【项目笔记】【bug】数组空指针异常

 1 package com.example.googleplay.ui.holder;
 2 
 3 import java.util.ArrayList;
 4 
 5 import android.view.View;
 6 import android.widget.ImageView;
 7 
 8 import com.example.googleplay.R;
 9 import com.example.googleplay.http.HttpHelper;
10 import com.example.googleplay.utils.BitmapHelper;
11 import com.example.googleplay.utils.UIUtils;
12 import com.lidroid.xutils.BitmapUtils;
13 
14 public class HomeScreenHolder extends BaseHolder<ArrayList<String>> {
15 
16     private ImageView[] mImages = null;
17     private BitmapUtils mBitmapUtils;
18 
19     @Override
20     public View initView() {
21         View view = UIUtils.inflate(R.layout.layout_detail_picinfo);
22 
23         mImages = new ImageView[5];
24         mImages[0] = (ImageView) view.findViewById(R.id.iv_pic1);
25         mImages[1] = (ImageView) view.findViewById(R.id.iv_pic2);
26         mImages[2] = (ImageView) view.findViewById(R.id.iv_pic3);
27         mImages[3] = (ImageView) view.findViewById(R.id.iv_pic4);
28         mImages[4] = (ImageView) view.findViewById(R.id.iv_pic5);
29         
30         mBitmapUtils = BitmapHelper.getBitmapUtils();
31         return view;
32     }
33 
34     @Override
35     public void refreshView(ArrayList<String> data) {
36         
37         for (int i = 0; i < mImages.length; i++) {
38             if(i>=data.size()){
39                 //多余的图片布局需要隐藏
40                 mImages[i].setVisibility(View.GONE);
41             }else {
42                 //要显示的图片
43                 mImages[i].setVisibility(View.VISIBLE);
44                 mBitmapUtils.display(mImages[i], HttpHelper.URL + "image?name=" + data.get(i));
45             }
46         }
47     }
48 }

在refreshView这个方法中mImages报空指针异常，其实是第16行的原因，数组赋值只能一次赋值，赋值之后再赋值无效，应该写成

1      private ImageView[] mImages;

但是可以给数组的每个元素再次赋值。