2016-08-20 102 views
-1

我不知道为什么我的代码不起作用? 这是listviewadapter代码的一部分: http://pastebin.com/wFBCpCgdAsyncTask执行错误

它是PutBitmap代码:http://pastebin.com/mpZqEGus

,我已经得到了这个错误:

08-20 08:45:24.607 27198-27217/com.example.bogna.hogmessanger E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1 
Process: com.example.bogna.hogmessanger, PID: 27198 
java.lang.RuntimeException: An error occured while executing doInBackground() 
at android.os.AsyncTask$3.done(AsyncTask.java:304) 
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) 
at java.util.concurrent.FutureTask.setException(FutureTask.java:222) 
at java.util.concurrent.FutureTask.run(FutureTask.java:242) 
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
at java.lang.Thread.run(Thread.java:818) 
Caused by: java.lang.NullPointerException 
at android.graphics.Bitmap.compress(Bitmap.java:1028) 
at com.example.bogna.hogmessanger.PutBitmap.doInBackground(PutBitmap.java:45) 
at com.example.bogna.hogmessanger.PutBitmap.doInBackground(PutBitmap.java:17) 
at android.os.AsyncTask$2.call(AsyncTask.java:292) 
at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)  
at java.lang.Thread.run(Thread.java:818)  

为什么呢? 请帮忙。谢谢

+0

的可能的复制(http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) – earthw0rmjim

+0

但是我不知道什么是空的 –

+0

在你的PutBitmap类中'img'是'null' – earthw0rmjim

回答

0

img 

位图对象为null。请确保它不应该是零,你也可以实现这样的检查:什么是一个NullPointerException,以及如何解决呢]

if(img!=null && !img.compress(Bitmap.CompressFormat.PNG, 100, fOut)){ 
     isOk = false; 
} 
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