2023年7月15日发(作者：)

AndroidPopupWindow的使⽤和分析

Android PopupWindow的使⽤和分析

PopupWindow使⽤ PopupWindow这个类⽤来实现⼀个弹出框，可以使⽤任意布局的View作为其内容，这个弹出框是悬浮在当前activity之上的。

PopupWindow使⽤Demo　　这个类的使⽤，不再过多解释，直接上代码吧。　　⽐如弹出框的布局： 弹出框布局

　　Activity的布局中只有⼀个按钮，按下后会弹出框，Activity代码如下：package opupwindow;import ;import ty;import t;import ;import Inflater;import Event;import ;import kListener;import hListener;import Params;import ;import indow;import ;public class MainActivity extends Activity { private Context mContext = null; @Override protected void onCreate(Bundle savedInstanceState) { te(savedInstanceState); setContentView(ty_main); mContext = this; Button button = (Button) findViewById(); lickListener(new kListener() { @Override public void onClick(View view) { showPopupWindow(view); } }); } private void showPopupWindow(View view) { // ⼀个⾃定义的布局，作为显⽰的内容 View contentView = (mContext).inflate( _window, null); // 设置按钮的点击事件 Button button = (Button) ewById(1); lickListener(new OnClickListener() { @Override public void onClick(View v) { xt(mContext, "button is pressed", _SHORT).show(); } }); final PopupWindow popupWindow = new PopupWindow(contentView, _CONTENT, _CONTENT, true); chable(true); chInterceptor(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { Log.i("mengdd", "onTouch : "); return false; // 这⾥如果返回true的话，touch事件将被拦截 // 拦截后 PopupWindow的onTouchEvent不被调⽤，这样点击外部区域⽆法dismiss } }); // 如果不设置PopupWindow的背景，⽆论是点击外部区域还是Back键都⽆法dismiss弹框 // 我觉得这⾥是API的⼀个bug kgroundDrawable(getResources().getDrawable( menu_bg_downward)); // 设置好参数之后再show DropDown(view); }}

　　弹出框的布局中有⼀个TextView和⼀个Button，Button点击后显⽰Toast，如图：

　　第⼀次实现的时候遇到了问题，就是弹出框不会在按下Back键的时候消失，点击弹框外区域也没有正常消失，搜索了⼀下，都说只要设置背景就好了。　　然后我就找了个图⽚，果然弹框能正常dismiss了(见注释)。

PopupWindow源码分析　　为了解答⼀下上⾯的问题，看看源码(最新API Level 19，Android 4.4.2)。1.显⽰⽅法　　显⽰提供了两种形式：　　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)　　最后⼀种带Gravity参数的⽅法是API 19新引⼊的。

　　弹出的⽅法中⾸先需要preparePopup()，最后再invokePopup()。　　prepare的⽅法中可以看到有⽆背景的分别： /** *

Prepare the popup by embedding in into a new ViewGroup if the * background drawable is not null. If embedding is required, the layout * parameters' height is mnodified to take into account the background's * padding.

* * @param p the layout parameters of the popup's content view */ private void preparePopup(Params 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 Params layoutParams = outParams(); int height = _PARENT; if (layoutParams != null && == _CONTENT) { height = _CONTENT; } // when a background is available, we embed the content view // within another view that owns the background drawable PopupViewContainer popupViewContainer = new PopupViewContainer(mContext); Params listParams = new Params( _PARENT, height ); kgroundDrawable(mBackground); w(mContentView, listParams); mPopupView = popupViewContainer; } else { mPopupView = mContentView; } mPopupViewInitialLayoutDirectionInherited = (LayoutDirection() == _DIRECTION_INHERIT); mPopupWidth = ; mPopupHeight = ; }

2.背景是否为空对Touch事件的影响　　如果有背景，则会在contentView外⾯包⼀层PopupViewContainer之后作为mPopupView，如果没有背景，则直接⽤contentView作为mPopupView。　　⽽这个PopupViewContainer是⼀个内部私有类，它继承了FrameLayout，在其中重写了Key和Touch事件的分发处理： @Override public boolean dispatchKeyEvent(KeyEvent event) { if (Code() == E_BACK) { if (getKeyDispatcherState() == null) { return chKeyEvent(event); } if (ion() == _DOWN && eatCount() == 0) { cherState state = getKeyDispatcherState(); if (state != null) { racking(event, this); } return true; } else if (ion() == _UP) { cherState state = getKeyDispatcherState(); if (state != null && king(event) && !eled()) { dismiss(); return true; } } return chKeyEvent(event); } else { return chKeyEvent(event); } } @Override public boolean dispatchTouchEvent(MotionEvent ev) { if (mTouchInterceptor != null && h(this, ev)) { return true; } return chTouchEvent(ev); } @Override public boolean onTouchEvent(MotionEvent event) { final int x = (int) (); final int y = (int) ();

if ((ion() == _DOWN) && ((x < 0) || (x >= getWidth()) || (y < 0) || (y >= getHeight()))) { dismiss(); return true; } else if (ion() == _OUTSIDE) { dismiss(); return true; } else { return hEvent(event); } }　　由于PopupView本⾝并没有重写Key和Touch事件的处理，所以如果没有包这个外层容器类，点击Back键或者外部区域是不会导致弹框消失的。

补充Case: 弹窗不消失,但是事件向下传递　　如上所述:　　设置了PopupWindow的background,点击Back键或者点击弹窗的外部区域,弹窗就会dismiss.　　相反,如果不设置PopupWindow的background,那么点击back键和点击弹窗的外部区域,弹窗是不会消失的.

　　那么,如果我想要⼀个效果,点击外部区域,弹窗不消失,但是点击事件会向下⾯的activity传递,⽐如下⾯是⼀个WebView,我想点击⾥⾯的链接等.

　　研究了半天，说是要给Window设置⼀个Flag，　　_NOT_TOUCH_MODAL　　　　看了源码，这个Flag的设置与否是由⼀个叫mNotTouchModal的字段控制，但是设置该字段的set⽅法被标记为@hide。　　所以要通过反射的⽅法调⽤： 　　/** * Set whether this window is touch modal or if outside touches will be sent * to * other windows behind it. * */ public static void setPopupWindowTouchModal(PopupWindow popupWindow, boolean touchModal) { if (null == popupWindow) { return; } Method method; try { method = laredMethod("setTouchModal", ); essible(true); (popupWindow, touchModal); } catch (Exception e) { tackTrace(); } }　　然后在程序中：　　upWindowTouchModal(popupWindow, false);　　该popupWindow外部的事件就可以传递给下⾯的Activity了。

Reference

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