我刚刚在javafx中学到了一些新闻，然后我想申请它们，所以我选择制作一个柜台;但是当我在我的标签上设置了不会改变它的文本时;我用System.out.print测试了它，效果很好。 那是我的代码：
public class Controller {
@FXML
private Label time;
@FXML
private Button start;
public void Counter(ActionEvent event)
{
start.setText("hello");
time.setText("00 : 00 : 00");
int h=0,m=0,s=0,i=0;
while(true)
{
try {
s++;
if(s==60) {s=0;m++;}
if(m==60) {m=0;h++;}
System.out.println(Integer.toString(h)+" : "+String.valueOf(m)+" : "+String.valueOf(s));
time.setText(Integer.toString(h)+" : "+String.valueOf(m)+" : "+String.valueOf(s));
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
感谢您的帮助！ ;）
答案 0 :(得分：1)
重要的是，您需要了解对UI的任何更新都需要在UI的主线程中完成。您还应该避免阻止UI的主线程，这将阻止UI更新。
首先，请阅读Concurrency in JavaFX
当您处理时间或持续时间时，应始终使用专用库，例如java.time。为什么？因为一天中实际上没有24小时或一分钟内没有60秒 - 我知道，不是很奇怪。
你可以......
Timeline import java.time.LocalDateTime;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;
public class Test extends Application {
private LocalDateTime startTime;
private Timeline timer;
private Label time;
@Override
public void start(Stage primaryStage) {
time = new Label("...");
Button btn = new Button();
btn.setText("Start");
btn.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
if (timer != null) {
timer.stop();
}
startTime = LocalDateTime.now();
timer = new Timeline(new KeyFrame(Duration.millis(500), new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
LocalDateTime now = LocalDateTime.now();
java.time.Duration duration = java.time.Duration.between(startTime, now);
time.setText(format(duration));
}
}));
timer.setCycleCount(Timeline.INDEFINITE);
timer.play();
}
});
VBox root = new VBox();
root.setAlignment(Pos.CENTER);
root.getChildren().add(time);
root.getChildren().add(btn);
Scene scene = new Scene(root, 300, 250);
primaryStage.setTitle("Hello World!");
primaryStage.setScene(scene);
primaryStage.show();
}
protected String format(java.time.Duration duration) {
long hours = duration.toHours();
long mins = duration.minusHours(hours).toMinutes();
long seconds = duration.minusMinutes(mins).toMillis() / 1000;
return String.format("%02dh %02dm %02ds", hours, mins, seconds);
}
public static void main(String[] args) {
launch(args);
}
}
AnimationTimer 这可能是首选解决方案，因为计时器与动画引擎的帧刷新同步调用
import java.time.LocalDateTime;
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class Test extends Application {
private LocalDateTime startTime;
private AnimationTimer timer;
private Label time;
@Override
public void start(Stage primaryStage) {
time = new Label("...");
Button btn = new Button();
btn.setText("Start");
btn.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
if (timer != null) {
timer.stop();
}
startTime = LocalDateTime.now();
timer = new AnimationTimer() {
@Override
public void handle(long click) {
LocalDateTime now = LocalDateTime.now();
java.time.Duration duration = java.time.Duration.between(startTime, now);
time.setText(format(duration));
}
};
timer.start();
}
});
VBox root = new VBox();
root.setAlignment(Pos.CENTER);
root.getChildren().add(time);
root.getChildren().add(btn);
Scene scene = new Scene(root, 300, 250);
primaryStage.setTitle("Hello World!");
primaryStage.setScene(scene);
primaryStage.show();
}
protected String format(java.time.Duration duration) {
long hours = duration.toHours();
long mins = duration.minusHours(hours).toMinutes();
long seconds = duration.minusMinutes(mins).toMillis() / 1000;
return String.format("%02dh %02dm %02ds", hours, mins, seconds);
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}
答案 1 :(得分：0)
你可以试试这个
public void Counter(ActionEvent event)
{
start.setText("hello");
time.setText("00 : 00 : 00");
AnimationTimer timer = new AnimationTimer() {
long then=0;
double sum=0;
int h=0,m=0,s=0;
@Override
public void handle(long now) {
long dt = now - then;
sum+=dt;
if(sum/1000000000>=1) {
s++;
if(s==60) {s=0;m++;}
if(m==60) {m=0;h++;}
System.out.println(Integer.toString(h)+" : "+String.valueOf(m)+" : "+String.valueOf(s));
time.setText(Integer.toString(h)+" : "+String.valueOf(m)+" : "+String.valueOf(s));
sum=0;
}
then=now;
}
};
timer.start();
}