BottomSheetBehavior 结合CoordinatorLayout实现底部栏

1.xml

<?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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <Button
            android:layout_height="40dp"
            android:layout_width="match_parent"
            android:id="@+id/btn"/>
    </LinearLayout>

    <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="100dp"
        app:layout_behavior="@string/bottom_sheet_behavior">
        <include
            layout="@layout/setting"/>
    </android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>

　　

2.

   View bottomSheet = findViewById(R.id.bottom_sheet);
        final BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
      behavior.setState(BottomSheetBehavior.STATE_HIDDEN);

        Button button= (Button) findViewById(R.id.btn);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(behavior.getState()==BottomSheetBehavior.STATE_HIDDEN){
                    behavior.setState(BottomSheetBehavior.STATE_EXPANDED);

                }else{
                    behavior.setState(BottomSheetBehavior.STATE_HIDDEN);

                }
            }
        });

　　

 3.区别：

  View bottomSheet = findViewById(R.id.bottom_sheet);
        final BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
        behavior.setState(BottomSheetBehavior.STATE_HIDDEN);
        Button button= (Button) findViewById(R.id.btn);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(behavior.getState()==BottomSheetBehavior.STATE_HIDDEN){
                    /**
                     * app:behavior_peekHeight="0dp"      behavior.setState(BottomSheetBehavior.STATE_EXPANDED); 只能响应一次
                     *
                     * app:behavior_peekHeight="0dp"  behavior.setState(BottomSheetBehavior.STATE_COLLAPSED); 点击时，底部表出不来
                     *
                     * app:behavior_peekHeight="100dp"  behavior.setState(BottomSheetBehavior.STATE_COLLAPSED); 点击按钮时，底部只弹出100dp,
                     *
                     * app:behavior_peekHeight="100dp"      behavior.setState(BottomSheetBehavior.STATE_EXPANDED); 点击按钮，底部表会完整弹出
                     */

                    behavior.setState(BottomSheetBehavior.STATE_EXPANDED);

                }else{
                    behavior.setState(BottomSheetBehavior.STATE_HIDDEN);

                }
            }
        });