Question

我的问题是，RecyclerView列表会出现，但会从列表中间的某个位置开始，一次只显示一行，而不是多行。我可以向上滚动到列表中的第一项，但我无法向下滚动。关于在Android 4.3中使用RecyclerView的stackoverflow，我发现了一些“问题”，但似乎没有人对我有类似的问题。使用早期版本的RecyclerView，它运行良好。使用三星Galaxy SIII。

我在我的应用中使用了recyclerview，如下所示：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
    android:id="@+id/list"
    android:name="na.com.company.myapp.List"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:orientation="vertical"
    tools:context="na.com.company.myapp.List"
    tools:listitem="@layout/a_row"/>

列表中的每一行都由以下内容组成：

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

    <TextView android:id="@+id/common_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:paddingTop="10dp"
        android:textSize="18sp"
        android:textStyle="bold"/>

    <TextView android:id="@+id/latin_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/common_name"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:paddingBottom="10dp"
        android:textStyle="italic"/>

    <CheckBox android:id="@+id/select_box"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:paddingBottom="10dp"
        android:paddingTop="10dp"/>

</RelativeLayout>

AppCompatActivity派生类中的代码如下（在onCreate函数中）：

RecyclerView recyclerView = (RecyclerView)findViewById(R.id.list);
LinearLayoutManager linear_layout = new LinearLayoutManager(this);
linear_layout.setOrientation(LinearLayoutManager.VERTICAL);
linear_layout.setAutoMeasureEnabled(true);
recyclerView.setLayoutManager(linear_layout);
Drawable dividerDrawable = ContextCompat.getDrawable(this, R.drawable.list_divider);
RecyclerView.ItemDecoration divider_decoration = new ListDivider(dividerDrawable);
recyclerView.addItemDecoration(divider_decoration);

app build.gradle文件包含：

compile 'com.android.support:appcompat-v7:23.4.0'
compile 'com.android.support:design:23.4.0'
compile 'com.android.support:support-v4:23.4.0'
compile 'com.android.support:recyclerview-v7:23.4.0'

ViewHolder代码：

public class TheViewHolder extends RecyclerView.ViewHolder implements OnClickListener
{
    private View the_view = null;
    private CheckBox selected_item = null;

    public TheViewHolder(final View individual_view)
    {
        super(individual_view);
        the_view = individual_view;
        the_view.setOnClickListener(this);
        selected_item = (CheckBox)the_view.findViewById(R.id.select_box);
    }

    public void AttachCursor(final Cursor data_cursor, String[] columns, int[] views, boolean is_selected)
    {
        TextView a_view = (TextView) the_view.findViewById(views[0]);
        a_view.setText(data_cursor.getString(data_cursor.getColumnIndex(columns[0])));
        a_view = (TextView) the_view.findViewById(views[1]);
        a_view.setText(data_cursor.getString(data_cursor.getColumnIndex(columns[1])) + " " + data_cursor.getString(data_cursor.getColumnIndex(columns[2])));
        selected_item.setChecked(is_selected);
    }

    @Override
    public void onClick(View clicked_view)
    {
        selected_item.setChecked(true);
    }
}

并且 getItemCount 函数中的适配器（ query_cursor.getCount（）当前返回值691）：

public class SimpleCursorRecyclerViewAdapter extends RecyclerView.Adapter<TheViewHolder>
{
    private Cursor query_cursor = null;
    private int layout_resource = 0;
    private String[] table_columns;
    private int[] layout_views;
    private View layout_view = null;
    private boolean checkbox_list[] = null;

    public SimpleCursorRecyclerViewAdapter(Context context, int layout_id, Cursor data_cursor, String[] columns, int[] views)
    {
        layout_resource = layout_id;
        query_cursor = data_cursor;
        table_columns = columns;
        layout_views = views;
    }

    public Cursor get_item(final int position)
    {
        if (query_cursor != null && !query_cursor.isClosed())
        {
            query_cursor.moveToPosition(position);
        }

        return query_cursor;
    }

    @Override
    public int getItemCount()
    {
        int size = 0;
        if (query_cursor != null)
        {
            size = query_cursor.getCount();
            checkbox_list = new boolean[size];
        }
        return size;
    }

    @Override
    public void onBindViewHolder(TheViewHolder view_holder, int position)
    {
        Cursor current_cursor = get_item(position);
        view_holder.AttachCursor(current_cursor, table_columns, layout_views, checkbox_list[position]);
    }

    @Override
    public TheViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
    {
        if (layout_view == null)
        {
            layout_view = LayoutInflater.from(parent.getContext()).inflate(layout_resource, parent, false);
        }
        return new TheViewHolder(layout_view);
    }
}

Answer 1

问题在于我的代码，特别是这种方法：

@Override
public TheViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
    if (layout_view == null)
    {
        layout_view = LayoutInflater.from(parent.getContext()).inflate(layout_resource, parent, false);
    }
    return new TheViewHolder(layout_view);
}

现在出现的列表应该是当我将onCreateViewHolder重写为：

 @Override
 public TheViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
 {
    layout_view = LayoutInflater.from(parent.getContext()).inflate(layout_resource, parent, false);
    return new TheViewHolder(layout_view);
}

版本23.4.0 RecyclerView列表在Android 4.3

1 个答案: