data = new TextView(this);
data.setTextSize(20);
data.setClickable(true);
data.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
GroupClick(v);
}
});
glayout.addView(data);
idvalue = cur.getInt(ID);
data.setId(idvalue);
data.setText("Group: " + idvalue);
}while(cur.moveToNext());
}
cur.close();
db.close();
} catch(Exception e) {
Toast.makeText(getApplicationContext(), "Open Group Exception: " + e.toString(), Toast.LENGTH_SHORT).show();
}
}
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评论（5）
今天早些时候我遇到了同样的错误消息。事实证明，我在列名中输入了错误。因此，如果它仍然适用，您可以去检查列名称是否有拼写错误。请注意，它也区分大小写。对我来说，错误是这样的：
I ran into the same error message earlier this day. All it turned out to was that I made a typo in the column name. So, if it still applies, you could go and check the column name for typo's. Note that its case sensitive aswell. Error for me was along the lines of:
好吧，我想通了。由于某种原因，当我尝试将我的应用程序转换到 3.0 时，当我的光标移动并获取字段的列索引时，在本例中（“groupid”）它返回值 -1。当游标尝试从 -1 开始时，它会崩溃，因为它在行（0）、列（-1）处找不到记录。所以我的解决方法是在获取 id 时仅向列索引添加 1。见下文。
通过将 1 添加到列索引，似乎已经解决了问题。
Alright I figured it out. For some reason when trying to transistion my application to 3.0 when my cursor goes and gets the column index for a field, in this case ("groupid") it is returning a value of -1. When the Cursor tries to start at -1 it crashes because it can't find a record at row(0), column(-1). So my fix was to just add one to the column index when getting the id. see below.
By adding 1 to the Column index it seems to have solved the problem.
如果 getColumnIndex 返回 -1，则该列不存在。
否则它返回从零开始的列索引。
If getColumnIndex returns -1, then the column doesn't exist.
Otherwize it returnes zero-based column index.
-1 是每个 sqlite 表都应具有的 _id 列，这是 Android 框架所要求的。如果你必须在索引中添加+1，那么你就在某个地方出错了。
-1 is the _id column which every sqlite table should have as is required by the android framework. If you have to add +1 to the index you are going wrong somewhere.
如果找不到“columnName”，则从 getColumnIndex(columnName) 返回 -1 值。检查列名称
The -1 value returns form getColumnIndex(columnName) if 'columnName' can't be found. Check the column names