錯誤嘗試加載與異步任務圖像

Question

我試圖實現圖像異步任務，我從這裏得到：

http://schimpf.es/asynctask-for-image-download/

然後我試圖在我的代碼來執行這樣的：

ImageView im1 = (ImageView) findViewById(R.id.image); 
ImageDownloadTask imageD = new ImageDownloadTask(im1); 
imageD.execute(e.mediumLabel); 

然後我得到這個錯誤：當你打電話給你記錄

06-19 15:22:23.480: E/AndroidRuntime(18376): FATAL EXCEPTION: AsyncTask #2 
06-19 15:22:23.480: E/AndroidRuntime(18376): java.lang.RuntimeException: An error occured while executing doInBackground() 
06-19 15:22:23.480: E/AndroidRuntime(18376): at android.os.AsyncTask$3.done(AsyncTask.java:299) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at java.util.concurrent.FutureTask.setException(FutureTask.java:219) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at java.util.concurrent.FutureTask.run(FutureTask.java:239) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at java.lang.Thread.run(Thread.java:856) 
06-19 15:22:23.480: E/AndroidRuntime(18376): Caused by: java.lang.NullPointerException: println needs a message 
06-19 15:22:23.480: E/AndroidRuntime(18376): at android.util.Log.println_native(Native Method) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at android.util.Log.e(Log.java:231) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at com.example.beerportfoliopro.ImageDownloadTask.doInBackground(ImageDownloadTask.java:42) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at com.example.beerportfoliopro.ImageDownloadTask.doInBackground(ImageDownloadTask.java:1) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at android.os.AsyncTask$2.call(AsyncTask.java:287) 
06-19 15:22:23.480: E/AndroidRuntime(18376): at java.util.concurrent.FutureTask.run(FutureTask.java:234) 

Answer 1

Log.e您沒有傳入有效的字符串，其中一個爲空。見ImageDownloadTask line 42