我已将代码移至异步任务以在后台线程上执行操作。代码如下:
public class AsynTaskActivity extends AsyncTask<HashMap<String, Integer>, Void, Void>
{
@Override
protected Void doInBackground(HashMap<String, Integer>... hashMaps)
{
HashMap<String, Integer> maps = hashMaps[0];
//
Set set = maps.entrySet();
for (Object aSet : set)
{
Map.Entry entry = (Map.Entry) aSet;
receiveBarcode(entry.getKey().toString());
}
return null;
}
}
但是,在运行代码库时。我遇到以下错误:
Process: com.touchsides.checkout.debug, PID: 7447
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6556)
at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:942)
我假设 doInbackground 正在单独的线程上运行,并且不应遇到此错误。
最佳答案
在 AsyncTask
中,您永远无法在 doInBackgound
中执行 UI 交互,但是如果您在 onProgressUpdate
中传递进度或结果,您仍然可以更新 UI > 和 onPostExecute
分别,这就是您重新获得 UI 线程的方式。您可以尝试将 AsyncTask
更改为:
public class AsynTaskActivity extends AsyncTask<HashMap<String, Integer>, String, Object> {
@Override
protected Object doInBackground(HashMap<String, Integer>... hashMaps) {
// non-ui thread
HashMap<String, Integer> maps = hashMaps[0];
Set set = maps.entrySet();
for (Object aSet : set) {
Map.Entry entry = (Map.Entry) aSet;
publishProgress(entry.getKey().toString()); // onProgressUpdate callback
}
return null; // onPostExecute callback
}
@Override
protected void onProgressUpdate(String... progress) {
// ui thread
receiveBarcode(progress);
}
@Override
protected void onPostExecute(Long result) {
// ui thread
}
}
AsyncTask有详细记录,您可以在线阅读更多相关信息。
关于java - 异步任务无法访问原始线程,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/53221028/