java 不能静态引用非静态方法（Android getApplicationContext()）
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Can't make static reference to non-static method ( Android getApplicationContext() )
提问by gcl1
I have been storing a global variable that's needed across Activities in my Android app by using a subclass of android.app.Application as explained by Soonil (in How to declare global variables in Android?).
我一直在使用 android.app.Application 的子类在我的 Android 应用程序中存储跨活动所需的全局变量，如 Soonil（在如何在 Android 中声明全局变量？中所述）。
The approach looks like this:
该方法如下所示：
class MyApp extends Application {
private String myState;
public String getState(){
return myState;
}
public void setState(String s){
myState = s;
}
}
class Blah extends Activity {
@Override
public void onCreate(Bundle b){
...
MyApp appState = ((MyApp)getApplicationContext());
String state = appState.getState();
...
}
}
Up to this point, this approach has worked fine for accessing the global variable from any of my Activities. But today using the same approach, I got the following error:
到目前为止，这种方法可以很好地从我的任何活动访问全局变量。但是今天使用相同的方法，我收到以下错误：
Cannot make a static reference to the non-static method getApplicationContext()
from the type ContextWrapper
The key difference from before is that the new Activity is actually a Fragment (SherlockFragmentActivity, to be precise).
与之前的关键区别在于新的Activity实际上是一个Fragment（准确地说是SherlockFragmentActivity）。
Any ideas why can't I access appState as I have before, and is there a good workaround?
任何想法为什么我不能像以前那样访问 appState，有没有好的解决方法？
Many thanks.
非常感谢。
EDIT: Good catch, Matt B. It turns out the place I'm actually calling getApplicationContext() is inside another class. Here's the calling point:
编辑：很好，马特 B。事实证明，我实际调用 getApplicationContext() 的地方在另一个类中。这是调用点：
public class MyActivity extends SherlockFragmentActivity {
public static class AccountListFragment extends SherlockListFragment {
MyApp appState = ((MyApp)getApplicationContext());
...
}
...
}
Also, as noted below, the error went away when I changed the call to
此外，如下所述，当我将调用更改为
MyApp appState = ((MyApp)getActivity().getApplicationContext());
采纳答案by vanleeuwenbram
getActivity().getApplication()
should work just fine.
应该工作得很好。
You first need a reference to activity, then to application
您首先需要对活动的引用，然后是对应用程序的引用
The difference is that you are now calling this function from a Fragment (even though you named it "Activity") instead of an Activity
不同之处在于您现在是从 Fragment 调用此函数（即使您将其命名为“Activity”）而不是 Activity
