【问题标题】:RecyclerView Adapter methods not called未调用 RecyclerView 适配器方法
【发布时间】:2015-07-12 20:04:43
【问题描述】:

我的适配器有一个奇怪的问题,即没有调用任何方法。构造函数可以工作,如果我有断点,它就会停在那里,但从那里什么也没有。onCreateViewHolder 没有被调用,onBindViewHolder 也没有甚至没有getItemCount.. 我尝试了所有可以在网上找到的东西,但似乎没有任何效果,所以我不知道该怎么做。有什么建议?这是我的代码: 片段:

public class FragmentPackageDetails extends Fragment {
    //other vars
    RecyclerView rvPackageDetails;
    DatabaseHandler database;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Bundle args = getArguments();
        String temp = args.getString(KEY_TRACKER_CODE);
        View v = inflater.inflate(R.layout.fragment_package_details_new, container, false);

        return v;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        rvPackageDetails = (RecyclerView) view.findViewById(R.id.rvPackageDetails);
        rvPackageDetails.setLayoutManager(new LinearLayoutManager(getActivity()));

        database = new DatabaseHandler(getActivity());
        selectedPackage = database.getPackage(trackerCode);

        RecyclerView.Adapter adapter = new MyAdapter(selectedPackage.getRecords());
        rvPackageDetails.setAdapter(adapter);
    }
    //other methods in class
}

我的适配器

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
    private ArrayList<TrackingRecordCheckedOut> mDataset;

    // Provide a reference to the views for each data item
    // Complex data items may need more than one view per item, and
    // you provide access to all the views for a data item in a view holder
    public class ViewHolder extends RecyclerView.ViewHolder {
        // each data item is just a string in this case
        public TextView tvPackageDetailsRowDayOfWeek, tvPackageDetailsRowDayOfMonth, tvPackageDetailsRowNameOfMonth,
                tvPackageDetailsRowDetailsTitle, tvPackageDetailsRowDetailsDescription, tvPackageDetailsRowDetialsTime;

        public ViewHolder(View v) {
            super(v);
            tvPackageDetailsRowDayOfWeek = (TextView) v.findViewById(R.id.tvPackageDetailsRowDayOfWeek);
            tvPackageDetailsRowDayOfMonth = (TextView) v.findViewById(R.id.tvPackageDetailsRowDayOfMonth);
            tvPackageDetailsRowNameOfMonth = (TextView) v.findViewById(R.id.tvPackageDetailsRowNameOfMonth);
            tvPackageDetailsRowDetailsTitle = (TextView) v.findViewById(R.id.tvPackageDetailsRowDetialsTime);
            tvPackageDetailsRowDetailsDescription = (TextView) v.findViewById(R.id.tvPackageDetailsRowDetailsDescription);
            tvPackageDetailsRowDetialsTime = (TextView) v.findViewById(R.id.tvPackageDetailsRowDetialsTime);
        }
    }

    // Provide a suitable constructor (depends on the kind of dataset)
    public MyAdapter(ArrayList<TrackingRecordCheckedOut> myDataset) {
        mDataset = myDataset;
    }

    // Create new views (invoked by the layout manager)
    @Override
    public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        // create a new view
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_list_item, parent, false);
        // set the view's size, margins, paddings and layout parameters
        ViewHolder vh = new ViewHolder(v);
        return vh;
    }

    // Replace the contents of a view (invoked by the layout manager)
    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        // - get element from your dataset at this position
        // - replace the contents of the view with that element
        TrackingRecordCheckedOut tr = mDataset.get(position);
        holder.tvPackageDetailsRowDayOfWeek.setText(tr.getDayOfWeek());
        holder.tvPackageDetailsRowDayOfMonth.setText(tr.getDayOfWeek());
        holder.tvPackageDetailsRowNameOfMonth.setText(tr.getMonthOfYear());
        holder.tvPackageDetailsRowDetailsTitle.setText(tr.getTitle());
        holder.tvPackageDetailsRowDetailsDescription.setText(tr.getDetails());
        holder.tvPackageDetailsRowDetialsTime.setText(tr.getTimeOfDay());

    }

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return mDataset.size();
    }

}

片段布局:

<?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">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rvPackageDetails"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

RecyclerView 行布局:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/llPackageDetailsRecyclerViewRow"
    android:layout_width="match_parent"
    android:layout_height="96dip"
    android:orientation="horizontal"
    android:weightSum="100">

    <LinearLayout
        android:layout_width="0dip"
        android:layout_height="match_parent"
        android:layout_weight="20"
        android:orientation="vertical"
        android:weightSum="10">


        <TextView
            android:id="@+id/tvPackageDetailsRowDayOfWeek"
            android:layout_width="match_parent"
            android:layout_height="0dip"
            android:layout_weight="3"/>

        <TextView
            android:id="@+id/tvPackageDetailsRowDayOfMonth"
            android:layout_width="match_parent"
            android:layout_height="0dip"
            android:layout_weight="4"/>

        <TextView
            android:id="@+id/tvPackageDetailsRowNameOfMonth"
            android:layout_width="match_parent"
            android:layout_height="0dip"
            android:layout_weight="3"/>


    </LinearLayout>

    <LinearLayout
        android:layout_width="0dip"
        android:layout_height="match_parent"
        android:layout_weight="80"
        android:orientation="vertical">

        <TextView
            android:id="@+id/tvPackageDetailsRowDetailsTitle"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="3"/>

        <TextView
            android:id="@+id/tvPackageDetailsRowDetailsDescription"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="4"/>

        <TextView
            android:id="@+id/tvPackageDetailsRowDetialsTime"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="3"/>

    </LinearLayout>

</LinearLayout>

【问题讨论】:

  • 您确定selectedPackage.getRecords() 没有返回空列表吗?
  • 是的。我里面有 4 件物品
  • 尝试将onViewCreated()里面的代码移动到onCreateView()(RecyclerView的实例化,适配器的创建...)
  • 我试过了......仍然没有运气......我将所有内容从我的片段移动到测试活动,我不需要更改任何东西并且它有效..我只是调整了代码形式片段到活动并完美运行..我不知道为什么..我想我会直接在活动中这样生活..

标签: java android android-fragments adapter android-recyclerview


【解决方案1】:

我遇到了同样的问题,onCreateViewHolder 或 onBindViewHolder 都没有被调用。在适配器的构造函数中保存对 Context 的引用,然后更改 onCreateViewHolder 方法以使用保存的对 Context 的引用而不是执行 parent.getContext() 应该修复它:

private Context mContext;

public MyAdapter(Context context, ArrayList<TrackingRecordCheckedOut> myDataset) {
    mDataset = myDataset;
    mContext = context;
}

public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    // create a new view using saved reference to Context (mContext)
    View v = LayoutInflater.from(mContext).inflate(R.layout.recyclerview_list_item, parent, false);
    // set the view's size, margins, paddings and layout parameters
    ViewHolder vh = new ViewHolder(v);
    return vh;
}

【讨论】:

    【解决方案2】:

    不幸的是,我查看了您的代码并没有真正发现问题。可能有问题的一件事是在 ViewHolder 构造函数中调用 super(v)。您可能需要调用 super((LinearLayout)v)。不过,这可能没有什么不同。

    祝你好运!

    【讨论】:

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