Question

我有以下代码

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    if(intent != null) {
        Log.i("INTENT", intent.getAction().toString());
    }
    return START_STICKY;
}

但它总是在线返回NullPointerException：

Log.i("INTENT", intent.getAction().toString());

为什么呢？如果“intent”变量不为null，我正在检查上面。如果是这种情况，请执行以下代码。但我仍然有nullpointerexception。

服务是从以下活动开始的：

startService(new Intent(this, MainService.class));

我做错了什么？

Answer 1

您收到NullPointerException，因为intent.getAction()似乎返回null。

您应该将支票延伸至：

if(intent != null && intent.getAction() != null) {

如果您想为意图添加动作，则需要致电setAction()：

Intent i = new Intent(this, MainService.class);
i.setAction("foo");
startService(i);

Answer 2

我得到了类似的堆栈，添加了支票

intent.getAction() != null

它有效。

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.example.languoguang.welcomeapp, PID: 17676
              java.lang.RuntimeException: Unable to start service com.example.languoguang.welcomeapp.CountService@f6049d4 with Intent { cmp=com.example.languoguang.welcomeapp/.CountService }: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String.toString()' on a null object reference
                  at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3698)
                  at android.app.ActivityThread.access$1500(ActivityThread.java:198)
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1668)
                  at android.os.Handler.dispatchMessage(Handler.java:106)
                  at android.os.Looper.loop(Looper.java:164)
                  at android.app.ActivityThread.main(ActivityThread.java:6649)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)
               Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String.toString()' on a null object reference
                  at com.example.languoguang.welcomeapp.CountService.onStartCommand(CountService.java:24)
                  at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3679)
                  at android.app.ActivityThread.access$1500(ActivityThread.java:198) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1668) 
                  at android.os.Handler.dispatchMessage(Handler.java:106) 
                  at android.os.Looper.loop(Looper.java:164) 
                  at android.app.ActivityThread.main(ActivityThread.java:6649) 
                  at java.lang.reflect.Method.invoke(Native Method) 
                  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)

I /处理：发送信号。 PID：17676 SIG：9

Intent始终为null onStartCommand

2 个答案: