悬浮框

1.在项目下的build.gradle中

allprojects {
    repositories {
        google()
        jcenter()
        maven { url 'https://jitpack.io' }
    }
}

2.添加依赖

implementation 'com.android.support:design:27.1.1'
implementation 'com.github.qdxxxx:StickyHeaderDecoration:1.0.1'

3.设置

private void Data() {
        mCars = new ArrayList<>();
        mCars.add(new Car("奥迪", "A"));
        mCars.add(new Car("阿尔法罗密欧", "A"));
        mCars.add(new Car("阿斯顿马丁", "A"));
        mCars.add(new Car("ALPINA", "A"));
        mCars.add(new Car("安凯客车", "A"));
        mCars.add(new Car("本田", "B"));
        mCars.add(new Car("别克", "B"));
        mCars.add(new Car("奔驰", "B"));
        mCars.add(new Car("宝马", "B"));
        mCars.add(new Car("保时捷", "B"));
        mCars.add(new Car("比亚迪", "B"));
        mCars.add(new Car("北京", "B"));
        mCars.add(new Car("宾利", "B"));
        mCars.add(new Car("巴博斯", "B"));
        mCars.add(new Car("布加迪威龙", "B"));
        mCars.add(new Car("长安", "C"));
        mCars.add(new Car("长城", "C"));
        mCars.add(new Car("大众", "D"));
        mCars.add(new Car("东南", "D"));
        mCars.add(new Car("东风", "D"));
        mCars.add(new Car("DS", "D"));
        mCars.add(new Car("道奇", "D"));
        mCars.add(new Car("东风小康", "D"));
    }

private void initView() {
//        final LayoutInflater inflater = LayoutInflater.from(this);
        mRlv = (RecyclerView) findViewById(R.id.rlv);
        mRlv.setLayoutManager(new LinearLayoutManager(this));
        RlvAdapter rlvAdapter = new RlvAdapter(mCars);
        //返回头布局的内容
        final NormalDecoration decoration = new NormalDecoration() {
            @Override
            public String getHeaderName(int i) {
                return mCars.get(i).headerName;
            }
        };
        //自定义头布局,可不设置
//        decoration.setOnDecorationHeadDraw(new NormalDecoration.OnDecorationHeadDraw() {
//            @Override
//            public View getHeaderView(final int i) {
//                View inflate = inflater.inflate(R.layout.item_header, null);
//                TextView tv = inflate.findViewById(R.id.tv);
//               tv.setText(mCars.get(i).headerName);
//                return inflate;
//            }
//        });
        mRlv.addItemDecoration(decoration);
        //头布局的点击事件
        decoration.setOnHeaderClickListener(new NormalDecoration.OnHeaderClickListener() {
            @Override
            public void headerClick(int i) {
                Toast.makeText(MainActivity.this, mCars.get(i).headerName, Toast.LENGTH_SHORT).show();
                startActivity(new Intent(MainActivity.this,FlowActivity.class));
            }
        });
        mRlv.setAdapter(rlvAdapter);
    }