2015-04-17 66 views
-2
错误
public class MainActivity extends Activity { 

    private ImageView iv1; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     iv1 = (ImageView) findViewById(R.id.iv1); 

     setContentView(R.layout.activity_main); 
     getImage("http://b.hiphotos.baidu.com/pic/w%3D310/sign=9b24260fd53f8794d3ff4e2fe21a0ead/f636afc379310a55ba781b43b64543a98226102c.jpg"); 
    } 


    public void getImage(String url){ 
     RequestQueue requestQueue = Volley.newRequestQueue(this); 
     final LruCache<String, Bitmap> lruCache = new LruCache<String, Bitmap>(20); 
     ImageCache imageCache = new ImageCache() { 

      @Override 
      public void putBitmap(String arg0, Bitmap arg1) { 
       lruCache.put(arg0, arg1); 
      } 

      @Override 
      public Bitmap getBitmap(String arg0) { 
       return lruCache.get(arg0); 
      } 
     }; 
     ImageLoader imageLoader = new ImageLoader(requestQueue, imageCache); 
     ImageListener listener = imageLoader.getImageListener(iv1, R.drawable.ic_launcher, R.drawable.ic_launcher); 
     System.out.println("listener:"+listener); 
     System.out.println("imageLoader"+imageLoader); 
     imageLoader.get(url, listener); 
    } 
} 

Android的凌空ImageLoader的NullPointerException异常

04-16 21:39:21.493: E/AndroidRuntime(3454): Caused by: java.lang.NullPointerException

04-16 21:39:21.493: E/AndroidRuntime(3454): at com.wise.volleydemo.MainActivity.getImage(MainActivity.java:79)

+1

添加一些文字来描述您的问题。不仅代码 – Nabin

+0

林不知道。移动iv1 =(ImageView)findViewById(R.id.iv1);设置内容视图后。请解释你面临的问题 – playmaker420

+0

我的答案有错,谢谢大家 – wudashan

回答

1

移动

iv1 = (ImageView) findViewById(R.id.iv1); 

setContentView(R.layout.activity_main); 

在当前的代码,你正在努力寻找你的ImageView您的观点当视图层次结构尚未完成时的层次结构尚未初始化。活动的根视图在setContentView()方法中初始化。所以你应该在尝试访问任何其他视图之前调用它。

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