RecyclerVIew实现悬浮吸顶效果

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

  <android.support.v7.widget.RecyclerView
    android:id="@+id/recycle"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

  <TextView
    android:id="@+id/tv_sticky_header_view"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:background="#EFFAE7"
    android:gravity="center"
    android:text="吸顶文本1" />

  <!--<include layout="@layout/layout_sticky_header_view"/>-->
</FrameLayout>

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

  <RelativeLayout
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:id="@+id/rl_content_wrapper"
    android:layout_width="match_parent"
    android:layout_height="30dp">

    <TextView
      android:id="@+id/name"
      android:layout_centerVertical="true"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />

    <TextView
      android:id="@+id/auto"
      android:layout_centerVertical="true"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentRight="true" />

    <View
      android:layout_width="match_parent"
      android:layout_height="1dp"
      android:layout_alignParentBottom="true"
      android:background="#ffffff"/>

  </RelativeLayout>

  <TextView
    android:id="@+id/tv_sticky_header_view"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:background="#EFFAE7"
    android:gravity="center"
    android:text="吸顶文本1" />

</FrameLayout>

public class MainActivity extends AppCompatActivity {

  private TextView tvStickyHeaderView;
  private RecyclerView recyclerView;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initView();
    initListener();
  }

  /**
   * 初始化View
   */
  private void initView() {
    recyclerView = (RecyclerView) findViewById(R.id.recycle);
    tvStickyHeaderView = (TextView) findViewById(R.id.tv_sticky_header_view);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    recyclerView.setAdapter(new StickyExampleAdapter(this, getData()));
  }

  /**
   * 初始化Listener
   */
  private void initListener() {
    recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
      @Override
      public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        View stickview = recyclerView.findChildViewUnder(0, 0);
        if (stickview != null && stickview.getContentDescription() != null) {
          if (!TextUtils.equals(tvStickyHeaderView.getText(), stickview.getContentDescription())) {
            tvStickyHeaderView.setText(stickview.getContentDescription());
          }
        }
        View transInfoView = recyclerView.findChildViewUnder(
            0, tvStickyHeaderView.getHeight() + 1);
        if (transInfoView.getTag() != null) {

          int transViewStatus = (int) transInfoView.getTag();
          int top = transInfoView.getTop();

          if (transViewStatus == StickyExampleAdapter.HAS_STICKY_VIEW) {
            if (top > 0) {
              int dealtY = top - tvStickyHeaderView.getMeasuredHeight();
              tvStickyHeaderView.setTranslationY(dealtY);
            } else {
              tvStickyHeaderView.setTranslationY(0);
            }
          } else if (transViewStatus == StickyExampleAdapter.NONE_STICKY_VIEW) {
            tvStickyHeaderView.setTranslationY(0);
          }
        }
      }
    });
  }

  public List<StickyBean> getData() {
    List<StickyBean> stickyExampleModels = new ArrayList<>();

    for (int index = 0; index < 100; index++) {
      if (index < 15) {
        stickyExampleModels.add(new StickyBean(
            "吸顶文本1", "name" + index, "gender" + index));
      } else if (index < 25) {
        stickyExampleModels.add(new StickyBean(
            "吸顶文本2", "name" + index, "gender" + index));
      } else if (index < 35) {
        stickyExampleModels.add(new StickyBean(
            "吸顶文本3", "name" + index, "gender" + index));
      } else {
        stickyExampleModels.add(new StickyBean(
            "吸顶文本4", "name" + index, "gender" + index));
      }
    }
    return stickyExampleModels;
  }
}

public class StickyExampleAdapter extends RecyclerView.Adapter<StickyExampleAdapter.RecyclerViewHolder> {
  //第一个吸顶
  private static final int FIRST_STICKY_VIEW = 1;
  //别的吸顶
  static final int HAS_STICKY_VIEW = 2;
  //正常View
  static final int NONE_STICKY_VIEW = 3;
  private final LayoutInflater mInflate;
  private final List<StickyBean> datas;

  StickyExampleAdapter(Context context, List<StickyBean> datas){
    mInflate = LayoutInflater.from(context);
    this.datas = datas;
  }

  @Override
  public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    View inflate = mInflate.inflate(R.layout.item_ui, parent, false);
    return new RecyclerViewHolder(inflate);
  }

  @Override
  public void onBindViewHolder(RecyclerViewHolder holder, int position) {
    StickyBean stickyBean = datas.get(position);
    holder.tvName.setText(stickyBean.name);
    holder.tvGender.setText(stickyBean.autor);

    if (position == 0) {
      holder.tvStickyHeader.setVisibility(View.VISIBLE);
      holder.tvStickyHeader.setText(stickyBean.sticky);
      holder.itemView.setTag(FIRST_STICKY_VIEW);
    } else {
      if (!TextUtils.equals(stickyBean.sticky, datas.get(position - 1).sticky)) {
        holder.tvStickyHeader.setVisibility(View.VISIBLE);
        holder.tvStickyHeader.setText(stickyBean.sticky);
        holder.itemView.setTag(HAS_STICKY_VIEW);
      } else {
        holder.tvStickyHeader.setVisibility(View.GONE);
        holder.itemView.setTag(NONE_STICKY_VIEW);
      }
    }
    //通过此处设置ContentDescription，作为内容描述，可以通过getContentDescription取出，功效跟setTag差不多。
    holder.itemView.setContentDescription(stickyBean.sticky);
  }

  @Override
  public int getItemCount() {
    return datas == null ? 0 : datas.size();
  }

  public class RecyclerViewHolder extends RecyclerView.ViewHolder{
    TextView tvStickyHeader;
    RelativeLayout rlContentWrapper;
    TextView tvName;
    TextView tvGender;
    RecyclerViewHolder(View itemView) {
      super(itemView);
      tvStickyHeader = (TextView) itemView.findViewById(R.id.tv_sticky_header_view);
      rlContentWrapper = (RelativeLayout) itemView.findViewById(R.id.rl_content_wrapper);
      tvName = (TextView) itemView.findViewById(R.id.name);
      tvGender = (TextView) itemView.findViewById(R.id.auto);
    }
  }
}

public class StickyBean {

  public String name;
  public String autor;
  public String sticky;

  public StickyBean(String sticky, String name, String autor) {
    this.sticky = sticky;
    this.name = name;
    this.autor = autor;
  }
}

apply plugin: 'com.android.application'

android {
  compileSdkVersion 26
  buildToolsVersion "25.0.3"
  defaultConfig {
    applicationId "com.lg.floating"
    minSdkVersion 15
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
  }
  buildTypes {
    release {
      minifyEnabled false
      proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
  }
}

dependencies {
  compile fileTree(dir: 'libs', include: ['*.jar'])
  androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
    exclude group: 'com.android.support', module: 'support-annotations'
  })
  compile 'com.android.support:appcompat-v7:26.0.0-alpha1'
  compile 'com.android.support:recyclerview-v7:23.1.0'
  testCompile 'junit:junit:4.12'
}