Question

我有一个在ListView中显示记录的类。用户可以删除记录，并且每次用户删除我想要使用新值从布局更新TextView的记录。

我有一个XML布局页面，这个类然后引用自定义适配器。当用户删除记录时，我从另一个类（HistoryOverview.java）触发一个函数，我想更新textview。问题是我已经编码没有错误，但我的TextView不会更新值。我在这里错过了什么或做错了吗？

1。 Layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TableLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <TableRow
            android:paddingLeft="5dp"
            android:paddingTop="5dp" >

            <ImageView
                android:id="@+id/barGraphUsed"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="left|bottom"
                android:background="#808080"
                android:contentDescription="@string/emptyTextfield" />
        </TableRow>


            <TextView
                android:id="@+id/overviewFinances"
                android:paddingLeft="5dp"
                android:paddingTop="5dp"
                android:textColor="#97ca3e"
                android:text="@string/emptyTextfield"
                android:textSize="16sp" />
    </TableLayout>

    <ListView
        android:id="@+id/listViewFinances"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:dividerHeight="1dp"
        android:paddingBottom="50dp"
        android:paddingLeft="5dp"
        android:paddingRight="5dp"
        android:paddingTop="20dp" />

</LinearLayout>

2。自定义适配器

    @Override
    public View getView(final int position, View convertView, final ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View rowView = inflater.inflate(R.layout.listviewitem_history, parent,
                false);
        //if users delete something
        final ImageView deleteFinance = (ImageView) rowView.findViewById(R.id.deleteFinance);

                //on long click to really delete the category.
                deleteFinance.setOnLongClickListener(new AdapterView.OnLongClickListener(){

                    public boolean onLongClick(View view) {
                        //getting id that we set in the tag a bit higher.
                        String financeId = view.getTag().toString();

                        //now convert to long to input in the db.
                        long deleteId = Long.valueOf(financeId);

                        //delete the note from the db, from the listview and update the adapter.
                        db.deleteFinance(deleteId);
                        values.remove(position);


                        getTotalIncomesAndExpenses();

                        notifyDataSetChanged();
                        return true;
                    }
                });

        //return the view.
        return rowView;
    }

    public void getTotalIncomesAndExpenses(){
        HistoryOverview HO = new HistoryOverview();

        //all the numbers get calculated here etc but I would like to keep this code private
        //its rather sensitive data. But all those variables are okay and do work.
        HO.notifyChange(sumExpenses, sumIncomes, currency);
    }

所以当我完成删除记录等时，我使用了在HistoryOverview类中的函数notifyChange。然后我来到这个功能：

第3。 HistoryOverview.Java

    public void notifyChange(int sumExpenses, int sumIncomes, String currency){
        Log.i("sumExpenses, incomes", String.valueOf(sumExpenses + " " + sumIncomes));
        LayoutInflater li = (LayoutInflater)contextForAdapter.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View vi = li.inflate(R.layout.activity_historyoverview, null);

        ListView listViewFinances = (ListView)vi.findViewById(R.id.listViewFinances);
        listViewFinances.setVisibility(vi.GONE);
        listViewFinances.setVisibility(View.GONE);
        vi.bringToFront();


        TextView tv = (TextView)vi.findViewById(R.id.overviewFinances);
        String text = "Sum incomes: " + sumIncomes + currency
                + "\tSum expenses: " + sumExpenses + currency
                + "\tMoney left: " + (sumIncomes - sumExpenses)
                + currency;
        tv.setText(text);
        tv.setBackgroundColor(Color.RED);

        Toast.makeText(contextForAdapter, 
                   text, Toast.LENGTH_LONG).show();
        Log.i("tv:", tv.getText().toString());
    }

我将最终更新textView。但不知怎的，它永远不会更新，虽然我的toast测试功能工作，我的日志都显示正确的值textView将不会更新。任何人都可以告诉我我做错了什么或我错过了什么？

Answer 1

确保在调用findViewById时获得正确的TextView。我相信你的电视不是你需要的TextView对象。您应该在正确的上下文中使用findViewById。如果您正在处理已经存在的视图，则无需夸大任何新内容。通过id找到它或以任何其他方式传递对视图的引用。

Answer 2

更改此

 getTotalIncomesAndExpenses();
 notifyDataSetChanged();

到这个

 notifyDataSetChanged();
 getTotalIncomesAndExpenses();

可能是一个原因。

删除自定义适配器中的记录时TextView不更新

2 个答案: