blocks|key|528183|text|大多数情况下，此错误的原因是未关闭的游标。确保在使用所有游标后将其关闭(即使在出现错误的情况下)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|528184|Cursor+cursor+=+null;
try+{
++++cursor+=+db.query(...
++++//+do+some+work+with+the+cursor+here.
}+finally+{
++++//+this+gets+called+even+if+there+is+an+exception+somewhere+above
++++if(cursor+!=+null)
++++++++cursor.close();
}|code-block|syntax|javascript|528185|要使你的应用程序在你不关闭光标时崩溃，你可以在你的应用程序onCreate中启用Strict+Mode+with+detectLeakedSqlLiteObjects：|offset|length|style|CODE|528186|StrictMode.VmPolicy+policy+=+new+StrictMode.VmPolicy.Builder()
+++.detectLeakedClosableObjects()
+++.detectLeakedSqlLiteObjects()
+++.penaltyDeath()
+++.penaltyLog()
+++.build();
StrictMode.setVmPolicy(policy);|528187|显然，您只需要为调试版本启用此功能。|528188|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.android.com/reference/android/os/StrictMode.VmPolicy.Builder#detectLeakedSqlLiteObjects()^0|0|0|T|8|1L|Q|14|17|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@$I|11|J|12|K|L]|$I|13|J|14|K|L]]|9|@$I|15|J|16|1|17]]|A|$]]|$1|M|3|N|5|D|7|18|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|19|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]]]

Most often the cause for this error are non closed cursors. Make sure you close all cursors after using them (even in the case of an error).

<pre><code>Cursor cursor = null;
try {
 cursor = db.query(...
 // do some work with the cursor here.
} finally {
 // this gets called even if there is an exception somewhere above
 if(cursor != null)
 cursor.close();
}
</code></pre>

To make your App crash when you are not closing a cursor you can enable <a href="https://developer.android.com/reference/android/os/StrictMode.VmPolicy.Builder#detectLeakedSqlLiteObjects()" rel="noreferrer">Strict Mode with <code>detectLeakedSqlLiteObjects</code></a> in your Applications <code>onCreate</code>: 

<pre><code>StrictMode.VmPolicy policy = new StrictMode.VmPolicy.Builder()
 .detectLeakedClosableObjects()
 .detectLeakedSqlLiteObjects()
 .penaltyDeath()
 .penaltyLog()
 .build();
StrictMode.setVmPolicy(policy);
</code></pre>

Obviously you would only enable this for debug builds.

blocks|key|528260|text|我刚刚经历了这个问题-建议的答案是在有效时不关闭光标，而不是我如何修复它。当SQLite试图重新填充它的游标时，我的问题是关闭数据库。我会打开数据库，查询数据库以获得指向数据集的游标，然后关闭数据库并迭代游标。我注意到，每当我点击光标上的某个记录时，我的应用程序都会崩溃，并在操作中出现同样的错误。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|528261|我假设为了让游标访问某些记录，它需要重新查询数据库，如果数据库被关闭，它将抛出这个错误。我修复了它，直到我完成了所有需要的工作才关闭数据库。|528262|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I have just experienced this issue - and the the suggested answer of not closing the cursor while valid, was not how I fixed it. My issue was closing the database when SQLite was trying to repopulate it's cursor. I would open the database, query the database to get a cursor to a data set, close the database and iterate over the cursor. I noticed whenever I hit a certain record in that cursor, my app would crash with this same error in OP.

I assume that for the cursor to access certain records, it needs to re-query the database and if it is closed, it will throw this error. I fixed it by not closing the database until I had completed all the work I needed.

blocks|key|311412|text|如果您必须深入研究大量的SQL代码，那么可以通过在MainActivity中添加以下代码片段来启用StrictMode，从而加快调试速度。如果检测到泄漏的数据库对象，那么您的应用程序现在将崩溃，日志信息将突出显示您的泄漏位置。这帮助我在几分钟内找到了一个流氓光标。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|311413|@Override
protected+void+onCreate(Bundle+savedInstanceState)+{
+++if+(BuildConfig.DEBUG)+{+++++
+++++++++StrictMode.setVmPolicy(new+StrictMode.VmPolicy.Builder()
+++++++++.detectLeakedSqlLiteObjects()
+++++++++.detectLeakedClosableObjects()
+++++++++.penaltyLog()
+++++++++.penaltyDeath()
+++++++++.build());
++++}
++++super.onCreate(savedInstanceState);
++++...
++++...|code-block|syntax|javascript|311414|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you're having to dig through a significant amount of SQL code you may be able to speed up your debugging by putting the following code snippet in your MainActivity to enable StrictMode. If leaked database objects are detected then your app will now crash with log info highlighting exactly where your leak is. This helped me locate a rogue cursor in a matter of minutes.

<pre><code>@Override
protected void onCreate(Bundle savedInstanceState) {
 if (BuildConfig.DEBUG) { 
 StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
 .detectLeakedSqlLiteObjects()
 .detectLeakedClosableObjects()
 .penaltyLog()
 .penaltyDeath()
 .build());
 }
 super.onCreate(savedInstanceState);
 ...
 ...
</code></pre>

blocks|key|528385|text|public+class+CursorWindowFixer+{

++public+static+void+fix()+{
++++try+{
++++++Field+field+=+CursorWindow.class.getDeclaredField("sCursorWindowSize");
++++++field.setAccessible(true);
++++++field.set(null,+102400+*+1024);
++++}+catch+(Exception+e)+{
++++++e.printStackTrace();
++++}
++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|528386|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>public class CursorWindowFixer {

 public static void fix() {
 try {
 Field field = CursorWindow.class.getDeclaredField("sCursorWindowSize");
 field.setAccessible(true);
 field.set(null, 102400 * 1024);
 } catch (Exception e) {
 e.printStackTrace();
 }
 }
}
</code></pre>

blocks|key|528456|text|Android+SQLite光标窗口确实有一个最大大小，那就是2MB，任何超过这个大小的都会导致上面的错误。大多数情况下，此错误是由sql数据库中存储为blob的大型图像字节数组或过长的字符串引起的。下面是我修复它的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|528457|创建一个java类。FixCursorWindow并将以下代码放入其中。|528458|++++public+static+void+fix()+{
++++++++try+{
++++++++++++Field+field+=+CursorWindow.class.getDeclaredField("sCursorWindowSize");
++++++++++++field.setAccessible(true);
++++++++++++field.set(null,+102400+*+1024);+//the+102400+is+the+new+size+added
++++++++}+catch+(Exception+e)+{
++++++++++++e.printStackTrace();
++++++++}
++++}|code-block|syntax|javascript|528459|现在转到您的应用程序类(如果您还没有的话，创建一个)并调用FixCursorWindow，如下所示|528460|公共类App扩展应用程序{|528461|public+void+onCreate()
{
++++super.onCreate();
++++CursorWindowFixer.fix();

}|528462|}|528463|最后，确保在应用程序标记的清单中包含应用程序类，如下所示|528464|++++android:name=".App">|528465|仅此而已，它现在应该可以完美地工作了。|528466|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|13|8|@]|9|@]|A|$G|H]]|$1|O|3|P|5|6|7|14|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|15|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|17|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|X|$]]

There is indeed a maximum size Android SQLite cursor windows can take and that is 2MB, anything more than this size would result into the above error. Mostly, this error is either caused by a large image byte array stored as blob in sql database or too long strings. Here is how i fixed it.

Create a java class eg. FixCursorWindow and put below code in it.

<pre><code> public static void fix() {
 try {
 Field field = CursorWindow.class.getDeclaredField("sCursorWindowSize");
 field.setAccessible(true);
 field.set(null, 102400 * 1024); //the 102400 is the new size added
 } catch (Exception e) {
 e.printStackTrace();
 }
 }
</code></pre>

Now go to your application class (create one if you don't have already) and make a call to the FixCursorWindow like this

public class App extends Application {

<pre><code>public void onCreate()
{
 super.onCreate();
 CursorWindowFixer.fix();

}
</code></pre>

}

Finally, ensure you include your application class in your manifest on the application tag like this



<pre><code> android:name=".App"&gt;
</code></pre>

That's all, it should work perfectly now.

blocks|key|528546|text|特别是当我们使用外部SQLite时，这是一个正常的异常。您可以通过关闭Cursor对象来解决此问题，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|528547|if(myCursor+!=+null)
++++++++myCursor.close();|code-block|syntax|javascript|528548|它的意思是，如果游标有内存，并且它是打开的，那么关闭它，这样应用程序就会更快，所有的方法都会占用更少的空间，并且与数据库相关的功能也会得到改进。|528549|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

This is a Normal Exception while we are using External SQLite especially. You can resolve it by closing the Cursor Object just like as follow:

<pre><code>if(myCursor != null)
 myCursor.close();
</code></pre>

What it means is, IF the cursor has memory and it's opened then close it so the Application will be faster, all the Methods will take less space, and the functionalities related to the Database will also be improved.

blocks|key|311614|text|如果你运行的是Android+P，你可以创建自己的光标窗口，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|311615|if(cursor+instanceof+SQLiteCursor+&&+Build.VERSION.SDK_INT+>=+Build.VERSION_CODES.P)+{
++++((SQLiteCursor)+cursor).setWindow(new+CursorWindow(null,+1024*1024*10));
}|code-block|syntax|javascript|311616|这允许您修改特定光标的光标窗口大小，而无需求助于反射。|311617|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

If you're running Android P, you can create your own cursor window like this:

<pre><code>if(cursor instanceof SQLiteCursor &amp;&amp; Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.P) {
 ((SQLiteCursor) cursor).setWindow(new CursorWindow(null, 1024*1024*10));
}
</code></pre>

This allows you to modify the cursor window size for a specific cursor without resorting to reflections.

I have a routine that runs different queries against an SQLite database many times per second. After a while I would get the error
<code>&quot;android.database.CursorWindowAllocationException: - Cursor window allocation of 2048 kb failed. # Open Cursors = &quot;</code> appear in LogCat.
I had the app log memory usage, and indeed when usage reaches a certain limit the I get this error, implying it runs out. My intuition tells me that the database engine is creating a NEW buffer (CursorWindow) every time I run a query, and even though .close() the cursors, neither the garbage collector nor <code>SQLiteDatabase.releaseMemory()</code> are quick enough at freeing memory. I think the solution may lie in &quot;forcing&quot; the database to always write into the same buffer, and not create new ones, but I have been unable to find a way to do this. I have tried instantiating my own CursorWindow, and tried setting SQLiteCursor to it, but to no avail.
¿Any ideas?
EDIT: re example code request from @GrahamBorland:
<pre><code>public static CursorWindow cursorWindow = new CursorWindow(&quot;cursorWindow&quot;); 
public static SQLiteCursor sqlCursor;
public static void getItemsVisibleArea(GeoPoint mapCenter, int latSpan, int lonSpan) {
query = &quot;SELECT * FROM Items&quot;; //would be more complex in real code
sqlCursor = (SQLiteCursor)db.rawQuery(query, null);
sqlCursor.setWindow(cursorWindow);
}
</code></pre>
Ideally I would like to be able to <code>.setWindow()</code> before giving a new query, and have the data put into the same <code>CursorWindow</code> everytime I get new data.

SQLite Android Database Cursor window allocation of 2048 kb failed

数据库

Android

SQLite

我有一个例程，每秒多次对SQLite数据库运行不同的查询。过了一段时间，我就会得到这个错误"android.database.CursorWindowAllocationException: - Cursor window allocation of 2048 kb failed. # Open Cursors = "...

问SQLite安卓数据库光标窗口分配2048kb失败
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