Prevent Recyclerview from intercepting scroll/touch events

Question

So I looked everywhere for this and I've been stuck for a few hours; I really need the help!

So I have a (fixed size) recyclerview inside another scrollview, which is the nestedscrollview. I also have the CollapsingToolbarLayout on this view. The problem is that when I scroll the entire view and I'm on the recyclerview, the CollapsingToolbarLayout doesnt expand/contract (it only does so when the CollapsingToolbarLayout has contracted, and I'm scrolling down and so it does expand). Otherwise, CollapsingToolbarLayout never reacts to scroll changes when Im on the recyclerview. I tried intercepting the touch and returning false and it nothing works.

Any advice?

UPDATE

A good example of what I'm trying to do is Whatsapp's profile activity, where it has the CollapsingToolbarLayout and if the profile is a group, it shows the list of users in that group. That's exactly what I'm trying to do here, but when Im scrolling inside that user list, it doesnt scroll the entire view (recylcler view is intercepting .. )

doubleA · Accepted Answer

public class ProgramRecyclerAdapter extends RecyclerView.Adapter {

/** 
This is an abstract class that all of my viewholders inherit from. 
This is a contract telling me that any subclasses that inherit from this
base class are required to write their own `public void bind(int position,
Program program);` method. 
*/
abstract class ProgramBaseViewHolder extends RecyclerView.ViewHolder {

    public ProgramBaseViewHolder(View itemView) {
        super(itemView);
    }

    public abstract void bindDataToView(int position, Program program);
}

/**`@Bind` and Butterknife.bind is part of a viewbinding library called 
Butterknife. This usage of "bind" is the equivalent of your `findViewById()` 
calls. */

/**
This is the Airtime view that holds airtimes. It is a view holder that
inherits from my base view holder and implements its own version if bind.
*/
class AirtimeViewHolder extends ProgramBaseViewHolder {
    @Bind(R.id.program_airtimes)
    TextView mProgramAirtimes;

    static final int viewType = 0;

    public AirtimeViewHolder(View itemView) {
        super(itemView);
        /**This call to butterknife can be replaced with an
        itemView.findViewById(R.id.yourview) */
        ButterKnife.bind(this, itemView);
    }

    //This is where you set your text and hide or show your views.
    @Override
    public void bindDataToView(int position, Program program) {
        List airtimes = program.getAirtimes();
        if (!airtimes.isEmpty()) {
            mProgramAirtimes.setText(Utils.getFriendlyAirtimes(airtimes));
        } else {
            mProgramAirtimes.setText(
                    Utils.getFriendlyAirTime(program.getAirtime()));
        }
    }
}

/**
This is the Description view that holds descriptions. It is a view holder  
that inherits from my base view holder and implements its own version if    
bind.
*/
class DescriptionViewHolder extends ProgramBaseViewHolder {
    @Bind(R.id.description_card_layout)
    TextView mProgramDescription;

    static final int viewType = 1;

    public DescriptionViewHolder(View itemView) {
        super(itemView);
        ButterKnife.bind(this, itemView);
    }

    @Override
    public void bindDataToView(int position, Program program) {
        mProgramDescription.setText(Html.fromHtml(program.getFullDescription()));
    }
}
//This is another type of view with another different type of layout.
class HostsViewHolder extends ProgramBaseViewHolder {
    @Bind(R.id.card_view_host_name)
    TextView mProgramHostName;

    static final int viewType = 2;

    public HostsViewHolder(View itemView) {
        super(itemView);
        ButterKnife.bind(this, itemView);
    }

    @Override
    public void bindDataToView(int position, Program program) {
        mProgramHostName.setText(program.getHosts().get(position - 2).getDisplayName());
    }
}
//Again another type of view extending my base view.
class CategoriesViewHolder extends ProgramBaseViewHolder {
    @Bind(R.id.program_categories)
    TextView mProgramCategories;
    static final int viewType = 42;

    public CategoriesViewHolder(View itemView) {
        super(itemView);
        ButterKnife.bind(this, itemView);
    }

    @Override
    public void bindDataToView(int position, Program program) {
        List categoryList = program.getCategories();
        StringBuilder stringBuilder = new StringBuilder();
        for (Category category : categoryList) {
            stringBuilder.append(category.getTitle())
                    .append(" ");
        }
        mProgramCategories.setText(stringBuilder.toString());
    }
}

//This is where the normal looking recycler view code comes in.
private Context mContext;
private LayoutInflater mInflater;
private Program mProgramData;
private int mNextProgramId;

public ProgramRecyclerAdapter(Context context) {
    mContext = context;
    mInflater = LayoutInflater.from(mContext);
}

/**This method is where I am determining what view type each item in my list 
will be. I wanted a single airtimes view followed by a single description 
view and then X amount of hosts views and a single category view. I return 
position in the third else if because the position helps me determine which 
host name to display in the bindDataToViews call of the HostViewHolder.*/
@Override
public int getItemViewType(int position) {
    if (position == AirtimeViewHolder.viewType) {
        return AirtimeViewHolder.viewType;
    } else if (position == DescriptionViewHolder.viewType) {
        return DescriptionViewHolder.viewType;
    } else if (position > DescriptionViewHolder.viewType
            && position <= DescriptionViewHolder.viewType + getHostsNum()) {
        return position;
    } else {
        return CategoriesViewHolder.viewType;
    }
}

//This method figures out how many hosts will be displayed
private int getHostsNum() {
    if (mProgramData != null) {
        return mProgramData.getHosts().size();
    }
    return 0;
}
// This method determines if I will show a category view or not.
private int getCategoriesNum() {
    if (mProgramData != null && mProgramData.getCategories().size() > 0) {
        return 1;
    }
    return 0;
}

/**This returns haw many items will be in the list. 1 Airtime view, 1 
Description view, x amount of Host views and 0 or 1 category views */
@Override
public int getItemCount() {
    return 2 + getHostsNum() + getCategoriesNum();
}

/** This returns the appropriate View holder for the requested view type that 
was set by getItemViewType()which is determined by position. I pass the inflated parent view and the data.     
*/
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (viewType == AirtimeViewHolder.viewType) {
        return new AirtimeViewHolder(mInflater.inflate(R.layout.airtime_card_layout, parent, false));
    } else if (viewType == DescriptionViewHolder.viewType) {
        return new DescriptionViewHolder(mInflater.inflate(R.layout.description_card_layout, parent, false));
    } else if (viewType > DescriptionViewHolder.viewType
            && viewType <= DescriptionViewHolder.viewType + getHostsNum()) {
        return new HostsViewHolder(mInflater.inflate(R.layout.hosts_card_layout, parent, false));
    } else
        return new CategoriesViewHolder(mInflater.inflate(R.layout.categories_card_layout, parent, false));
}

/*This method is what ties everything together. After I ensure that the data 
is not null I call bindDataToView on a ProgramBaseViewHolder. Depending on 
which type of subclass it is will determine which overridden bindData code to 
use and what view to display. */
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    ProgramBaseViewHolder baseViewHolder = (ProgramBaseViewHolder) holder;
    if (mProgramData != null) {
        baseViewHolder.bindDataToView(position, mProgramData);
    }
}

//This is used to set the data for this program
public void setProgramData(Program program) {
    mProgramData = program;
}

public Program getProgramData() {
    return mProgramData;
}

public boolean isEmpty() {
    return mProgramData == null;
}
}

This is the Airtime layout

This is my host layout. You will notice that I am not using most of the views here because this is an app in progress and the same layout is used for a different activity that includes the host picture and their programs.

And here is the layout for the activity that handles the above recycler adapter.

My cardviews have margins on the tops and bottoms so If you play with the margins on the card views I am sure you can accomplish the same type of view as WhatsApp where it looks like the same card. Its really multiple card views with 0 top and bottom margins. In the whatsApp view you were talking about where it shows participants of a group The participants, add participants and even the ExitGroup button views are all part of the same recycler view. I doubt that it is a recycler view inside a nested scroll view they are not meant to work together.

This is the view that is produced with some data. The Categories view is cut off but it is there.

Prevent Recyclerview from intercepting scroll/touch events

Answers (1)

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