ViewPager in fragment無效無顯示

Question

此前我在Activity類中使用ViewPager作爲圖像滑塊，但是我發佈了一個問題here。 所以，我添加了一個片段，並嘗試添加ViewPager的圖像滑塊，但沒有運氣。代碼執行成功，但ViewPager不顯示其內容。

其實我想在我的主頁使用image slider，也需要從URL 任何幫助打開應用程序的功能！提前致謝。

這裏是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> 

這裏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"); 
    } 
    } 
} 

這裏是片段類

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); 
    } 
} 

這裏適配器類

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中返回錯誤的視圖。你在膨脹rootView，那麼你應該回報！

嘗試更換：

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

與

回報rootView;