我正在尝试使用异步任务与线程并行执行一些代码。但由于某种原因，在 android 4.2.2 中不起作用。
我有这个代码在主类中：
new XmlDownloader();
task=new SendTask().execute("");
和以下课程：
private class SendTask extends AsyncTask<String,String,String>{
@Override
protected void onPreExecute(){
}
@Override
protected String doInBackground(String...strings){
while(true){
Log.w("outside", "hello");
}
}
return strings[0];
}
@Override
protected void onPostExecute(String country){
}
}
和
public class XmlDownloader extends Activity {
public XmlDownloader(int pos) {
DownloaderTask task = new DownloaderTask();
task.execute("");
}
private String downloadXml(String s,int pos1) {
return null;
}
private class DownloaderTask extends AsyncTask<String, Void, String> {
public DownloaderTask() {
}
@Override
// Actual download method, run in the task thread
protected String doInBackground(String... params) {
while(true){
Log.w("down", "asdasdasssasdasdasdasd");
if(isCancelled())
return null;
};
return null;
}
@Override
// Once the image is downloaded, associates it to the imageView
protected void onPostExecute(String bitmap) {
}
}
}
在 android 2.3.3 中，logcat 显示了这个序列
Log.w("down", "asdasdasssasdasdasdasd");
Log.w("down", "asdasdasssasdasdasdasd");
Log.w("down", "asdasdasssasdasdasdasd");
Log.w("outside", "hello");
Log.w("outside", "hello");
Log.w("down", "asdasdasssasdasdasdasd");
但在 android 4.2.2 中只显示
Log.w("down", "asdasdasssasdasdasdasd");
Log.w("down", "asdasdasssasdasdasdasd");
Log.w("down", "asdasdasssasdasdasdasd");
Log.w("down", "asdasdasssasdasdasdasd");
Log.w("down", "asdasdasssasdasdasdasd");
任何想法为什么线程不起作用？