Android 支付宝头部啥的~

https://blog.kyleduo.com/2017/07/21/alipay-home-3-alipay-home/

平滑

https://github.com/leifu1107/AlipayHome

有点那啥 但是那啥

---

开始实践~

---

https://github.com/zhangqifan1/Demo_ok9

implementation 'com.android.support:design:28.0.0'

widgts 包 粘贴~改改import decarition 不用可以删 其他 都是 核心~看不懂的;了

ids 也得粘贴

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.as.alipayhome.widgets.APHeaderView
        android:id="@+id/alipay_header"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <com.as.alipayhome.widgets.APSnapView
            android:id="@id/alipay_snap"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            >

          <TextView
              android:background="#f0f0"
              android:gravity="center"
              android:text="我是内容内容可以自定义,一会我就盖上去,嘿嘿"
              android:textStyle="bold"
              android:textSize="22sp"
              android:layout_width="match_parent"
              android:layout_height="wrap_content" />

        </com.as.alipayhome.widgets.APSnapView>

        <LinearLayout
            android:background="#f050f0"
            android:id="@+id/alipay_grid_menu"
            android:layout_width="match_parent"
            android:layout_height="500dp"
            android:orientation="vertical">

            <TextView
                android:gravity="center"
                android:text="不盖上去,只是顶上去,,可以当RecyclerView首条目"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                />

        </LinearLayout>

        <com.as.alipayhome.widgets.APBarView
            android:id="@id/alipay_bar"
            android:layout_width="match_parent"
            android:layout_height="48dp"
            >
            <LinearLayout
                android:id="@+id/bar1"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical">

                <TextView
                    android:background="#ff0"
                    android:gravity="center"
                    android:text="顶上去会显示"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" />
            </LinearLayout>
            <LinearLayout
                android:id="@+id/bar2"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical">
                <TextView
                    android:background="#f00"
                    android:gravity="center"
                    android:text="顶上去会隐藏"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" />
            </LinearLayout>


        </com.as.alipayhome.widgets.APBarView>

    </com.as.alipayhome.widgets.APHeaderView>




    <android.support.v7.widget.RecyclerView
        android:id="@+id/alipay_rv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="com.as.alipayhome.widgets.APScrollingBehavior"
        android:overScrollMode="never"/>


</android.support.design.widget.CoordinatorLayout>

注意xml 里 和 ids  一样的 id 就一样吧 不出幺蛾子~

这里短暂的一瞬间空白 是因为 俩个View /bar1 bar2 的 透明度 啥的 都到了极限 所以 只会显示背景色 我的白色的 支付宝的蓝色的 So

MainAc

public class MainActivity extends AppCompatActivity {
    RecyclerView mRecyclerView;
    APHeaderView mHeaderView;
    AlipayAdapter mAdapter;

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

        mRecyclerView = (RecyclerView) findViewById(R.id.alipay_rv);
        mHeaderView = (APHeaderView) findViewById(R.id.alipay_header);

        final LinearLayoutManager lm = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false) {

            @Override
            public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
                int scrolled = super.scrollVerticallyBy(dy, recycler, state);
                if (dy < 0 && scrolled != dy) {
                    // 有剩余
                    APHeaderView.Behavior behavior = mHeaderView.getBehavior();
                    if (behavior != null) {
                        int unconsumed = dy - scrolled;
                        int consumed = behavior.scroll((CoordinatorLayout) mHeaderView.getParent(), mHeaderView, unconsumed, -mHeaderView.getScrollRange(), 0);
                        scrolled += consumed;
                    }
                }
                return scrolled;
            }
        };

        mHeaderView.setOnHeaderFlingUnConsumedListener(new APHeaderView.OnHeaderFlingUnConsumedListener() {
            @Override
            public int onFlingUnConsumed(APHeaderView header, int targetOffset, int unconsumed) {
                APHeaderView.Behavior behavior = mHeaderView.getBehavior();
                int dy = -unconsumed;
                if (behavior != null) {
                    mRecyclerView.scrollBy(0, dy);
                }
                return dy;
            }
        });

        ArrayList<String> titles = new ArrayList<>();
        for (int i = 0; i < 30; i++) {
            titles.add("item " + i);
        }

        mRecyclerView.setLayoutManager(lm);
        mAdapter = new AlipayAdapter(titles);
        mRecyclerView.setAdapter(mAdapter);
        mRecyclerView.addItemDecoration(new CommonListDecoration());
        mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
                if (newState == RecyclerView.SCROLL_STATE_IDLE) {
                    APHeaderView.Behavior behavior = mHeaderView.getBehavior();
                    if (behavior != null) {
                        behavior.checkSnap((CoordinatorLayout) mHeaderView.getParent(), mHeaderView);
                    }
                }
            }
        });

    }


    static class AlipayItemViewHolder extends RecyclerView.ViewHolder {

        TextView titleTv;

        public AlipayItemViewHolder(View itemView) {
            super(itemView);
            titleTv = (TextView) itemView;
        }
    }

    private static class AlipayAdapter extends RecyclerView.Adapter<AlipayItemViewHolder> {

        private List<String> mTitles;

        public AlipayAdapter(List<String> titles) {
            mTitles = titles;
        }

        @Override
        public AlipayItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            return new AlipayItemViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_content, parent, false));
        }

        @Override
        public void onBindViewHolder(AlipayItemViewHolder holder, int position) {
            holder.titleTv.setText(mTitles.get(position));
        }

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