Question

我在ViewPager中有一个包含两个片段的程序，一个常规片段和一个ListFragment。我在常规片段中弹出一个AlertDialog，将数据添加到SQLite数据库中。但是，我想使用常规Fragment中的数据刷新ListFragment中的列表。经过几天的挣扎，我放弃了，想在这里发布我的代码，看看是否有人可以帮我解决这个问题。提前感谢您的任何回复。

这是我的ListFragment类：

import java.util.ArrayList;

import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;

public class ClassListFragment extends ListFragment {

    private ArrayList<Long> ids = new ArrayList<Long>();
    private ArrayList<String> classes = new ArrayList<String>();
    private ArrayList<Double> currentGrades = new ArrayList<Double>();
    private ArrayList<Double> desiredGrades = new ArrayList<Double>();
    private ArrayList<Double> finalGrades = new ArrayList<Double>();
    private ClassListAdapter adapter;
    private DataHandler dh;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        return inflater.inflate(R.layout.class_list, container, false);
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        dh = new DataHandler(getActivity().getBaseContext());
        dh.open();
        adapter = new ClassListAdapter(getActivity().getBaseContext(), classes, currentGrades, desiredGrades, finalGrades);
        setListAdapter(adapter);
    }

    @Override
    public void onStart() {
        super.onStart();
        refreshList();
        adapter.notifyDataSetChanged();
    }

    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);
        dh.deleteRow(ids.get(position));
        adapter.notifyDataSetChanged();
    }

    private void refreshList() {
        adapter.clear();
        ids.clear();
        Cursor data = dh.returnData();
        if (data.moveToFirst()) {
            do {
                ids.add(data.getLong(0));
                classes.add(data.getString(1));
                currentGrades.add(data.getDouble(2));
                desiredGrades.add(data.getDouble(3));
                finalGrades.add(data.getDouble(4));
            }while(data.moveToNext());
        }
    }

}

这是我的Fragment类，删除问题不需要自定义方法：

import java.text.DecimalFormat;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.TextView;

public class QuickCalc extends Fragment {

    private TextView tv;
    private DataHandler dh;

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.quickcalc_layout, container, false);
        tv = (TextView) v.findViewById(R.id.tv);
        Button button = (Button) v.findViewById(R.id.calculateButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                clicked();
            }
        });

        return v;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        dh = new DataHandler(getActivity().getBaseContext());
    }

public void clicked() {
        EditText currentGradeBox = (EditText) getView().findViewById(R.id.currentGrade);
        EditText desiredGradeBox = (EditText) getView().findViewById(R.id.desiredGrade);
        RadioGroup rg = (RadioGroup) getView().findViewById(R.id.radioGroup);
        int rbID = rg.getCheckedRadioButtonId();
        final Double currentGrade = Double.parseDouble(currentGradeBox.getText().toString());
        final String desiredGrade = desiredGradeBox.getText().toString();
        Object[] values = getValues(rbID, desiredGrade);
        if (values != null) {
            final String answer = doCalculations(values, currentGrade);
            if (Double.parseDouble(answer) <= 100.0) {
                if (String.valueOf(values[0]).contains("A")) {
                    tv.setText("You need to get a " + answer + "% in order to get an " + values[0] + " (" + values[1] + "%) in this class.\n \nWould you like to save this to your class list?");
                }
                else {
                    tv.setText("You need to get a " + answer + "% in order to get a " + values[0] + " (" + values[1] + "%) in this class.\n \nWould you like to save this to your class list?");
                }
                Button addButton = (Button) getView().findViewById(R.id.addClass);
                addButton.setVisibility(Button.VISIBLE);
                addButton.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        AlertDialog.Builder alert = new AlertDialog.Builder(getActivity());
                        alert.setTitle("Add Class");
                        final EditText className = new EditText(getActivity());
                        className.setHint("Class Name");
                        alert.setView(className);
                        alert.setPositiveButton("Create", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                dh.open();
                                dh.insertData(className.getText().toString(), currentGrade, Double.parseDouble(desiredGrade), Double.parseDouble(answer));
                                dh.close();
                            }
                        });
                        alert.setNegativeButton("Cancel", null);

                        AlertDialog dialog = alert.create();
                        dialog.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
                        dialog.show();
                    }
                });
            }
            else {
                tv.setText("The grade that you wish to achieve is impossible.");
            }
        }
        else {
            tv.setText("ERROR in one of the text boxes. Please fix it.");
        }
    }

Answer 1

我看不到你在哪里调用refreshList（），你只从onStart调用吗？在这种情况下它将无法工作..你需要onRefresh

从另一个片段AND片段活动刷新ListFragment

1 个答案: