【问题标题】:Refreshing the fragment after deleting a row from a list view从列表视图中删除一行后刷新片段
【发布时间】:2021-01-06 13:11:58
【问题描述】:

我已经设法创建了一个自定义列表视图,并为每一行添加了一个删除按钮。删除按钮运行良好,当我单击该按钮时,该行将从数据库中删除。问题是,当我删除一行时,它会保留在列表中,直到我通过移动到另一个片段来刷新片段并返回,然后它从列表中消失。我想要的是,当我删除一行时,它会立即从列表视图中消失。我尝试了一些解决方案来刷新整个片段或删除完成后的列表视图,但它们不起作用!

这是我为适配器类中的删除按钮编写的代码

public View getView(final int position, View convertView, ViewGroup parent) {

        View theView = super.getView(position, convertView, parent);     // It took me three days to fix :) I posed a question for it in StackOverFlow
        Button deleteButt = (Button) theView.findViewById(R.id.deleteButton);
        deleteButt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                // This code to delete a row from the class Orders was taken from Back4app help https://www.back4app.com/docs/android/parse-objects/crud
                ParseQuery<ParseObject> query = ParseQuery.getQuery("Orders");
                query.whereEqualTo("objectId", mainObjectsArray.get(position)[3]);  // mainObjectsArray.get(position)[3] We fetched the object id and stored it in mainObjectArray. position is the position of the item in the list which is the same position of the the same item in the mainObjectArray. Smart isn't it?! :)
                query.findInBackground(new FindCallback<ParseObject>() {
                    @Override
                public void done(final List<ParseObject> object, ParseException e) {
                    if (e == null) {

                        // The dialog 
                        AlertDialog.Builder alert = new AlertDialog.Builder(getActivity());
                        alert.setMessage("Are you sure you want to delete this order?")
                                .setNegativeButton("No", null)
                                .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {

                                        //Delete based on the position
                                        object.get(0).deleteInBackground(new DeleteCallback() {
                                            @Override
                                            public void done(ParseException e) {
                                                if (e == null) {
                                                    Toast.makeText(getActivity(), "Deleted!", Toast.LENGTH_SHORT).show();
                                                    
                                                } else {
                                                    Toast.makeText(
                                                            getApplicationContext(),
                                                            e.getMessage().toString(),
                                                            Toast.LENGTH_LONG
                                                    ).show();
                                                }
                                            }
                                        });

                                    }
                                        });

                        alert.create().show();


                    } else {
                        Toast.makeText(
                                getApplicationContext(),
                                e.getMessage().toString(),
                                Toast.LENGTH_LONG
                        ).show();
                    }
                };
            });

            }
        });

        return theView;
    }

之后

Toast.makeText(getActivity(), "Deleted!", Toast.LENGTH_SHORT).show();

我应该编写代码来刷新片段,以便从数据库中获取新数据。 将寻求任何帮助! 非常感谢。

【问题讨论】:

    标签: android listview android-fragments android-listview


    【解决方案1】:

    单击删除按钮后,立即从适配器列表中删除该项目并使用notifyDataSetChanged(),它将更新您的列表项目。您无需为此更新完整片段。

    编辑:- 您可以使用 notifyItemRemoved() 而不是使用 notifyDataSetChanged(),因为这将更新您的整个 recyclerView,这是一项繁重的操作。 Here你可以在notifyItemRemoved()找到更多细节。

    【讨论】:

      【解决方案2】:

      一旦订单被删除,只需从适配器列表中删除订单并通知适配器。

      【讨论】:

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