[Android]PopupWindow 点击外部区域无法关闭的问题

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在android4.0/5.0系统上,使用popupWindow时,点击内容外部区域无法关闭,但是在6.0机子上又是正常的,而我在代码中明明已经进行了如下设置:

mPopupWindow = new PopupWindow(popView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT, true);
// 点击其他地方消失
mPopupWindow.setOutsideTouchable(true);

google了一下都说要添加一句:

mPopupWindow.setBackgroundDrawable(new BitmapDrawable());

测试了果然ok,不过还是想知道下所以然,稍微探究一下:
既然是点击没效果,搜索一下touch事件好了:
在4.0/5.0的 PopupWindow.java 源码中发现是在 PopupViewContainer 类中设置的,而在6.0源码中则是位于 PopupDecorView 类;

继续查找在哪里初始化的,发现 preparePopup(),它是在显示(showAtLocation() , showAsDropDown())的时候调用的,而 preparePopup() 的具体内容:

// PopupWindow.java @ api 14/19/21
private void preparePopup(WindowManager.LayoutParams p) {
    if (mContentView == null || mContext == null || mWindowManager == null) {
        throw new IllegalStateException("You must specify a valid content view by "
                + "calling setContentView() before attempting to show the popup.");
    }

    if (mBackground != null) {
        final ViewGroup.LayoutParams layoutParams = mContentView.getLayoutParams();
        int height = ViewGroup.LayoutParams.MATCH_PARENT;
        if (layoutParams != null &&
                layoutParams.height == ViewGroup.LayoutParams.WRAP_CONTENT) {
            height = ViewGroup.LayoutParams.WRAP_CONTENT;
        }

        // when a background is available, we embed the content view
        // within another view that owns the background drawable
        PopupViewContainer popupViewContainer = new PopupViewContainer(mContext);
        PopupViewContainer.LayoutParams listParams = new PopupViewContainer.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT, height
        );
        popupViewContainer.setBackgroundDrawable(mBackground);
        popupViewContainer.addView(mContentView, listParams);

        mPopupView = popupViewContainer;
    } else {
        mPopupView = mContentView;
    }
    mPopupWidth = p.width;
    mPopupHeight = p.height;
}

这里可以看到当background不为null的时候,在contentView外面套了一层PopupViewContainer,而PopupViewContainer中才有关于touch,key的监听事件,因此若未设置背景,则点击外部区域无法取消popupwindow,即使设置了:

mPopupWindow.setOutsideTouchable(true);

而在android6.0中:

// PopupWindow.java @ api 23
private void preparePopup(WindowManager.LayoutParams p) {
    ......

    // When a background is available, we embed the content view within
    // another view that owns the background drawable.
    if (mBackground != null) {
        mBackgroundView = createBackgroundView(mContentView);
        mBackgroundView.setBackground(mBackground);
    } else {
        mBackgroundView = mContentView;
    }

    // 无论background是否为空,都会创建decorView,它是PopupDecorView的实例,其实就是一个FrameLayout,里面有touch事件的监听,因此无需设置背景也可以点击外部区域取消popupwindow的
    mDecorView = createDecorView(mBackgroundView);
    ......
}

总之,跟网友说的一致,添加背景图片就可以了:

Bitmap bmp = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.bg_popup_window);
Drawable drawable = new BitmapDrawable(getContext().getResources(), bmp);
// 不带参的方法已经deprecated
popupWindow.setBackgroundDrawable(drawable);