ViewPager無法正確顯示查看

Question

我正在使用V4兼容性JAR。我有一個顯示某些樂隊信息的ViewPager。當我創建PagerAdapter時，我將它傳遞給Band對象的ArrayList。

在模擬器中，它總是顯示首先顯示ArrayList信息中的第二個band。當我翻到最後一個視圖時，視圖始終沒有數據。當我來回翻轉時，數據會變得非常麻煩。

BandsActivity

private ViewPager mBandsPager; 
private BandsPagerAdapter mBandsPagerAdapter; 
private static final String TAG = "Paging"; 

@Override 
public void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 
    setContentView(R.layout.awesomepager); 

    // Build a couple bands; 
    ArrayList<Band> bands = new ArrayList<Band>(); 
    bands.add(new Band(1, "Led Zeppelin")); 
    bands.add(new Band(37, "Brand New")); 
    bands.add(new Band(49, "Jay-Z")); 

    mBandsPagerAdapter = new BandsPagerAdapter(this, bands); 

    mBandsPager = (ViewPager) findViewById(R.id.awesomepager); 
    mBandsPager.setAdapter(mBandsPagerAdapter); 

} 

BandsPagerAdapter

private Context mCtx; 
private ArrayList<Band> mBands; 

public BandsPagerAdapter(Context ctx, ArrayList<Band> bands) { 
    mCtx = ctx; 
    mBands = bands; 
} 


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

@Override 
public Object instantiateItem(View collection, int position) { 

    // Inflate and create the view 
    LayoutInflater layoutInflater = (LayoutInflater)mCtx.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    View view = layoutInflater.inflate(R.layout.featured_bands_layout, null); 

    // Build UI 
    TextView name = (TextView)collection.findViewById(R.id.featured_band_name); 

    // Populate UI with band data 
    Band band = mBands.get(position); 
    if(name != null) { 
     name.setText("Name: " + band.getName() + ", Pos: " + position); 
    } 

    // Add View to the ViewPager collection 
    ((ViewPager)collection).addView(view,0); 

    return view; 
} 


@Override 
public void destroyItem(View collection, int position, Object view) { 

    ((ViewGroup) collection).removeView((View)view); 
} 

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


@Override 
public void finishUpdate(View arg0) {} 


@Override 
public void restoreState(Parcelable arg0, ClassLoader arg1) {} 

@Override 
public Parcelable saveState() { 
    return null; 
} 

@Override 
public void startUpdate(View arg0) {} 

有什麼建議？我看到提到實現ViewPager.SimpleOnPageChangeListener，但沒有看到它如何正確使用。

Answer 1

您的BandsPagerAdapter似乎是問題所在。以下是我將如何實施它。看看它是否有所作爲！

public class BandsPagerAdapter extends PageAdaptor{ 

    private ArrayList<Band> mBands; 

    public BandsPagerAdapter(ArrayList<Band> bands) { 
     mBands = bands; 
    } 


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

    @Override 
    public Object instantiateItem(View collection, int position) { 

     // Inflate and create the view 
     LayoutInflater layoutInflater = (LayoutInflater) collection.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     View view = layoutInflater.inflate(R.layout.featured_bands_layout, null); 

     // Build UI 
     TextView name = (TextView) view.findViewById(R.id.featured_band_name); 

     // Populate UI with band data 
     Band band = mBands.get(position); 
     if(name != null) { 
      name.setText("Name: " + band.getName() + ", Pos: " + position); 
     } 

     // Add View to the ViewPager collection 
     ((ViewPager) collection).addView(view,0); 

     return view; 
    } 


    @Override 
    public void destroyItem(View collection, int position, Object view) 
     ((ViewPager) collection).removeView((View) view); 
    } 

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


    @Override 
    public void finishUpdate(View arg0) {} 


    @Override 
    public void restoreState(Parcelable arg0, ClassLoader arg1) {} 

    @Override 
    public Parcelable saveState() { 
     return null; 
    } 

    @Override 
    public void startUpdate(View arg0) {} 
}