單個ListView作為片段不會出現

Question

我嘗試將ListView添加到我的MainActivity中，但我不知道為什么它不會出現在App中。

我創建了一個名為“list_item_forecast.xml”的新布局資源文件 - 在那里我放置了一個帶有id：“list_item_forecast_textview”的TextView。

在“content_main.xml”中我有ListView：

<ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/listview_forecast" />

然后我在MainActivity類中有這個類：

 public static class PlaceholderFragment extends Fragment{
    ArrayAdapter<String> mForecastAdapter;
    public PlaceholderFragment(){

    }
    @TargetApi(Build.VERSION_CODES.M)
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        View rootView = inflater.inflate(R.layout.content_main, container,false);

        String[] forecastArray = {
                "Heute - Sonnig - 34°",
                "Morgen - Sonnig - 30°",
                "Montag - Regen - 10°",
                "Dienstag - Bewölkt - 20°",
                "Mittwoch - Schnee - 10°",
                "Donnerstag - Schnee - 15°",
                "Freitag - Sonne - 33°"
        };
        List<String> weekForecast = new ArrayList<String>(Arrays.asList(forecastArray));
        mForecastAdapter = new ArrayAdapter<String>(getContext(), R.layout.list_item_forecast, R.id.list_item_forecast_textview, weekForecast);
        ListView listView = (ListView) rootView.findViewById(
                R.id.listview_forecast);
        listView.setAdapter(mForecastAdapter);
        return rootView;
    }

}

這是整個項目： https ： //github.com/Zaniyar/sunshine/tree/master/app/src/main

Answer 1

你應該在你的主要活動的第41行new它之后將你的片段添加到活動中，我的意思是這個文件

    FragmentTransaction transaction = getFragmentManager().beginTransaction();
    transaction.add(x, "some_tag");

另請參閱此鏈接以獲取更多信息

• 鏈接1
• 鏈接2

Answer 2

我必須在PlaceholderFragment.java中將“getContext（）”更改為“this.getActivity（）”：

List<String> weekForecast = new ArrayList<String>(Arrays.asList(forecastArray));
    mForecastAdapter = new ArrayAdapter<String>(getContext(), R.layout.list_item_forecast, R.id.list_item_forecast_textview, weekForecast);
    ListView listView = (ListView) rootView.findViewById(
            R.id.listview_forecast);
    listView.setAdapter(mForecastAdapter);