內存泄露

雖然是小問題一個，但也困擾了我一段時間，現在記下來，給自己做個備忘，也可以給其他人一個參考 

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01-08 01:49:27.874: ERROR/WindowManager(473): Activity com.photos.MainActivity has leaked window android.widget.ImageButton@43e40d10 that was originally added here
01-08 01:49:27.874: ERROR/WindowManager(473): android.view.WindowLeaked: Activity com.photos.MainActivity has leaked window android.widget.ImageButton@43e40d10 that was originally added here
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.view.ViewRoot.<init>(ViewRoot.java:247)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.view.Window$LocalWindowManager.addView(Window.java:424)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.widget.PopupWindow.invokePopup(PopupWindow.java:828)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.widget.PopupWindow.showAtLocation(PopupWindow.java:688)
01-08 01:49:27.874: ERROR/WindowManager(473):     at com.photos.MainActivity.showCommonPopup(MainActivity.java:256)
01-08 01:49:27.874: ERROR/WindowManager(473):     at com.photos.MainActivity.access$3(MainActivity.java:255)
01-08 01:49:27.874: ERROR/WindowManager(473):     at com.photos.MainActivity$2.handleMessage(MainActivity.java:88)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.os.Looper.loop(Looper.java:123)
01-08 01:49:27.874: ERROR/WindowManager(473):     at android.app.ActivityThread.main(ActivityThread.java:4627)
01-08 01:49:27.874: ERROR/WindowManager(473):     at java.lang.reflect.Method.invokeNative(Native Method)
01-08 01:49:27.874: ERROR/WindowManager(473):     at java.lang.reflect.Method.invoke(Method.java:521)
01-08 01:49:27.874: ERROR/WindowManager(473):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-08 01:49:27.874: ERROR/WindowManager(473):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-08 01:49:27.874: ERROR/WindowManager(473):     at dalvik.system.NativeStart.main(Native Method)

按字面瞭解，Window Leaked大概就是說一個窗體泄漏了，也就是我們常說的內存泄漏，爲什麼窗體會泄漏呢？ 

產生原因： 
我們知道Android的每一個Activity都有個WindowManager窗體管理器，同樣，構建在某個Activity之上的對話框、PopupWindow也有相應的WindowManager窗體管理器。因爲對話框、PopupWindown不能脫離Activity而單獨存在着，所以當某個Dialog或者某個PopupWindow正在顯示的時候我們去finish()了承載該Dialog(或PopupWindow)的Activity時，就會拋Window Leaked異常了，因爲這個Dialog(或PopupWindow)的WindowManager已經沒有誰可以附屬了，所以它的窗體管理器已經泄漏了。 

android.view.WindowLeaked一般會發生在Activity 與Dialog的顯示。 

       Activity 中create 一個Dialog，若你先關閉Dialog再關閉Activity就是正常的，若你先關閉Activity再關閉Dialog就會報錯這個android.view.WindowLeaked錯誤了。 
       分析這個原因是：Dialog是基於Activity而創建的：new ProgressDialog(this)；this 就是Activity。 Activtity先finish,那Dialog就沒得依附了，所以就會報android.view.WindowLeaked。 




解決方法： 
關閉(finish)某個Activity前，要確保附屬在上面的Dialog或PopupWindow已經關閉(dismiss)了。 
   也可在OnCreateDialog()中創建Dialog，讓系統去管理對話框