Question

我试图在宽度小于500px的屏幕上隐藏两个TextView。

我尝试了以下（这不是我的完整代码，但必不可少）：

public class HeaderFooterFragment extends Fragment {
private TextView lable;
private TextView app;

@Override
    public void onActivityCreated(Bundle savedInstanceState)
    {
     lable = (TextView) fragmentView.findViewById(R.id.lable);
     app = (TextView) fragmentView.findViewById(R.id.app);
// some code...

     super.onActivityCreated(savedInstanceState);
    }

    public void setLableInvisible()
    {
        lable.setVisibility(View.INVISIBLE);
        app.setVisibility(View.INVISIBLE);
    }

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

        DisplayMetrics dm = new DisplayMetrics();
        getActivity().getWindowManager().getDefaultDisplay().getMetrics(dm);
        int screenWidth = dm.widthPixels;

        if(screenWidth < 500){
            setLableInvisible();
        }

        return fragmentView;
    }
}

我的XML是：

      <TextView
            android:layout_width="wrap_content"
            android:layout_height="@dimen/toolbar_height"
            android:id="@+id/lable"
            android:layout_weight="0.3"
            android:textAlignment="gravity"
            android:gravity="left"
            android:text="@string/app_name"
            android:textSize="@dimen/site_fontsize"
            android:paddingTop="@dimen/site_paddingtop"
            android:paddingLeft="@dimen/site_paddingleft"
            android:textColor="@color/site_color"
            android:scaleType="fitCenter"
            android:visibility="visible"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="@dimen/toolbar_height"
            android:layout_weight="0.05"
            android:id="@+id/app"
            android:textAlignment="gravity"
            android:gravity="left"
            android:text="@string/app_name_extra"
            android:textSize="@dimen/apptitlex_fontsize"
            android:paddingTop="@dimen/apptitlex_paddingtop"
            android:paddingLeft="@dimen/apptitlex_paddingleft"
            android:textColor="@color/colorAccent"
            android:textAllCaps="true"
            android:layout_alignParentRight="true"
            android:scaleType="fitCenter"
            android:visibility="visible"
            />

当我在宽度为480px的智能手机上启动应用程序时，我得到一个空对象引用。如果我在更大的屏幕上启动应用程序，应用程序不会崩溃。

提前致谢。

Answer 1

我不确定在OnActivityCreated中是否已创建视图，请尝试在OnCreateView中初始化textView

     lable = (TextView) fragmentView.findViewById(R.id.lable);
     app = (TextView) fragmentView.findViewById(R.id.app);

Answer 2

try this and delete onactivitycreated method

    @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            // Inflate the layout for this fragment
            fragmentView = inflater.inflate(R.layout.fragment_header_footer, container, false);
    lable = (TextView) fragmentView.findViewById(R.id.lable);
         app = (TextView) fragmentView.findViewById(R.id.app);
            DisplayMetrics dm = new DisplayMetrics();
            getActivity().getWindowManager().getDefaultDisplay().getMetrics(dm);
            int screenWidth = dm.widthPixels;

            if(screenWidth < 500){
                setLableInvisible();
            }

            return fragmentView;
        }

Answer 3

声明 TextView onCreateView而不是onActivityCreated部分

   View RootView; //Declare Global

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

        RootView = inflater.inflate(R.layout.fragment_header_footer, container, false);
        lable = (TextView) RootView.findViewById(R.id.lable);
        app = (TextView) RootView.findViewById(R.id.app);

       // Add Your staff here 

       return RootView;
    }

Answer 4

而不是这个

setLableInvisible();

使用以下代码隐藏textview

app.setVisibility(View.INVISIBLE)

同样将其用于第二次textview。感谢

在小屏幕上隐藏TextView

4 个答案: