android - 如何在 android 中的 Recyclerview 上添加页眉/页脚

Question

我花了一些时间试图找出如何将页眉/页脚添加到我的 recyclerview，但它不起作用。页脚显示但页眉和列表项不显示在模拟器上。我的适配器

package com.example.system2.tranxav.adapters;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.example.system2.tranxav.R;
import com.example.system2.tranxav.model.Problems;

import java.util.List;
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder>{

Context context;
private List<Problems> mDataset;
private static final int TYPE_HEADER = 0;
private static final int TYPE_FOOTER = 1;
private static final int TYPE_ITEM = 2;

public class ViewHolder extends RecyclerView.ViewHolder{
    public TextView tvProblems, tvPrice;
    public Button btnProblem;

    public ViewHolder(View itemView) {
        super(itemView);

    }
}

public void add(int position, Problems item){
    mDataset.add(position, item);
    notifyItemInserted(position);
}

public void remove(Problems item){
    int position = mDataset.indexOf(item);
    mDataset.remove(position);
    notifyItemRemoved(position);
}

public MyAdapter(List<Problems> myDataset){
    mDataset = myDataset;
}
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {


    View itemView;
    Log.i("info", String.valueOf(viewType));
    if (viewType == TYPE_ITEM) {
        //Inflating recycle view item layout
        itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_problems, parent, false);
        ViewHolder vh = new ViewHolder(itemView);
        return  vh;
    } else if (viewType == TYPE_HEADER) {
        //Inflating header view
        itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.problem_recycler_header, parent, false);
        ViewHolder vh = new ViewHolder(itemView);
        return  vh;
    } else if (viewType == TYPE_FOOTER) {
        //Inflating footer view
        itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.problem_recycler_footer, parent, false);
        ViewHolder vh = new ViewHolder(itemView);
        return  vh;
    }
    throw new RuntimeException("there is no type that matches the type " + viewType + " + make sure your using types correctly");
}

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    try {
    if (holder instanceof HeaderViewHolder) {
        HeaderViewHolder headerHolder = (HeaderViewHolder) holder;
        headerHolder.tvHeader.setText("Please kindly ask the mechanic what the problem is and check them to continue");

    } else if (holder instanceof FooterViewHolder) {
        FooterViewHolder footerHolder = (FooterViewHolder) holder;

        footerHolder.btnProblem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.i("info", "the button is clicked");
            }
        });
    }
    else if (holder instanceof ItemViewHolder) {
        ItemViewHolder itemView = (ItemViewHolder) holder;
        itemView.tvPrice.setText(mDataset.get(position).getPrice());
        itemView.tvProblems.setText(mDataset.get(position).getProblems());
    }
    } catch (Exception e) {
        e.printStackTrace();
    }
}
@Override
public int getItemCount() {
    return mDataset.size()+2;
}

public int getItemViewType(int position) {


    if (position == 0) {
        return TYPE_HEADER;
    } else if (position == mDataset.size() + 1) {
        return TYPE_FOOTER;
    }
    return TYPE_ITEM;
}

private class HeaderViewHolder extends MyAdapter.ViewHolder {
    TextView tvHeader;

    public HeaderViewHolder(View view) {
        super(view);
        tvHeader = (TextView) view.findViewById(R.id.tvHeader);
    }
}
private class FooterViewHolder extends MyAdapter.ViewHolder {
    Button btnSubmitProblem;

    public FooterViewHolder(View view) {
        super(view);
        btnSubmitProblem = (Button) view.findViewById(R.id.btnProblem);
    }
}

private class ItemViewHolder extends MyAdapter.ViewHolder {
    TextView tvProblems, tvPrice;

    public ItemViewHolder(View itemView) {
        super(itemView);
        tvProblems = (TextView) itemView.findViewById(R.id.tvProblems);
        tvPrice = (TextView) itemView.findViewById(R.id.tvPrice);
    }
}

problem_recycler_header.xml

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

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/tvHeader" />
 </LinearLayout>

footer_problem_recycler.xml

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

<Button
    android:text="Button"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/btnProblem" />
 </LinearLayout>

Activity 问题.xml

  <LinearLayout 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:orientation="vertical"
android:paddingBottom="@dimen/zerodimen"
android:paddingLeft="@dimen/zerodimen"
android:paddingRight="@dimen/zerodimen"
android:paddingTop="16dp"
tools:context="com.example.system2.tranxav.ProblemsActivity">
<android.support.v7.widget.RecyclerView
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:paddingBottom="0dp"
    android:layout_marginBottom="0dp"
    android:scrollbars="none"
    android:id="@+id/problem_recycle_view"
    xmlns:android="http://schemas.android.com/apk/res/android" />

<TextView
    android:id="@+id/tvProblems"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:textSize="16dp"
    android:textStyle="bold" />

<TextView
    android:id="@+id/tvPrice"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:textStyle="bold" />

</LinearLayout>

我已经检查了代码，知道问题出在哪里，但我无法弄清楚。我正在从我的数据集中获取数据，但它没有显示在模拟器上。

Answer 1

我认为 onBindViewHolder 的位置有一个小问题

你能不能像这样改变你的代码并试一试。

else if (holder instanceof ItemViewHolder) {
        ItemViewHolder itemView = (ItemViewHolder) holder;
        itemView.tvPrice.setText(mDataset.get(position - 1).getPrice());
        itemView.tvProblems.setText(mDataset.get(position - 1).getProblems());
      } 

您的代码的问题是您返回相同的 viewholder 您应该在 onCreateViewHolder 中像这样更改代码

    View itemView;
    Log.i("info", String.valueOf(viewType));
    if (viewType == TYPE_ITEM) {
        //Inflating recycle view item layout
        itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_problems, parent, false);
        ViewHolder vh = new ViewHolder(itemView);
        return  vh;
    } else if (viewType == TYPE_HEADER) {
        //Inflating header view
        itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.problem_recycler_header, parent, false);
        HeaderViewHolder vh = new HeaderViewHolder(itemView);
        return  vh;
    } else if (viewType == TYPE_FOOTER) {
        //Inflating footer view
        itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.problem_recycler_footer, parent, false);
        FooterViewHolder vh = new FooterViewHolder(itemView);
        return  vh;
    }