Android 已停止使用游标适配器填充ListView

对不起，我的英语不好。我开始使用安卓系统。在一周内，我尝试使用游标和sqlite适配器创建ListView。我模仿他。我制作了3个java文件主活动、TodoCursorAdapter、TOODatabaseHandler和2个xml文件活动和项目。当我运行应用程序时，应用程序停止。请帮帮我。这是我的代码：

MainActivity.java

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        TodoDatabaseHandler handler = new TodoDatabaseHandler(this);

        SQLiteDatabase db = handler.getWritableDatabase();

        Cursor todoCursor = db.rawQuery("SELECT  * FROM todo_items", null);


        ListView lvItems = (ListView) findViewById(R.id.lvItems);

        TodoCursorAdapter todoAdapter = new TodoCursorAdapter(this, todoCursor);

        lvItems.setAdapter(todoAdapter);


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        int id = item.getItemId();


        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

TodoCursorAdapter.java

import android.content.Context;
import android.database.Cursor;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CursorAdapter;
import android.widget.TextView;


public class TodoCursorAdapter extends CursorAdapter {
    public TodoCursorAdapter(Context context, Cursor cursor) {
        super(context, cursor);
    }

    // The newView method is used to inflate a new view and return it,
    // you don't bind any data to the view at this point.
    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {
        return LayoutInflater.from(context).inflate(R.layout.item_todo, parent, false);
    }

    // The bindView method is used to bind all data to a given view
    // such as setting the text on a TextView.
    @Override
    public void bindView(View view, Context context, Cursor cursor) {
        // Find fields to populate in inflated template
        TextView tvBody = (TextView) view.findViewById(R.id.tvBody);
        TextView tvPriority = (TextView) view.findViewById(R.id.tvPriority);
        // Extract properties from cursor
        String body = cursor.getString(cursor.getColumnIndexOrThrow("body"));
        int priority = cursor.getInt(cursor.getColumnIndexOrThrow("priority"));
        // Populate fields with extracted properties
        tvBody.setText(body);
        tvPriority.setText(String.valueOf(priority));
    }
}

TodoDatabaseHandler.java

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


public class TodoDatabaseHandler extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "todo_items.db";
    public static final String TABLE_NAME = "todo_items";
    public static final String COL1 = "body";
    public static final String COL2 = "priority";

    public TodoDatabaseHandler(Context context) {
        super(context, DATABASE_NAME, null, 1);

    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        sqLiteDatabase.execSQL("create table " + TABLE_NAME + " (body text, priority integer);");
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
        sqLiteDatabase.execSQL("drop table if exists " + TABLE_NAME);
        onCreate(sqLiteDatabase);
    }

    public boolean add(){
        SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(COL1, "Get milk");
        values.put(COL1, "Do laundry");
        values.put(COL2, "2");
        values.put(COL2, "3");
        sqLiteDatabase.insert(TABLE_NAME, null, values);
        return true;

    }

}

item_todo.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/tvBody"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Study cursors"
        android:textAppearance="?android:attr/textAppearanceLarge" />
    <TextView
        android:id="@+id/tvPriority"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:text="3"
        android:textAppearance="?android:attr/textAppearanceMedium" />

</LinearLayout>

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <ListView
        android:id="@+id/lvItems"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Spinner
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:spinnerMode="dropdown"
        ></Spinner>

</RelativeLayout>

---

我认为在创建表时需要提供一个_id列。尝试将onCreate方法更改为以下内容

@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
    sqLiteDatabase.execSQL("create table " + TABLE_NAME + " ( _id integer primary key autoincrement, body text, priority integer);");
}

---

试试下面的链接，你的问题在这里解决了

方法从Oncreate调用

@Override
    protected void onCreate(Bundle savedInstanceState) 
    {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        try
        {
        openDB();

    populateListViewFromDB();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }

}

---

我必须在哪里添加logcat？嘿，bidha，谢谢你的回答。我已经添加了代码。但应用程序仍然停止了。你能帮我用你自己的方式用sqlite填充listview吗？这是正确的方法。您是否收到相同的错误？是，相同的错误应用程序已停止，我将您的代码id添加到onCreate。您需要检查日志。可能是另一个错误。您需要清除应用程序数据或取消安装并重新启动。Bcz数据库已创建，表中没有_id列，请删除并重新创建