考慮mainActivity的代碼中,我們使用的AsyncTask這樣呼叫的AsyncTask從不同的活動
new SearchTask(SearchPage.this).execute("1", query);
得到結果後,並顯示它們在列表中的用戶,用戶點擊一個項目,並遷移到另一個活動。在第二個活動,我們必須顯示所選項目的全部數據,並檢索互聯網數據,我們必須使用這些代碼:
new SearchTask(DetailsPage.this).execute("2", id);
new SearchTask(DetailsPage.this).execute("3", id);
但問題是,這些線路將不起作用:/,甚至應用程序崩潰或不顯示數據.... 我該如何解決這個問題?
UPDATE 這是我的日誌貓 導致這些代碼行不會產生任何數據備份,應用程序崩潰拋出NPE
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.shahroozevsky.myfirstapp/com.shahroozevsky.myfirstapp.DetailsPage}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.shahroozevsky.myfirstapp.DetailsPage.onCreate(DetailsPage.java:51)
at android.app.Activity.performCreate(Activity.java:5104)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
[logcat會告訴你什麼原因你的應用程序已停止](http://stackoverflow.com/questions/23353173/uncomfort-myapp-has-stopped-how-can-i-solve-this)。請用它編輯你的問題。 –
發佈您的'DetailsPage'類代碼 – rafsanahmad007