ViewPager in fragment无效无显示

Question

此前我在Activity类中使用ViewPager作为图像滑块，但是我发布了一个问题here。 所以，我添加了一个片段，并尝试添加ViewPager的图像滑块，但没有运气。代码执行成功，但ViewPager不显示其内容。

其实我想在我的主页使用image slider，也需要从URL 任何帮助打开应用程序的功能！提前致谢。

这里是XML

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

<android.support.v4.view.ViewPager 
    android:id="@+id/view_pager" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" /> 
</LinearLayout> 

这里MainActivity.java

public class MainActivity extends AppCompatActivity 
    implements NavigationView.OnNavigationItemSelectedListener { 
IAppManager imService; 
Boolean mIsBound=false; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    startService(new Intent(this, BackgroundService.class)); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
      this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close); 
    drawer.setDrawerListener(toggle); 
    toggle.syncState(); 

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); 
    navigationView.setNavigationItemSelectedListener(this); 
    navigationView.setItemIconTintList(null); 
    Fragment fragment= new HomeFragment(); 
    if (fragment != null) { 
     FragmentManager fragmentManager = getSupportFragmentManager(); 
     FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); 
     fragmentTransaction.replace(R.id.container_body, fragment); 
     fragmentTransaction.commit(); 

     // set the toolbar title 
     getSupportActionBar().setTitle("Home"); 
    } 
    } 
} 

这里是片段类

public class HomeFragment extends Fragment { 

ViewPager viewPager; 
Timer timer; 
@Override 
public void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
} 

@Nullable 
@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View rootView = inflater.inflate(R.layout.fragment_home, container, false); 
    //image slider 
    viewPager = (ViewPager) rootView.findViewById(R.id.view_pager); 
    ImageAdapter adapter = new ImageAdapter(getActivity()); 
    viewPager.setAdapter(adapter); 
    //viewPager.setPageTransformer(false, new DepthPageTransformer()); 


    return super.onCreateView(inflater, container, savedInstanceState); 
} 
@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    return super.onOptionsItemSelected(item); 
} 

@Override 
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 
    super.onCreateOptionsMenu(menu, inflater); 
    } 
} 

这里适配器类

public class ImageAdapter extends PagerAdapter { 
Context context; 
private int[] GalImages = new int[] { 
     R.drawable.a1, 
     R.drawable.a2, 
     R.drawable.a3, 
     R.drawable.a4, 
}; 
public ImageAdapter(Context context){ 
    this.context=context; 
} 
@Override 
public int getCount() { 
    return GalImages.length; 
} 

@Override 
public boolean isViewFromObject(View view, Object object) { 
    return view == ((ImageView) object); 
} 

@Override 
public Object instantiateItem(ViewGroup container, int position) { 
    ImageView imageView = new ImageView(context); 
    //int padding = context.getResources().getDimensionPixelSize(R.dimen.padding_medium); 
    //imageView.setPadding(padding, padding, padding, padding); 
    imageView.setScaleType(ImageView.ScaleType.CENTER_INSIDE); 
    imageView.setImageResource(GalImages[position]); 
    ((ViewPager) container).addView(imageView, 0); 
    return imageView; 
} 

@Override 
public void destroyItem(ViewGroup container, int position, Object object) { 
    ((ViewPager) container).removeView((ImageView) object); 
} 


} 

Answer 1

您在片段的OnCreateView中返回错误的视图。你在膨胀rootView，那么你应该回报！

尝试更换：

返回super.onCreateView（充气，容器，savedInstanceState）;

与

回报rootView;