Question

我正在尝试从点击View时添加到View的孩子Button中获取项目。但是，当我尝试获取已创建的子项View中的元素时，它会返回null。

java.lang.NullPointerException: Attempt to invoke virtual method'android.view.View android.view.View.findViewById(int)' on a null object reference

<Button
    android:id="@+id/buttonAddPerson"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Add Another Person"
    android:layout_alignParentBottom="true"
    android:layout_alignParentStart="true" />

<ScrollView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/scrollView" >

    <LinearLayout
        android:id="@+id/linearLayoutPeople"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></LinearLayout>
</ScrollView>

按钮点击添加的布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dp"
android:layout_marginTop="5dp"
android:id="@+id/linearLayoutPerson">

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/editTextFirstName"
    android:hint="First Name"
    android:inputType="textPersonName"
    />

 public View onCreateView(final LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

     view = inflater.inflate(R.layout.fragment_create_occupants, container, false);
    Button addPersonButton = (Button)view.findViewById(R.id.buttonAddPerson);


      root = (LinearLayout)view.findViewById(R.id.linearLayoutPeople);

    View child = inflater.inflate(R.layout.list_person_layout,null);
    root.addView(child);

   addPersonButton.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {

         //  createPersonAdapter.notifyDataSetChanged();
           View child = inflater.inflate(R.layout.list_person_layout,null);
           root.addView(child);

       }
   });

    return view;
}

当我尝试获取信息时：

public void  SaveCall(){

   EditText firstName;

    for (int i =1;i<=root.getChildCount();i++){         
        View child = root.getChildAt(i);
//null at this line            
firstName = (EditText) child.findViewById(R.id.editTextFirstName);

    }
}

Answer 1

你有没有试过这个

将此i<=root.getChildCount();更改为i<root.getChildCount();并从i=0;

开始

 for (int i =0;i<root.getChildCount();i++){         
        View child = root.getChildAt(i);
//null at this line            
firstName = (EditText) child.findViewById(R.id.editTextFirstName);

    }

Answer 2

在动态创建视图时，可以将每个EditText添加到arrayList。然后通过该列表进行循环。

用于子视图的findViewById

2 个答案: