Android ArrayAdapter未将数据绑定到ListView

Android ArrayAdapter未将数据绑定到ListView,android,listview,android-fragments,android-arrayadapter,Android,Listview,Android Fragments,Android Arrayadapter,我正在尝试学习Android并构建一个非常基本的ListView,使用ArrayAdapter设置的数据没有显示出来。我的活动代码是: MainActivity类默认无更改 list_item_forecast.xml fragment_main.xml activity_main.xml 我所有的申请代码如上所述。我尝试过调整代码,也尝试过,但无法让它工作。请提供帮助。您设置的listview适配器不是您在片段中返回的listview 若你们在答案中添加一些解释,让用户知道为什么当前的代码片段

我正在尝试学习Android并构建一个非常基本的ListView,使用ArrayAdapter设置的数据没有显示出来。我的活动代码是:

MainActivity类默认无更改

list_item_forecast.xml

fragment_main.xml

activity_main.xml

我所有的申请代码如上所述。我尝试过调整代码,也尝试过,但无法让它工作。请提供帮助。

您设置的listview适配器不是您在片段中返回的listview


若你们在答案中添加一些解释,让用户知道为什么当前的代码片段不起作用,那个就更好了——若你们的阳光很小,它就起作用了。据我所知,这是与java对象概念相关的问题,如果您也能解释一下这里的错误,那会很有帮助。好的,我认为问题是没有返回使用setAdapter的View对象。fragment将在CreateView返回时显示View。您膨胀视图并在其中找到listview和setAdapter。但是您没有在CreateView中返回它。你给一辆新车充气,然后返回。
`public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

       Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}`


**MainActivityFragment class**

    public class MainActivityFragment extends Fragment {

    private ListAdapter arrayAdapter;

    public MainActivityFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        ArrayList<String> myEntries = new ArrayList<String>();
        myEntries.add("Unix");
        myEntries.add("Java");
        myEntries.add("Android");

        arrayAdapter = new ArrayAdapter<String>(getActivity(), R.layout.list_item_forecast, R.id.list_forecast_item_textview, myEntries);


        ListView listView = (ListView)inflater.inflate(R.layout.fragment_main, container, false).findViewById(R.id.list_view_forecast);

listView.setAdapter(arrayAdapter);

        return inflater.inflate(R.layout.fragment_main, container, false);
    }
}
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content" android:layout_height="wrap_content"

    android:minHeight="?android:listPreferredItemHeight"
    android:gravity="center_vertical"
    android:text=""
    android:id="@+id/list_forecast_item_textview">

</TextView>
<FrameLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:showIn="@layout/activity_main"
    tools:context=".MainActivityFragment"
    android:id="@+id/forecastFragment">


    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/list_view_forecast" />

    <include layout="@layout/list_item_forecast" />

</FrameLayout>
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:fitsSystemWindows="true"
    tools:context=".MainActivity">

    <android.support.design.widget.AppBarLayout android:layout_height="wrap_content"
    android:layout_width="match_parent" android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar android:id="@+id/toolbar"
        android:layout_width="match_parent" android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main" />

    <android.support.design.widget.FloatingActionButton android:id="@+id/fab"
        android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"         android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        ArrayList<String> myEntries = new ArrayList<String>();
        myEntries.add("Unix");
        myEntries.add("Java");
        myEntries.add("Android");

        arrayAdapter = new ArrayAdapter<String>(getActivity(), R.layout.list_item_forecast, R.id.list_forecast_item_textview, myEntries);

View view =inflater.inflate(R.layout.fragment_main, container, false);
        ListView listView = (ListView)view .findViewById(R.id.list_view_forecast);

listView.setAdapter(arrayAdapter);

        return view ;
    }