我试图在一个片段中创建一个ImageView,它将引用我在XML中为片段创建的ImageView元素。但是,findViewById方法仅在扩展Activity类时有效。我是否也可以在Fragment中使用它?

public class TestClass extends Fragment {
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        ImageView imageView = (ImageView)findViewById(R.id.my_image);
        return inflater.inflate(R.layout.testclassfragment, container, false);
    }
}

findViewById方法有一个错误,说明该方法未定义。


当前回答

你需要膨胀Fragment的视图,并在它返回的视图上调用findViewById()。

public View onCreateView(LayoutInflater inflater, 
                         ViewGroup container, 
                         Bundle savedInstanceState) {
     View view = inflater.inflate(R.layout.testclassfragment, container, false);
     ImageView imageView = (ImageView) view.findViewById(R.id.my_image);
     return view;
}

其他回答

布局增压机进入图片这里。布局扩展器是一个使我们能够在java代码中使用XML视图的类。因此,您可以使用以下代码在变量v中扩展根xml视图。然后使用v,你可以找到根视图v的子视图。

public class TestClass extends Fragment {
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.testclassfragment, container, false);
    ImageView imageView = (ImageView)v.findViewById(R.id.my_image);
    return v;
    }
}

试试这个,对我有用

public class TestClass extends Fragment {
    private ImageView imageView;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.testclassfragment, container, false);
        findViews(view);
        return view;
    }

    private void findViews(View view) {
        imageView = (ImageView) view.findViewById(R.id.my_image);
    }
}
ImageView imageView;
public View onCreateView(LayoutInflater inflater, 
                     ViewGroup container, 
                     Bundle savedInstanceState) {
 View view = inflater.inflate(R.layout.testclassfragment, container, false);
 imageView = view.findViewById(R.id.my_image);
 return view;

}

注意:

从API级别26开始,您也不需要专门强制转换findViewById的结果,因为它对其返回类型使用推断。

现在你可以简单地做,

public View onCreateView(LayoutInflater inflater, 
                         ViewGroup container, 
                         Bundle savedInstanceState) {
     View view = inflater.inflate(R.layout.testclassfragment, container, false);
     ImageView imageView =  view.findViewById(R.id.my_image); //without casting the return type
     return view;
}

非常简单的方法:

 @Nullable
        @Override
        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            View fragmentView = inflater.inflate(R.layout.testclassfragment, container, false);
            ImageView imageView = (ImageView)fragmentView.findViewById(R.id.my_image);
            return fragmentView;
       }