Android異常一、非同步任務導致的視窗控制代碼泄漏問題

先貼異常：

05-05 10:36:41.009: E/WindowManager(4243): Activity com.tao.MyActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@405241b0 that was originally added here05-05 10:36:41.009: E/WindowManager(4243): android.view.WindowLeaked: Activity com.tao.MyActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@405241b0 that was originally added here05-05 10:36:41.009: E/WindowManager(4243):     at android.view.ViewRoot.<init>(ViewRoot.java:265)05-05 10:36:41.009: E/WindowManager(4243):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)05-05 10:36:41.009: E/WindowManager(4243):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)05-05 10:36:41.009: E/WindowManager(4243):     at android.view.Window$LocalWindowManager.addView(Window.java:424)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.Dialog.show(Dialog.java:241)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.ProgressDialog.show(ProgressDialog.java:107)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.ProgressDialog.show(ProgressDialog.java:95)05-05 10:36:41.009: E/WindowManager(4243):     at com.unifable.activity.MySecretaryActivity.onCreate(MySecretaryActivity.java:50)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)05-05 10:36:41.009: E/WindowManager(4243):     at android.os.Handler.dispatchMessage(Handler.java:99)05-05 10:36:41.009: E/WindowManager(4243):     at android.os.Looper.loop(Looper.java:130)05-05 10:36:41.009: E/WindowManager(4243):     at android.app.ActivityThread.main(ActivityThread.java:3683)05-05 10:36:41.009: E/WindowManager(4243):     at java.lang.reflect.Method.invokeNative(Native Method)05-05 10:36:41.009: E/WindowManager(4243):     at java.lang.reflect.Method.invoke(Method.java:507)05-05 10:36:41.009: E/WindowManager(4243):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:906)05-05 10:36:41.009: E/WindowManager(4243):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:664)05-05 10:36:41.009: E/WindowManager(4243):     at dalvik.system.NativeStart.main(Native Method)這是在做一個項目的時候遇到的問題：在第一介面的Activity中，為了避免程式假死帶來的糟糕的使用者體驗，採用非同步任務AsyncTask來訪問網路，與伺服器進行互動，並用ProgressDialog控制項來告知使用者當前的程式進度。在網上查了下別人的資料。才終於明白了原因。上面的異常的意思是：存在視窗控制代碼的泄漏，即未能及時的銷毀某個PhoneWindow.為什麼會出現這樣的情況，因為，在非同步任務裡面已經發生了嚴重的錯誤，而導致Activity的強制關閉。Activity強制關閉了，可是ProgressDialog並沒有dismiss()掉，所以出現了視窗控制代碼的泄漏。 而且，更嚴重的是，這個異常會覆蓋我們在AsyncTask裡面發生的真正異常，這往往會誤導我們，把過多的精力放在尋找所謂的記憶體流失的上面，而不是尋找AsyncTask中出現的錯誤。參照別人的解決方案：本解決方案並不能真正的解決問題，但是在一定程度上可以將真正導致錯誤的異常資訊顯露出來。即重寫Activity的onDestory()方法，在該方法中調用dismiss()來解除對ProgressDialog的引用。