我想在执行某些任务时弹出进度指示器。为了做到这一点,我对我的程序进行了如下编码。。
public void handleCheckButtonOnAction(Button button, DBConnect conn) {
ProgressForm pForm = new ProgressForm();
Task<Void> task = new Task<Void>() {
@Override
public Void call() throws InterruptedException {
checkTargetDatabaseInfo();
updateProgress(-1, -1);
return null;
}
};
pForm.activateProgressBar(task);
task.setOnSucceeded(event -> {
pForm.getDialogStage().close();
});
pForm.getDialogStage().show();
Thread thread = new Thread(task);
thread.start();
}
checkTargetDatabaseInfo方法中有一个函数用于更改标签。
还有这样的错误。。
Exception in thread "Thread-5" java.lang.IllegalStateException: Not on FX application thread; currentThread = Thread-5
at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:236)
at com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:423)
at javafx.scene.Parent$2.onProposedChange(Parent.java:367)
at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:113)
at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:108)
at com.sun.javafx.scene.control.skin.LabeledSkinBase.updateChildren(LabeledSkinBase.java:575)
at com.sun.javafx.scene.control.skin.LabeledSkinBase.handleControlPropertyChanged(LabeledSkinBase.java:204)
at com.sun.javafx.scene.control.skin.LabelSkin.handleControlPropertyChanged(LabelSkin.java:49)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.lambda$registerChangeListener$61(BehaviorSkinBase.java:197)
at com.sun.javafx.scene.control.MultiplePropertyChangeListenerHandler$1.changed(MultiplePropertyChangeListenerHandler.java:55)
at javafx.beans.value.WeakChangeListener.changed(WeakChangeListener.java:89)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:182)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
at javafx.beans.property.StringPropertyBase.fireValueChangedEvent(StringPropertyBase.java:103)
at javafx.beans.property.StringPropertyBase.markInvalid(StringPropertyBase.java:110)
at javafx.beans.property.StringPropertyBase.set(StringPropertyBase.java:144)
at javafx.beans.property.StringPropertyBase.set(StringPropertyBase.java:49)
at javafx.beans.property.StringProperty.setValue(StringProperty.java:65)
at javafx.scene.control.Labeled.setText(Labeled.java:145)
at managerworld.controller.SetEnvironmentViewerController.checkTargetDatabaseInfo(SetEnvironmentViewerController.java:142)
at managerworld.controller.SetEnvironmentViewerController.access$600(SetEnvironmentViewerController.java:42)
at managerworld.controller.SetEnvironmentViewerController$1.call(SetEnvironmentViewerController.java:109)
at managerworld.controller.SetEnvironmentViewerController$1.call(SetEnvironmentViewerController.java:98)
at javafx.concurrent.Task$TaskCallable.call(Task.java:1423)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.lang.Thread.run(Thread.java:745)
Andreas,我终于自己找到了答案,无论如何,我非常感谢,你的评论对我很有帮助。
我在Platform.runLater方法中插入了一些更新UI方法的代码,它运行得很好。这是我的代码。。
private void checkDBVersion () {
ProgressForm pForm = new ProgressForm();
Task<Void> task = new Task<Void>() {
@Override
public Void call() throws InterruptedException {
SimpleStringProperty version = new SimpleStringProperty();
Connection targetDBconn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
targetDBconn = globalTargetConn.connect();
Platform.runLater(new Runnable(){@Override public void run() {logWriter.writeLogs(logTextArea, LogWriter.INFO, "Checking this database version...");}});
pstmt = new LoggableStatement(targetDBconn, SqlList.checkTargetDBVersionSQL);
String SQL = ((LoggableStatement) pstmt).getQueryString();
Platform.runLater(new Runnable(){@Override public void run() {logWriter.writeLogs(logTextArea, LogWriter.INFO, "See the query below...");}});
Platform.runLater(new Runnable(){@Override public void run() {logWriter.writeLogs(logTextArea, LogWriter.INFO, SQL);}});
rs = pstmt.executeQuery();
while (rs.next()) {
version.set(rs.getString(1));
targetDatabaseInfo.setVersion(version);
}
Platform.runLater(new Runnable(){@Override public void run() {logWriter.writeLogs(logTextArea, LogWriter.INFO, "Your database version is " + version.getValue());}});
} catch (SQLException ex) {Platform.runLater(new Runnable(){@Override public void run() {logWriter.writeLogs(logTextArea, LogWriter.ERROR, ex.getMessage());}});
} finally {
if (rs != null ) try {rs.close();} catch(SQLException ex) {}
if (pstmt != null ) try {pstmt.close();} catch(SQLException ex) {}
if (targetDBconn != null ) try {targetDBconn.close();} catch(SQLException ex) {}
}
_DB_VERSION = version;
updateProgress(-1, -1);
return null;
}
};
pForm.activateProgressBar(task);
task.setOnSucceeded(event -> {
pForm.getDialogStage().close();
});
pForm.getDialogStage().show();
Thread thread = new Thread(task);
thread.start();
}
完成后,我只是好奇是否是背景工作。进度条是后台工作吗??