Question

早上好，我是Android开发的新手，我练习CRUD操作，但是在删除列表视图中的所选项目时遇到错误，我想在删除后更新列表视图。

这是我要在Database Helper中删除的代码

public void deletegroce(int groceId){
    String groceid[] = {String.valueOf(groceId)};
    SQLiteDatabase sqdb = this.getWritableDatabase();
    sqdb.delete(TABLE_NAME, KEY_GROCE_ID + " = ?", groceid);
    sqdb.close();
}

}

这是我的清单代码

public class Grocery_list extends Activity {
ListView lvGorc;
DatabaseHelper dbhelper;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_grocery_list);
    lvGorc = (ListView) findViewById(R.id.lvGroc);
    dbhelper = new DatabaseHelper(Grocery_list.this);
    final ArrayList<String> aList = dbhelper.getAllGroceries();
    ArrayAdapter<String> La = new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, aList);
    lvGorc.setAdapter(La);


    lvGorc.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(final AdapterView<?> adapterView, View view, int i, long l) {
            AlertDialog.Builder adb = new AlertDialog.Builder(Grocery_list.this);
            adb.setTitle("Option");
            adb.setMessage("What do you want to do?");
            adb.setPositiveButton("Update", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {

                }
            });
            adb.setNegativeButton("Delete", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {
                    dbhelper.deletegroce(i);

                }
            });
            adb.show();
        }
    });
    La.notifyDataSetChanged();
    lvGorc.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
            AlertDialog.Builder adb = new AlertDialog.Builder(Grocery_list.this);
            adb.setTitle("Delete?");
            adb.setMessage(aList.get(position));
            adb.setPositiveButton("Delete", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dbhelper.deletegroce(aList.get(position));
                }
            });
            adb.show();
            return  true;
        }
    });
}

}

非常感谢

Answer 1

您的deleteGroce（）方法需要一个int（groceId），但是您的ArrayAdapter get（）方法将返回一个String值，您需要使用Int.parseInt（aList.get（position））而不是aList.get（位置）在调用方法中：）

DatabaseHelper中的DeleteFunction（Long）不能应用于java.lang.String

1 个答案: