ViewPageIndicator強力關閉問題

Question

我有這個logcat，我不知道我的錯誤是什麼。我不知道我的錯誤在哪裏。

http://pastebin.com/jzCZKWKG < - logcat的

我使用的是帶適配器的ViewPage指標。這裏是我的代碼

Activity3

package com.example.jcw; 


import android.os.Bundle; 
import android.app.Activity; 
import android.support.v4.view.PagerAdapter; 
import android.support.v4.view.ViewPager; 

import com.viewpagerindicator.UnderlinePageIndicator; 

public class activity3 extends Activity 
{ 


    ViewPager viewPager; 
    PagerAdapter adapter; 
    int[] flag; 
    String[] rank; 
    UnderlinePageIndicator mIndicator; 




    @Override public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.app3); 


     rank = new String[] { "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14" }; 


     flag = new int[] { R.drawable.gr, R.drawable.calvitcdetails, 
       R.drawable.barleydetails, R.drawable.hilifedetails, 
       R.drawable.kapedetails, R.drawable.glutafitdetails, R.drawable.omnidaydetails, 
       R.drawable.omnipinkishdetails, R.drawable.omnisoapdetails, R.drawable.omnitonerdetails 
       , R.drawable.organicbarleyjuicedetails, R.drawable.pgtdetails, R.drawable.shuyadetails 
       , R.drawable.spirulinadetails }; 

    // Locate the ViewPager in viewpager_main.xml 
    viewPager = (ViewPager) findViewById(R.id.pager); 
    // Pass results to ViewPagerAdapter Class 
    adapter = new ViewPagerAdapter(activity3.this, flag , rank); 
    // Binds the Adapter to the ViewPager 
    viewPager.setAdapter(adapter); 

    // ViewPager Indicator 
    mIndicator = (UnderlinePageIndicator) findViewById(R.id.indicator); 
    mIndicator.setFades(false); 
    mIndicator.setViewPager(viewPager); 




    } 






} 

ViewPageAdapter

package com.example.jcw; 

    import android.content.Context; 
    import android.support.v4.view.PagerAdapter; 
    import android.support.v4.view.ViewPager; 
    import android.view.LayoutInflater; 
    import android.view.View; 
    import android.view.ViewGroup; 
    import android.widget.ImageView; 
    import android.widget.RelativeLayout; 

    public class ViewPagerAdapter extends PagerAdapter { 
     // Declare Variables 
     Context context; 
     int[] flag; 
     String[] rank; 
     LayoutInflater inflater; 

     public ViewPagerAdapter(Context context, int[] flag, String[] rank) { 
      this.flag = flag; 
      this.rank = rank; 
     } 

     @Override 
     public int getCount() { 
      return rank.length; 
     } 

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

     @Override 
     public Object instantiateItem(ViewGroup container, int position) { 

      ImageView imgflag; 

      inflater = (LayoutInflater) context 
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      View itemView = inflater.inflate(R.layout.app3x, container, 
        false); 



      // Locate the ImageView in viewpager_item.xml 
      imgflag = (ImageView) itemView.findViewById(R.id.imageView); 
      // Capture position and set to the ImageView 
      imgflag.setImageResource(flag[position]); 

      // Add viewpager_item.xml to ViewPager 
      ((ViewPager) container).addView(itemView); 

      return itemView; 
     } 

     @Override 
     public void destroyItem(ViewGroup container, int position, Object object) { 
      // Remove viewpager_item.xml from ViewPager 
      ((ViewPager) container).removeView((RelativeLayout) object); 

     } 
    } 

APP3 XML

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

    <android.support.v4.view.ViewPager 
     android:id="@+id/pager" 
     android:layout_width="fill_parent" 
     android:layout_height="0dp" 
     android:layout_weight="1" /> 

    <com.viewpagerindicator.UnderlinePageIndicator 
     android:id="@+id/indicator" 
     android:layout_width="fill_parent" 
     android:layout_height="5dp" /> 

</LinearLayout> 

app3x XML

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:gravity="center" 
    android:padding="10dp" > 


    <ImageView 
     android:id="@+id/flag" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentRight="true" 
     android:background="#000000" 
     android:padding="1dp" /> 

</RelativeLayout> 

Answer 1

context爲空在ViewPagerAdapter，造成NullPointerException在：

inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

更改您的構造函數如下：

public ViewPagerAdapter(Context context, int[] flag, String[] rank) { 
    this.context = context; 
    this.flag = flag; 
    this.rank = rank; 
} 

你也有一個不正確的ID爲ImageView的。變化：

imgflag = (ImageView) itemView.findViewById(R.id.imageView); 

到：這裏

imgflag = (ImageView) itemView.findViewById(R.id.flag);