Android ViewPager內Layoutinflator

Question

我建立一個項目。但我有問題。 我的項目有網頁A，網頁B

從圖片http://s20.postimg.org/5pupjbuyl/untitled.png

頁A是的FrameLayout（ID =佈局），在FrameLayout裏已經LinearLayout中和的FrameLayout（ID =含量） 頁B是的FrameLayout（ID =尋呼機），在FrameLayout裏有Viewpager

我會採取的FrameLayout（ID =含量）網頁A頁含B的FrameLayout（ID =尋呼機）

（注意：我要儘量減少我的代碼，因爲它的許多行）

PageIndicatorActivity的.java

public class PageIndicatorActivity extends Activity { 
... 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    .. 
    .. 
    ViewGroup Content = (ViewGroup)findViewById(R.id.layout); 
    ViewBookAdapter pager = new ViewBookAdapter(this); 
      Content.addView(pager.getView()); 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    getMenuInflater().inflate(R.menu.activity_main,menu); 
    return true; 
}} 

pager.java

public class Pager extends PagerAdapter { 

Activity activity; 
private static String content[] = {"file:///android_asset/html/page1.html","file:///android_asset/html/page2.html"}; 

public Pager(Activity act) { 
    activity = act; 
} 


public int getCount() { 
    return content.length; 
} 

public Object instantiateItem(View collection, int position) { 
    WebView view = new WebView(activity); 
    view.loadUrl(content[position]); 
    view.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT)); 
    ((ViewPager) collection).addView(view, 0); 



    return view; 
} 

@Override 
public void destroyItem(View arg0, int arg1, Object arg2) { 
    ((ViewPager) arg0).removeView((View) arg2); 
} 

@Override 
public boolean isViewFromObject(View arg0, Object arg1) { 
    return arg0 == ((View) arg1); 
} 

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

和ViewBookAdapter.java

class ViewBookAdapter { 
Activity activity; 
private LayoutInflater minflate; 
private ViewPager myPager; 

public ViewBookAdapter(Activity act){ 
    activity = act; 
    myPager = (ViewPager)act.findViewById(R.id.viewPager); 
    Pager p = new Pager(act); 
    myPager.setAdapter(p); // <--- THIS PROBLEM --- 


} 

public View getView(){ 
    LayoutInflater minflate = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    View v = minflate.inflate(R.layout.pager, null); 
    return v; 
}} 

我有一個probleam在myPager.setAdapter（P）;

Android Report Bug is NullPointerException

如何解決？

謝謝你的回答^^

PS。抱歉，英語。

Answer 1

發生這種情況是因爲您的Activity版面中沒有ViewPager。它在另一個佈局。您需要做setAdapter的getView()

Answer 2

您當前的PageIndicatorActivity版面沒有ViewPager。如果你需要繼續這種方式，你必須移動到Activity（頁面B）並按照你的實施。