问题描述

如何删除数据库中的数据?

当我点击列表视图中的一个选项时，如何删除数据库中的数据?我使用下面的方法来选择列表视图的选项。

listview.setOnItemClickListener(new OnItemClickListener(){
        public void onItemClick(AdapterView adapterView, View convertView, int position, long id)
        {
            AlertDialog.Builder alertDialog = new AlertDialog.Builder(AndroidSpinnerFromSQLiteActivity.this);
            alertDialog.setTitle("Confirm Delete...");
            alertDialog.setMessage("Are you sure you want delete this?");
            alertDialog.setIcon(R.drawable.delete);
            alertDialog.setPositiveButton("YES",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog,int which) {
                        }
                    });
            alertDialog.setNegativeButton("NO",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                        }
                    });
            alertDialog.show();
            }
        });
    };

数据库类：

public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "spinnerExample";
private static final String TABLE_LABELS = "labels";
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
public DatabaseHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
    String CREATE_CATEGORIES_TABLE = "CREATE TABLE " + TABLE_LABELS + "("
            + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT" +")";
    db.execSQL(CREATE_CATEGORIES_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_LABELS);
    onCreate(db);
}
public void insertLabel(String label){
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_NAME, label);
    db.insert(TABLE_LABELS, null, values);
    db.close();
}
public List<String> getAllLabels(){
    List<String> labels = new ArrayList<String>();
    String selectQuery = "SELECT  * FROM " + TABLE_LABELS;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    if (cursor.moveToFirst()) {
        do {
            labels.add(cursor.getString(1));
        } while (cursor.moveToNext());
    }
    cursor.close();
    db.close();
    return labels;
}
}

解决方案

在你的数据库类的代码中添加一个方法。如果你想删除所有的原始表单，使用

db.execSQL("DELETE from "+Table_Name);

如果想删除表格中特定的行，使用

 db.delete(Table_Name, "Raw_Field_Name" + "='" + Raw_field_value+"'", null);

列表视图项的点击事件使用

 Listview lv;
//on create method
     lv = (ListView) findViewById(R.id.list_contact_name);

              lv.setOnItemClickListener(new OnItemClickListener()
                {
                    public void onItemClick(AdapterView<?> arg0, View v, int position,
                            long id) {
                      // call DELETE method here
                    }
                });

解决方案二：

http://blog.csdn.net/zlqqhs/article/details/8607849
在单击事件中调用delete方法

解决方案三：

在 Helper 类中添加：

public boolean deleteData(String name)
{
    SQLiteDatabase db=getWritableDatabase();
    return db.delete(TABLE_NAME, KEY_NAME+"= ?", new String[]{name})>0;
}

用标签的名字调用这个方法。你会在列表视图 OnItemClickListener 中获得 onItemClick 方法。