在实现滑动删除功能时，我不小心使我的前景视图的视图保持透明。在这样做的过程中，我发现了一个错误，即我的 ItemTouchHandler 没有改变背景或在应该改变的时候隐藏文本。
在我看来，我的 ItemTouchHelper 没有应用于我的 ReycleViewAdapter 中的每个视图和/或视图没有被更新，或者它们都共享某种类型的单一父级，经过数小时的尝试调试后，我无计可施，我已经包含了这个问题的一个方便的 gif。
ItemTouchHelper 的 onDrawChild() 和 onDrawChildOver() 方法被传递给我的片段以处理操作
代码：
AllLists_fragment.java：
public class showAllLists_fragment extends android.support.v4.app.Fragment implements RecycleItemTouchHelper.RecyclerItemTouchHelperListener {
private static final String TAG = "showAllLists";
private RecyclerView mAllItemsView = null;
private DataCommunication mData = null;
private ItemTouchHelper.SimpleCallback itemTouchHelper = null;;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = inflater.inflate(R.layout.show_all_lists_frag, container, false);
this.mAllItemsView = (RecyclerView) view.findViewById(R.id.allItems);
this.itemTouchHelper = new RecycleItemTouchHelper(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT, this);
new ItemTouchHelper(this.itemTouchHelper).attachToRecyclerView(this.mAllItemsView);
this.mAllItemsView.setAdapter(this.mData.getAdapter());
this.mAllItemsView.setLayoutManager(new LinearLayoutManager(getActivity()){
//
@Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
try {
super.onLayoutChildren(recycler, state);
} catch (IndexOutOfBoundsException e) {
Log.d(TAG, "Inconsistent Exception Caught -See stack trace");
e.printStackTrace();
}
}
});
viewShadow();
return view;
}
@TargetApi(21)
public void viewShadow(){
this.mAllItemsView.setTranslationZ(100);
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
try {
this.mData = (DataCommunication) context;
} catch (ClassCastException e) {
throw new ClassCastException(context.toString()
+ " must implement DataCommunication");
}
}
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if(isVisibleToUser){
this.mData.getAdapter().notifyDataSetChanged();
this.mData.refresh();
}
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction, int position) {
int noSwipeSize = mData.getAllToDo().size();
if (direction == ItemTouchHelper.LEFT) {
mData.deleteTask(mData.getAdapter().getResults().get(viewHolder.getAdapterPosition()));
mData.getAdapter().notifyItemRangeRemoved(viewHolder.getAdapterPosition(), noSwipeSize);
} else if (direction == ItemTouchHelper.RIGHT) {
mData.completeTask(mData.getAdapter().getResults().get(viewHolder.getAdapterPosition()));
mData.getAdapter().notifyItemRangeRemoved(viewHolder.getAdapterPosition(), noSwipeSize);
}
}
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
final View foregroundView = ((com.lab1.ac01220.bloomv2.ViewHolder) viewHolder).getForeground();
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
if(dX < 0){
this.mData.getViewHolder().getDeleteText().setVisibility(View.VISIBLE);
this.mData.getViewHolder().getCompleteText().setVisibility(View.INVISIBLE);
this.mData.getViewHolder().getBackground().setBackgroundColor(getResources().getColor(R.color.colorAccent));
} else if(dX >0){
this.mData.getViewHolder().getCompleteText().setVisibility(View.VISIBLE);
this.mData.getViewHolder().getDeleteText().setVisibility(View.INVISIBLE);
this.mData.getViewHolder().getBackground().setBackgroundColor(getResources().getColor(R.color.colorComplete));
}
}
ItemTouchHelper.SimpleCallback.getDefaultUIUtil().onDraw(c, recyclerView, foregroundView, dX, dY,actionState, isCurrentlyActive);
}
@Override
public void onChildDrawOver(Canvas c, RecyclerView recyclerView, ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
final View foregroundView = ((com.lab1.ac01220.bloomv2.ViewHolder) viewHolder).getForeground();
ItemTouchHelper.SimpleCallback.getDefaultUIUtil().onDrawOver(c, recyclerView, foregroundView, dX, dY,actionState, isCurrentlyActive);
}
}
RecycleitemTouchHelper.java
public RecycleItemTouchHelper(int dragDirs, int swipeDirs, RecyclerItemTouchHelperListener listener) {
super(dragDirs, swipeDirs);
this.listener = listener;
}
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
this.listener.onSwiped(viewHolder, direction, viewHolder.getAdapterPosition());
}
@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
this.listener.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
@Override
public void onChildDrawOver(Canvas c, RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder, float dX, float dY,
int actionState, boolean isCurrentlyActive) {
this.listener.onChildDrawOver(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
final View foregroundView = ((ViewHolder) viewHolder).getForeground();
getDefaultUIUtil().clearView(foregroundView);
}
@Override
public int convertToAbsoluteDirection(int flags, int layoutDirection) {
return super.convertToAbsoluteDirection(flags, layoutDirection);
}
public interface RecyclerItemTouchHelperListener {
void onSwiped(RecyclerView.ViewHolder viewHolder, int direction, int position);
void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive);
void onChildDrawOver(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive);
}
}
RecycleViewAdapter.java：
public class RecycleViewAdapter extends RecyclerView.Adapter<ViewHolder>{
private LayoutInflater inflater = null;
private List<GlobalLists> results = null;
private DataCommunication mData = null;
public RecycleViewAdapter(Context context, List<GlobalLists> results){
this.inflater = LayoutInflater.from(context);
this.results = results;
this.mData = (DataCommunication)context;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.custom_row, parent, false);
ViewHolder holder = new ViewHolder(view);
this.mData.setViewHolder(holder);
return holder;
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
GlobalLists item = this.results.get(position);
holder.setRowTitle(item.getTitle());
//Grab the first 14 characters of the contents if the row is not null
if(item.getContents() != null){
StringBuffer currentContent = new StringBuffer(item.getContents().substring(0, Math.min(item.getContents().length(),28)));
if(item.getContents().length() > 28) currentContent.append("...");
holder.setRowContent(currentContent.toString());
}
}
public void reloadAdapterData(List<GlobalLists> refresh){
this.results = refresh;
}
@Override
public int getItemCount() {
return this.results == null || this.results.isEmpty() ? 0 : this.results.size();
}
public List<GlobalLists> getResults(){
return this.results;
}
}