java - 传递在 Activity 之间单击的 ListView 项目

Question

我的主要 Activity 有一个 ListView ，它从数据库获取数据。

我遇到的问题是根据用户在列表中选择的内容将文本传递到下一个 Activity 。

我正在获取 ListView 以打开下一个 Activity 并向下一个 Activity 发送一些奇怪的字符串，但这不是发送的正确信息。这是我的代码:

主要 Activity 代码:

package com.example.chris.gymtracker;

import android.content.Intent;
import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;


public class Days extends AppCompatActivity {
    dbAddDays dbAddDays;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_days);
        dbAddDays = new dbAddDays(this);
        final ListView daysListView = (ListView) findViewById(R.id.daysListView);
        String[] fromFieldNames = new String[]{dbAddDays.ADDDAYS_KEY_DAYS};

        Button addDaysButton = (Button) findViewById(R.id.addDaysButton);
        Button refreshButton = (Button)findViewById(R.id.refreshButton);

        addDaysButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                Intent startAddDaysActivity = new Intent(Days.this, addDays.class);
                startActivity(startAddDaysActivity);
            }
        });
        refreshButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                populateDaysListView();
            }
        });

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, android.R.id.text1, fromFieldNames);
        daysListView.setAdapter(adapter);
        daysListView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id){
                Intent myIntent = new Intent(view.getContext(),selectWorkout.class);
                String s = daysListView.getItemAtPosition(position).toString();
                myIntent.putExtra("itemSelected",s);

                startActivityForResult(myIntent,position);
            }
        });
    }
    public void populateDaysListView() {
        Cursor cursor = dbAddDays.getDaysData();
        String[] fromFieldNames = new String[]{dbAddDays.ADDDAYS_KEY_DAYS};
        int[] toViewIDs = new int[]{R.id.addDaysDaysTextView};
        SimpleCursorAdapter myCursorAdapter;
        myCursorAdapter = new SimpleCursorAdapter(getBaseContext(), R.layout.activity_add_day_text_view, cursor, fromFieldNames, toViewIDs, 0);
        ListView myList = (ListView) findViewById(R.id.daysListView);
        myList.setAdapter(myCursorAdapter);
    }
}

第二个 Activity 代码:

package com.example.chris.tracker;

import android.content.Intent;
import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.GridView;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;

public class selectWork extends AppCompatActivity {
    dbAddDays dbAddDays;
    Days Days;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_select_work);
        Intent intentExtras = getIntent();
        //Bundle bun = intentExtras.getExtras();
        String s = intentExtras.getStringExtra("itemSelected");
        TextView textView = (TextView)findViewById(R.id.textView3);
        textView.setText(s);
        dbAddDays = new dbAddDays(this);
        populateWorkoutGridView();
    }
    public void populateWorkGridView() {
        Cursor cursor = dbAddDays.getWorkoutData();
        String[] fromFieldNames = new String[]{dbAddDays.ADDDAYS_KEY_WORKOUT};
        int[] toViewIDs = new int[]{R.id.workoutWorkoutTextView};
        SimpleCursorAdapter myCursorAdapter;
        myCursorAdapter = new SimpleCursorAdapter(getBaseContext(), R.layout.activity_workout_text_view, cursor, fromFieldNames, toViewIDs, 0);
        GridView myGrid = (GridView) findViewById(R.id.workoutGridView);
        myGrid.setAdapter(myCursorAdapter);
    }
}

问题:

Everything here works fine

But that bold Android. ... text view should show the text of the item clicked.

Answer 1

由于您使用的是 CursorAdapter，因此 getItemAtPosition 调用将返回光标对象，如通过对该对象调用 toString() 所看到的那样。

尝试下面的代码。它尝试检索游标对象，然后通过 fromFieldNames 数组中的列名获取数据。

Cursor cursor = (Cursor)daysListView.getItemAtPosition(position);
cursor.getString(cursor.getColumnIndex(fromFieldNames[column]))