blocks|key|1153442|text|执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1153443|在Android+Manifest文件中，声明以下内容。|1153444|<application+android:name="com.xyz.MyApplication">

</application>|code-block|syntax|javascript|1153445|然后编写类：|1153446|public+class+MyApplication+extends+Application+{

++++private+static+Context+context;

++++public+void+onCreate()+{
++++++++super.onCreate();
++++++++MyApplication.context+=+getApplicationContext();
++++}

++++public+static+Context+getAppContext()+{
++++++++return+MyApplication.context;
++++}
}|1153447|现在，无论在哪里，都可以静态地调用MyApplication.getAppContext()来获取应用程序上下文。|offset|length|style|CODE|1153448|entityMap^0|0|0|0|0|0|H|T|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|Z|8|@$O|10|P|11|Q|R]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

Do this:

In the Android Manifest file, declare the following.

<pre><code>&lt;application android:name="com.xyz.MyApplication"&gt;

&lt;/application&gt;
</code></pre>

Then write the class:

<pre><code>public class MyApplication extends Application {

 private static Context context;

 public void onCreate() {
 super.onCreate();
 MyApplication.context = getApplicationContext();
 }

 public static Context getAppContext() {
 return MyApplication.context;
 }
}
</code></pre>

Now everywhere call <code>MyApplication.getAppContext()</code> to get your application context statically.

blocks|key|1368508|text|不，我不认为有。不幸的是，您不得不从Activity或Context的其他子类中调用getApplicationContext()。此外，this问题也有一定的关联性。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1368509|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/987072/using-application-context-everywhere^0|I|8|R|7|16|N|1X|4|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]]|E|$]]|$1|F|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

No, I don't think there is. Unfortunately, you're stuck calling <code>getApplicationContext()</code> from <code>Activity</code> or one of the other subclasses of <code>Context</code>. Also, <a href="https://stackoverflow.com/questions/987072/using-application-context-everywhere">this</a> question is somewhat related.

blocks|key|1153469|text|这取决于您使用上下文的目的。我能想到这种方法至少有一个缺点：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1153470|如果您尝试使用AlertDialog.Builder创建AlertDialog，则Application上下文将无法工作。我相信您需要当前Activity的上下文...|offset|length|style|CODE|1153471|entityMap^0|0|7|J|S|B|15|B|1X|8|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]|$D|P|E|Q|F|G]|$D|R|E|S|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|I|$]]

It depends on what you are using the context for. I can think of at least one disadvantage to that method:

If you are trying to create an <code>AlertDialog</code> with <code>AlertDialog.Builder</code>, the <code>Application</code> context won't work. I believe you need the context for the current <code>Activity</code>...

blocks|key|1368633|text|如果您愿意使用RoboGuice，那么可以将上下文注入到您想要的任何类中。这里有一个如何使用RoboGuice+2.0+(撰写本文时是Beta4)的小示例。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1368634|import+android.content.Context;
import+android.os.Build;
import+roboguice.inject.ContextSingleton;

import+javax.inject.Inject;

@ContextSingleton
public+class+DataManager+{
++++@Inject
++++public+DataManager(Context+context)+{
++++++++++++Properties+properties+=+new+Properties();
++++++++++++properties.load(context.getResources().getAssets().open("data.properties"));
++++++++}+catch+(IOException+e)+{
++++++++}
++++}
}|code-block|syntax|javascript|1368635|entityMap|0|LINK|mutability|MUTABLE|url|http://code.google.com/p/roboguice/^0|7|9|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

If you're open to using <a href="http://code.google.com/p/roboguice/" rel="noreferrer">RoboGuice</a>, you can have the context injected into any class you want. Here's a small sample of how to do it with RoboGuice 2.0 (beta 4 at time of this writing)

<pre><code>import android.content.Context;
import android.os.Build;
import roboguice.inject.ContextSingleton;

import javax.inject.Inject;

@ContextSingleton
public class DataManager {
 @Inject
 public DataManager(Context context) {
 Properties properties = new Properties();
 properties.load(context.getResources().getAssets().open("data.properties"));
 } catch (IOException e) {
 }
 }
}
</code></pre>

blocks|key|1368887|text|Kotlin|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1368888|open+class+MyApp+:+Application()+{
++++override+fun+onCreate()+{
++++++++super.onCreate()
++++++++mInstance+=+this
++++}

++++companion+object+{
++++++++lateinit+var+mInstance:+MyApp
++++++++fun+getContext():+Context?+{
++++++++++++return+mInstance.applicationContext
++++++++}
++++}
}|code-block|syntax|javascript|1368889|并获取上下文，如|1368890|MyApp.mInstance|1368891|或|1368892|MyApp.getContext()|1368893|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

<h3>Kotlin</h3>
<pre><code>open class MyApp : Application() {
 override fun onCreate() {
 super.onCreate()
 mInstance = this
 }

 companion object {
 lateinit var mInstance: MyApp
 fun getContext(): Context? {
 return mInstance.applicationContext
 }
 }
}
</code></pre>
and get Context like
<pre><code>MyApp.mInstance
</code></pre>
or
<pre><code>MyApp.getContext()
</code></pre>

blocks|key|1153868|text|在Kotlin中，将上下文/应用程序上下文放在伴生对象中仍然会产生警告Do+not+place+Android+context+classes+in+static+fields;+this+is+a+memory+leak+(and+also+breaks+Instant+Run)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1153869|或者，如果你使用类似这样的东西：|1153870|++++companion+object+{
++++++++lateinit+var+instance:+MyApp
++++}|code-block|syntax|javascript|1153871|没有发现内存泄漏只是在欺骗lint，App实例仍然会产生内存泄漏，因为Application类及其后代是一个上下文。|1153872|或者，您可以使用函数接口或函数属性来帮助您获取应用程序上下文。|1153873|只需创建一个对象类：|1153874|object+CoreHelper+{
++++lateinit+var+contextGetter:+()+->+Context
}|1153875|或者您可以使用nullable类型来更安全地使用它：|1153876|object+CoreHelper+{
++++var+contextGetter:+(()+->+Context)?+=+null
}|1153877|在你的App类中添加下面这一行：|1153878|class+MyApp:+Application()+{

++++override+fun+onCreate()+{
++++++++super.onCreate()
++++++++CoreHelper.contextGetter+=+{
++++++++++++this
++++++++}
++++}
}|1153879|并在清单中将应用程序名称声明为.+MyApp|1153880|++++<application
++++++++++++android:name=".MyApp"|1153881|当您想获取上下文时，只需调用：|1153882|CoreHelper.contextGetter()

//+or+if+you+use+the+nullable+version
CoreHelper.contextGetter?.invoke()|1153883|希望这能有所帮助。|1153884|entityMap^0|Z|2Y|0|0|0|0|0|0|0|0|0|0|0|F|7|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1H|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|1I|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1J|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|1K|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1L|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|1M|8|@]|D|@]|E|$K|L]]|$1|U|3|V|5|6|7|1N|8|@]|D|@]|E|$]]|$1|W|3|X|5|J|7|1O|8|@]|D|@]|E|$K|L]]|$1|Y|3|Z|5|6|7|1P|8|@]|D|@]|E|$]]|$1|10|3|11|5|J|7|1Q|8|@]|D|@]|E|$K|L]]|$1|12|3|13|5|6|7|1R|8|@$9|1S|A|1T|B|C]]|D|@]|E|$]]|$1|14|3|15|5|J|7|1U|8|@]|D|@]|E|$K|L]]|$1|16|3|17|5|6|7|1V|8|@]|D|@]|E|$]]|$1|18|3|19|5|J|7|1W|8|@]|D|@]|E|$K|L]]|$1|1A|3|1B|5|6|7|1X|8|@]|D|@]|E|$]]|$1|1C|3|-4|5|6|7|1Y|8|@]|D|@]|E|$]]]|1D|$]]

in Kotlin, putting Context/App Context in companion object still produce warning <code>Do not place Android context classes in static fields; this is a memory leak (and also breaks Instant Run)</code> 

or if you use something like this:

<pre><code> companion object {
 lateinit var instance: MyApp
 }
</code></pre>

It's simply fooling the lint to not discover the memory leak, the App instance still can produce memory leak, since Application class and its descendant is a Context.

Alternatively, you can use functional interface or Functional properties to help you get your app context.

Simply create an object class:

<pre><code>object CoreHelper {
 lateinit var contextGetter: () -&gt; Context
}
</code></pre>

or you could use it more safely using nullable type:

<pre><code>object CoreHelper {
 var contextGetter: (() -&gt; Context)? = null
}
</code></pre>

and in your App class add this line:

<pre><code>
class MyApp: Application() {

 override fun onCreate() {
 super.onCreate()
 CoreHelper.contextGetter = {
 this
 }
 }
}
</code></pre>

and in your manifest declare the app name to <code>. MyApp</code>

<pre><code>
 &lt;application
 android:name=".MyApp"
</code></pre>

When you wanna get the context simply call:

<pre><code>CoreHelper.contextGetter()

// or if you use the nullable version
CoreHelper.contextGetter?.invoke()
</code></pre>

Hope it will help.

blocks|key|1153665|text|您可以使用以下内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1153666|MainActivity.this.getApplicationContext();|code-block|syntax|javascript|1153667|MainActivity.java：|1153668|...
public+class+MainActivity+...+{
++++static+MainActivity+ma;
...
++++public+void+onCreate(Bundle+b)+{
+++++++++super...
+++++++++ma=this;
+++++++++...|1153669|任何其他类：|1153670|public+...
++++public+ANY_METHOD...+{
+++++++++Context+c+=+MainActivity.ma.getApplicationContext();|1153671|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You can use the following:

<pre><code>MainActivity.this.getApplicationContext();
</code></pre>

MainActivity.java:

<pre><code>...
public class MainActivity ... {
 static MainActivity ma;
...
 public void onCreate(Bundle b) {
 super...
 ma=this;
 ...
</code></pre>

Any other class:

<pre><code>public ...
 public ANY_METHOD... {
 Context c = MainActivity.ma.getApplicationContext();
</code></pre>

blocks|key|1368586|text|我认为getAppContext()方法需要一个主体：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1368587|public+static+Context+getAppContext()
+++return+MyApplication.context;+|code-block|syntax|javascript|1368588|entityMap^0|3|F|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

I think you need a body for the <code>getAppContext()</code> method:

<pre><code>public static Context getAppContext()
 return MyApplication.context; 
</code></pre>

blocks|key|1368714|text|我刚刚发布了一个受jQuery启发的安卓框架，名为Vapor+API，旨在简化应用程序开发。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1368715|中央$+facade+class维护一个指向当前Activity上下文的WeakReference+(链接到Ethan+Nicholas撰写的关于这一点的令人敬畏的Java博客文章)，您可以通过调用以下命令来检索该上下文：|style|CODE|1368716|$.act()|code-block|syntax|javascript|1368717|WeakReference在不阻止垃圾回收回收原始对象的情况下维护一个引用，因此您应该不会遇到内存泄漏的问题。|1368718|当然，缺点是您冒着$.act()可能返回空的风险。不过，我还没有遇到这种情况，所以这可能只是一个最小的风险，值得一提的是。|1368719|如果不使用VaporActivity作为Activity类，也可以手动设置上下文：|1368720|$.act(Activity);|1368721|此外，Vapor+API框架的大部分都固有地使用这个存储的上下文，这可能意味着如果您决定使用该框架，则根本不需要自己存储它。有关更多信息和示例，请查看site。|1368722|我希望这能有所帮助:)|1368723|entityMap|0|LINK|mutability|MUTABLE|url|http://vapor-api.com/|1|http://vapor-api.com/core/$|2|http://weblogs.java.net/blog/2006/05/04/understanding-weak-references|3|http://vapor-api.com/core/activity|4|5^0|P|9|0|0|2|1|O|8|10|D|2|E|1|10|D|2|0|0|0|D|0|9|7|0|5|D|K|8|5|D|3|0|0|3|9|4|23|4|5|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@$A|1F|B|1G|1|1H]]|C|$]]|$1|D|3|E|5|6|7|1I|8|@$A|1J|B|1K|F|G]|$A|1L|B|1M|F|G]|$A|1N|B|1O|F|G]]|9|@$A|1P|B|1Q|1|1R]|$A|1S|B|1T|1|1U]]|C|$]]|$1|H|3|I|5|J|7|1V|8|@]|9|@]|C|$K|L]]|$1|M|3|N|5|6|7|1W|8|@$A|1X|B|1Y|F|G]]|9|@]|C|$]]|$1|O|3|P|5|6|7|1Z|8|@$A|20|B|21|F|G]]|9|@]|C|$]]|$1|Q|3|R|5|6|7|22|8|@$A|23|B|24|F|G]|$A|25|B|26|F|G]]|9|@$A|27|B|28|1|29]]|C|$]]|$1|S|3|T|5|J|7|2A|8|@]|9|@]|C|$K|L]]|$1|U|3|V|5|6|7|2B|8|@]|9|@$A|2C|B|2D|1|2E]|$A|2F|B|2G|1|2H]]|C|$]]|$1|W|3|X|5|6|7|2I|8|@]|9|@]|C|$]]|$1|Y|3|-4|5|6|7|2J|8|@]|9|@]|C|$]]]|Z|$10|$5|11|12|13|C|$14|15]]|16|$5|11|12|13|C|$14|17]]|18|$5|11|12|13|C|$14|19]]|1A|$5|11|12|13|C|$14|1B]]|1C|$5|11|12|13|C|$14|15]]|1D|$5|11|12|13|C|$14|15]]]]

I just released a jQuery-inspired framework for Android called <a href="http://vapor-api.com" rel="nofollow">Vapor API</a> that aims to make app development simpler.

The central <a href="http://vapor-api.com/core/$" rel="nofollow"><code>$</code> facade class</a> maintains a <a href="http://weblogs.java.net/blog/2006/05/04/understanding-weak-references" rel="nofollow"><code>WeakReference</code></a> (link to awesome Java blog post about this by Ethan Nicholas) to the current <code>Activity</code> context which you can retrieve by calling:

<pre><code>$.act()
</code></pre>

A <code>WeakReference</code> maintains a reference without preventing the garbage collection reclaiming the original object, so you shouldn't have a problem with memory leaks.

The downside of course is that you run the risk that <code>$.act()</code> could return null. I have not come across this scenario yet though, so it's perhaps just a minimal risk, worth mentioning.

You can also set the context manually if you are not using <a href="http://vapor-api.com/core/activity" rel="nofollow"><code>VaporActivity</code></a> as your <code>Activity</code> class:

<pre><code>$.act(Activity);
</code></pre>

Also, much of the <a href="http://vapor-api.com" rel="nofollow">Vapor API</a> framework uses this stored context inherently which might mean you needn't store it yourself at all if you decide to use the framework. Check out the <a href="http://vapor-api.com" rel="nofollow">site</a> for more information and samples.

I hope that helps :)

blocks|key|1153752|text|如果出于某种原因，您需要在任何类中使用应用程序上下文，而不仅仅是那些扩展应用程序/活动的类，可能是一些工厂类或助手类。您可以在您的应用程序中添加以下单例。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1153753|public+class+GlobalAppContextSingleton+{
++++private+static+GlobalAppContextSingleton+mInstance;
++++private+Context+context;

++++public+static+GlobalAppContextSingleton+getInstance()+{
++++++++if+(mInstance+==+null)+mInstance+=+getSync();
++++++++return+mInstance;
++++}

++++private+static+synchronized+GlobalAppContextSingleton+getSync()+{
++++++++if+(mInstance+==+null)+mInstance+=+
++++++++++++++++new+GlobalAppContextSingleton();
++++++++return+mInstance;
++++}

++++public+void+initialize(Context+context)+{
++++++++this.context+=+context;
++++}

++++public+Context+getApplicationContext()+{
++++++++return+context;
++++}
}|code-block|syntax|javascript|1153754|然后在应用程序类的onCreate中使用|1153755|GlobalAppContextSingleton.getInstance().initialize(this);|1153756|在任何地方都可以通过调用|1153757|GlobalAppContextSingleton.getInstance().getApplicationContext()|1153758|但是，除了应用程序上下文之外，我不推荐使用这种方法。因为它会导致内存泄漏。|1153759|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

If you for some reason want Application context in any class, not just those extending application/activity, maybe for some factory or helper classes. You can add the following singleton to your app.

<pre><code>public class GlobalAppContextSingleton {
 private static GlobalAppContextSingleton mInstance;
 private Context context;

 public static GlobalAppContextSingleton getInstance() {
 if (mInstance == null) mInstance = getSync();
 return mInstance;
 }

 private static synchronized GlobalAppContextSingleton getSync() {
 if (mInstance == null) mInstance = 
 new GlobalAppContextSingleton();
 return mInstance;
 }

 public void initialize(Context context) {
 this.context = context;
 }

 public Context getApplicationContext() {
 return context;
 }
}
</code></pre>

then initialize it in your application class's onCreate with

<pre><code>GlobalAppContextSingleton.getInstance().initialize(this);
</code></pre>

use it anywhere by calling

<pre><code>GlobalAppContextSingleton.getInstance().getApplicationContext()
</code></pre>

I don't recommend this approach to anything but application context however. As it can cause memory leaks.

blocks|key|1368848|text|罗希特的答案似乎是正确的。然而，请注意，据我所知，AndroidStudio的“即时运行”依赖于代码中没有static+Context属性。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1368849|entityMap^0|1H|E|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|$]]

Rohit's answer seems correct. However, be aware that AndroidStudio's "Instant Run" depends on not having <code>static Context</code> attributes in your code, as far as I know.

blocks|key|1153956|text|如今，拥有context的正确方式是使用依赖注入。例如，可以使用Hilt在任何需要的地方注入上下文。假设在某个数据库管理器中需要context，则可以通过以下方式解决此问题：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1153957|在Gradle中添加Hilt：|1153958|implementation+"com.google.dagger:hilt-android:2.35"
kapt+"com.google.dagger:hilt-android-compiler:2.35"|code-block|syntax|javascript|1153959|使用@HiltAndroidApp注释定义应用程序类(例如，让它注入数据库管理器)：|1153960|@HiltAndroidApp
class+MyApplication+:+Application()+{

++++@Inject
++++lateinit+var+dbManager:+DBManager

++++override+fun+onCreate()+{
++++++++super.onCreate()
++++++++dbManager.initDB()
++++}
}|1153961|定义数据库管理器(例如，让它也是@Singleton+)：|1153962|@Singleton
class+DBManager+@Inject+constructor(
++++@ApplicationContext+private+val+context:+Context
)+{

++++fun+initDB()+{
++++++++//+context+is+avaiable
++++++++databaseInit(context)
++++}
}|1153963|就是这样。DBManager可以以正确的方式访问上下文，而不会发生内存泄漏。|1153964|entityMap^0|5|7|1S|7|0|0|0|2|F|0|0|G|A|0|0|5|9|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|13|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|19|8|@$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|S|3|T|5|J|7|1C|8|@]|D|@]|E|$K|L]]|$1|U|3|V|5|6|7|1D|8|@$9|1E|A|1F|B|C]]|D|@]|E|$]]|$1|W|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]]|X|$]]

Today the right way to have <code>context</code> is to use dependency injection.
For instance, one can use Hilt to inject context at any place it is needed. Let's say one needs <code>context</code> in some database manager, then this can be resolved in the following way:
Add Hilt in Gradle:
<pre><code>implementation &quot;com.google.dagger:hilt-android:2.35&quot;
kapt &quot;com.google.dagger:hilt-android-compiler:2.35&quot;
</code></pre>
Define Application class with <code>@HiltAndroidApp</code> annotation (let it inject the database manager for example):
<pre><code>@HiltAndroidApp
class MyApplication : Application() {

 @Inject
 lateinit var dbManager: DBManager

 override fun onCreate() {
 super.onCreate()
 dbManager.initDB()
 }
}
</code></pre>
Define Database manager (let it be <code>@Singleton</code> for example as well):
<pre><code>@Singleton
class DBManager @Inject constructor(
 @ApplicationContext private val context: Context
) {

 fun initDB() {
 // context is avaiable
 databaseInit(context)
 }
}
</code></pre>
And that's it. The <code>DBManager</code> can access context in the right way without memory leaks.

blocks|key|1154017|text|在不对Application对象进行子类化和不使用隐藏类的情况下获取context的另一种方法是使用ContentProvider。一旦调用了onCreate方法，上下文就应该可用了。你可以在Kotlin中做这样的事情|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1154018|class+ContextContentProvider+:+ContentProvider()+{
++++override+fun+delete(uri:+Uri,+selection:+String?,+selectionArgs:+Array<String>?)+=+0

++++override+fun+getType(uri:+Uri):+String?+=+null

++++override+fun+insert(uri:+Uri,+values:+ContentValues?):+Uri?+=+null

++++override+fun+onCreate():+Boolean+{
++++++++applicationContext+=+context
++++++++return+true
++++}

++++override+fun+query(
++++++++uri:+Uri,+projection:+Array<String>?,+selection:+String?,
++++++++selectionArgs:+Array<String>?,+sortOrder:+String?
++++):+Cursor?+=+null

++++override+fun+update(
++++++++uri:+Uri,+values:+ContentValues?,+selection:+String?,
++++++++selectionArgs:+Array<String>?
++++)+=+0

++++companion+object+{
++++++++private+var+applicationContext:+Context?+=+null

++++++++@JvmStatic
++++++++fun+applicationContext()+=+applicationContext
++++}
}|code-block|syntax|javascript|1154019|在需要上下文的任何地方，都可以调用ContextContentProvider.applicationContext()方法|1154020|如果您已经有另一个内容提供者，并且该内容提供者没有被导出，请确保在AndroidManifest.xml中使用不同的授权。|1154021|<application>
++++<provider
++++++++android:name=".ContextContentProvider"
++++++++android:authorities="${applicationId}.ContextContentProvider"
++++++++android:enabled="true"
++++++++android:exported="false"+/>
</application>|1154022|entityMap^0|3|B|Y|7|1Z|8|0|0|H|17|0|X|J|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|13|8|@$9|14|A|15|B|C]]|D|@]|E|$]]|$1|O|3|P|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|Q|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|R|$]]

Another alternative to get <code>context</code> without subclassing the <code>Application</code> object and without using hidden classes would be to use a ContentProvider. Once the <code>onCreate</code> method is called, the context should be available. You can do something like this in Kotlin
<pre><code>class ContextContentProvider : ContentProvider() {
 override fun delete(uri: Uri, selection: String?, selectionArgs: Array&lt;String&gt;?) = 0

 override fun getType(uri: Uri): String? = null

 override fun insert(uri: Uri, values: ContentValues?): Uri? = null

 override fun onCreate(): Boolean {
 applicationContext = context
 return true
 }

 override fun query(
 uri: Uri, projection: Array&lt;String&gt;?, selection: String?,
 selectionArgs: Array&lt;String&gt;?, sortOrder: String?
 ): Cursor? = null

 override fun update(
 uri: Uri, values: ContentValues?, selection: String?,
 selectionArgs: Array&lt;String&gt;?
 ) = 0

 companion object {
 private var applicationContext: Context? = null

 @JvmStatic
 fun applicationContext() = applicationContext
 }
}
</code></pre>
Anywhere you need the context, you can call <code>ContextContentProvider.applicationContext()</code> method
Make sure to use a different authority in the <code>AndroidManifest.xml</code> if you already have another content provider and the content provider is not exported.
<pre><code>&lt;application&gt;
 &lt;provider
 android:name=&quot;.ContextContentProvider&quot;
 android:authorities=&quot;${applicationId}.ContextContentProvider&quot;
 android:enabled=&quot;true&quot;
 android:exported=&quot;false&quot; /&gt;
&lt;/application&gt;
</code></pre>

Is there a way to get the current <code>Context</code> instance inside a static method? 

I'm looking for that way because I hate saving the 'Context' instance each time it changes.

Static way to get 'Context' in Android?

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有没有办法在静态方法中获取当前的Context实例？我之所以寻找这种方式，是因为我讨厌每次“Context”实例发生变化时都保存它。

问在Android中获取“上下文”的静态方式？
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