Question

当我单击“回收者视图”项目时，我正在尝试更改其背景。数据实际上已更改，但UI并未更改。我已经尝试了很多尝试不同的方法，但是没有任何效果。虽然我正在调用notifyItemChanged（），但是它没有用。

任何使该功能正常工作的解决方案都将非常有帮助。

**我的代码：**

@Override
    public void onBindViewHolder(@NonNull final ViewHolder viewHolder, final int i) {


        customNoteView = notesList.get(i);
        notesText = viewHolder.notesWriteArea;
        notesImage = viewHolder.notesImage;
        notesAudio = viewHolder.notesAudio;
        notesAudioPlayButton = viewHolder.notesAudioPlayButton;
        notesAudioSeekBar = viewHolder.notesAudioSeekBar;
        notesAudioDeleteButton = viewHolder.notesAudioDeleteButton;



        if(customNoteView.getNoteText()!=null){
            editTextList.add(notesText);
            notesText.setVisibility(View.VISIBLE);
            notesImage.setVisibility(View.GONE);
            notesAudio.setVisibility(View.GONE);
            notesText.requestFocus();
            focussedEditText = notesText;
            notesText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
                @Override
                public void onFocusChange(View view, boolean b) {
                    if(b){
                        focussedEditText = ((CustomEditText)view);
                        //Toast.makeText(context, ((CustomEditText) view).getText().toString(), Toast.LENGTH_SHORT).show();
                    }
                }
            });
        }
        else if(customNoteView.getImageUri()!=0){
            notesImage.setVisibility(View.VISIBLE);
            notesText.setVisibility(View.GONE);
            notesAudio.setVisibility(View.GONE);
            Glide.with(notesImage.getContext())
                    .load(notesImage.getContext().getDrawable(customNoteView.getImageUri()))
                    .into(notesImage);

            notesImage.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent intent = new Intent(context, FullScreen.class);
                    ActivityOptionsCompat options =  ActivityOptionsCompat.makeSceneTransitionAnimation((Activity) context,
                            notesImage,
                            ViewCompat.getTransitionName(notesImage)
                            );

                    context.startActivity(intent, options.toBundle());

                }
            });
        }
        else if(customNoteView.getAudioUri()!=null){
            notesAudio.setVisibility(View.VISIBLE);
            notesImage.setVisibility(View.GONE);
            notesText.setVisibility(View.GONE);
            notesAudioPlayButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    notesAudioPlayButton.setBackground(context.getDrawable(R.drawable.ic_pause));
                    notesAudio.setBackground(context.getDrawable(R.drawable.gray_rectangular_background));
                    notifyItemChanged(viewHolder.getAdapterPosition());

                    Toast.makeText(context, ""+viewHolder.getAdapterPosition(), Toast.LENGTH_SHORT).show();
                }
            });

        }

    }

Answer 1

最后，我设法找到了自己的问题的答案，并且没有更改UI的根本原因。

错误：

我实际上是在onBindViewHolder(...)方法中设置点击侦听器的。

解决方案：

如果您想在点击事件上更新回收站视图时避免使用notifyItemChanged(position)和其他内容，则应在viewHolder类而不是onBindViewHolder

中设置点击侦听器

PS： 应用此更改对我来说效果很好。@ Blind Kai的解决方案也有效，但需要刷新视图。我很确定这是一个更简单，更有效的方法。不过，我感谢他的努力。

Answer 2

如果您想要获得这种类型的行为，则可以尝试在类中添加字段，并在每次将onBindViewHolder方法中的项目绑定时进行检查：

if (current.isClicked) {
    viewHolder.itemView.setBackgroundColor(*needed_color*);
} else {
    viewHolder.itemView.setBackgroundColor(*default_color*);
}

viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        current.isClicked = !current.isClicked;
        notifyItemChanged(viewHolder.getAdapterPosition());
    }
});

current-您列表中i位置上的项目；
itemView-项目的根视图；

如果您需要更多详细信息，请随时提出评论。（答案已被编辑并清理了几次）

Answer 3

尝试以下代码：

1）MainActivity.class：

public class MainActivity extends AppCompatActivity {

private final String TAG = MainActivity.class.getSimpleName();
private RecyclerView rv;

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

    rv = (RecyclerView) findViewById(R.id.rv);
    rv.setLayoutManager(new LinearLayoutManager(MainActivity.this));
    List<String> data = new ArrayList<>();
    List<Boolean> selection_states = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        data.add("Item " + (i + 1));
        selection_states.add(false);
    }
    rv.setAdapter(new MyRecyclerViewAdapter(MainActivity.this, data, selection_states));
}

public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {

    private List<String> mData;
    private List<Boolean> mSelectionStates;
    private LayoutInflater mInflater;

    MyRecyclerViewAdapter(Context context, List<String> data, List<Boolean> selection_states) {
        this.mInflater = LayoutInflater.from(context);
        this.mData = data;
        this.mSelectionStates = selection_states;
    }

    @Override
    @NonNull
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.recycler_view_item, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, final int position) {

        holder.tv.setText(mData.get(position));

        holder.ll.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                int previous_selected = -1;
                for (int i = 0; i < getSelectionStates().size(); i++) {
                    if (getSelectionStates().get(i)) {
                        previous_selected = i;
                        break;
                    }
                }
                if (previous_selected == -1) { // nothing is selected
                    setSelectionState(position, true);
                    notifyItemChanged(position);
                } else if (previous_selected != position) { // selected (other than current selected)
                    setSelectionState(previous_selected, false);
                    setSelectionState(position, true);
                    notifyItemChanged(previous_selected);
                    notifyItemChanged(position);
                }
            }
        });

        if (mSelectionStates.get(position)) {
            //Log.i(TAG, "Select " + position);
            holder.ll.setBackgroundColor(ContextCompat.getColor(MainActivity.this, android.R.color.holo_red_dark));
        } else {
            //Log.i(TAG, "De-Select " + position);
            holder.ll.setBackgroundColor(ContextCompat.getColor(MainActivity.this, android.R.color.white));
        }

    }

    private List<Boolean> getSelectionStates() {
        return mSelectionStates;
    }

    private void setSelectionState(int position, boolean state) {
        mSelectionStates.set(position, state);
    }

    @Override
    public int getItemCount() {
        return mData.size();
    }


    private class ViewHolder extends RecyclerView.ViewHolder {
        final LinearLayout ll;
        final TextView tv;

        ViewHolder(View itemView) {
            super(itemView);
            ll = (LinearLayout) itemView.findViewById(R.id.ll);
            tv = (TextView) itemView.findViewById(R.id.tv);
        }

    }

}

}

2）activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<androidx.recyclerview.widget.RecyclerView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/rv">
</androidx.recyclerview.widget.RecyclerView>

</RelativeLayout>

3）recycler_view_item.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:padding="20dp"
android:id="@+id/ll"
android:layout_height="wrap_content">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/tv"
    android:gravity="center"
    android:textSize="20sp"/>

</LinearLayout>

4）结果：

Android：点击项目后，Recycler视图的UI不会改变吗？

3 个答案: