Recyclerview(在Recyclerview上获取项目)

Question

我在github上使用它实现了SearchView + Recyclerview.GITHUB
我的下一步是将物品放在recyclerview上的选定部分.
然后我看到一些代码让孩子进入recyclerview.
当getChildAt(index)= 0时,代码正在运行.
但是当我把索引= 12或更大时.
该计划崩溃了.

mRecyclerView.setAdapter(mAdapter);
        mRecyclerView.addOnItemTouchListener(
                new RecyclerItemClickListener(getContext(), new RecyclerItemClickListener.OnItemClickListener() {
                    @Override
                    public void onItemClick(View view, int position) {
                        final int valueThisIteration = position;
                        mRecyclerView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                            @Override
                            public void onGlobalLayout() {
                                TextView textViewDrawerTitle = (TextView) mRecyclerView.getChildAt(valueThisIteration).findViewById(R.id.tvText);
                                textViewDrawerTitle.setText("Checked");
                                mRecyclerView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
                            }
                        });

                    }
                })
        );

我得到这个错误.

11-04 09:36:02.818 1629-1629/? E/AndroidRuntime: FATAL EXCEPTION: main
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime: Process: com.thesis.juandirection.juandirectionfinale, PID: 1629
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at com.thesis.juandirection.juandirectionfinale.fragments.FragmentSearch$1$1.onGlobalLayout(FragmentSearch.java:94)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.ViewTreeObserver.dispatchOnGlobalLayout(ViewTreeObserver.java:815)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1867)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.Choreographer.doCallbacks(Choreographer.java:580)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.Choreographer.doFrame(Choreographer.java:550)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:739)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:95)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:135)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5221)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
11-04 09:36:02.818 1629-1629/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

Answer 1

为了处理RecyclerView中的项目点击,我建议您将逻辑移动到适配器的ViewHolder中.您可以拥有ViewHolder工具View.OnClickListener,并覆盖该onClick()方法以执行操作.如果您的操作取决于单击的项目,您可以使用它来引用它getAdapterPosition().代码看起来像这样:

public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
   public MyViewHolder(View view) {
      super(view);

      view.setOnClickListener(this);
   }

   @Override
   public void onClick(View view) {
      // Get the item clicked
      // For this example, I'm assuming your data source is of type `List<MyObject>`
      MyObject myObject = mDataSource.get(getAdapterPosition());
      // Then you can do any actions on it, for example: 
      myObject.setChecked();
   }
}

很明显,内部发生的逻辑onClick会改变你的例子,但我希望这会让你走上正轨.有关此问题的另一个示例,以及对ViewHolder中处理点击逻辑的好处的一些解释,请查看我写的比较RecyclerView和ListView 的博客文章(查找标记为"更明确的点击监听器"的部分) .