Question

当我尝试在我的Fragment类上创建一个intent来移动我的活动页面 HomeScreenActivity ，

Intent intent = new Intent(getActivity(), HomeScreenActivity.class);
startActivity(intent);
getActivity().finish();

我在Fabric上收到关注错误Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference。我在 Galaxy S7 Edge 上使用os版本 7 时出现此错误。执行第Intent intent = new Intent(getActivity(), HomeScreenActivity.class);行时（LoginFragment.java上的行号 338 ）

以下是我在Fabric上获得的完整日志，

Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
       at android.content.ComponentName.<init>(ComponentName.java:128)
       at android.content.Intent.<init>(Intent.java:5359)
       at com.example.android.fragments.LoginFragment.handleValidateEmployeeResponse(LoginFragment.java:338)
       at com.example.android.fragments.LoginFragment.access$100(LoginFragment.java:53)
       at com.example.android.fragments.LoginFragment$3.onResponse(LoginFragment.java:249)
       at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:68)
       at android.os.Handler.handleCallback(Handler.java:751)
       at android.os.Handler.dispatchMessage(Handler.java:95)
       at android.os.Looper.loop(Looper.java:154)
       at android.app.ActivityThread.main(ActivityThread.java:6692)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)

Answer 1

我做了类似的事，

点击 Activity 参考

MainActivity activity = (MainActivity) getActivity();

然后将对象传递到您想要的位置，例如

Intent intent = new Intent(activity , HomeScreenActivity.class);
activity.finish();

Answer 2

尝试使用attach方法

public Activity mActivity;

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    this.mActivity = activity;
}

并像这样使用

Intent intent = new Intent(mActivity, HomeScreenActivity.class);
startActivity(intent);
mActivity.finish();

尝试在getActivity（）上调用虚方法＆＃39; java.lang.String android.content.Context.getPackageName（）

2 个答案: