我正在嘗試建立一個
javafx輸入對話框,我把它放在一個任務中,但我的代碼沒有建立任何對話框.
Task passwordBox = new Task() {
@Override
protected Void call() throws Exception {
TextInputDialog dialog = new TextInputDialog("walter");
dialog.setTitle("Text Input Dialog");
dialog.setHeaderText("Look, a Text Input Dialog");
dialog.setContentText("Please enter your name:");
// Traditional way to get the response value.
Optional result = dialog.showAndWait();
if (result.isPresent()){
System.out.println("Your name: " + result.get());
}
// The Java 8 way to get the response value (with lambda expression).
result.ifPresent(name -> System.out.println("Your name: " + name));
return null;
}
};
Thread pt = new Thread(passwordBox);
pt.start();
在調試時,它将進入以下Task類的catch方法
catch (final Throwable th) {
// Be sure to set the state after setting the cause of failure
// so that developers handling the state change events have a
// throwable to inspect when they get the FAILED state. Note
// that the other way around is not important -- when a developer
// observes the causeOfFailure is set to a non-null value, even
// though the state has not yet been updated, he can infer that
// it will be FAILED because it can be nothing other than FAILED
// in that circumstance.
task.runLater(() -> {
task._setException(th);
task.setState(State.FAILED);
});
// Some error occurred during the call (it might be
// an exception (either runtime or checked), or it might
// be an error. In any case, we capture the throwable,
// record it as the causeOfFailure, and then rethrow. However
// since the Callable interface requires that we throw an
// Exception (not Throwable), we have to wrap the exception
// if it is not already one.
if (th instanceof Exception) {
throw (Exception) th;
} else {
throw new Exception(th);
}
如果我沒有将對話框放在任務中,則導緻應用程式挂起.
最佳答案 您必須確定在
JavaFX Application Thread上打開對話框,因為每次GUI更新都必須在JavaFX中的此線程上進行.
你可以實作它：
Task passwordBox = new Task() {
@Override
protected Void call() throws Exception {
Platform.runLater(new Runnable() {
@Override
public void run() {
TextInputDialog dialog = new TextInputDialog("walter");
dialog.setTitle("Text Input Dialog");
dialog.setHeaderText("Look, a Text Input Dialog");
dialog.setContentText("Please enter your name:");
// Traditional way to get the response value.
Optional result = dialog.showAndWait();
if (result.isPresent()){
System.out.println("Your name: " + result.get());
}
// The Java 8 way to get the response value (with lambda expression).
result.ifPresent(name -> System.out.println("Your name: " + name));
}
});
return null;
}
};