RecyclerView.Adapter的onCreateViewHolder和onBindViewHolder方法没有被调用

时间:2015-09-08 16:54:07

标签: android simplecursoradapter android-recyclerview android-viewholder

我正在尝试按照该链接中提供的示例项目在我的项目中实现TwoWayView。我实现了一切,我的代码工作没有任何错误,但实际的List没有得到膨胀。在调试时,我发现适配器设置正确,getItemCount方法也返回正数,但其他两个重写方法onCreateViewHolderonBindViewHolder未被调用。我不知道为什么它不起作用。请参阅下面的部分代码,任何帮助表示赞赏。感谢。

MyAdapter.java

public class MyAdapter extends RecyclerView.Adapter < MyViewHolder > {

    private MySimpleCursorAdapter mCursor;
    //some other private fields here

    public MyAdapter(Context context, Cursor c, int resourceId, ViewType viewType, String containerId) {
        mCursor = new MySimpleCursorAdapter(a1,a2,a3,a4,a5,a6); //Passed necessary arguments
        ....
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        Log.w("onCreateViewHolder", "--------->executed"); //Line not executed
        final View view = mCursor.newView(mContext, mCursor.getCursor(), parent);
        return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        Log.w("onBindViewHolder", "--------->executed"); //Line not executed
        mCursor.bindView(holder.itemView, mContext, mCursor.getCursor());
    }

    @Override
    public int getItemCount() {
        Log.w("count", Integer.toString(mCursor.getCount())); //This is executed
        return mCursor.getCount();
    }

    private class MySimpleCursorAdapter extends SimpleCursorAdapter {

        public MySimpleCursorAdapter(Context context, int layout, Cursor c, String[] from, int[] to, int flags) {
            super(context, layout, c, from, to, flags);
        }

        @Override
        public View newView(Context context, Cursor cursor, ViewGroup parent) {
            View view = mLayoutInflater.inflate(mLayoutToInflate, null);
            ....
            return view;
        }

        @Override
        public void bindView(final View view, Context context, Cursor cursor) {
            //Implemented this method for inflating all subviews inside each item of the list
        }
    }
 }

注意:我已经遇到了类似的问题,但我提供的答案与我的问题无关,因为我的RecyclerView不在ScrollView内,而且{{1返回正数。

2 个答案:

答案 0 :(得分:9)

我想你忘记了回收者视图上的setLayoutManager(LayoutManager)。如果没有布局管理器,则仅调用getItemCount()

尝试使用yourRecyclerview.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));

答案 1 :(得分:0)

首先,在实例化适配器时,应该保留对Context的引用:

public class MyAdapter extends RecyclerView.Adapter < MyViewHolder > {

private MySimpleCursorAdapter mCursor;
private Context context;  // <-- add this line
//some other private fields here

public MyAdapter(Context context, Cursor c, int resourceId, ViewType viewType, String containerId) {
    mCursor = new MySimpleCursorAdapter(a1,a2,a3,a4,a5,a6); 
    this.context = context;  // <-- add this line
    //Passed necessary arguments
    ....
}

然后,在onCreateViewHolder方法中,使用对Context的引用来为ViewHolder创建视图:

    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    Log.w("onCreateViewHolder", "--------->executed"); //Line not executed
    final View view = mCursor.newView(context, mCursor.getCursor(), parent);
    return new MyViewHolder(view);
}

然后在CursorAdapter中按如下方式对视图进行充气:

        public View newView(Context context, Cursor cursor, ViewGroup parent) {
        View view = LayoutInflater.from(context).inflate(mLayoutToInflate, parent, false);
        return view;
    }

我遇到了同样的问题,虽然我使用JSON调用来检索数据而不是Cursor Adapter,但这些更改解决了问题。