CoordinatorLayout是design包里的控件，主要用来实现悬浮效果，下面简单介绍一下实现过程
- 添加依赖
implementation 'com.android.support:design:26.1.0'
就是添加design包
- 创建布局
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.yuntu.coordinatorlayoutsimple.CoordinatorLayoutActivity"
>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#00000000"
app:elevation="0dp"
>
<ImageView
android:layout_width="match_parent"
android:layout_height="100dp"
android:background="#FF352E"
app:layout_scrollFlags="scroll"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="40dp"
android:background="#4E65FE"
android:gravity="center_vertical"
android:text="测试"
/>
</android.support.design.widget.AppBarLayout>
<com.scwang.smartrefresh.layout.SmartRefreshLayout
android:id="@+id/refresh"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#eeeeee"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/recycleview"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</com.scwang.smartrefresh.layout.SmartRefreshLayout>
</android.support.design.widget.CoordinatorLayout>
布局顶层是CoordinatorLayout，上半部分采用的是AppBarLayout，当页面上滑时，AppBarLayout会随整个页面一起滑动，当ImageView滑动顶部消失时，下面的TextView会悬浮到顶部，不再滑动，下面的SmartRefreshLayout开始滑动，这就是悬浮效果，里面最关键的两个属性是app:layout_scrollFlags="scroll" 跟app:layout_behavior="@string/appbar_scrolling_view_behavior"> ，介绍layout_scrollFlags 的五种属性，介绍layoutbehavior，这两篇比较详细，这里主要说一下，下面下拉加载更多是遇到的一个小问题。
- 下拉加载遇到的小问题
public class CoordinatorLayoutActivity extends AppCompatActivity {
private int mCurrentPage = 1;
@Override protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_coordinator_layout);
initView();
}
private void initView() {
RecyclerView recyclerView = findViewById(R.id.recycleview);
recyclerView.setLayoutManager(
new LinearLayoutManager(CoordinatorLayoutActivity.this, LinearLayoutManager.VERTICAL,
false));
final RecycleViewAdapter recycleViewAdapter =
new RecycleViewAdapter(CoordinatorLayoutActivity.this);
recyclerView.setAdapter(recycleViewAdapter);
SmartRefreshLayout refreshLayout = findViewById(R.id.refresh);
//模拟加载数据
ArrayList<String> strings = new ArrayList<>();
for (int i = 0; i < 10; i++) {
strings.add("测试数据" + i);
}
recycleViewAdapter.setCollection(strings);
//禁止下拉加载
refreshLayout.setEnableRefresh(false);
refreshLayout.setHeaderHeight(0);
//实现上拉加载更多
refreshLayout.setOnLoadmoreListener(new OnLoadmoreListener() {
@Override public void onLoadmore(RefreshLayout refreshlayout) {
mCurrentPage++;
if (mCurrentPage < 4) {
ArrayList<String> strings = new ArrayList<>();
for (int i = 0; i < 10; i++) {
strings.add("测试数据" + i);
}
recycleViewAdapter.addCollection(strings);
refreshlayout.finishLoadmore();
} else {
refreshlayout.finishLoadmoreWithNoMoreData();
}
}
});
}
}
这个是页面代码，当下拉加载更多完成后，必须调用refreshlayout.finishLoadmore()，如果不调用，会出现滑动错乱的情况，上下两部分一起滑动。
