Question

我有这个logcat，我不知道我的错误是什么。我不知道我的错误在哪里。

http://pastebin.com/jzCZKWKG＆lt; - LOGCAT

我使用适配器的viewpage指示器。这是我的代码

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中的

ViewPagerAdapter为空，导致NullPointerException位于：

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

按如下方式更改构造函数：

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

您还有一个不正确的ImageView ID。变化：

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

为：

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

ViewPagerIndicator强制关闭问题

1 个答案: