我正在尝试将Twitter集成到我的应用程序中。我想要一个弹出窗口，用户可以在其中输入他的推文。
现在，当用户已经登录时，应用程序正常运行，但如果用户需要先登录，那么应用程序将打开登录的Twitter Web界面。从那里，我无法回到我的应用程序并显示“输入 - 推文”弹出窗口。
请帮忙。
Exception:
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): java.lang.RuntimeException: Unable to resume activity {mad.android.MyTwitterApp/mad.android.MyTwitterApp.AndroidTwitterSample}: java.lang.NullPointerException
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3128)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3143)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2059)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at android.os.Handler.dispatchMessage(Handler.java:99)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at android.os.Looper.loop(Looper.java:123)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at android.app.ActivityThread.main(ActivityThread.java:4627)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at java.lang.reflect.Method.invokeNative(Native Method)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at java.lang.reflect.Method.invoke(Method.java:521)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:871)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629)
04-02 00:16:53.511: ERROR/AndroidRuntime(5992): at dalvik.system.NativeStart.main(Native Method)