如何从领域正确修改或删除对象？

Question

我有一个应用程序，当用户从列表视图中单击一个项目时，有关该项目的信息将显示在另一个页面中，用户可以单击编辑或删除按钮从列表中删除该项目。

问题是删除的代码不起作用。 详情页面只是关闭并返回列表页面，无需删除或修改任何内容。

试图

列表页

    list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            Intent in=new Intent(showAll.this,editCar.class);
            in.putExtra("car_id",position);
            startActivity(in);
        }
    });

详情页面

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


    Button btnDelete=(Button) findViewById(R.id.button4);
    Button btnEdit=(Button)findViewById(R.id.edut);

    final EditText comName=(EditText)findViewById(R.id.edit_comp);
    final EditText model=(EditText)findViewById(R.id.edit_model);
    final CheckBox status=(CheckBox)findViewById(R.id.checkbox);

    final int i=getIntent().getIntExtra("car_id",0);

    Realm.init(getApplicationContext());
    final  Realm realm = Realm.getDefaultInstance();

    realm.beginTransaction();

    final RealmResults<Car> cars =realm.where(Car.class).findAll();
    realm.commitTransaction();
    final Car car3=cars.get(i);
    realm.close();


    comName.setText(car3.getName());
    model.setText(car3.getModel());
    status.setChecked(car3.isStatus());
    
    final Context context=this;
    
     btnDelete.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            new AlertDialog.Builder(editCar.this).setTitle("warning").setMessage("are you sure you want to delete this car ?")
                    .setPositiveButton("yes", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {


                            Realm.init(getApplicationContext());
                            Realm realm = Realm.getDefaultInstance();
                            realm.beginTransaction();
                            car3.deleteFromRealm();
                            realm.commitTransaction();
                            realm.close();
                        }
                    })
                    .setNegativeButton("No", new DialogInterface.OnClickListener() { //if user choose no do nothing
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            Toast.makeText(context,"no",Toast.LENGTH_SHORT).show();

                        }
                    }).show(); //show dialog

Answer 1

单击删除按钮即可添加此功能。 这对我有用。 :)

这里Notifications是我的模型类。

Realm realm =  Realm.getDefaultInstance();

final Notifications deletedItem = yourArrayList.get(indexPosition);

realm.executeTransaction(new Realm.Transaction() {
                        @Override
                        public void execute(Realm realm) {
                            runOnUiThread(new Runnable() {
                                @Override
                                public void run() {

                                    try {
                                        RealmResults<Notifications> **rows** = realm.where(Notifications.class).equalTo("columnKeyName", columnKeyValue).findAll();
                                        **rows**.deleteAllFromRealm();
                                    } catch (Exception e) {
                                        e.printStackTrace();
                                    }
                                }
                            });
                        }
                    });

final int deletedIndex = indexPosition;

// remove the item from recycler view and notify adapter
yourArrayList.remove(deletedIndex);
adapter.notifyDataSetChanged();

希望这对你也有帮助。 :)