关于popupWindow底部与导航栏（ navigation bar）重叠，显示不全的问题分析

最近在做项目遇到个问题：自定义popupWindow,调用

public void showAtBottom(View parent) {
        View view = mPopupLayout.findViewById(getContentViewId());
        setAnimation(view);//自定义动画
        showAtLocation(parent, Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL, 0, 0);
    }

结果：

这个是测试demo里的效果。

看表面现象应该是系统的navigation bar遮挡住了popupWindow布局，怀着这个心思，自然想到popupWindow的setContentView设置布局方法。

以下是源码部分：

public void setContentView(View contentView) {
        if (isShowing()) {
            return;
        }

        mContentView = contentView;

        if (mContext == null && mContentView != null) {
            mContext = mContentView.getContext();
        }

        if (mWindowManager == null && mContentView != null) {
            mWindowManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
        }

        // Setting the default for attachedInDecor based on SDK version here
        // instead of in the constructor since we might not have the context
        // object in the constructor. We only want to set default here if the
        // app hasn't already set the attachedInDecor.
        if (mContext != null && !mAttachedInDecorSet) {//这个是会走的，源码就不分析了
            // Attach popup window in decor frame of parent window by default for
            // {@link Build.VERSION_CODES.LOLLIPOP_MR1} or greater. Keep current
            // behavior of not attaching to decor frame for older SDKs.
            setAttachedInDecor(mContext.getApplicationInfo().targetSdkVersion
                    >= Build.VERSION_CODES.LOLLIPOP_MR1);
        }

    }

定位到最后一行：

setAttachedInDecor(mContext.getApplicationInfo().targetSdkVersion
                    >= Build.VERSION_CODES.LOLLIPOP_MR1);//api22

sdk做了下api适配：

/**
     * 
This will attach the popup window to the decor frame of the parent window to avoid
     * overlaping with screen decorations like the navigation bar. Overrides the default behavior of
     * the flag {@link WindowManager.LayoutParams#FLAG_LAYOUT_ATTACHED_IN_DECOR}.
     *
     * 
By default the flag is set on SDK version {@link Build.VERSION_CODES#LOLLIPOP_MR1} or
     * greater and cleared on lesser SDK versions.
     *
     * @param enabled true if the popup should be attached to the decor frame of its parent window.
     *
     * @see WindowManager.LayoutParams#FLAG_LAYOUT_ATTACHED_IN_DECOR
     */
    public void setAttachedInDecor(boolean enabled) {
        mAttachedInDecor = enabled;
        mAttachedInDecorSet = true;
    }

注释的大概意思是：这将把弹出窗口附加到其父窗体的装饰框（个人理解应该是类似于窗体的根布局decorview概念） 目的是避免popupWindow布局与屏幕装饰物重叠，比如导航栏。重写了默认的windowManager.LayoutParams为 FLAG_LAYOUT_ATTACHED_IN_DECOR

看下参数的含义：如果enabled为true那么就会避免与导航栏重叠

FLAG_LAYOUT_ATTACHED_IN_DECOR又是什么鬼？

/**
         * Window flag: When requesting layout with an attached window, the attached window may
         * overlap with the screen decorations of the parent window such as the navigation bar. By
         * including this flag, the window manager will layout the attached window within the decor
         * frame of the parent window such that it doesn't overlap with screen decorations.
         */
        public static final int FLAG_LAYOUT_ATTACHED_IN_DECOR = 0x40000000;

大体意思和上面的翻译吻合。原来如此，现在已经明确了

原来系统通过

setAttachedInDecor

方法设置windowManager.Layoutparams,如果api>=22就设置为true，反之false

那setAttachedInDecor里的 mAttachedInDecor 字段在哪里生效的呢？继续看源码：

在PopupWindow里的computeFlags方法里：

if (mAttachedInDecor) {
            curFlags |= WindowManager.LayoutParams.FLAG_LAYOUT_ATTACHED_IN_DECOR;
        }

与上面的翻译注释吻合。

下面是api=24，华为荣耀8的结果（显示正常）：

现在的问题是我测试机api21，所以方法设置为false了。

更令人可恶的是setAttachedInDecor(boolean)方法只能api22以上调用

 

怎么办呢？

解决方案1：

1.将api<21的设备，popupWindow的布局上移导航栏的高度

代码：

@Override
    protected void setAnimation(final View view) {
        final int final_location;
        if (view.getContext().getApplicationInfo().targetSdkVersion
                < Build.VERSION_CODES.LOLLIPOP_MR1) {//api<22,这个地方就好比给sdk里打了个补丁
            final_location = -ScreenUtils.getNavBarHeight(view.getContext());
        } else {
            final_location = 0;
        }
        view.post(new Runnable() {
            @Override
            public void run() {
                int height = view.getHeight();
                ValueAnimator animator = ObjectAnimator
                        .ofFloat(view, "translationY", height,final_location );//如果不需要动画，可以直接将布局上移这个高度
                animator.setDuration(200).start();
            }
        });
    }

获取导航栏高度：

public static int getNavBarHeight(Context context) {
        Resources resources = context.getResources();
        int resourceId = resources.getIdentifier("navigation_bar_height", "dimen", "android");
        if (resourceId > 0) {
            return resources.getDimensionPixelSize(resourceId);
        }
        return 0;
    }

目前这种解决方案在真机都没问题，但是夜神模拟器比较特殊，夜神底下没有导航栏，但是获取的导航栏的高度却不是0，难道他获取的导航栏在右侧？？

解决方案2：

在popupWindow的布局里添加个高度>=0的可滚动的列表（比如ListView,RecyclerView,ScrollView），如果不需要此控件，高度可设置为0

顺便贴下basePopupWindow的代码：

public abstract class BasePopupWindow extends PopupWindow {
    private View mPopupLayout;
    private View.OnClickListener mListener;

    protected List mBeans;

    public BasePopupWindow(Context context, View.OnClickListener listener, List beans) {
        super(context);
        initView(context);
        mBeans = beans;
        mListener = listener;
    }

    private void initView(Context context) {
        mPopupLayout = ((LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(getLayoutId(), null);
        setContentView(mPopupLayout);
        setWidth(ViewGroup.LayoutParams.MATCH_PARENT);
        setHeight(ViewGroup.LayoutParams.MATCH_PARENT);
        setFocusable(true);
        ColorDrawable dw = new ColorDrawable(0xb0000000);
        setBackgroundDrawable(dw);
        mPopupLayout.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, final MotionEvent event) {
                mPopupLayout.findViewById(getContentViewId()).post(new Runnable() {
                    @Override
                    public void run() {
                        int height = mPopupLayout.findViewById(getContentViewId()).getTop();
                        int y = (int) event.getY();
                        if (event.getAction() == MotionEvent.ACTION_UP) {
                            if (y < height) {
                                dismiss();
                            }
                        }
                    }
                });

                return true;
            }
        });
        setData();
    }

    private View getView(int viewId) {
        return mPopupLayout.findViewById(viewId);
    }

    /**
     * 如果有必要-子类根据model返回的数据写逻辑
     *
     * @return
     */
    protected BasePopupWindow setData() {
        return this;
    }

    public BasePopupWindow setListener(int viewId) {
        getView(viewId).setOnClickListener(mListener);
        return this;
    }

    /**
     * 位置-底部
     *
     * @param parent
     */
    public void showAtBottom(View parent) {
        View view = mPopupLayout.findViewById(getContentViewId());
        setAnimation(view);
        showAtLocation(parent, Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL, 0, 0);
    }

    protected void setAnimation(View target) {

    }

    /**
     * 点击不消失的content view
     *
     * @return
     */
    protected abstract int getContentViewId();

    protected abstract int getLayoutId();

动画写在继承他的子类里。