Question

我创建了一个包含三个表的数据库，并将该数据库放入资产文件夹中。现在我想显示列表视图中一列的值和复选框，然后用户选择想要将它们插入到另一个表中。那怎么能这样做呢。

到目前为止，我所做的是获取数据并显示在列表中。但是如何放置复选框然后获取我不知道的值。我使用的代码在

下面

1.主要活动

package com.example;

import android.app.ListActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.widget.ListAdapter;
import android.widget.SimpleCursorAdapter;

public class MainActivity extends ListActivity {

    private Cursor employees;
    private MyDatabase db;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        db = new MyDatabase(this);
        employees = db.getEmployees(); // you would not typically call this on the main thread

        ListAdapter adapter = new SimpleCursorAdapter(this, 
                android.R.layout.simple_list_item_1, 
                employees, 
                new String[] {"FullName"}, 
                new int[] {android.R.id.text1});

        getListView().setAdapter(adapter);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        employees.close();
        db.close();
    }

}

2.Mydatabase.java

package com.example;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteQueryBuilder;

import com.readystatesoftware.sqliteasset.SQLiteAssetHelper;

public class MyDatabase extends SQLiteAssetHelper {

    private static final String DATABASE_NAME = "northwind";
    private static final int DATABASE_VERSION = 2;

    public MyDatabase(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);  
        //setForcedUpgradeVersion(2);
    }

    public Cursor getEmployees() {

        SQLiteDatabase db = getReadableDatabase();
        SQLiteQueryBuilder qb = new SQLiteQueryBuilder();

        String [] sqlSelect = {"0 _id", "FullName"}; 
        String sqlTables = "Employees";

        qb.setTables(sqlTables);
        Cursor c = qb.query(db, sqlSelect, null, null,
                null, null, null);

        c.moveToFirst();
        return c;

    }

}

请建议我，我该怎么做...任何帮助必须得到赞赏

Answer 1

在我看来，您应该为ListView创建自定义适配器并手动迭代结果数据集，更新ArrayList<MyObject>（您还应该创建）。

然后在自定义适配器中创建一些函数以获取“选定”项，或创建一些函数，如public void setSelected(int position)，相应地更改复选框，private boolean isSelected(int position)返回是否选中复选框或不

首先，我们需要对象类来保存数据集：

  class MyObject {
      //properties with setters and getters
      boolean selected;
  }

活动：

private MyActivity extends Activity {
  ...
  ArrayList<MyObject> data = new ArrayList<MyObject>();
  ...
  //get dataset
  for(int i=0; i<cursor.getCount(); i++) {
     //create and set MyObject
     data.add(MyObject); 
  }     
  ...
  CustomAdapter myAdapter = new CustomAdapter(..., data);
  listView.setAdapter(myAdapter);
  ...
}

在CustomAdapter类中：

class CustomAdapter extends BaseAdapter {
   ArrayList<MyObject> data;
   //constructor, properties, getters, setters
   //implement methods

   public void setSelected(int position) {
      data.get(position).setSelected(true); //boolean selected property defines whether the checkbox is selected or not
      notifyDatasetChanged(); //update the UI
   }

   @Override
   getView() {
      CheckBox checkBox; //the check box of the list row
      ...
      if(data.get(position).isSelected()) {
         checkBox.setSelected(true);
      } else {
         checkBox.setSelected(false);
      } //update the checkbox accordingly
   }
}

我非常简短地写下来给你一个概述。有很多代码要写，但我给你的是“热门篇章”。

如何使用带有ListView的复选框并在android中的Sqlite数据库中插入值

1 个答案: