ExpandRecyclerView使用demo

效果

导入依赖

  implementation 'com.thoughtbot:expandablerecyclerview:1.0'
    implementation 'com.android.support:recyclerview-v7:28.0.0'

父级类名GroupText 和xml名group_view_holder

@SuppressLint("ParcelCreator")
public class GroupText extends ExpandableGroup<ChildText> {
    public GroupText(String title, List<ChildText> items) {
        super(title, items);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/black">

    <TextView
        android:id="@+id/mobile_os"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:drawablePadding="5dp"
        android:drawableRight="@mipmap/ic_launcher"
        android:gravity="left|center"
        android:padding="8dp"
        android:textColor="#e6e600" />

</RelativeLayout>

子级类名ChildText 和xml名 child_view_holder

public class ChildText implements Parcelable {
    private String name;

    public ChildText(Parcel in) {
        name = in.readString();
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public ChildText(String name) {
        this.name = name;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(name);
    }

    @Override
    public int describeContents() {
        return 0;
    }

    public static final Creator<ChildText> CREATOR = new Creator<ChildText>() {
        @Override
        public ChildText createFromParcel(Parcel in) {
            return new ChildText(in);
        }

        @Override
        public ChildText[] newArray(int size) {
            return new ChildText[size];
        }
    };
}

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

    <TextView
        android:id="@+id/phone_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:padding="10dp"/>
</RelativeLayout>

适配器RecyclerAdapter

public class RecyclerAdapter extends ExpandableRecyclerViewAdapter <RecyclerAdapter.GroupContentViewHolder, RecyclerAdapter.ChildContentViewHolder>{

    private Activity activity;

    public RecyclerAdapter(Activity activity, List<? extends ExpandableGroup> groups) {
        super(groups);
        this.activity = activity;
    }

    @Override
    public GroupContentViewHolder onCreateGroupViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = (LayoutInflater) activity.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.group_view_holder, parent, false);
        return new GroupContentViewHolder(view);
    }

    @Override
    public ChildContentViewHolder onCreateChildViewHolder(ViewGroup parent, final int viewType) {
        LayoutInflater inflater = (LayoutInflater) activity.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.child_view_holder, parent, false);
        return new ChildContentViewHolder(view);
    }

    @Override
    public void onBindChildViewHolder(ChildContentViewHolder holder, int flatPosition, ExpandableGroup group, int childIndex) {
        final ChildText child = ((GroupText) group).getItems().get(childIndex);
        holder.onBind(child,group);
    }

    @Override
    public void onBindGroupViewHolder(GroupContentViewHolder holder, int flatPosition, ExpandableGroup group) {
        holder.setGroupName(group);
    }
    public class GroupContentViewHolder extends GroupViewHolder {

        private TextView name;

        public GroupContentViewHolder(View itemView) {
            super(itemView);
            name = (TextView) itemView.findViewById(R.id.mobile_os);
        }

        @Override
        public void expand() {
            name.setCompoundDrawablesWithIntrinsicBounds(0, 0, R.mipmap.ic_launcher, 0);
        }

        @Override
        public void collapse() {
            name.setCompoundDrawablesWithIntrinsicBounds(0, 0, R.mipmap.ic_launcher, 0);
        }

        public void setGroupName(ExpandableGroup group) {
            name.setText(group.getTitle());
        }
    }
    public class ChildContentViewHolder extends ChildViewHolder {
        private TextView name;
        public ChildContentViewHolder(View itemView) {
            super(itemView);
            name = (TextView) itemView.findViewById(R.id.phone_name);
        }

        public void onBind(ChildText child, ExpandableGroup group) {
            name.setText(child.getName());
            if (group.getTitle().equals("水果")) {
                name.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_launcher_background, 0, 0, 0);
            } else if (group.getTitle().equals("球类")) {
                name.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_launcher_background, 0, 0, 0);
            } else {
                name.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_launcher_background, 0, 0, 0);
            }
        }
    }

}

界面ExpandRecyclerViewActivity

public class ExpandRecyclerViewActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private ArrayList<GroupText> mobileOSes;
    private RecyclerAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_expand_recyclerview_layout);
        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        mobileOSes = new ArrayList<>();

        setData();
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        adapter = new RecyclerAdapter(this, mobileOSes);
        recyclerView.setAdapter(adapter);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        adapter.onSaveInstanceState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        adapter.onRestoreInstanceState(savedInstanceState);
    }

    private void setData() {
        ArrayList<ChildText> iphones = new ArrayList<>();
        iphones.add(new ChildText("苹果"));
        iphones.add(new ChildText("橘子"));
        iphones.add(new ChildText("芒果"));
        iphones.add(new ChildText("香蕉"));
        iphones.add(new ChildText("火龙果"));
        iphones.add(new ChildText("草莓"));
        iphones.add(new ChildText("柚子"));
        iphones.add(new ChildText("哈密瓜"));

        ArrayList<ChildText> nexus = new ArrayList<>();
        nexus.add(new ChildText("足球"));
        nexus.add(new ChildText("篮球"));
        nexus.add(new ChildText("乒乓球"));
        nexus.add(new ChildText("棒球"));
        nexus.add(new ChildText("保龄球"));
        nexus.add(new ChildText("溜溜球"));
        nexus.add(new ChildText("橄榄球"));

        ArrayList<ChildText> windowPhones = new ArrayList<>();
        windowPhones.add(new ChildText("单击游戏"));
        windowPhones.add(new ChildText("主机游戏"));
        windowPhones.add(new ChildText("FPS游戏"));
        windowPhones.add(new ChildText("挂机游戏"));
        windowPhones.add(new ChildText("小游戏"));
        windowPhones.add(new ChildText("手游"));

        mobileOSes.add(new GroupText("水果", iphones));
        mobileOSes.add(new GroupText("球类", nexus));
        mobileOSes.add(new GroupText("游戏", windowPhones));
    }
}