掌握Popupwindow实现弹出列表效果及自定义效果

1、PopupWindow与AlertDialog的区别

PopupWindow和AlertDialog很相似,都是一个悬浮的窗口遮挡在当前页面,但是它们是有区别的,最关键的区别是AlertDialog不能指定显示位置，只能默认显示在屏幕最中间（当然也可以通过设置WindowManager参数来改变位置）。而PopupWindow是可以指定显示位置的，随便哪个位置都可以，更加灵活。

2.显示函数

image.png

3.设置点击外部消失PopupWindow

//必须先设置背景
popupWindow.setBackgroundDrawable(null);
popupWindow.setOutsideTouchable(true);

4.为菜单添加阴影（了解）

View inflate = LayoutInflater.from(this).inflate(R.layout.pop, null, false);
final PopupWindow popupWindow = new PopupWindow(inflate, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
inflate.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
           popupWindow.dismiss();
         }
    });
//popupWindow.setBackgroundDrawable(null);
popupWindow.setOutsideTouchable(true);
WindowManager.LayoutParams attributes = getWindow().getAttributes();
attributes.alpha = 0.3f;
getWindow().addFlags(WindowManager.LayoutParams.FLAGS_CHANGED);
getWindow().setAttributes(attributes);
popupWindow.setOnDismissListener(new PopupWindow.OnDismissListener() {
      @Override
     public void onDismiss() {
          WindowManager.LayoutParams attributes = getWindow().getAttributes();
          attributes.alpha = 1.0f;
          getWindow().addFlags(WindowManager.LayoutParams.FLAGS_CHANGED);
          getWindow().setAttributes(attributes);
        }
});
//在某个view的下方,如果有偏移量,在某个view下方开始加减对应偏移量即popwindow的位置       popupWindow.setAnimationStyle(R.style.PopAnimation);
popupWindow.showAsDropDown(inflate,Gravity.CENTER,0,0);

5.加动画

popupWindow.setAnimationStyle(R.style.PopAnimation);

anim_exit.xml:

anim_enter.xml

6.又想有阴影,又想在某个随着屏幕滑动位置变化的某个view下面

View inflate = LayoutInflater.from(this).inflate(R.layout.pop, null, false);
final PopupWindow popupWindow = new PopupWindow(inflate, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
    //点击非菜单部分退出
   inflate.setOnClickListener(new View.OnClickListener() {
        @Override
         public void onClick(View v) {
              popupWindow.dismiss();
          }
      });
popupWindow.setBackgroundDrawable(null); 
popupWindow.setOutsideTouchable(true);
popupWindow.setAnimationStyle(R.style.PopAnimation);
//相对于屏幕的位置
int[] position = new int[2];
mBtn2.getLocationOnScreen(position);
LinearLayout llCotainer = inflate.findViewById(R.id.ll_container);
//获取状态栏高度
 int result = 0;
 int resourceId = getResources().getIdentifier("status_bar_height", "dimen", "android");
 if (resourceId > 0) {
        result = getResources().getDimensionPixelSize(resourceId);
 }
LinearLayout.LayoutParams par = (LinearLayout.LayoutParams) llCotainer.getLayoutParams();
par.setMargins(position[0],position[1]+mBtn2.getHeight()-result,0,0);
popupWindow.showAtLocation(mBtn2, Gravity.NO_GRAVITY,0,0);