java - 为什么在将数据从一个片段发送到另一个片段时出现错误

Question

已经阅读了这些问题和许多其他问题，但没有人能简单解释

使用 bundle 将数据从一个片段发送到另一个片段。我试过这个。它不工作 为什么我不能让我的应用程序成功地将数据从一个片段发送到另一个片段？

嗨，我对编程和 stackoverflow 很陌生

我创建了一个 MainActivity，其中有两个片段

<fragment
    android:id="@+id/fragment1"
    android:name="fragments.first"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1">

</fragment>

<fragment
    android:id="@+id/fragment2"
    android:name="fragments.second"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1">
</fragment>

在我的第一个片段中，当我单击按钮时，我想将数据发送到第二个框架

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        String question = questions1.getText().toString();
        String ans1 = answer1.getText().toString();
        String ans2 = answer2.getText().toString();
        String ans3 = answer3.getText().toString();
        String ans4 = answer3.getText().toString();
        Map<String,String> hashMap = new HashMap<String,String>();
        hashMap.put("Answer 1",ans1);
        hashMap.put("Answer 2",ans2);
        hashMap.put("Answer 3",ans3);
        hashMap.put("Answer 4",ans4);

        Bundle bundle = new Bundle();
        bundle.putString("Question1",question);
        bundle.putString("Answer 1",ans1);
        bundle.putString("Answer 2",ans2);
        bundle.putString("Answer 3",ans3);
        bundle.putString("Answer 4",ans4);

        String correctAnswer= CorrectAnswer;

        second mfragment=new second();
        mfragment.setArguments(bundle);

        getActivity().getSupportFragmentManager().beginTransaction().replace(R.id.fragment1, mfragment).commit();
        Toast.makeText(getActivity(),question,Toast.LENGTH_SHORT).show();

    }
});

在第二个片段中

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Bundle bundle = getArguments();// i am receiving error here. what should i do?
    String question = bundle.getString("Question1");


}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View root = inflater.inflate(R.layout.fragment_second, container, false);

    return root;


}

但收到错误

2021-05-04 03:19:28.676 23166-23166/com.example.mcqapp E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.mcqapp, PID: 23166
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mcqapp/com.example.mcqapp.activities.AdminPost}: android.view.InflateException: Binary XML file line #25 in com.example.mcqapp:layout/activity_admin_post: Binary XML file line #25 in com.example.mcqapp:layout/activity_admin_post: Error inflating class fragment
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3556)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3703)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2216)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:237)
        at android.app.ActivityThread.main(ActivityThread.java:7948)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1075)
     Caused by: android.view.InflateException: Binary XML file line #25 in com.example.mcqapp:layout/activity_admin_post: Binary XML file line #25 in com.example.mcqapp:layout/activity_admin_post: Error inflating class fragment
     Caused by: android.view.InflateException: Binary XML file line #25 in com.example.mcqapp:layout/activity_admin_post: Error inflating class fragment
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.os.Bundle.getString(java.lang.String)' on a null object reference
        at fragments.second.onCreate(second.java:20)
        at androidx.fragment.app.Fragment.performCreate(Fragment.java:2586)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:838)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1133)
        at androidx.fragment.app.FragmentManagerImpl.addFragment(FragmentManagerImpl.java:1393)
        at androidx.fragment.app.FragmentManagerImpl.onCreateView(FragmentManagerImpl.java:3205)
        at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:134)
        at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:357)
        at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:336)
        at android.view.LayoutInflater.tryCreateView(LayoutInflater.java:1069)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:997)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:961)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1123)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1126)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:682)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:481)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
        at com.example.mcqapp.activities.AdminPost.onCreate(AdminPost.java:24)
        at android.app.Activity.performCreate(Activity.java:7955)
        at android.app.Activity.performCreate(Activity.java:7944)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3531)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3703)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
2021-05-04 03:19:28.677 23166-23166/com.example.mcqapp E/AndroidRuntime:     at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2216)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:237)
        at android.app.ActivityThread.main(ActivityThread.java:7948)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1075)

标签： javaandroidbundle

Answer 1

我解决了。我从活动中删除了第二个片段，并将第一个片段转换为帧布局，因为数据重叠并以编程方式添加了第一个片段

<FrameLayout
    android:id="@+id/fragment1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

</FrameLayout>

getSupportFragmentManager().beginTransaction().add(R.id.fragment1,new first()).commit();

并像这样在 createView 上编辑了第二个片段：

Bundle bundle = getArguments();
if (bundle != null){

    String question = bundle.getString("Question1");
    String Question  = question.toString();
    textView.setText(Question);

我阅读了很多 StackOverflow 问题并使用了框架布局，因为发生了重叠，对吗？