从片段中检索上下文 [英] Retrieve Context from a fragment

问题描述

我创建了一个类来从PHP文件中检索JSON编码的注释。此类，从AsyncTask扩展：

I created a class to retrieve comments from a JSON encoding from a PHP file. This class, extends from AsyncTask:

public class RecuperarComentarisFoto extends AsyncTask<String, String, String>{

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(????);
        pDialog.setMessage("Creating Product..");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    @Override
    protected String doInBackground(String... arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    protected void onPostExecute(String result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
    }

}

如你所见，我'我试图在doInBackground进程工作时显示ProgressDialog。但是progressDialog构造函数，请求一个Context，我不知道如何提供它。

As you can see, I'm trying to show a ProgressDialog while the "doInBackground" proccess is working. But progressDialog constructor, asks for a Context, and I don't know how to provide it.

我从片段中调用这个类，所以我不能访问这样的上下文：

I'm calling this class from a Fragment, so I can't access the context like this:

pDialog = new ProgressDialog(MyFragmentA.context);

调用主活动：AndroidViewPagerActivity扩展了FragmentActivity。

The "main" acitivity is called: AndroidViewPagerActivity which extends FragmentActivity.

（主要是，我的意思是它是创建标签，并管理它们之间的导航。）

(By main, I mean that it's the one that is creating the tabs, and managing the navigation between them.)

这是它的代码：

public class AndroidViewPagerActivity extends FragmentActivity {
ViewPager mViewPager;
TabsAdapter mTabsAdapter;


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mViewPager = new ViewPager(this);
    mViewPager.setId(R.id.pager);
    setContentView(mViewPager);

    final ActionBar bar = getActionBar();
    bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_HOME);
    bar.hide();

    mTabsAdapter = new TabsAdapter(this, mViewPager);
    mTabsAdapter.addTab(bar.newTab().setText("Fragment A"), MyFragmentA.class, null);

    if (savedInstanceState != null) {
        bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0));
    }

}

如何访问上下文？我应该使用哪种上下文？ AndroidViewPagerActivity上下文？那么如何从片段中访问其上下文？

How can I access the context? Which context should I use? "AndroidViewPagerActivity" context? So how can I access its context from a fragment?

谢谢。

Sergi

推荐答案

在片段 getActivity（） $ c>获取可以传递的 Context 。这是有效的，因为活动继承自上下文。

Use getActivity() inside the Fragment to obtain a Context that you can pass along. That works, as Activity inherits from Context.

作为替代方案，您可以使用 getApplicationContext（）来获取上下文。

As alternative you can use getApplicationContext() to obtain the Context.

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