blocks|key|2943014|text|编写您自己的加载器，使用您的数据库类而不是内容提供者。最简单的方法是从兼容性库中获取CursorLoader类的源代码，并将提供程序查询替换为对您自己的db+helper类的查询。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2943015|entityMap^0|16|C|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Write your own loader that uses your database class instead of a content provider. The easiest way is just to take the source of the <code>CursorLoader</code> class from the compatibility library, and replace provider queries with queries to your own db helper class.

blocks|key|2943017|text|我编写了一个不需要内容提供商的simple+CursorLoader：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2943018|import+android.content.Context;
import+android.database.Cursor;
import+android.support.v4.content.AsyncTaskLoader;

/**
+*+Used+to+write+apps+that+run+on+platforms+prior+to+Android+3.0.+When+running
+*+on+Android+3.0+or+above,+this+implementation+is+still+used;+it+does+not+try
+*+to+switch+to+the+framework's+implementation.+See+the+framework+SDK
+*+documentation+for+a+class+overview.
+*
+*+This+was+based+on+the+CursorLoader+class
+*/
public+abstract+class+SimpleCursorLoader+extends+AsyncTaskLoader<Cursor>+{
++++private+Cursor+mCursor;

++++public+SimpleCursorLoader(Context+context)+{
++++++++super(context);
++++}

++++/*+Runs+on+a+worker+thread+*/
++++@Override
++++public+abstract+Cursor+loadInBackground();

++++/*+Runs+on+the+UI+thread+*/
++++@Override
++++public+void+deliverResult(Cursor+cursor)+{
++++++++if+(isReset())+{
++++++++++++//+An+async+query+came+in+while+the+loader+is+stopped
++++++++++++if+(cursor+!=+null)+{
++++++++++++++++cursor.close();
++++++++++++}
++++++++++++return;
++++++++}
++++++++Cursor+oldCursor+=+mCursor;
++++++++mCursor+=+cursor;

++++++++if+(isStarted())+{
++++++++++++super.deliverResult(cursor);
++++++++}

++++++++if+(oldCursor+!=+null+&&+oldCursor+!=+cursor+&&+!oldCursor.isClosed())+{
++++++++++++oldCursor.close();
++++++++}
++++}

++++/**
+++++*+Starts+an+asynchronous+load+of+the+contacts+list+data.+When+the+result+is+ready+the+callbacks
+++++*+will+be+called+on+the+UI+thread.+If+a+previous+load+has+been+completed+and+is+still+valid
+++++*+the+result+may+be+passed+to+the+callbacks+immediately.
+++++*+
+++++*+Must+be+called+from+the+UI+thread
+++++*/
++++@Override
++++protected+void+onStartLoading()+{
++++++++if+(mCursor+!=+null)+{
++++++++++++deliverResult(mCursor);
++++++++}
++++++++if+(takeContentChanged()+%7C%7C+mCursor+==+null)+{
++++++++++++forceLoad();
++++++++}
++++}

++++/**
+++++*+Must+be+called+from+the+UI+thread
+++++*/
++++@Override
++++protected+void+onStopLoading()+{
++++++++//+Attempt+to+cancel+the+current+load+task+if+possible.
++++++++cancelLoad();
++++}

++++@Override
++++public+void+onCanceled(Cursor+cursor)+{
++++++++if+(cursor+!=+null+&&+!cursor.isClosed())+{
++++++++++++cursor.close();
++++++++}
++++}

++++@Override
++++protected+void+onReset()+{
++++++++super.onReset();

++++++++//+Ensure+the+loader+is+stopped
++++++++onStopLoading();

++++++++if+(mCursor+!=+null+&&+!mCursor.isClosed())+{
++++++++++++mCursor.close();
++++++++}
++++++++mCursor+=+null;
++++}
}|code-block|syntax|javascript|2943019|它只需要AsyncTaskLoader类。要么是Android+3.0或更高版本的版本，要么是兼容包附带的版本。|style|CODE|2943020|我还使用了wrote+a+ListLoader，它与LoadManager兼容，用于检索通用的java.util.List集合。|2943021|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/1217628|1|https://github.com/casidiablo/groundy/blob/d60a51760582b8a03ea9a06ea7ca938d3785ea15/library/src/main/java/com/telly/groundy/loader/ListLoader.java^0|F|J|0|0|0|4|F|0|D|A|Q|B|1B|E|5|I|1|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|13|8|@$A|14|B|15|K|L]]|9|@]|C|$]]|$1|M|3|N|5|6|7|16|8|@$A|17|B|18|K|L]|$A|19|B|1A|K|L]|$A|1B|B|1C|K|L]]|9|@$A|1D|B|1E|1|1F]]|C|$]]|$1|O|3|-4|5|6|7|1G|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]|W|$5|R|S|T|C|$U|X]]]]

I wrote a <a href="https://gist.github.com/1217628" rel="noreferrer">simple CursorLoader</a> that does not need a content provider:

<pre><code>import android.content.Context;
import android.database.Cursor;
import android.support.v4.content.AsyncTaskLoader;

/**
 * Used to write apps that run on platforms prior to Android 3.0. When running
 * on Android 3.0 or above, this implementation is still used; it does not try
 * to switch to the framework's implementation. See the framework SDK
 * documentation for a class overview.
 *
 * This was based on the CursorLoader class
 */
public abstract class SimpleCursorLoader extends AsyncTaskLoader&lt;Cursor&gt; {
 private Cursor mCursor;

 public SimpleCursorLoader(Context context) {
 super(context);
 }

 /* Runs on a worker thread */
 @Override
 public abstract Cursor loadInBackground();

 /* Runs on the UI thread */
 @Override
 public void deliverResult(Cursor cursor) {
 if (isReset()) {
 // An async query came in while the loader is stopped
 if (cursor != null) {
 cursor.close();
 }
 return;
 }
 Cursor oldCursor = mCursor;
 mCursor = cursor;

 if (isStarted()) {
 super.deliverResult(cursor);
 }

 if (oldCursor != null &amp;&amp; oldCursor != cursor &amp;&amp; !oldCursor.isClosed()) {
 oldCursor.close();
 }
 }

 /**
 * Starts an asynchronous load of the contacts list data. When the result is ready the callbacks
 * will be called on the UI thread. If a previous load has been completed and is still valid
 * the result may be passed to the callbacks immediately.
 * &lt;p/&gt;
 * Must be called from the UI thread
 */
 @Override
 protected void onStartLoading() {
 if (mCursor != null) {
 deliverResult(mCursor);
 }
 if (takeContentChanged() || mCursor == null) {
 forceLoad();
 }
 }

 /**
 * Must be called from the UI thread
 */
 @Override
 protected void onStopLoading() {
 // Attempt to cancel the current load task if possible.
 cancelLoad();
 }

 @Override
 public void onCanceled(Cursor cursor) {
 if (cursor != null &amp;&amp; !cursor.isClosed()) {
 cursor.close();
 }
 }

 @Override
 protected void onReset() {
 super.onReset();

 // Ensure the loader is stopped
 onStopLoading();

 if (mCursor != null &amp;&amp; !mCursor.isClosed()) {
 mCursor.close();
 }
 mCursor = null;
 }
}
</code></pre>

It only needs the <code>AsyncTaskLoader</code> class. Either the one in Android 3.0 or higher, or the one that comes with the compatibility package.

I also <a href="https://github.com/casidiablo/groundy/blob/d60a51760582b8a03ea9a06ea7ca938d3785ea15/library/src/main/java/com/telly/groundy/loader/ListLoader.java" rel="noreferrer">wrote a <code>ListLoader</code></a> which is compatible with the <code>LoadManager</code> and is used to retrieve a generic <code>java.util.List</code> collection.

blocks|key|259807|text|SimpleCursorLoader是一个简单的解决方案，但是它不支持在数据发生变化时更新加载器。CommonsWare有一个loaderex库，它添加了一个SQLiteCursorLoader，并支持对数据更改的重新查询。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|259808|https://github.com/commonsguy/cwac-loaderex|offset|length|259809|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|17|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@$D|O|E|P|1|Q]]|A|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|C]]]]

The SimpleCursorLoader is a simple solution, however it doesn't support updating the loader when the data changes. CommonsWare has a loaderex library that adds a SQLiteCursorLoader and supports re-query on data changes.

<a href="https://github.com/commonsguy/cwac-loaderex">https://github.com/commonsguy/cwac-loaderex</a>

blocks|key|3157177|text|第三种选择是简单地覆盖loadInBackground|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3157178|public+class+CustomCursorLoader+extends+CursorLoader+{
++++private+final+ForceLoadContentObserver+mObserver+=+new+ForceLoadContentObserver();

++++@Override
++++public+Cursor+loadInBackground()+{
++++++++Cursor+cursor+=+...+//+get+your+cursor+from+wherever+you+like

++++++++if+(cursor+!=+null)+{
++++++++++++//+Ensure+the+cursor+window+is+filled
++++++++++++cursor.getCount();
++++++++++++cursor.registerContentObserver(mObserver);
++++++++}

++++++++return+cursor;
++++}
};|code-block|syntax|javascript|3157179|这还将负责在数据库更改时重新查询游标。|3157180|唯一的警告:你必须定义另一个观察者，因为Google在它的无限智慧中决定将他们的包设置为私有。如果您将类放入与原始类(或compat类)相同的包中，则可以实际使用原始观察者。观察者是一个非常轻量级的对象，不会在其他任何地方使用，所以这并没有太大的区别。|3157181|entityMap^0|B|G|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|V|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

A third option would be to simply override <code>loadInBackground</code>:

<pre><code>public class CustomCursorLoader extends CursorLoader {
 private final ForceLoadContentObserver mObserver = new ForceLoadContentObserver();

 @Override
 public Cursor loadInBackground() {
 Cursor cursor = ... // get your cursor from wherever you like

 if (cursor != null) {
 // Ensure the cursor window is filled
 cursor.getCount();
 cursor.registerContentObserver(mObserver);
 }

 return cursor;
 }
};
</code></pre>

This will also take care of re-querying your cursor when the database changes.

Only caveat: You'll have to define another observer, since Google in it's infinite wisdom decided to make theirs package private. If you put the class into the same package as the original one (or the compat one) you can actually use the original observer. The observer is a very lightweight object and isn't used anywhere else, so this doesn't make much of a difference.

blocks|key|3157262|text|Timo+Ohr提出的第三个选择，加上杨的评论，提供了最简单的答案(奥卡姆剃刀)。下面是一个为我工作的完整类的示例。使用这个类有两条规则。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3157263|当底层数据库发生变化(例如，在插入或删除之后)时，|3157264|扩展这个抽象类并实现方法getCursor()和getContentUri().|ordered-list-item|3157265|Any，请确保调用|3157266|3157267|getContentResolver().notifyChange(myUri，null)；|3157268|其中，myUri与您的方法getContentUri().的实现返回的相同|3157269|下面是我使用的类的代码：|3157270|package+com.example.project;

import+android.content.Context;
import+android.database.Cursor;
import+android.content.CursorLoader;
import+android.content.Loader;

public+abstract+class+AbstractCustomCursorLoader+extends+CursorLoader
++{
++++private+final+Loader.ForceLoadContentObserver+mObserver+=+new+Loader.ForceLoadContentObserver();

++++public+AbstractCustomCursorLoader(Context+context)
++++++{
++++++++super(context);
++++++}

++++@Override
++++public+Cursor+loadInBackground()
++++++{
++++++++Cursor+cursor+=+getCursor();

++++++++if+(cursor+!=+null)
++++++++++{
++++++++++++//+Ensure+the+cursor+window+is+filled
++++++++++++cursor.getCount();
++++++++++++cursor.registerContentObserver(mObserver);
++++++++++}

++++++++cursor.setNotificationUri(getContext().getContentResolver(),+getContentUri());
++++++++return+cursor;
++++++}

++++protected+abstract+Cursor+getCursor();
++++protected+abstract+Uri+getContentUri();
++}|code-block|syntax|javascript|3157271|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|Z|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|11|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|12|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|13|8|@]|9|@]|A|$]]|$1|P|3|Q|5|R|7|14|8|@]|9|@]|A|$S|T]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

The third option proposed by Timo Ohr, together with the comments by Yeung, provide the simplest answer (Occam's razor). Below is an example of a complete class that works for me. There are two rules for using this class.

<ol>
<li>Extend this abstract class and implement methods getCursor() and getContentUri().</li>
<li>Any time that the underlying database changes (e.g., after an insert or delete), make sure to call

<pre><code>getContentResolver().notifyChange(myUri, null);
</code></pre>

where myUri is the same one returned from your implementation of method getContentUri().</li>
</ol>

Here is the code for the class that I used:

<pre><code>package com.example.project;

import android.content.Context;
import android.database.Cursor;
import android.content.CursorLoader;
import android.content.Loader;

public abstract class AbstractCustomCursorLoader extends CursorLoader
 {
 private final Loader.ForceLoadContentObserver mObserver = new Loader.ForceLoadContentObserver();

 public AbstractCustomCursorLoader(Context context)
 {
 super(context);
 }

 @Override
 public Cursor loadInBackground()
 {
 Cursor cursor = getCursor();

 if (cursor != null)
 {
 // Ensure the cursor window is filled
 cursor.getCount();
 cursor.registerContentObserver(mObserver);
 }

 cursor.setNotificationUri(getContext().getContentResolver(), getContentUri());
 return cursor;
 }

 protected abstract Cursor getCursor();
 protected abstract Uri getContentUri();
 }
</code></pre>

Android SDK documentation says that <code>startManagingCursor()</code> method is depracated:

<blockquote>
 This method is deprecated. Use the new CursorLoader class with LoaderManager instead; this is also available on older platforms through the Android compatibility package. This method allows the activity to take care of managing the given Cursor's lifecycle for you based on the activity's lifecycle. That is, when the activity is stopped it will automatically call deactivate() on the given Cursor, and when it is later restarted it will call requery() for you. When the activity is destroyed, all managed Cursors will be closed automatically. If you are targeting HONEYCOMB or later, consider instead using LoaderManager instead, available via getLoaderManager()
</blockquote>

So I would like to use <code>CursorLoader</code>. But how can I use it with custom <code>CursorAdapter</code> and without <code>ContentProvider</code>, when I needs URI in constructor of <code>CursorLoader</code>?

CursorLoader usage without ContentProvider

数据库

Android

Android SDK文档中说startManagingCursor()方法已经过时了：此方法已弃用。将新的CursorLoader类与LoaderManager一起使用；在较旧的平台上，也可以通过Android兼容包使用这个类。此方法允许活动根据活动的生命周期为您管理给定游标的生命周期。也就是说，当活动停止时，它将在...

问不使用ContentProvider时的CursorLoader使用
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