无法在 Fragment 中获取 MainActivity 上下文

Question

我是 android 编程的新手，我构建了一个片段，我试图将 mainactivity 上下文放在 ListViewAdapter 中，但我收到一条错误消息：android.app.activity cannot无法应用于 android.content.context 我不确定为什么会在 ListViewAdapter 中发生这种情况，而在 InputStream 下面似乎没有问题。

 import android.app.Fragment;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ListView;

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.ArrayList;
 import java.util.HashMap;

 import Model.Statistics;
 import util.DatabaseHelper;

 import static com.example.sheyda.scorestats.Constants.FIFTH_COLUMN;
 import static com.example.sheyda.scorestats.Constants.FIRST_COLUMN;
 import static com.example.sheyda.scorestats.Constants.FOURTH_COLUMN;
 import static com.example.sheyda.scorestats.Constants.SECOND_COLUMN;
 import static com.example.sheyda.scorestats.Constants.SIXTH_COLUMN;
 import static com.example.sheyda.scorestats.Constants.THIRD_COLUMN;

public class TopFragment extends Fragment {
private InputStreamReader fileReader;
private BufferedReader buffReader;
private ArrayList<HashMap<String, String>> list;

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

    View v = inflater.inflate(R.layout.layout_f1, container, false);
    ListView listview = (ListView) v.findViewById(R.id.listView_SID);
    try {
        populateLV("stats.txt");
    } catch (IOException e) {
        e.printStackTrace();
    }
    ListViewAdapter adapter = new ListViewAdapter(getActivity().getBaseContext(), list);
    listview.setAdapter(adapter);
    return v;
}


public void populateLV(String fileName) throws IOException {

    list = new ArrayList<HashMap<String, String>>();
    Statistics stat = new Statistics();


    InputStream descriptor = getActivity().getBaseContext().getAssets().open(fileName);
    fileReader = new InputStreamReader(descriptor);
    buffReader = new BufferedReader(fileReader);
    String line;
    // Counter stops at 40 because maximum number of students allowed is 40
    int count = 0;
    while ((line = buffReader.readLine()) != null && count <= 40) {
        String[] l = line.split("~");
        HashMap<String, String> temp = new HashMap<String, String>();
        temp.put(FIRST_COLUMN, l[0]);
        temp.put(SECOND_COLUMN, l[1]);
        temp.put(THIRD_COLUMN, l[2]);
        temp.put(FOURTH_COLUMN, l[3]);
        temp.put(FIFTH_COLUMN, l[4]);
        temp.put(SIXTH_COLUMN, l[5]);
        list.add(temp);
        count++;
    }
}
 }

Answer 1

到处使用getActivity()而不是getActivity().getBaseContext()。

无法在 Fragment 中获取 MainActivity 上下文

Trouble getting MainActivityContext in Fragment

android

listview-adapter