先吐槽一下android studio 1.5 beta版编译的时候真的挺慢的，虽说热编译速度上来了，有时候还是会编译错误

BottomSheets 在项目中用到了这个组件之前使用Dialog写的， 今天上班的时候说google在support library23.2中增加了这个组件，今天上午试了下，遇到了一些问题

先记录一下BottomSheets的用法吧

我们要在布局中添加一个属性
app:layout_behavior="android.support.design.widget.BottomSheetBehavior"
这个布局一定要是CoordinatorLayout的子布局

app:behavior_peekHeight 这个属性的意思是提升的高度
app:behavior_hideable 是否可以隐藏
基本上就是这两个属性了，具体可以看这里http://android-developers.blogspot.com/2016/02/android-support-library-232.html

<LinearLayout
        android:id="@+id/buttom_sheet"
        android:layout_width="match_parent"
        android:layout_height="400dp"
        android:background="@color/colorAccent"
        android:orientation="vertical"
        app:layout_behavior="android.support.design.widget.BottomSheetBehavior"
        app:behavior_peekHeight="50dp">
<LinearLayout>

 // The View with the BottomSheetBehavior   
View bottomSheet = coordinatorLayout.findViewById(R.id.bottom_sheet);   
BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
behavior.setBottomSheetCallback(new BottomSheetCallback() {
@Override
public void onStateChanged(@NonNull View bottomSheet, int newState) {
// React to state change      
}
@Override
public void onSlide(@NonNull View bottomSheet, float slideOffset) {
// React to dragging events
}   
}); 

代码添加的很简单
运行之后的效果就是这样的了

Paste_Image.png

底下的button少了一部分，折腾了一上午才找到，我在父控件中添加了一句android:fitsSystemWindows="true"，是为了改变statusBar的颜色，Material Design嘛！
这个button就是少了statusBar的高度了，所以就改了下代码，思路是，当创建bottomsheets时向上移动statusbar的高度，当bottomsheets发生移动时，就让bottomsheets的高度还原，思路是这样了，贴代码，省的以后用到了忘记

package org.cycling.tiny;

import android.app.Activity;
import android.graphics.Rect;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomSheetBehavior;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;

public class ScrollingActivity extends AppCompatActivity {
    private boolean first = true;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        View bottomSheet = findViewById(R.id.buttom_sheet);
        bottomSheet.setTranslationY(-getStatusHeight(this));

        BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);

        behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
                @Override
                public void onStateChanged(@NonNull
                View bottomSheet, int newState) {
                }

                @Override
                public void onSlide(@NonNull
                View bottomSheet, float slideOffset) {
                    if (first) {
                        bottomSheet.setTranslationY(0);
                        first = false;
                    }
                }
            });
    }

    /**
     * @param activity
     * @return > 0 success; <= 0 fail
     */
    public static int getStatusHeight(Activity activity) {
        int statusHeight = 0;
        Rect localRect = new Rect();
        activity.getWindow().getDecorView()
                .getWindowVisibleDisplayFrame(localRect);
        statusHeight = localRect.top;

        if (0 == statusHeight) {
            Class<?> localClass;

            try {
                localClass = Class.forName("com.android.internal.R$dimen");

                Object localObject = localClass.newInstance();
                int i5 = Integer.parseInt(localClass.getField(
                            "status_bar_height").get(localObject).toString());
                statusHeight = activity.getResources().getDimensionPixelSize(i5);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (InstantiationException e) {
                e.printStackTrace();
            } catch (NumberFormatException e) {
                e.printStackTrace();
            } catch (IllegalArgumentException e) {
                e.printStackTrace();
            } catch (SecurityException e) {
                e.printStackTrace();
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            }
        }

        return statusHeight;
    }
}

以下是修改完之后的运行效果

Paste_Image.png

Paste_Image.png