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我有两个 AsyncTask:第一个寻找素数,如果成功,我必须调用第二个 AsyncTask 显示单词“Yop!” (将这个词添加到数组列表中,并显示在AsyncTask三)。
如果我从 onProgressUpdate 调用第二个 AsyncTask,我有错误:
Process: com.egoriku.asynctask, PID: 3274
java.lang.IllegalStateException: Cannot execute task: the task has already been executed (a task can be executed only once)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:605)
at android.os.AsyncTask.execute(AsyncTask.java:560)
at com.egoriku.asynctask.activities.MainActivity$MyTaskTwo.onProgressUpdate(MainActivity.java:175)
at com.egoriku.asynctask.activities.MainActivity$MyTaskTwo.onProgressUpdate(MainActivity.java:153)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:680)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:6066)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:770)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:660)
我的任务一:
private class MyTaskTwo extends AsyncTask<Void, Integer, Void> {
public MyTaskTwo() {
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
}
@Override
protected void onProgressUpdate(Integer... values) {
Log.e("T2", "onProgressUpdate");
super.onProgressUpdate(values);
tempListMessages.add(hintThreadTwo + " " + String.valueOf(values[0]));
Log.e("T2", "add to list");
myTaskFour.execute();
Log.e("T2", "tast 3 execute");
Log.e("T2", "end");
}
@Override
protected Void doInBackground(Void... params) {
Log.e("T2", "doInBackground");
int nowDigit = 1;
while (!isCancelled()) {
boolean flag = true;
for (int i = 2; i < nowDigit; i++) {
if (nowDigit % i == 0) {
flag = false;
}
}
if (flag) {
try {
Thread.sleep(450);
} catch (InterruptedException e) {
e.printStackTrace();
}
callThreadFour = true;
publishProgress(nowDigit);
}
nowDigit++;
}
return null;
}
}
我的任务二
rivate class MyTaskFour extends AsyncTask<Void, Void, Void> {
public MyTaskFour() {
}
@Override
protected Void doInBackground(Void... params) {
Log.e("T4", "doInBackground");
publishProgress();
return null;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected void onPostExecute(Void aVoid) {
Log.e("T4", "onPostExecute");
super.onPostExecute(aVoid);
}
@Override
protected void onProgressUpdate(Void... values) {
Log.e("T4", "onProgressUpdate");
super.onProgressUpdate(values);
tempListMessages.add(hintThreadFour + " " + textThreadFour);
callThreadFour = false;
}
}
最佳答案
myTaskFour
对象已经在您的代码某处执行。尝试将 MyTaskTwo
类上的 onProgressUpdate()
方法更改为这样
@Override
protected void onProgressUpdate(Integer... values) {
Log.e("T2", "onProgressUpdate");
super.onProgressUpdate(values);
tempListMessages.add(hintThreadTwo + " " + String.valueOf(values[0]));
Log.e("T2", "add to list");
new MyTaskFour.execute(); // creates a new MyTaskFour instance
Log.e("T2", "tast 3 execute");
Log.e("T2", "end");
}
关于android - 如何从另一个 AsyncTask 调用 AsyncTask?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/36829886/
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