它从 channel 读取图像并将其写入卡。卡片中的图像已完全写入并且很好。唯一的问题是线程挂起并且在该循环之后不执行任何行。
protected Bitmap doInBackground(String... arg0) {
// TODO Auto-generated method stub'
// Runtime.getRuntime().availableProcessors();
System.out.println("Inside doinback"+ RemoteScreen.out.toString());
try {
RemoteScreen.out.write(210);
//Home.threadloop = false;
Bitmap bitmap = null;
String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String fileName = "a.png";
String imageInSD = baseDir + File.separator + fileName;
System.out.println(imageInSD);
if (is!= null) {
FileOutputStream fos = null;
BufferedOutputStream bos = null;
try {
// Log.i("IMSERVICE", "FILERECCC-1");
//ContextWrapper context = null;
fos = new FileOutputStream(imageInSD);
bos = new BufferedOutputStream(fos);
byte[] aByte = new byte[1024];
int bytesRead;
//thread stuck in this loop and does not move forward
while ( (bytesRead = is.read(aByte)) > 0 ) {
if (bytesRead == 1)
break;
bos.write(aByte, 0, bytesRead);
System.out.println("Loop"+aByte);
}
bos.close();
Log.i("IMSERVICE", "out of loop");
java.io.FileInputStream in = new FileInputStream(imageInSD);
bitmap = BitmapFactory.decodeStream(in);
bitmap = BitmapFactory.decodeFile(imageInSD);
Log.i("IMSERVICE", "saved");
if (bitmap != null)
System.out.println(bitmap.toString());
} catch (IOException ex) {
// Do exception handling
// Log.i("IMSERVICE", "exception ");
}
}
publishProgress(b);
b = null;
ch = 4646;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
日志跟踪显示以下错误。
05-10 20:34:42.715: E/AndroidRuntime(1135): FATAL EXCEPTION: AsyncTask #3
05-10 20:34:42.715: E/AndroidRuntime(1135): java.lang.RuntimeException: An error occured while executing doInBackground()
05-10 20:34:42.715: E/AndroidRuntime(1135): at android.os.AsyncTask$3.done(AsyncTask.java:299)
05-10 20:34:42.715: E/AndroidRuntime(1135): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
05-10 20:34:42.715: E/AndroidRuntime(1135): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
05-10 20:34:42.715: E/AndroidRuntime(1135): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
05-10 20:34:42.715: E/AndroidRuntime(1135): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
05-10 20:34:42.715: E/AndroidRuntime(1135): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
05-10 20:34:42.715: E/AndroidRuntime(1135): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
05-10 20:34:42.715: E/AndroidRuntime(1135): at java.lang.Thread.run(Thread.java:856)
05-10 20:34:42.715: E/AndroidRuntime(1135): Caused by: java.lang.NullPointerException
05-10 20:34:42.715: E/AndroidRuntime(1135): at com.rms.remotedesktop1.screencahnge.doInBackground(screencahnge.java:43)
05-10 20:34:42.715: E/AndroidRuntime(1135): at com.rms.remotedesktop1.screencahnge.doInBackground(screencahnge.java:1)
05-10 20:34:42.715: E/AndroidRuntime(1135): at android.os.AsyncTask$2.call(AsyncTask.java:287)
05-10 20:34:42.715: E/AndroidRuntime(1135): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
最佳答案
根据 logcat，代码在第 43 行崩溃并出现空指针异常，我无法分辨第 43 行是哪一行。然而:
- 您是否检查过
Environment.getExternalStorageDirectory().getAbsolutePath()是否返回非null？可能没有外部存储目录，或者你没有权限知道。 - 开发者页面也值得一读，http://developer.android.com/reference/android/os/Environment.html#getExternalStorageDirectory() ，请注意您不应该写入该目录，而您似乎正在这样做。
关于java - Android:线程停止工作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16489998/