- 简单的调用
- 背景变暗
- 一些不同版本导致的小坑
简单调用
// 一个自定义的布局，作为显示的内容
View contentView = LayoutInflater.from(mContext).inflate(R.layout.pop_window, null);
PopupWindow popupWindow = new PopupWindow(contentView,
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, true);
popupWindow.setTouchable(true);
popupWindow.setTouchInterceptor(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
popupWindow.dismiss();//点击自身关闭
// 返回 false 表示不拦截 touch 事件，
// 拦截后 PopupWindow 的 onTouchEvent 不被调用，这样点击外部区域无法 dismiss
return false;
}
});
popupWindow.showAsDropDown(view);//将窗口显示在 view 的下面
指定弹出位置的一些方法：
//showAtLocation()显示在指定位置，有两个方法重载：
public void showAtLocation(View parent, int gravity, int x, int y)
public void showAtLocation(IBinder token, int gravity, int x, int y)
//showAsDropDown()显示在一个参照物View的周围，有三个方法重载：
public void showAsDropDown(View anchor)
public void showAsDropDown(View anchor, int xoff, int yoff)
public void showAsDropDown(View anchor, int xoff, int yoff, int gravity)
重写 PopupWindow
public popupWindow(Context context){
this.context = context;
LayoutInflater inflater = LayoutInflater.from(context);
rootView = inflater.inflate(R.layout.popup,null);
setContentView(rootView);
this.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
this.setWidth(ViewGroup.LayoutParams.MATCH_PARENT);
this.setFocusable(true);//设置成可获取焦点状态
//当单击Back键或者其他地方使其消失、需要设置这个属性。
rootView.setOnTouchListener(this);
rootView.setOnKeyListener(this);
rootView.setFocusable(true);
rootView.setFocusableInTouchMode(true);
this.setAnimationStyle(R.style.dialog_anim);//设置出现和消失的动画
//实例化一个ColorDrawable颜色为半透明
ColorDrawable dw = new ColorDrawable(0xb0000000);
//设置SelectPicPopupWindow弹出窗体的背景
this.setBackgroundDrawable(dw);
//这样设置虽然有半透明的背景，但是出现的方式不太对
}
@Override
public void setOnDismissListener(OnDismissListener onDismissListener) {
//在弹出框消失时
super.setOnDismissListener(onDismissListener);
}
//点back键消失
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && this.isShowing()) {
//如果点击了返回键，而且弹出框已经出现
this.dismiss();
return true;
}
return false;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
int height = rootView.findViewById(R.id.popup_linear).getTop();
// 这个height 是弹出框中的 LinearLayout 在屏幕的位置
int y = (int) event.getY();
//获取点击的 y 轴，点击的位置如果在弹出框的上面，是 y < height
if (event.getAction() == MotionEvent.ACTION_UP) {
if (y < height) {
dismiss();
}
}
return true;
}
调用
LinearLayout linearLayout = (LinearLayout) LayoutInflater.from(getContext())
.inflate(R.layout.me_layout, null);
popupWindow popupwindow = new popupWindow(getContext());
popupwindow.showAtLocation(linearLayout, Gravity.BOTTOM,0,0);
//这里的 linearLayout 是布局中的最外层的 LinearLayout ，所以这个 pop 出现在最下面
这里的例子没有获取布局中的按钮设置 onClick 事件，
这个是和在其他地方一样的，不表
背景变暗
搜到的很多资料的方法都基本一样，用的最多的就是：
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.alpha = 0.7f;
getWindow().setAttributes(lp); //让背景变暗
mPopupWindow.setOnDismissListener(new OnDismissListener() {
@Override
public void onDismiss() {
//在关闭 PopupWindow 之后，恢复背景
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.alpha = 1f;
getWindow().setAttributes(lp);
}
});
这个方法有局限性，还有一些是靠添加一个半透明的 View：
动画弹出 PopupWindow 并使背景变暗
还有一些值得参考的：
Android - 利用动画实现背景逐渐变暗
其实如果需要这种效果，还是用 Dialog 会比较简单和理想，
详细见于我的另一篇 Dialog 弹出框 笔记
6.0 版本不能 dismiss
简而言之，6.0 版本下的 PopupWindow 需要指定背景，否则点击外部和返回键都不能 dismiss，setOutsideTouchable(true) 无效，
popupWindow.setBackgroundDrawable(new BitmapDrawable());
对比 6.0 之前的版本，发现原因是 preparePopup() 的改动导致：
//6.0 版本下的源码
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;
}
//6.0 之前的版本
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.");
}
// The old decor view may be transitioning out. Make sure it finishes
// and cleans up before we try to create another one.
if (mDecorView != null) {
mDecorView.cancelTransitions();
}
// 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;
}
mDecorView = createDecorView(mBackgroundView);
// The background owner should be elevated so that it casts a shadow.
mBackgroundView.setElevation(mElevation);
// We may wrap that in another view, so we'll need to manually specify
// the surface insets.
p.setSurfaceInsets(mBackgroundView, true /*manual*/, true /*preservePrevious*/);
mPopupViewInitialLayoutDirectionInherited =
(mContentView.getRawLayoutDirection() == View.LAYOUT_DIRECTION_INHERIT);
}
两者最大区别在于 6.0 以前不管有没有设置 background 都会创建一个 PopupDecorView，而这个 PopupDecorView 正是负责处理 PopupWindow 的点击事件。
6.0 下 mBackground == null 则不会创建 PopupDecorView，导致不能响应到点击事件。
7.0 下 PopupWindow 跑到了界面的顶部
7.0 下 PopupWindow.update( ) 方法会导致 PopupWindow的位置出现在界面顶部：
public void update() {
if (!isShowing() || mContentView == null) {
return;
}
......
final int newGravity = computeGravity();
if (newGravity != p.gravity) {
p.gravity = newGravity;
update = true;
}
......
}
原因在于 update() 方法中调用的 computeGravity():
private int computeGravity() {
int gravity = Gravity.START | Gravity.TOP;
if (mClipToScreen || mClippingEnabled) {
gravity |= Gravity.DISPLAY_CLIP_VERTICAL;
}
return gravity;
}
