片段布局不显示任何东西？

Question

在此布局中，我制作了带有片段活动的标签布局，并且希望显示一些内容，但是片段活动中没有显示任何内容。 这是该片段正在取得change.xml

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/activity_change" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    app:layout_collapseParallaxMultiplier="0.5" 
    tools:context="com.example.alpit.formula2.Change"> 

    <RelativeLayout 
     android:layout_width="match_parent" 
     android:layout_height="match_parent"> 

     <android.support.design.widget.AppBarLayout 
      android:id="@+id/change_appbar" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content"> 

      <android.support.v7.widget.Toolbar 
       android:id="@+id/change" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:background="?attr/colorPrimary" 
       app:popupTheme="@style/AppTheme.NoActionBar.PopupOverlay"></android.support.v7.widget.Toolbar> 

      <android.support.design.widget.TabLayout 
       android:id="@+id/change_tab" 
       android:layout_width="match_parent" 
       android:layout_height="?attr/actionBarSize" 
       app:tabGravity="fill"> 

      </android.support.design.widget.TabLayout> 


     </android.support.design.widget.AppBarLayout> 

     <android.support.v4.view.ViewPager 
      android:id="@+id/change_viewpager" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:layout_below="@id/change_appbar" 
      app:layout_behavior="@string/appbar_scrolling_view_behavior"> 

     </android.support.v4.view.ViewPager> 
    </RelativeLayout> 

    <android.support.design.widget.NavigationView 
     android:id="@+id/nav_change" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:layout_gravity="start" 
     app:menu="@menu/navigation_menu" 
     app:theme="@style/NavigationTheme"> 

    </android.support.design.widget.NavigationView> 
</android.support.v4.widget.DrawerLayout> 

这是标签布局

import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 


public class Distance extends Fragment { 


    protected View onCreate(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     return inflater.inflate(R.layout.activity_distance, container, false); 
    } 
} 

此的Java代码基座XML是距离的XML代码

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/activity_distance" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" 
    tools:context="com.example.alpit.formula2.Distance" 

    > 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:padding="10dp" 
     android:text="Weight in kg" /> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:padding="10dp" 
     android:text="Weight in kg" /> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:padding="10dp" 
     android:text="Weight in kg" 
     android:textSize="100sp" /> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:padding="10dp" 
     android:text="Weight in kg" /> 


</LinearLayout> 

这是我在布局中添加制表符的java代码

import android.os.Bundle; 
import android.support.design.widget.NavigationView; 
import android.support.design.widget.TabLayout; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentPagerAdapter; 
import android.support.v4.view.ViewPager; 
import android.support.v4.widget.DrawerLayout; 
import android.support.v7.app.ActionBarDrawerToggle; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 
import android.view.MenuItem; 

import java.util.ArrayList; 
import java.util.List; 


class Change extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener { 
    private ActionBarDrawerToggle toggle3; 
    private ViewPager viewPager; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_change); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.change); 
     setSupportActionBar(toolbar); 
     DrawerLayout drawerLayout = (DrawerLayout) findViewById(R.id.activity_change); 
     toggle3 = new ActionBarDrawerToggle(this, drawerLayout, R.string.open, R.string.Close); 
     drawerLayout.addDrawerListener(toggle3); 
     toggle3.syncState(); 
     getSupportActionBar().setDisplayHomeAsUpEnabled(true); 
     NavigationView navigationView = (NavigationView) findViewById(R.id.nav_change); 
     navigationView.setItemIconTintList(null); 
     navigationView.setNavigationItemSelectedListener(this); 
     setTitle("Conversion"); 
     viewPager = (ViewPager) findViewById(R.id.change_viewpager); 
     setUpViewpager(viewPager); 
     TabLayout tabs = (TabLayout) findViewById(R.id.change_tab); 
     tabs.setupWithViewPager(viewPager); 


    } 

    public boolean onOptionsItemSelected(MenuItem menuItem) { 
     if (toggle3.onOptionsItemSelected(menuItem)) { 
      return true; 
     } 
     return onOptionsItemSelected(menuItem); 
    } 

    private void setUpViewpager(ViewPager upViewpager) { 
     Adapter_tab adapter = new Adapter_tab(getSupportFragmentManager()); 
     adapter.addFragment(new Distance(), "Distance"); 
     adapter.addFragment(new Mass(), "Mass"); 
     upViewpager.setAdapter(adapter); 

    } 


    @Override 
    public boolean onNavigationItemSelected(MenuItem item) { 
     return false; 
    } 

    static class Adapter_tab extends FragmentPagerAdapter { 
     private final List<Fragment> mFragmentList = new ArrayList<>(); 
     private final List<String> mFragmentTitleList = new ArrayList<>(); 

     public Adapter_tab(FragmentManager fm) { 
      super(fm); 
     } 

     @Override 
     public Fragment getItem(int position) { 
      return mFragmentList.get(position); 
     } 

     @Override 
     public int getCount() { 
      return mFragmentTitleList.size(); 
     } 

     public void addFragment(Fragment fragment, String title) { 
      mFragmentList.add(fragment); 
      mFragmentTitleList.add(title); 
     } 

     public CharSequence getPageTitle(int position) { 
      return mFragmentTitleList.get(position); 
     } 


    } 
} 

Answer 1

只需在距离上添加onCreateView