考虑mainActivity的代码中,我们使用的AsyncTask这样呼叫的AsyncTask从不同的活动
new SearchTask(SearchPage.this).execute("1", query);
得到结果后,并显示它们在列表中的用户,用户点击一个项目,并迁移到另一个活动。在第二个活动,我们必须显示所选项目的全部数据,并检索互联网数据,我们必须使用这些代码:
new SearchTask(DetailsPage.this).execute("2", id);
new SearchTask(DetailsPage.this).execute("3", id);
但问题是,这些线路将不起作用:/,甚至应用程序崩溃或不显示数据.... 我该如何解决这个问题?
UPDATE 这是我的日志猫 导致这些代码行不会产生任何数据备份,应用程序崩溃抛出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会告诉你什么原因你的应用程序已停止](http://stackoverflow.com/questions/23353173/uncomfort-myapp-has-stopped-how-can-i-solve-this)。请用它编辑你的问题。 –
发布您的'DetailsPage'类代码 – rafsanahmad007