java - 为什么我的 fragment 不起作用

Question

我的一侧有一个 ListView，另一侧有一个 fragment 。我正在尝试制作一个简单的应用程序来弄清楚 fragment 是如何工作的。这是我的代码:

主要 Activity :

    public class MainActivity extends Activity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // storing string resources into Array
        //
        setContentView(R.layout.activity_main);
        String[] adobe_products = getResources().getStringArray(R.array.adobe_products);
        //List view
        final ListView list = (ListView)findViewById(R.id.questionsList);
        ArrayAdapter<String> adapter;
        adapter = new ArrayAdapter<String>(this, R.layout.list_item, adobe_products);

         //final TextView text = (TextView)findViewById(R.id.textView1);

        list.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id){

                //String selectedFromList =(String) (list.getItemAtPosition(position));
                //text.setText(selectedFromList);

            }
        });

        list.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }


    @SuppressLint("ValidFragment")
    public class MyFragment extends Fragment {
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            // Inflate the layout for this fragment
            return inflater.inflate(R.layout.activity_fragment, container, false);
        }
    }

}

主要 Activity XML 布局

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/questionsList"
        android:layout_width="144dp"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_weight="0.07" >

    </ListView>

    <fragment android:name="com.example.Layout.MyFragment"
              android:id="@+id/article_fragment"
              android:layout_weight="2"
              android:layout_width="0dp"
              android:layout_height="match_parent" />



</LinearLayout>

更新:感谢您的帮助，我注意到该 fragment 是一个子类，因此我将其包含在我的 Activity 中。但仍然得到相同的结果。它停止了，甚至没有打开。无论如何，我更新了 logCat 的整个代码。

日志猫:

    02-22 00:06:50.944: E/AndroidRuntime(2886): FATAL EXCEPTION: main
02-22 00:06:50.944: E/AndroidRuntime(2886): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.layout/com.example.layout.MainActivity}: android.view.InflateException: Binary XML file line #21: Error inflating class fragment
02-22 00:06:50.944: E/AndroidRuntime(2886):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
02-22 00:06:50.944: E/AndroidRuntime(2886):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
02-22 00:06:50.944: E/AndroidRuntime(2886):     at android.app.ActivityThread.access$600(ActivityThread.java:141)

有什么办法让它发挥作用吗？

Answer 1

我建议您浏览http://developer.android.com/guide/components/fragments.html和 http://developer.android.com/training/basics/fragments/creating.html

我在您的代码中发现了许多结构和设计问题，一旦您浏览上面的链接您就会理解它，还可以下载上面链接页面上提供的示例应用程序，如果您仍然无法做到，我一定会尝试用示例代码给出解释。祝你好运

在代码中进行以下更改

1.add the fragment in activity layout like below and don't forget to replace YOUR PACKAGE NAME specified in class attribute 

<fragment
        android:id="@+id/article_fragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="2"
        class="YOUR PACKAGE NAME.MyFragment" />

2. Create MyFragment as a separate Class (Should not be inside the Main Activity):

3. Main Activity must extends FragmentAcivity instead of Actvity

4. if you need Listview and fragment side by side change LinearLayout Orientation to  android:orientation="horizontal"

它会起作用