Ahs*_*fiq 9 android visibility android-recyclerview
背景/背景:
在我的主要活动中,我有一个选项卡布局有两个选项卡。每个选项卡包含两个片段,SearchVehicleFragment 和 VehicleListFragment。
以下是 VehicleListFragment 的布局文件。
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".ui.fragments.VehicleListFragment"
android:orientation="vertical">
<com.boulevardclan.vvp.ui.recyclerviews.VehicleRecyclerView
android:id="@+id/rvVehicleList"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<TextView
android:id="@+id/tvNoSearchedVehicles"
style="?android:attr/textAppearanceMedium"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:gravity="center"
android:text="You haven't searched for any vehicles yet." />
</LinearLayout>
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我的 VehicleRecyclerView 的创建与此处提供的 AttractionsRecyclerView 完全一样。这是因为我想为我的 VehicleRecyclerView 实现空状态机制。此外,在初始化期间,我的 VehicleRecyclerView 有setHasFixedSize(true)
public class VehicleRecyclerView extends RecyclerView {
private View mEmptyView;
public VehicleRecyclerView(Context context) {
super(context);
}
private AdapterDataObserver mDataObserver = new AdapterDataObserver() {
@Override
public void onChanged() {
super.onChanged();
updateEmptyView();
}
@Override
public void onItemRangeRemoved(int positionStart, int itemCount) {
super.onItemRangeRemoved(positionStart, itemCount);
try{
updateEmptyView();
}catch(Exception e){
// TODO
}
}
@Override
public void onItemRangeInserted(int positionStart, int itemCount) {
super.onItemRangeInserted(positionStart, itemCount);
updateEmptyView();
}
@Override
public void onItemRangeChanged(int positionStart, int itemCount) {
super.onItemRangeChanged(positionStart, itemCount);
updateEmptyView();
}
@Override
public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {
super.onItemRangeMoved(fromPosition, toPosition, itemCount);
updateEmptyView();
}
};
public VehicleRecyclerView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public VehicleRecyclerView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
/**
* Designate a view as the empty view. When the backing adapter has no
* data this view will be made visible and the recycler view hidden.
*
*/
public void setEmptyView(View emptyView) {
mEmptyView = emptyView;
}
@Override
public void setAdapter(RecyclerView.Adapter adapter) {
if (getAdapter() != null) {
getAdapter().unregisterAdapterDataObserver(mDataObserver);
}
if (adapter != null) {
adapter.registerAdapterDataObserver(mDataObserver);
}
super.setAdapter(adapter);
updateEmptyView();
}
private void updateEmptyView() {
if (mEmptyView != null && getAdapter() != null) {
boolean showEmptyView = getAdapter().getItemCount() == 0;
if(showEmptyView){
mEmptyView.setVisibility(VISIBLE);
setVisibility(GONE);
}else {
mEmptyView.setVisibility(GONE);
setVisibility(VISIBLE);
}
}
}
}
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我的 VehicleAdaptersetHasStableIds(true)
和 overriden 一样getItemId(position)
。
public class VehicleAdapter extends RecyclerView.Adapter<VehicleAdapter.VehicleViewHolder> {
private List<Vehicle> vehicleList = new ArrayList<>();
private Context mContext;
public VehicleAdapter(Context context, List<Vehicle> vehicles) {
vehicleList.addAll(vehicles);
setHasStableIds(true);
mContext = context;
}
@Override
public VehicleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new VehicleViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.vehicle_list_item_card_view, parent, false));
}
@Override
public void onBindViewHolder(VehicleViewHolder holder, int position) {
holder.bind(vehicleList.get(position));
}
@Override
public int getItemCount() {
return vehicleList.size();
}
@Override
public long getItemId(int position) {
return vehicleList.get(position).getId();
}
public void addVehicle(Vehicle vehicle){
if(vehicleList != null){
vehicleList.add(0, vehicle);
notifyItemInserted(0);
}
}
public void removeVehicle(int position){
if(vehicleList.get(position).delete()){
vehicleList.remove(position);
notifyItemRemoved(position);
}else {
// TODO
}
}
public void updateVehicle(Vehicle vehicle, int position){
vehicleList.set(position, vehicle);
notifyItemChanged(position);
}
class VehicleViewHolder extends RecyclerView.ViewHolder{
TextView tvRegistrationNumber;
TextView tvOwnerName;
TextView tvColor;
TextView tvOwnerCity;
TextView tvLookupDate;
TextView tvManufacturer;
TextView tvModel;
TextView tvMakeYear;
ImageView ivDetail;
ImageView ivBookmark;
ImageView ivDelete;
public VehicleViewHolder(View itemView) {
super(itemView);
tvRegistrationNumber = (TextView) itemView.findViewById(R.id.tvRegistrationNumber);
tvOwnerName = (TextView) itemView.findViewById(R.id.tvOwnerName);
tvColor = (TextView) itemView.findViewById(R.id.tvColor);
tvOwnerCity = (TextView) itemView.findViewById(R.id.tvOwnerCity);
tvLookupDate = (TextView) itemView.findViewById(R.id.tvLookupDate);
tvManufacturer = (TextView) itemView.findViewById(R.id.tvManufacturer);
tvModel = (TextView) itemView.findViewById(R.id.tvModel);
tvMakeYear = (TextView) itemView.findViewById(R.id.tvMakeYear);
ivDetail = (ImageView) itemView.findViewById(R.id.ivDetail);
ivBookmark = (ImageView) itemView.findViewById(R.id.ivBookmark);
ivDelete = (ImageView) itemView.findViewById(R.id.ivDelete);
}
void setOwnerName(String ownerName){
tvOwnerName.setText(ownerName);
}
void setColor(String color){
tvColor.setText(color);
}
void setOwnerCity(String ownerCity){
tvOwnerCity.setText(ownerCity);
}
void setLookupDate(String lookupDate){
tvLookupDate.setText(lookupDate);
}
void setManufacturer(String manufacturer){
tvManufacturer.setText(manufacturer);
}
void setMakeYear(int makeYear){
tvMakeYear.setText(String.format(Locale.getDefault(),"%s",makeYear));
}
void setModel(String model){
tvModel.setText(model);
}
void setBookmarked(boolean isBookmarked){
ivBookmark.setImageDrawable(ViewUtils.getDrawable(mContext, (isBookmarked ? R.drawable.ic_favorite_black_24dp: R.drawable.ic_favorite_border_black_24dp)));
}
void bind(final Vehicle vehicle){
tvRegistrationNumber.setText(vehicle.getRegistrationNumber());
setOwnerName(vehicle.getOwnerName());
setColor(vehicle.getColor());
setOwnerCity(vehicle.getOwnerCity());
setLookupDate(DateTimeUtils.getPKTDateTime(vehicle.getModifiedAt()));
setManufacturer(vehicle.getManufacturer());
setModel(vehicle.getMakeType());
setMakeYear(vehicle.getMakeYear());
setBookmarked(vehicle.isBookmarked());
setupClickListeners(vehicle);
}
private void setupClickListeners(final Vehicle vehicle) {
ivDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new MaterialDialog.Builder(mContext)
.title(R.string.confirm_delete_vehicle_heading)
.content(R.string.confirm_delete_vehicle_label)
.positiveText(R.string.confirm_response_yes)
.negativeText(R.string.confirm_response_cancel)
.stackingBehavior(StackingBehavior.ALWAYS)
.onPositive(new MaterialDialog.SingleButtonCallback() {
@Override
public void onClick(@NonNull MaterialDialog dialog, @NonNull DialogAction which) {
if(getAdapterPosition() != RecyclerView.NO_POSITION){
removeVehicle(getAdapterPosition());
}
}
})
.show();
}
});
}
}
}
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问题:
当 recyclerview 中没有项目并且我通过 向 recyclerview 添加一个或多个新项目时notifyItemInserted(0)
,一切正常。但是当 recyclerview 中只有一个项目时,我通过删除该项目notifyItemRemoved(position)
,现在通过添加一个新项目到 recyclerview via notifyItemInserted(0)
,有一个过渡/动画效果,在隐藏 emptyView 后,recyclerview 显示为之前删除的项目几分之一秒,然后新添加的项目淡入视口。
因此,这是应该遵循的“理想”事件序列:
更新:您可以在此处查看问题:https : //media.giphy.com/media/l0IydcuJDAqPNlmla/giphy.gif
我期待着一种方法来摆脱这种在很短的时间内显示旧项目/recyclerview 状态的 flickr/blink 效果。
我尝试过的:
RecyclerView.ItemAnimator animator = mVehicleListRV.getItemAnimator();
if (animator instanceof SimpleItemAnimator) {
((SimpleItemAnimator) animator).setSupportsChangeAnimations(false);
}
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免责声明:
我是 Android 开发的新手,并且在这个问题上困了好几个小时。寻求来自SO的伟大思想家的帮助/指点,以畅通无阻。请容忍我有限的知识。
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