高仿网易严选底部弹出菜单

在网易严选的看东西的时候在商品详情页里看到他的底部弹出菜单，本能反应是想用DottomSheetDialog或者PopupWindow来实现，可是发现实现不了他那种效果，于是就自己模仿一个像严选这样的底部弹出菜单。

不管是DottomSheetDialog或者PopupWindow他们的阴影背景都是全部覆盖的，这就造成除了菜单内容的View之外其他都是阴影的，而严选不是这样的。唠叨到此，首先展示效果图如下：

是不是还可以呢，由于代码量不多却注释详细，所以先贴出代码再一一详说:

BottomPopupWindowView类：

public class BottomPopupWindowView extends LinearLayout{    private AnimatorListener animatorListener;    //底部内容的View    private FrameLayout base_view;    //内容的View    private FrameLayout content_view;    //背景的View    private RelativeLayout popup_bg;    //xml加载的View    private View bottomPopouView;    //外部加载的内容View    private View contentView;    //外部加载的底部内容View    private View baseView;    //手势的最小值    private float minVelocity=0;    //加载一次的判断值    private boolean mDrawable=true;    public void setAnimatorListener(AnimatorListener animatorListener) {        this.animatorListener = animatorListener;    }    public void setBaseView(View baseView){        this.baseView=baseView;    }    public void setContextView(View view){        this.contentView=view;    }    public void setContentView(int id){        this.contentView=LayoutInflater.from(getContext()).inflate(id,null);    }    public BottomPopupWindowView(Context context) {        this(context,null);    }    public BottomPopupWindowView(Context context, @Nullable AttributeSet attrs) {        this(context,attrs,0);    }    public BottomPopupWindowView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        //初始化各种数值        minVelocity=ViewConfiguration.get(getContext()).getScaledTouchSlop();        bottomPopouView= LayoutInflater.from(getContext()).inflate(R.layout.layout_bottom_popup,null);        base_view=(FrameLayout)bottomPopouView.findViewById(R.id.bottom_view);        content_view=(FrameLayout)bottomPopouView.findViewById(R.id.content_view);        popup_bg=(RelativeLayout)bottomPopouView.findViewById(R.id.popup_bg);        //把整个View都加载在LinearLayout里以显示出来        addView(bottomPopouView);        //背景颜色监听        popup_bg.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                disMissPopupView();            }        });        //屏蔽内容区域点击事件        content_view.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View view){}        });        //屏蔽底部内容区域点击事件        base_view.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View view){}        });        //内容区域判断是否向下，手势向下就关闭弹框        content_view.setOnTouchListener(new OnTouchListener() {            @Override            public boolean onTouch(View view, MotionEvent motionEvent) {                float y1=0,y2=0;                if(motionEvent.getAction() == MotionEvent.ACTION_DOWN) {                    y1 = motionEvent.getY();                }                if(motionEvent.getAction() == MotionEvent.ACTION_UP){                    y2 = motionEvent.getY();                    if((y2-y1)>minVelocity){                        disMissPopupView();                    }                }                return false;            }        });    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        if(mDrawable&&baseView!=null){            //刚开始加载底部内容区域，只需一次就行，多次报错            base_view.addView(baseView);            mDrawable=false;        }    }    public void showPopouView(){        if(contentView!=null){            //开始动画数据            startAnimation();            //开启背景颜色的渐变动画            popup_bg.setVisibility(View.VISIBLE);            popup_bg.setAnimation(AnimationUtils.loadAnimation(getContext(), R.anim.bp_bottom_bg_in));            //把这个区域全部显示出来            ((BottomPopupWindowView)this).setLayoutParams(new RelativeLayout.LayoutParams(                    RelativeLayout.LayoutParams.MATCH_PARENT,RelativeLayout.LayoutParams.MATCH_PARENT));            //假如内容区域            content_view.addView(contentView,0);            content_view.setVisibility(View.VISIBLE);            //开启内容区域动画            content_view.setAnimation(AnimationUtils.loadAnimation(getContext(),R.anim.bp_bottom_view_in));        }    }    public void disMissPopupView(){        //开始关闭动画数据        endAnimation();        //开启内容区域动画        content_view.setVisibility(View.GONE);        Animation animation=AnimationUtils.loadAnimation(getContext(),R.anim.bp_bottom_view_out);        animation.setAnimationListener(new Animation.AnimationListener() {            @Override            public void onAnimationStart(Animation animation) {}            @Override            public void onAnimationRepeat(Animation animation) {}            @Override            public void onAnimationEnd(Animation animation) {                //等内容区域动画结束后，清楚所有View                content_view.removeAllViews();                //开启背景颜色的渐变动画                popup_bg.setVisibility(View.GONE);                popup_bg.setAnimation(AnimationUtils.loadAnimation(getContext(), R.anim.bp_bottom_bg_out));                //把整个控件的大小恢复到底部View区域的大小                RelativeLayout.LayoutParams layoutParams=new RelativeLayout.LayoutParams(                        RelativeLayout.LayoutParams.MATCH_PARENT,getViewHeight((BottomPopupWindowView)BottomPopupWindowView.this));                layoutParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM,-1);                ((BottomPopupWindowView)BottomPopupWindowView.this).setLayoutParams(layoutParams);            }        });        //开始动画        content_view.setAnimation(animation);    }    //获取View的高度    public int getViewHeight(View view){        int width =View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);        int height =View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);        view.measure(width,height);        return view.getMeasuredHeight();    }    //开始动画数据变化    public void startAnimation(){        ValueAnimator valueAnimator = ValueAnimator.ofInt(0,40);        valueAnimator.setDuration(250);        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {            @Override            public void onAnimationUpdate(ValueAnimator valueAnimator) {                if(animatorListener!=null){                    animatorListener.startValue((int) valueAnimator.getAnimatedValue());                }            }        });        valueAnimator.start();    }    //结束动画数值变化    public void endAnimation() {        ValueAnimator valueAnimator = ValueAnimator.ofInt(40,0);        valueAnimator.setDuration(250);        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {            @Override            public void onAnimationUpdate(ValueAnimator valueAnimator) {                if(animatorListener!=null){                    animatorListener.endValue((int) valueAnimator.getAnimatedValue());                }            }        });        valueAnimator.start();    }}

对应的加载的xml布局是：
layout_bottom_popou.xml如下：

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:background="#707A7A7A">    <RelativeLayout        android:id="@+id/popup_bg"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="#707A7A7A"        android:layout_above="@+id/bottom_view"></RelativeLayout>    <FrameLayout        android:id="@+id/content_view"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_above="@+id/bottom_view"        android:orientation="horizontal">    </FrameLayout>    <FrameLayout        android:id="@+id/bottom_view"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"></FrameLayout></RelativeLayout>

1.在BottomPopupWindowView是继承LinearLayout，而layout_bottom_popou.xml是这整个BottomPopupWindowView里的骨架，然后在BottomPopupWindowView初始化的时候通过addView()来加载整个骨架布局。在onDraw()里只需加载一次baseView就可以了，不然后重复加载导致报错。这样就初始化成功了，刚开始只会加载baseView的界面，就相当于严选最下面的购物车立即购买等界面。

baseView.png

2.当调用showPopouView()时显示菜单的。startAnimation()方法只是为了产生动画的数据。popup_bg.setVisibility(View.VISIBLE);popup_bg.setAnimation(AnimationUtils.loadAnimation(getContext(), R.anim.bp_bottom_bg_in));只是为了开启背景渐变的动画没什么说的。最重要的是显示菜单实现是把BottomPopupWindowView的大小扩展到全屏，所以设置((BottomPopupWindowView)this).setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,RelativeLayout.LayoutParams.MATCH_PARENT));,然后把弹出菜单的View即contentView装进content_view即可，然后开启弹出动画就实现了。

3.最后是disMissPopupView()方法关闭弹窗。endAnimation()方法只是为了产生动画的数据。再启动内容域View即content_View的退出动画，在动画结束后用content_view.removeAllViews();
起初菜单内容，再像上面一样开启背景颜色渐变动画，最后只需使BottomPopupWindowView恢复原来的baseView的大小及可以了，具体如下:RelativeLayout.LayoutParams layoutParams=new RelativeLayout.LayoutParams( RelativeLayout.LayoutParams.MATCH_PARENT,getViewHeight((BottomPopupWindowView)BottomPopupWindowView.this)); layoutParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM,-1); ((BottomPopupWindowView)BottomPopupWindowView.this).setLayoutParams(layoutParams);。这就是核心的代码功能了，代码量不多具体细节看上面的源码。

有人或许会问返回动画的数据有什么用，很简单就是为了实现严选菜单框出来时整个上面详情的缩放。具体看如下demo,首先给出界面xml,如下:

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <LinearLayout        android:id="@+id/main_view"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="@color/colorAccent"        android:orientation="vertical">        <ImageView            android:id="@+id/banner_img"            android:layout_width="match_parent"            android:layout_height="300dp"            android:scaleType="fitXY"            android:src="@mipmap/banner"/>        <View            android:layout_width="match_parent"            android:layout_height="0.1dp"            android:background="@color/colorPrimary"></View>        <RelativeLayout            android:id="@+id/guige"            android:layout_width="match_parent"            android:layout_height="50dp"            android:background="#ffffff">            <TextView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_centerVertical="true"                android:layout_marginLeft="15dp"                android:textSize="15dp"                android:text="规格数量选择"/>            <ImageView                android:layout_width="20dp"                android:layout_height="20dp"                android:layout_alignParentRight="true"                android:layout_centerVertical="true"                android:layout_marginRight="15dp"                android:src="@mipmap/ic_jiantou"/>        </RelativeLayout>        <View            android:layout_width="match_parent"            android:layout_height="0.1dp"            android:background="@color/colorPrimary"></View>    </LinearLayout>    <com.jack.bottompopupwindowview.BottomPopupWindowView        android:id="@+id/bottom_popup"        android:layout_width="match_parent"        android:layout_height="50dp"        android:background="@android:color/transparent"        android:layout_alignParentBottom="true">    </com.jack.bottompopupwindowview.BottomPopupWindowView></RelativeLayout>

这就是上面效果图的界面布局，没什么可以说的，再看事例代码如下：

public class MainActivity extends AppCompatActivity implements View.OnClickListener, AnimatorListener {    private BottomPopupWindowView bottomPopupWindowView;    private View contentView;    private View bottomView;    private LinearLayout mainView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mainView=(LinearLayout)findViewById(R.id.main_view);        bottomView=LayoutInflater.from(this).inflate(R.layout.layout_bottom_view,null);        (bottomView.findViewById(R.id.promptly_buy)).setOnClickListener(this);        (findViewById(R.id.guige)).setOnClickListener(this);        bottomPopupWindowView=(BottomPopupWindowView)findViewById(R.id.bottom_popup);        bottomPopupWindowView.setOnClickListener(this);        bottomPopupWindowView.setBaseView(bottomView);        contentView=LayoutInflater.from(this).inflate(R.layout.layout_content_view,null);        bottomPopupWindowView.setContextView(contentView);        (contentView.findViewById(R.id.ic_cancel)).setOnClickListener(this);        bottomPopupWindowView.setAnimatorListener(this);    }    @Override    public void onClick(View view) {        switch(view.getId()){            case R.id.promptly_buy:            case R.id.ic_cancel:                bottomPopupWindowView.disMissPopupView();                break;            case R.id.guige:                bottomPopupWindowView.showPopouView();                break;        }    }    @Override    public void startValue(int value) {        setMargins (mainView,value-10,value,value-10,value);    }    @Override    public void endValue(int value) {        setMargins (mainView,value,value,value,value);    }    public static void setMargins (View v, int l, int t, int r, int b) {        if (v.getLayoutParams() instanceof ViewGroup.MarginLayoutParams) {            ViewGroup.MarginLayoutParams p = (ViewGroup.MarginLayoutParams) v.getLayoutParams();            p.setMargins(l, t, r, b);            v.requestLayout();        }    }}

其中设置内容菜单的View
BottomPopupWindowView.setContextView(bottomView);
设置没有显示菜单时候显示的View(注:bottomView的高度要和BottomPopupWindowView的高度一样，具体看demo)
BottomPopupWindowView.setBaseView(bottomView);而回调的
public void startValue(int value)和public void endValue(int value)设置动画监听放回的数据，以便根据数据实现动画，严选的弹出和显示商品详情动画很简单就是不断设设置View的间距就可以了。