滚动时带有 ImageView 位置的 Listview 混乱答案

【问题标题】：Listview with ImageView position is messed up when scrolling滚动时带有 ImageView 位置的 Listview 混乱
【发布时间】：2015-10-26 00:28:42
【问题描述】：

我有一个有 12 行的 ListView。每个行项包含一个 ImageView 和两个 TextView。 ImageViews 的可见性都设置为 INVISIBLE。当我单击一行时，我将 ImageView 的可见性更改为 VISIBLE。

所以，我点击第一行，它的 ImageView 变得可见，这很好。但是，当我滚动 ListView 时，我发现其他行的 ImageViews 也变得可见。我做了很多搜索，发现这是由于我使用 ViewHolder 模式而回收视图。

我查看了以下链接

Solution 1

Solution 2

但无法在我的代码中实现它。老实说，我不知道该怎么做。下面是我的相关代码

listview_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:gravity="center_vertical"
    android:background="@color/frame_background"
    android:padding="5dp"
    >

    <!-- the innner view - provides the white rectangle -->
    <RelativeLayout android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/frame" >

        <!-- the icon view -->
        <ImageView android:id="@+id/ivIcon"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="5dp"
            android:scaleType="fitXY"
            android:layout_alignParentLeft="true"
            android:visibility="invisible"
            />

        <!-- the container view for the title and description -->
        <RelativeLayout android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@id/ivIcon"
            android:layout_centerVertical="true"
            >

            <!-- the title view -->
            <TextView android:id="@+id/tvTitle"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="@android:style/TextAppearance.Medium" />

            <!-- the description view -->
            <TextView android:id="@+id/tvDescription"
                android:layout_below="@id/tvTitle"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="@android:style/TextAppearance.Small" />
        </RelativeLayout>

    </RelativeLayout>

</RelativeLayout>

ListViewItem.java

public class ListViewItem {

    public final String title;        // the text for the ListView item title
    public final String description;  // the text for the ListView item description
    public final int drawableRef; //Ref to drawable so Picassco can load it
    public boolean visible;

    public ListViewItem(int drawableRef, String title, String description) {
        this.drawableRef=drawableRef;
        this.title = title;
        this.description = description;
    }

    public void setVisible(boolean value)
    {
        visible = value;
    }

    public boolean getVisible()
    {
        return visible;
    }
}

ListViewDemoAdapter.java

public class ListViewDemoAdapter extends ArrayAdapter<ListViewItem> {


    public ListViewDemoAdapter(Context context, List<ListViewItem> items) {
        super(context, R.layout.listview_item,items);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;

        if(convertView == null) {
            // inflate the GridView item layout
            LayoutInflater inflater = LayoutInflater.from(getContext());
            convertView = inflater.inflate(R.layout.listview_item, parent, false);

            // initialize the view holder
            viewHolder = new ViewHolder();
            viewHolder.ivIcon = (ImageView) convertView.findViewById(R.id.ivIcon);
            //viewHolder.ivIcon.setVisibility(View.INVISIBLE);
            viewHolder.tvTitle = (TextView) convertView.findViewById(R.id.tvTitle);
            viewHolder.tvDescription = (TextView) convertView.findViewById(R.id.tvDescription);
            convertView.setTag(viewHolder);
        } else {
            // recycle the already inflated view
            viewHolder = (ViewHolder) convertView.getTag();
        }

        if(position==ListViewDemoFragment.getSelectedPosition())
        {
            viewHolder.ivIcon.setVisibility(View.VISIBLE);
        }
        // update the item view
        ListViewItem item = getItem(position);
        //viewHolder.ivIcon.setImageDrawable(item.icon);
        Picasso.with(getContext()).load(item.drawableRef).into(viewHolder.ivIcon);
        viewHolder.tvTitle.setText(item.title);
        viewHolder.tvDescription.setText(item.description);


        return convertView;
    }

    private static class ViewHolder {
        ImageView ivIcon;
        TextView tvTitle;
        TextView tvDescription;
    }
}

ListViewDemoFragment.java

public class ListViewDemoFragment extends ListFragment {

    private static List<ListViewItem> mItems;        // ListView items list
    private static int mSelectedItem=-1;
    private static ListViewDemoAdapter adapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // initialize the items list
        mItems = new ArrayList<ListViewItem>();
        Resources resources = getResources();

        mItems.add(new ListViewItem(R.drawable.harley1, "TITLE 1", "DESCRIPTION 1"));
        mItems.add(new ListViewItem(R.drawable.harley2, "TITLE 2", "DESCRIPTION 2"));
        mItems.add(new ListViewItem(R.drawable.harley3, "TITLE 3", "DESCRIPTION 3"));

        mItems.add(new ListViewItem(R.drawable.harley4, "TITLE 4", "DESCRIPTION 4"));
        mItems.add(new ListViewItem(R.drawable.harley5, "TITLE 5", "DESCRIPTION 5"));
        mItems.add(new ListViewItem(R.drawable.harley6, "TITLE 6", "DESCRIPTION 6"));

        mItems.add(new ListViewItem(R.drawable.harley7, "TITLE 7", "DESCRIPTION 7"));
        mItems.add(new ListViewItem(R.drawable.harley8, "TITLE 8", "DESCRIPTION 8"));
        mItems.add(new ListViewItem(R.drawable.harley9, "TITLE 9", "DESCRIPTION 9"));

        mItems.add(new ListViewItem(R.drawable.harley10, "TITLE 10", "DESCRIPTION 10"));
        mItems.add(new ListViewItem(R.drawable.harley11, "TITLE 11", "DESCRIPTION 11"));
        mItems.add(new ListViewItem(R.drawable.harley12, "TITLE 12", "DESCRIPTION 12"));

        // initialize and set the list adapter

        adapter = new ListViewDemoAdapter(getActivity(), mItems);
        setListAdapter(adapter);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        // remove the dividers from the ListView of the ListFragment
        getListView().setDivider(null);
    }

    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {
        // retrieve theListView item
        ListViewItem item = mItems.get(position);
        mSelectedItem = position;
        adapter.notifyDataSetChanged();
        // do something
        Toast.makeText(getActivity(), item.title, Toast.LENGTH_SHORT).show();
    }

    public static int getSelectedPosition()
    {
        return mSelectedItem;
    }

    public static List<ListViewItem> getList()
    {
        return mItems;
    }

    public static ListViewDemoAdapter getAdapter()
    {
        return adapter;
    }

}

我想我需要修改我的 ListViewItem.java 和我的适配器，但是在实施我所看到的解决方案时遇到了麻烦。

编辑

ListViewItem.java

 public boolean visible = false;

    public ListViewItem(int drawableRef, String title, String description) {
        //this.icon = Resources.getSystem().getDrawable(drawableRef);
        //this.icon = icon;
        this.drawableRef=drawableRef;
        this.title = title;
        this.description = description;
    }

    public void setVisible(boolean value)
    {
        visible = value;
    }

    public boolean getVisible()
    {
        return visible;
    }

ListViewDemoFragment onClick 方法变更

public void onListItemClick(ListView l, View v, int position, long id) {
    // retrieve theListView item
    ListViewItem item = mItems.get(position);
    mSelectedItem = position;

    item.setVisible(true);
    adapter.notifyDataSetChanged();
    // do something
    Toast.makeText(getActivity(), item.title, Toast.LENGTH_SHORT).show();
}

getView() 函数变化

else {
            // recycle the already inflated view
            viewHolder = (ViewHolder) convertView.getTag();
        }

        ListViewItem item = getItem(position);
        if(position==ListViewDemoFragment.getSelectedPosition())
        {
            if(item.getVisible()==true) {
                viewHolder.ivIcon.setVisibility(View.VISIBLE);
            }
        }
        // update the item view

        //viewHolder.ivIcon.setImageDrawable(item.icon);
        Picasso.with(getContext()).load(item.drawableRef).into(viewHolder.ivIcon);
        viewHolder.tvTitle.setText(item.title);
        viewHolder.tvDescription.setText(item.description);


        return convertView;

【问题讨论】：

您是否希望已设置为visible 的图像在滚出屏幕然后重新打开后保持可见？
@steve 是的，我希望图像在被点击后保持可见，无论它们在屏幕上的哪个位置。
我会为您的ListViewItem 添加一个类似于boolean imageVisibile = false 的属性，当单击某个项目时，您可以将其更改为true。然后在适配器的 getView 方法中，您可以检查属性并切换 ImageView 的可见性
您需要获取被点击视图的索引，在该索引处检索ListViewItem，并将imageVisible 属性切换为true。不幸的是，我没有时间模拟代码。
@steve 我做了你建议的更改，但仍然遇到同样的问题。我已经编辑了我的帖子，所以你可以看到我做了什么。

标签： android listview scroll imageview picasso

【解决方案1】：

由于您有boolean visible 来记录状态，因此没有必要这样做：

if(position==ListViewDemoFragment.getSelectedPosition())
    {
        if(item.getVisible()==true) {
            viewHolder.ivIcon.setVisibility(View.VISIBLE);
        }
    }

让数据决定ImageView 的知名度。将以下代码写入您的 getView

ListViewItem item = getItem(position);
if (item.getVisible()) {
    viewHolder.ivIcon.setVisibility(View.VISIBLE);
} else {
    viewHolder.ivIcon.setVisibility(View.INVISIBLE);
}

【讨论】：

哇，效果惊人。我也完全忘记了将其他项目设置为不可见。我制作的这个 ListView 是我想在工作中做的事情的简化版本（我必须通过 OnProgressUpdate 更新 ListView 中 ImageViews 的可见性）。希望我可以遵循这一点并在那里应用类似的东西。非常感谢。