如何从数据库中检索数据并在带有多个复选框的列表视图中显示？

Question

大家好，请帮我处理这段代码...

我在这里从数据库中检索数据并使用复选框将其显示在列表视图中...

问题是，我正在从“attendrecords”表中检索学生的姓名，但它没有在 listview 上显示学生的姓名，而不是在 listview 中显示 TextView 来代替每个姓名。 以下是我的代码请帮助... 在此先感谢..

文件优先...

TakeAttend.java

package com.example.myattendance;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class TakeAttend extends Activity {

public Button save_attendance;
public Button cancel;
public ListView take_attend_list;
public TextView textView;
public ArrayList<String> attendList;
DatabaseHandler handler;
MyAdapter adapter;
//ArrayAdapter<String> adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.take_attend);

    save_attendance = (Button) findViewById(R.id.submit_button);
    cancel = (Button) findViewById(R.id.cancel_button);
    take_attend_list = (ListView) findViewById(R.id.take_attend_list);
    textView = (TextView) findViewById(R.id.layout_textview);

    handler = new DatabaseHandler(getApplicationContext());

    attendList = new ArrayList<String>();
    attendList = handler.getdata();

    adapter = new MyAdapter(TakeAttend.this,attendList);
    take_attend_list.setAdapter(adapter);

    //adapter = new ArrayAdapter<String>(this, 
        //  android.R.layout.simple_list_item_multiple_choice,attendList);

    //take_attend_list.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
    //take_attend_list.setAdapter(adapter);


    save_attendance.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            Toast.makeText(TakeAttend.this, "Saved", Toast.LENGTH_LONG).show();
            //adapter.notifyDataSetChanged();
        }
    });


    cancel.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
        Intent intent = new Intent(TakeAttend.this,NextActivity.class);
        startActivity(intent);
        }
    });
}
}`

第二个文件...

MyAdapter.java...

package com.example.myattendance;

import java.util.ArrayList;
import java.util.zip.Inflater;

import android.net.wifi.WifiConfiguration.Status;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView.FindListener;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Toast;

public class MyAdapter extends BaseAdapter {

public TakeAttend takeAttend;
ArrayList<String> attendList;
LayoutInflater inflater;
public MyAdapter(TakeAttend takeAttend, ArrayList<String> attendList) {
    // TODO Auto-generated constructor stub
    this.takeAttend = takeAttend;
    this.attendList = attendList;
    inflater = inflater.from(takeAttend);
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    int size = attendList.size();
    return size;
}

@Override
public Object getItem(int arg0) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public long getItemId(int arg0) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public View getView(final int position, View v, ViewGroup arg2) {
    // TODO Auto-generated method stub
    v=inflater.inflate(R.layout.attend_layout, null);
    CheckBox box = (CheckBox) v.findViewById(R.id.layout_checkBox);

    box.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

            Toast.makeText(takeAttend, "" + position,Toast.LENGTH_SHORT).show();

        }
    });


    return v;
}

}

第三个文件 ....

DatabaseHandler.java

package com.example.myattendance;

import java.util.ArrayList;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHandler extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "NewAttendance";
//private static final String TABLE_NAME = "records";

public DatabaseHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    // TODO Auto-generated constructor stub
}

@Override

public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub

    db.execSQL("CREATE TABLE attndrecords(id INTEGER PRIMARY KEY,firstname TEXT,middlename TEXT,lastname TEXT)");

}

@Override
public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
    // TODO Auto-generated method stub
    db.execSQL("DROP TABLE IF EXIST : attndrecords");
    onCreate(db);
//db.execSQL("DROP TABLE IF EXIST :"+TABLE_NAME);   
}

public void savedata(String fname,String mname,String lname) {
    // TODO Auto-generated method stub

    SQLiteDatabase db = this.getReadableDatabase();
    ContentValues values = new ContentValues();
    values.put("firstname", fname);
    values.put("middlename", mname);
    values.put("lastname", lname);

    db.insert("attndrecords", null, values);

    db.close();
}

public ArrayList<String> getdata()
{
    SQLiteDatabase db = this.getReadableDatabase();
    ArrayList<String> list = new ArrayList<String>();
    Cursor cursor = db.rawQuery("SELECT * FROM attndrecords", null);
    //Cursor cursor = db.rawQuery("SELECT firstname,lastname FROM attndrecords", null);
    if(cursor.moveToFirst())
    {
        do
        {
            list.add(cursor.getString(1));
        }while(cursor.moveToNext());
    }

    return list;

}

}

Answer 1

好的，您需要为适配器中的每条记录创建 TextView。你只是得到复选框。此外，您应该从参加者列表中获取每一行的数据，然后使用学生的姓名更新 TextView（所有内容都在适配器内）

@Override
public Object getItem(int arg0) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public long getItemId(int arg0) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public View getView(final int position, View v, ViewGroup arg2) {
    // TODO Auto-generated method stub
    v=inflater.inflate(R.layout.attend_layout, null);
    // Get current value
    String currentAttendent = attendList.Get(position);
    CheckBox box = (CheckBox) v.findViewById(R.id.layout_checkBox);
    // Create TextView
    TextView txt = (TextView) v.findVIewByID(R.id.layout_YourTextViewName) 
    //Set value                                                                      
    txt.SetText(currentAttendent);
    box.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

            Toast.makeText(takeAttend, "" + position,Toast.LENGTH_SHORT).show();

        }
    });


    return v;
}

}

好的，所以你需要创建自己的 SQLiteOpenHelper 类，你可以找到教程for example here。那么当你想将数据保存到数据库时，你需要提供更多数据吗？ 我将向您展示如何在每次检查 CheckBox 时执行此操作，但您应该在单击按钮或类似的操作时执行此操作，这样会更有效。我可以看到你有一些 DateBaseHandler 但我不知道你是如何使用它的。请提供更多信息，这样会更容易为您提供帮助。

public class MyAdapter extends BaseAdapter {

public TakeAttend takeAttend;
ArrayList<String> attendList;
LayoutInflater inflater;
//Add new variables Context and your custom SQLiteOpenHelper 
Context context ;
DateBaseHelper DBHelper; // you need to create this class first
public MyAdapter(TakeAttend takeAttend, ArrayList<String> attendList , Context context) {
    // TODO Auto-generated constructor stub
    this.takeAttend = takeAttend;
    this.attendList = attendList;
    inflater = inflater.from(takeAttend);
    this.context = Context;
    DBHelper = new DateBaseHelper(context); // initialize DateBase helper

}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    int size = attendList.size();
    return size;
}
    @Override
    public Object getItem(int arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(final int position, View v, ViewGroup arg2) {
        // TODO Auto-generated method stub
        v=inflater.inflate(R.layout.attend_layout, null);
        // Get current value
        final String currentAttendent = attendList.Get(position);
        CheckBox box = (CheckBox) v.findViewById(R.id.layout_checkBox);
        // Create TextView
        TextView txt = (TextView) v.findVIewByID(R.id.layout_YourTextViewName) 

       //Setvalue                                                                      
        txt.SetText(currentAttendent);
        box.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

                if(isChecked == true){
                   DBHelper.insert(currentAttendent);
                 }
                else{
                   // it depends on how you'd implement DateBaseHelper
                   long ID = DBHelper.GetID(currentAttendent);
                   DBHelper.delete(ID);
                    }

            }
        });


        return v;
    }

    }

并将您的活动更改为：

package com.example.myattendance;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class TakeAttend extends Activity {

public Button save_attendance;
public Button cancel;
public ListView take_attend_list;
public TextView textView;
public ArrayList<String> attendList;
DatabaseHandler handler;
MyAdapter adapter;
//ArrayAdapter<String> adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.take_attend);

    save_attendance = (Button) findViewById(R.id.submit_button);
    cancel = (Button) findViewById(R.id.cancel_button);
    take_attend_list = (ListView) findViewById(R.id.take_attend_list);
    textView = (TextView) findViewById(R.id.layout_textview);

    handler = new DatabaseHandler(getApplicationContext());

    attendList = new ArrayList<String>();
    attendList = handler.getdata();

    adapter = new MyAdapter(TakeAttend.this,attendList,this); //'this' means context
    take_attend_list.setAdapter(adapter);

    //adapter = new ArrayAdapter<String>(this, 
        //  android.R.layout.simple_list_item_multiple_choice,attendList);

    //take_attend_list.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
    //take_attend_list.setAdapter(adapter);


    save_attendance.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            Toast.makeText(TakeAttend.this, "Saved", Toast.LENGTH_LONG).show();
            //adapter.notifyDataSetChanged();
        }
    });


    cancel.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
        Intent intent = new Intent(TakeAttend.this,NextActivity.class);
        startActivity(intent);
        }
    });
}
}`