片段中的findViewById

Question

我试图在片段中创建一个ImageView,它将引用我在片段的XML中创建的ImageView元素.但是,该findViewById方法仅在扩展Activity类时才有效.无论如何,我还可以在片段中使用它吗？

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);
    }
}

该findViewById方法有一个错误,表明该方法是未定义的.

Answer 1

使用getView()或View参数来实现该 onViewCreated方法.它返回片段的根视图(onCreateView()方法返回的视图).有了它,你可以打电话findViewById().

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    ImageView imageView = (ImageView) getView().findViewById(R.id.foo);
    // or  (ImageView) view.findViewById(R.id.foo); 

由于getView()只有在工作onCreateView(),你不能用它里面onCreate()或onCreateView()方法的片段.

Answer 2

您需要膨胀片段的观点,并呼吁findViewById()在View它的回报.

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;
}

Answer 3

在内部Fragment类中,您将获得onViewCreated()覆盖方法,您应始终初始化视图,因为在此方法中您可以使用视图对象来查找您的视图,如:

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    view.findViewById(R.id.yourId).setOnClickListener(this);

    // or
    getActivity().findViewById(R.id.yourId).setOnClickListener(this);
}

永远记住,在Fragment的情况下,onViewCreated()如果返回null或super.onCreateView()从onCreateView()方法返回,则不会自动调用该方法.默认情况下将在案件被称为ListFragment是ListFragment返回FrameLayout默认.

注意:通过使用getView()一次onCreateView()成功执行,您可以在类中的任何位置获取片段视图.即

getView().findViewById("your view id");

Answer 4

我意识到这是一个古老的问题,但是流行的答案还有待改进.

问题不明确是什么imageView- 我们将其作为视图传回,还是仅仅为以后保存参考？

无论哪种方式,如果ImageView来自膨胀的布局,正确的方法是:

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;
    }
}

Answer 5

首先获取片段视图,然后从此视图中获取ImageView.

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;
}

Answer 6

您也可以在onActivityCreated方法中执行此操作.

public void onActivityCreated(Bundle savedInstanceState) { 
      super.onActivityCreated(savedInstanceState);
}

就像他们在这里一样:http ://developer.android.com/reference/android/app/Fragment.html (在API级别28中弃用)

getView().findViewById(R.id.foo);

和

getActivity().findViewById(R.id.foo);

是可能的.

Answer 7

getView() 将给出根视图

View v = getView().findViewByID(R.id.x); 

Answer 8

您可以覆盖在所有视图被夸大后立即调用的onViewCreated().这是填写Fragment成员View变量的正确位置.这是一个例子:

class GalleryFragment extends Fragment {
    private Gallery gallery;

    (...)

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        gallery = (Gallery) view.findViewById(R.id.gallery);
        gallery.setAdapter(adapter);
        super.onViewCreated(view, savedInstanceState);
    }
}

Answer 9

getView()方法不适用于OnCreate和类似方法之外的片段.

您有两种方法,将视图传递给oncreate上的函数(这意味着您只能在创建视图时运行函数)或将视图设置为变量:

private View rootView;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
    Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_contatos, container, false);
}

public void doSomething () {
    ImageView thumbnail = (ImageView) rootView.findViewById(R.id.someId);
}

Answer 10

1)首先膨胀Fragment的布局,然后你可以使用findviewbyId.

View view = inflater.inflate(R.layout.testclassfragment, container, false);
             ImageView imageView = (ImageView) view.findViewById(R.id.my_image);
             return view;

Answer 11

EditText name = (EditText) getView().findViewById(R.id.editText1);
EditText add = (EditText) getView().findViewById(R.id.editText2);  

Answer 12

同意呼吁findViewById()观点.

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;
}

Answer 13

使用

imagebutton = (ImageButton) getActivity().findViewById(R.id.imagebutton1);

imageview = (ImageView) getActivity().findViewById(R.id.imageview1);

它会工作

Answer 14

注意 :

从API级别26开始,您也不需要专门转换findViewById的结果,因为它使用其返回类型的推断.

所以现在你可以做到,

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;
}

Answer 15

使用getView()返回片段的视图,然后您可以调用findViewById()访问片段视图中的任何视图元素.

Answer 16

根据API级别11的文档

参考,在Back Stack http://developer.android.com/reference/android/app/Fragment.html中

短代码

/**
 * The Fragment's UI is just a simple text view showing its
 * instance number.
 */
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.hello_world, container, false);
    View tv = v.findViewById(R.id.text);
    ((TextView)tv).setText("Fragment #" + mNum);
    tv.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.gallery_thumb));
    return v;
}

Answer 17

在Fragment类内部，您将获得onViewCreated()重写方法，在该方法中应始终初始化视图，因为在此方法中，您将获得view对象，通过该对象可以找到视图，例如：

class MyFragment extends Fragment {
    private ImageView imageView;

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

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) 
        super.onViewCreated(view, savedInstanceState);

        //initialize your view here for use view.findViewById("your view id")
        imageView = (ImageView) view.findViewById(R.id.my_image);
    }
}

Answer 18

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);
    }
}

Answer 19

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;
}

Answer 20

实现此目的的最佳方法如下:

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

rootView = inflater.inflate(R.layout.testclassfragment, container, false);
        ImageView imageView = (ImageView) rootView.findViewById(R.id.my_image);
        return rootView
}

通过这种方式,rootView可以用于xml布局中定义的每个控件,并且代码更加清晰.

希望这可以帮助 :)

Answer 21

1)声明您的布局文件.

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

2)然后,获取您的视图的ID

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    TextView nameView = (TextView) view.findViewById(R.id.textview1);
}

Answer 22

尝试这个：

View v = inflater.inflate(R.layout.testclassfragment, container, false);
ImageView img = (ImageView) v.findViewById(R.id.my_image);

return v;

Answer 23

尝试

private View myFragmentView;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
{
myFragmentView = inflater.inflate(R.layout.myLayoutId, container, false);
myView = myFragmentView.findViewById(R.id.myIdTag)
return myFragmentView;
}