问题
Hi I want to skip some items from recyclerview.
Here is the bit of code
item_Data.xml
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_marginTop="10dp"
android:id="@+id/mainlayout"
android:layout_height="wrap_content">
<ImageView
android:visibility="gone"
android:id="@id/image"
android:layout_gravity="center"
android:layout_width="100dp"
android:layout_height="100dp" />
<TextView
android:visibility="gone"
android:textStyle="bold"
android:id="@id/title"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp"
android:maxLength="15" />
And recycler view is
@Override
public void onBindViewHolder(final MovieViewHolder holder, final int position) {
String download= news.get((position)).getDownloadLinkForApkNew();
String desc_new = news.get(position).getApkJData();
if (download.isEmpty()==false && desc_new.isEmpty()==false) {
holder.movieTitle.setVisibility(View.VISIBLE);
holder.imageView.setVisibility(View.VISIBLE);
Picasso.with(context).load(news.get((position)).getBetterFeaturedImage().getSourceUrl()).into(holder.imageView);
holder.movieTitle.setText(news.get(position).getTitle().getRendered());
}
I don't want the items that doesn't have download and desc_new. My logic works items are not visible but they leave there space. how can I remove the spaces between the items.
回答1:
Lets go in depth as of how recycler view works
we have 2 functions onCreateView and onBindview. As the names of functions are quite self explaining onCreateView creates the view and onBindView takes the created view and binds data into it
now lets assume that entire view type is similar and you use an array of objects or cursor to populate the entire view.
so in bindView in order to fetch data you must have used either
cursor.moveToPosition(position)
or
mList.get(position)
as you can see that binding is happening based on the position that we get from onBindView arguments
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
//mList.get(position) or cursor.moveToPosition
}
so you can use this knowledge to specifically skip binding of view
say you have a function which accepts postion as parameter and returns actual position as result
private int getActualPostion(int position){
//your logic to skip the given postion
//say if(position == 4){return postion+2}
}
so you can implement something like this
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
mList.get(getActualPosition(position));
}
this will allow you to skip those view which are not to be shown
finally in method getCount which is used by recycler view to decide the number of views
@Override
public int getItemCount() {
//foreach in array { if(already downloaded) i++}
// return array.size - i
}
I hope this helps this will also give your more flexibility in a way that u may add more filters and use same dataset ... skip views more easily
回答2:
There's a very simple fix for this:
If you perform view.setVisibility(View.GONE); on the view while binding it to the ViewHolder, the view would be hidden but there would still be a space right where the view was supposed to be; therefore, this approach isn't efficient.
How then do we solve this problem?
All you need to do is to set the height and/or width of the view you're trying to hide to zero. Here's a simple way to achieve this:
View Holder:
public class MyViewHolder extends RecyclerView.ViewHolder{
public LinearLayout.LayoutParams params;
public LinearLayout rootView //the outermost view from your layout. Note that it doesn't necessarily have to be a LinearLayout.
//todo: Don't forget to add your other views
public MyViewHolder(View itemView){
super(itemView);
params = new LinearLayout.LayoutParams(0, 0);
rootView = itemView.findViewById(R.id.rootView);
//todo: Don't forget to initialize your views
}
}
onBindViewHolder:
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position){
if(your_condition){
holder.rootView.setLayoutParams(holder.params);
//this line hides the view completely
}
else{
//todo: Do your regular stuff
}
}
I hope this helps. Merry coding!
回答3:
You can remove the items from arraylist an then pass updated array list to adapter by this way you don't need to play with visibility of your views
回答4:
you should use View.GONE instead of View.INVISIBLE
INVISIBLE
This view is invisible, but it still takes up space for layout purposes.
GONE
This view is invisible, and it doesn’t take any space for layout purposes.
if (download.isEmpty()==true && desc_new.isEmpty()==true) {
holder.movieTitle.setVisibility(View.GONE);
holder.imageView.setVisibility(View.GONE);
}else {
holder.movieTitle.setVisibility(View.VISIBLE);
holder.imageView.setVisibility(View.VISIBLE);
Picasso.with(context).load(news.get((position)).getBetterFeaturedImage().getSourceUrl()).into(holder.imageView);
holder.movieTitle.setText(news.get(position).getTitle().getRendered())
}
回答5:
By making them View.INVISIBLE you are not removing the reserved spaces. Instead you could use View.GONE to make them invisible and allow the reserved space to be taken.
Since you are setting the Views visible again you have to undo it with the if-else clause e.g.
if (!download.isEmpty() && !desc_new.isEmpty()) {
// make visible
} else {
// make invisible with gone e.g.
holder.movieTitle.setVisibility(View.GONE);
holder.imageView.setVisibility(View.GONE);
}
回答6:
You need to set visibility to your holder, not your views.
if (download.isEmpty()==true && desc_new.isEmpty()==true) {
holder.setVisibility(View.GONE);
}else {
holder.setVisibility(View.VISIBLE);
Picasso.with(context).load(news.get((position)).getBetterFeaturedImage().getSourceUrl()).into(holder.imageView);
holder.movieTitle.setText(news.get(position).getTitle().getRendered())
}
also delete visibility from your xml
回答7:
if (download.isEmpty()==true && desc_new.isEmpty()==true) {
//Hide the items
holder.movieTitle.setVisibility(View.GONE);
holder.imageView.setVisibility(View.GONE);
}else {
holder.movieTitle.setVisibility(View.VISIBLE);
holder.imageView.setVisibility(View.VISIBLE);
Picasso.with(context).load(news.get((position)).getBetterFeaturedImage().getSourceUrl()).into(holder.imageView);
holder.movieTitle.setText(news.get(position).getTitle().getRendered())
}
来源：https://stackoverflow.com/questions/46582604/skip-items-in-recycler-view