安卓错误: java.lang.IllegalStateException:尝试重新查询已关闭的光标
安卓错误: java.lang.IllegalStateException:尝试重新查询已关闭的光标
提问于 2011-05-07 02:33:32
环境(运行HoneyComb 3.0.1的Xoom平板电脑的Linux/Eclipse Dev )
在我的应用程序中，我使用相机(startIntentForResult())来拍照。在拍摄图片之后，我得到了onActivityResult()回调，并且能够使用通过“拍摄图片”意图传递的Uri来加载位图。此时，我的活动继续进行，尝试将图像重新加载到图库时出现错误：
FATAL EXCEPTION: main
ERROR/AndroidRuntime(4148): java.lang.RuntimeException: Unable to resume activity {...}:
java.lang.IllegalStateException: trying to requery an already closed cursor
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2243)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1019)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:126)
at android.app.ActivityThread.main(ActivityThread.java:3997)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalStateException: trying to requery an already closed cursor
at android.app.Activity.performRestart(Activity.java:4337)
at android.app.Activity.performResume(Activity.java:4360)
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2205)
... 10 more我使用的唯一光标逻辑是，在拍摄图像之后，我使用以下逻辑将Uri转换为文件
String [] projection = {
MediaStore.Images.Media._ID,
MediaStore.Images.ImageColumns.ORIENTATION,
MediaStore.Images.Media.DATA
};
Cursor cursor = activity.managedQuery(
uri,
projection, // Which columns to return
null, // WHERE clause; which rows to return (all rows)
null, // WHERE clause selection arguments (none)
null); // Order-by clause (ascending by name)
int fileColumnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
if (cursor.moveToFirst()) {
return new File(cursor.getString(fileColumnIndex));
}
return null;你知道我做错了什么吗？
回答 5
Stack Overflow用户
回答已采纳
发布于 2011-05-07 02:40:55
看起来managedQuery()调用在Honeycomb API中已被弃用。
managedQuery()的文档为：
This method is deprecated.
Use CursorLoader instead.
Wrapper around query(android.net.Uri, String[], String, String[], String)
that the resulting Cursor to call startManagingCursor(Cursor) so that the
activity will manage its lifecycle for you. **If you are targeting HONEYCOMB
or later, consider instead using LoaderManager instead, available via
getLoaderManager()**.另外，我注意到我在查询之后调用了cursor.close()，我想这是个禁忌。我也找到了这个really helpful link。经过一些阅读之后，我想出了这个似乎有效的改变。
// causes problem with the cursor in Honeycomb
Cursor cursor = activity.managedQuery(
uri,
projection, // Which columns to return
null, // WHERE clause; which rows to return (all rows)
null, // WHERE clause selection arguments (none)
null); // Order-by clause (ascending by name)
// -------------------------------------------------------------------
// works in Honeycomb
String selection = null;
String[] selectionArgs = null;
String sortOrder = null;
CursorLoader cursorLoader = new CursorLoader(
activity,
uri,
projection,
selection,
selectionArgs,
sortOrder);
Cursor cursor = cursorLoader.loadInBackground();Stack Overflow用户
发布于 2012-02-04 19:28:54
根据记录，我在我的代码(运行在Android1.6和更高版本上)中修复了这个问题:我的问题是，我无意中通过调用CursorAdapter.changeCursor()关闭了托管游标。在更改游标之前对适配器的游标调用Activity.stopManagingCursor()解决了这个问题：
// changeCursor() will close current one for us: we must stop managing it first.
Cursor currentCursor = ((SimpleCursorAdapter)getListAdapter()).getCursor(); // *** adding these lines
stopManagingCursor(currentCursor); // *** solved the problem
Cursor c = db.fetchItems(selectedDate);
startManagingCursor(c);
((SimpleCursorAdapter)getListAdapter()).changeCursor(c);Stack Overflow用户
发布于 2011-09-19 18:17:24
修复:使用context.getContentResolver().query而不是activity.managedQuery。
Cursor cursor = null;
try {
cursor = context.getContentResolver().query(uri, PROJECTION, null, null, null);
} catch(Exception e) {
e.printStackTrace();
}
return cursor;页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/5915597
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