当我的应用程序关闭时(即用户从应用程序切换菜单中删除),它会在onMessageReceived()
中崩溃。
这是onMessageReceived()
:
@Override
public void onMessageReceived(String from, Bundle data) {
String message = data.getString("message");
from = data.getString("sender");
File notificationsFile = Constants.getNotificationsFlagFile();
...
}
它在最后一行崩溃,给出null pointer exception
:
08-13 21:15:25.535 23201-23216 / com.example.myapp E / AndroidRuntime: 致命异常:AsyncTask#1 java.lang.ExceptionInInitializerError 在com.example.myapp.chatGCM.MyGcmListenerService.onMessageReceived(MyGcmListenerService.java:52) 在com.google.android.gms.gcm.GcmListenerService.zzs(未知来源) 在com.google.android.gms.gcm.GcmListenerService.zzk(未知来源) 在com.google.android.gms.gcm.GcmListenerService.zza(未知来源) 在com.google.android.gms.gcm.GcmListenerService $ 1.run(未知来源) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) at java.util.concurrent.ThreadPoolExecutor $ Worker.run(ThreadPoolExecutor.java:573) at java.lang.Thread.run(Thread.java:841)引起:java.lang.NullPointerException at helpers.Constants。(Constants.java:54) 在com.example.myapp.chatGCM.MyGcmListenerService.onMessageReceived(MyGcmListenerService.java:52) 在com.google.android.gms.gcm.GcmListenerService.zzs(未知来源) 在com.google.android.gms.gcm.GcmListenerService.zzk(未知来源) 在com.google.android.gms.gcm.GcmListenerService.zza(未知来源) 在com.google.android.gms.gcm.GcmListenerService $ 1.run(未知来源) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) at java.util.concurrent.ThreadPoolExecutor $ Worker.run(ThreadPoolExecutor.java:573) 在java.lang.Thread.run(Thread.java:841)
这里是getNotificationsFlagFile()
:
public static File getNotificationsFlagFile()
{
return new File(MainApplication.getAppContext().getFilesDir(), "notifications_"+getSession());
}
最后:
private static String getSession()
{
File file = new File(MainApplication.getAppContext().getFilesDir(), "session");
int length = (int) file.length();
byte[] bytes = new byte[length];
FileInputStream in = null;
try {
in = new FileInputStream(file);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
try {
try {
in.read(bytes);
} catch (IOException e) {
e.printStackTrace();
}
} finally {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return (new String(bytes));
}
我所使用的只是静态变量和函数。为什么会这样?