在 CardView 包含的 RelativeLayout 上设置 onClickListener

Question

我正在尝试为每个 CardView 元素设置 onClickListener。由于我无法在卡片本身上设置 onClickListener（请参阅 ), I thought about setting it to the RelativeLayout contained by the cards. Right now I am using the native CardView library and applied this 教程。

这是我的 MainActivity 的 onCreate:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    recycleCardView = (RecyclerView) findViewById(R.id.cardList);
    recycleCardView.setHasFixedSize(true);

    LinearLayoutManager llmanager = new LinearLayoutManager(this);
    llmanager.setOrientation(LinearLayoutManager.VERTICAL);
    recycleCardView.setLayoutManager(llmanager);

    data = createList(9);

    ContactAdapter ctadapter = new ContactAdapter(data);
    //...
    recycleCardView.setAdapter(ctadapter);

这是item_card_view xml:

 <?xml version="1.0" encoding="utf-8"?> 
 <android.support.v7.widget.CardView
       xmlns:card_view="http://schemas.android.com/apk/res-auto"
       xmlns:android="http://schemas.android.com/apk/res/android"
       android:id="@+id/card_view"
       android:layout_width="match_parent" android:layout_height="match_parent"
       card_view:cardCornerRadius="4dp"
       android:layout_margin="5dp">

    <RelativeLayout android:id="@+id/nativecardlayout"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:clickable="true"
       android:background="?android:selectableItemBackground">        

      <!--some more layout-->

    </RelativeLayout>
 </android.support.v7.widget.CardView>

这是我的 ContactAdapter 的 onCreateViewHolder:

@Override
public ContactViewHolder onCreateViewHolder(final ViewGroup viewGroup, int i) {
    View itemView = LayoutInflater.from(viewGroup.getContext())
                            .inflate(R.layout.item_card_view, viewGroup, false);

    RelativeLayout cardlayout = (RelativeLayout)
              viewGroup.findViewById(R.id.nativecardlayout); //NullPointerException here
    cardlayout.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(viewGroup.getContext(), "Clickable card", Toast.LENGTH_LONG).show();
        }
    });
    return new ContactViewHolder(itemView);
}

我的问题是，我尝试加载的 RelativeLayout（位于 cardview 元素内）为空。因此我得到一个 NullPointerException.

如何在每个 RelativeLayout 上设置 onClickListener？这可能吗？

Answer 1

您可以为所有视图设置监听器。所以这是可能的。
替换这个

RelativeLayout cardlayout = (RelativeLayout)
          viewGroup.findViewById(R.id.nativecardlayout);

有了这个

RelativeLayout cardlayout = (RelativeLayout)
          itemView.findViewById(R.id.nativecardlayout);

Answer 2

见下文编辑，其逻辑错误：

RelativeLayout cardlayout = (RelativeLayout)itemView.findViewById(R.id.nativecardlayout);

在 CardView 包含的 RelativeLayout 上设置 onClickListener

Set onClickListener on the RelativeLayout contained by CardView

android

android-layout

android-cardview

android-recyclerview