尝试在getActivity()上调用虚拟方法'java.lang.String android.content.Context.getPackageName() [英] Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName() on getActivity()

问题描述

当我尝试在Fragment类上创建意图以移动我的活动页面 HomeScreenActivity 时，

When I try to create an intent on my Fragment class to move my activity page HomeScreenActivity using,

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

我遇到以下错误致命异常:java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法'java.lang.String android.content.Context.getPackageName()'在 Fabric 上.我在操作系统为 7 的 Galaxy S7 Edge 上收到此错误.当执行行 Intent intent = new Intent(getActivity()，HomeScreenActivity.class); (LoginFragment.java上的行号 338 )

I'm getting following error Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference on Fabric. I got this error on Galaxy S7 Edge with os version 7. While executing line Intent intent = new Intent(getActivity(), HomeScreenActivity.class); (Line number 338 on LoginFragment.java)

这是我从 Fabric ，

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)

推荐答案

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();

这篇关于尝试在getActivity()上调用虚拟方法'java.lang.String android.content.Context.getPackageName()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！