基于从sqlite生成的listview的OnItemClickListner检索数据

Question

在我的应用中，我将数据保存到 SQLite 并显示在 listview 中，但稍后我想基于 onitemClickListner listview进入 edittext 中的下一个活动。但我无法做到这一点。如何基于id生成用于获取数据的选择查询？

我的databasehelper类

public class DatabaseHelper extends SQLiteOpenHelper {

//Constants for Database name, table name, and column names
public static final String DB_NAME = "NamesDB";
public static final String TABLE_NAME = "names";
public static final String COLUMN_ID = "id";
public static final String COLUMN_NAME = "name";
public static final String COLUMN_STATUS = "status";


//Constructor
public DatabaseHelper(Context context) {
    super(context, DB_NAME, null, DB_VERSION);
}

//creating the database
@Override
public void onCreate(SQLiteDatabase db) {
    String sql = "CREATE TABLE " + TABLE_NAME
            + "(" + COLUMN_ID +
            " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN_NAME +
            " VARCHAR, " + COLUMN_STATUS +
            " TINYINT);";
    db.execSQL(sql);
}


   public boolean addName(String name, int status) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues contentValues = new ContentValues();

    contentValues.put(COLUMN_NAME, name);
    contentValues.put(COLUMN_STATUS, status);


    db.insert(TABLE_NAME, null, contentValues);
    db.close();
    return true;
}

这就是我将数据保存到sqlite的方式

private NameAdapter nameAdapter;
//saving the name to local storage
private void saveNameToLocalStorage(String name, int status) {
    editTextName.setText("");
    db.addName(name, status);
    Name n = new Name(name, status);
    names.add(n);
    refreshList();
}

将数据加载到listview

private DatabaseHelper db;

private void loadNames() {
    names.clear();
    Cursor cursor = db.getNames();
    if (cursor.moveToFirst()) {
        do {
            Name name = new Name(
                    cursor.getString(cursor.getColumnIndex(DatabaseHelper.COLUMN_NAME)),
                    cursor.getInt(cursor.getColumnIndex(DatabaseHelper.COLUMN_STATUS))
            );
            names.add(name);
        } while (cursor.moveToNext());
    }

    nameAdapter = new NameAdapter(this, R.layout.names, names);
    listViewNames.setAdapter(nameAdapter);
}

它在listview中显示数据

我获取了listview中单击项的id并将其发送到我想运行查询的下一个活动，并获取特定ID的数据，但我无法执行此操作。

listViewNames.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int id, long l) {

            Toast.makeText(MainActivity.this, id+"", Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(this,Second.class);
            intent.putExtra("id", id);
            startActivity(intent);

        }
    });

Answer 1

您需要从列表项中检索名称并查询数据库。添加列表项onclick。并使用position从适配器中检索名称和查询db之后。 db添加为intent的额外结果并打开新活动

Answer 2

你的NameAdapter应该有这个方法：

public Name getItem(int position) {
    return yourItems.get(position);
}

然后使用适配器按位置获取项目：

listViewNames.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
            Name yourObject = nameAdapter.getItem(position);
            Toast.makeText(MainActivity.this, yourObject+"", Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(this,Second.class);
            intent.putExtra("yourObject", yourObject);
            startActivity(intent);

        }
    });

如果你想把你的对象作为Extra传递，它应该实现Serializable或Parcelable。

<强>更新

选择方法：

public Cursor getNames(int id){
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery("SELECT id, name, status FROM names where id = " + id, null);
return c;
}