Android Support Library 23.2里的 Design Support Library新加了一个Bottom Sheets控件,一个底部表,就是我们经常在分享或者地图、音乐等app看到的效果
昨天晚上Support Library 23.2包还没能更新,官方视频就已经透露出了,视频地址,从视频看出Support Library 23.2包新增了:
-
- Support Vector Drawables and Animated Vector Drawables
-
- AppCompat DayNight theme
-
- Design Support Library: Bottom Sheets
-
- Support v4: MediaBrowserServiceCompat
-
- RecyclerView
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- Custom Tabs
-
- Leanback for Android TV
具体可以上官网博客看看。
这篇文章我给大家说说BottomSheetBehavior的使用及注意的地方
##Usage ###(1)在布局文件xml中
<?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:id="@ id/cl"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
>
<android.support.v4.widget.NestedScrollView
android:id="@ id/bottom_sheet"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:behavior_hideable="true"
app:behavior_peekHeight="50dp"
app:layout_behavior="@string/bottom_sheet_behavior"
>
<!-- NestedScrollView里设置你的底部表长什么样的-->
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
###(2)在java代码中
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_ns);
// The View with the BottomSheetBehavior
CoordinatorLayout coordinatorLayout = (CoordinatorLayout) findViewById(R.id.cl);
View bottomSheet = coordinatorLayout.findViewById(R.id.bottom_sheet);
final BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
@Override
public void onStateChanged(@NonNull View bottomSheet, int newState) {
//这里是bottomSheet 状态的改变回调
}
@Override
public void onSlide(@NonNull View bottomSheet, float slideOffset) {
//这里是拖拽中的回调,根据slideOffset可以做一些动画
}
});
}
其实也挺简单的,我来解释一下。通过附加一个BottomSheetBehavior 给CoordinatorLayout的子视图,上文xml中的是NestedScrollView(adding app:layout_behavior = " android.support.design.widget.BottomSheetBehavior”),当然,RecyclerView也是可以的。如果需要BottomSheet View可以保持滚动,需要支持 nested scrolling (例如: NestedScrollView, RecyclerView, or ListView/ScrollView on API 21 ).
app:behavior_hideable="true"
app:behavior_peekHeight="50dp"
这两个属性我说说,peekHeight是当Bottom Sheets关闭的时候,底部下表我们能看到的高度,hideable 是当我们拖拽下拉的时候,bottom sheet是否能全部隐藏。 如果你需要监听Bottom Sheets回调的状态,可以通过setBottomSheetCallback来实现,onSlide方法是拖拽中的回调,根据slideOffset可以做一些动画 onStateChanged方法可以监听到状态的改变,总共有5种
- STATE_COLLAPSED: 关闭Bottom Sheets,显示peekHeight的高度,默认是0
- STATE_DRAGGING: 用户拖拽Bottom Sheets时的状态
- STATE_SETTLING: 当Bottom Sheets view摆放时的状态。
- STATE_EXPANDED: 当Bottom Sheets 展开的状态
- STATE_HIDDEN: 当Bottom Sheets 隐藏的状态
我也简单的写了BottomSheetBehavior和BottomSheetDialog的demo,你可以看我源码是怎么用的
使用就这些了,接下来我们来讲讲该注意的地方,应该说怎样更好的使用它。
###(1)关闭Bottom Sheets的行为 可以通过下图的形式,拖拽、点击bottom sheet之外的地方和通过‘x’按钮
###(2)合适的视图设计
上图你可明显的看到第二幅这种设计是不合适的,空白太多,不美观,对吧!
如果Bottom Sheets 展开或者上拉覆盖了ActionBar or ToolBar 这种方式也是不合适的.
###(3)尺寸的设计 为了符合Material Design 设计,我们对尺寸有严格的要求,当然,你想随意我也阻止不了
我想说的就这些了,如果还有补充,欢迎PR!
又写了一篇:BottomSheets源码解析
Github:Android-CJJ------能 follow 下我就更好了
微博:Android_CJJ-------能 关注 下我就更好了
GitHub小伙伴交流群'' 477826523,很难进的哦!
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