使用CursorAdapter维护listview中的复选框状态

Question

对于我的Android项目,我有一个列表视图,其中包含每个项目的复选框.使用CursorAdapter类从SQLite数据库加载数据.但是,每当我滚动时,复选框位置将被移动并被移动到列表视图的下一部分.我该如何解决这个问题？ 我的CheckBox问题的GIF 这是我的游标适配器类:

public class VocabCursorAdapter extends CursorAdapter {

private static final int DIFFICULT = 0;
private static final int FAMILIAR = 1;
private static final int EASY = 2;
private static final int PERFECT = 3;

public VocabCursorAdapter(Context context, Cursor c, int flags) {
    super(context, c, 0);
}

@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
    return LayoutInflater.from(context).inflate(R.layout.item_vocab, parent, false);
}

@Override
public void bindView(View view, Context context, Cursor cursor) {
    // Find fields to populate in inflated template
    TextView tvVocabName = (TextView) view.findViewById(R.id.vocabName);
    TextView tvVocabDefinition = (TextView) view.findViewById(R.id.vocabDefinition);
    ImageView tvVocabLevel = (ImageView) view.findViewById(R.id.vocabLevel);
    // Extract properties from cursor
    String vocab = cursor.getString(cursor.getColumnIndexOrThrow(VocabDbContract.COLUMN_NAME_VOCAB));
    String definition = cursor.getString(cursor.getColumnIndexOrThrow(VocabDbContract.COLUMN_NAME_DEFINITION));
    int level = cursor.getInt(cursor.getColumnIndexOrThrow(VocabDbContract.COLUMN_NAME_LEVEL));
    // Populate fields with extracted properties
    tvVocabName.setText(vocab);
    tvVocabDefinition.setText(definition);

    if (level == DIFFICULT) {
        tvVocabLevel.setImageResource(R.drawable.level_bars_difficult);
        tvVocabLevel.setTag(DIFFICULT);
    }
    else if (level == FAMILIAR) {
        tvVocabLevel.setImageResource(R.drawable.level_bars_familiar);
        tvVocabLevel.setTag(FAMILIAR);
    }
    else if (level == EASY) {
        tvVocabLevel.setImageResource(R.drawable.level_bars_easy);
        tvVocabLevel.setTag(EASY);
    }
    else if (level == PERFECT) {
        tvVocabLevel.setImageResource(R.drawable.level_bars_perfect);
        tvVocabLevel.setTag(PERFECT);
    }
}

这是我的列表项xml,item_vocab.xml:

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

<ImageView
    android:layout_width="36sp"
    android:layout_height="36sp"
    android:id="@+id/vocabLevel"
    android:layout_gravity="right"
    android:src="@drawable/level_bars"
    android:scaleType="fitXY"
    android:contentDescription="@string/vocab_level"
    android:layout_centerVertical="true"
    android:layout_toLeftOf="@+id/editCheckbox"
    android:layout_toStartOf="@+id/editCheckbox"/>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="Large Text"
    android:id="@+id/vocabName"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_toLeftOf="@+id/vocabLevel"
    android:layout_toStartOf="@+id/vocabLevel"/>

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:text="Small Text"
    android:id="@+id/vocabDefinition"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_toLeftOf="@+id/vocabLevel"
    android:layout_toStartOf="@+id/vocabLevel"
    android:layout_below="@id/vocabName"/>

<CheckBox
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/editCheckbox"
    android:layout_centerVertical="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"/>

</RelativeLayout>

这是我的xml,其中包含listview

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:tools="http://schemas.android.com/tools"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context=".controller.MyVocab"
            android:paddingLeft="5dp">

<ListView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/mVocabList"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"/>

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/empty_text_view"
    android:id="@android:id/empty"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"/>

</RelativeLayout>

我在StackOverflow上看了很多不同的解决方案,但我无法在自己的应用程序中成功完成.举个例子,这个帖子有类似的问题,但是它的解决方案使用了getView,我无法理解如何用newView和bindView来实现它.

并且一些其他解决方案可能是不涉及cursoradapter的示例.非常感谢任何帮助,非常感谢!编辑#1:在合并Phan的更改后,复选框状态将重置为false而不是在滚动列表视图时保持其状态(请参阅).

Answer 1

原因： ListView 重用了视图。

解决方案 ：

class VocabCursorAdapter extends CursorAdapter {
    List<Integer> selectedItemsPositions;//to store all selected items position

    public VocabCursorAdapter(Context context, Cursor c,int flags) {
        super(context, c,0);
        selectedItemsPositions = new ArrayList<>();
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup viewGroup) {
        View view = LayoutInflater.from(context).inflate(R.layout.item_vocab, viewGroup, false);
        CheckBox box = (CheckBox) view.findViewById(R.id.editCheckbox);
        box.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
                int position = (int) compoundButton.getTag();
                if (b) {
                    //check whether its already selected or not
                    if (!selectedItemsPositions.contains(position))
                        selectedItemsPositions.add(position);
                } else {
                    //remove position if unchecked checked item
                    selectedItemsPositions.remove((Object) position);
                }
            }
        });
        return view;
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {

        //your other stuff

        CheckBox box = (CheckBox) view.findViewById(R.id.editCheckbox);
        box.setTag(cursor.getPosition());

        if (selectedItemsPositions.contains(cursor.getPosition()))
            box.setChecked(true);
        else
            box.setChecked(false);
    }
}