更新 JavaFX 8 UI / Multithread

Question

几天来，我一直在尝试更新Javafx用户界面，同时自动发送2封或更多的电子邮件。UI应该用“连接”、“发送”和“已发送”来更新标签。我读过关于Runnables，Tasks，TimeLine的文章，但是我真的不知道我应该使用哪种方法，以及它是如何工作的。

在我阅读Platform.runLater()的任何地方，我都使用它，但是我的JavaFX Gui中的动画冻结了，只有当所有的电子邮件都已发送时，标签才会改变。

我将很快用我的代码更新这篇文章，但有人能告诉我应该使用哪种线程，以及如何轻松更新ui吗？

//编辑

谢谢你的帮助，布拉尼斯拉夫，但现在我得到了“不在外汇申请线程”-错误。下面的代码不是我的“扩展应用程序”类，请看一下。

public class ControllerOCM implements Initializable{



    @FXML
    private ComboBox<String> comboEmpf;

    @FXML
    private Label lblStatus;

    @FXML
    private Label lblStatus1;


    @Override
    public void initialize(URL location, ResourceBundle resources) {
        hint.setText("some hint");
    }

    public void sende(ActionEvent event) throws Exception {

        switch (comboEmpf.getValue()) {
        case "A": System.out.println("A");break;
        case "B":
        File fTEST = new File("C:\\B\\");
        File[] fpathTEST = fTEST.listFiles();
        String[] fnameTEST = fTEST.list();

    for (int i=0; i<fpathTEST.length; i++) {
        SendenTask sendTEST = new SendenTask([e-mail],
                "bodycontent",
                "subject", 
                fpathTEST[i].toString(),    
                fnameTEST[i],               
                i,                      //count
                fpathTEST.length);      //max

        new Thread(sendTEST).start();
    }
            break;
        }
    }

     public class SendenTask extends Task<Void> {
            private String adr;
            private String body;
            private String subj;
            private String fp;
            private String fn;
            private int count;
            private int max;

         public SendenTask(String adr, String body, String subj, String fp, String fn, int count, int max) {
            this.adr = adr;
            this.body = body;
            this.subj = subj;
            this.fp = fp;
            this.fn = fn;
            this.count = count;
            this.max = max;

         }

         @Override 
         protected Void call() throws Exception {

         lblStatus1.setText("connecting");
         //doing connectionAction

         lblStatus1.setText("sending");
         updateMessage("sending");
         //doing sendingthingys


         //sending complete
         lblStatus1.setText("sent");
         System.out.println("done");
         updateMessage("done");

             return null;
         }
     }
}

编辑2

现在程序正在一个接一个地发送电子邮件，但text属性无法正常工作。它没有刷新文本，它只清空标签。如果我删除取消绑定行（成功），它只在我运行发送任务时工作一次。之后，对于所有其他发送任务，它再次为空。

public class ControllerOCM implements Initializable{



        @FXML
        private ComboBox<String> comboEmpf;

        @FXML
        private Label lblStatus;

        @FXML
        private Label lblStatus1;


        @Override
        public void initialize(URL location, ResourceBundle resources) {
            hint.setText("some hint");
        }

        public void sende(ActionEvent event) throws Exception {

            switch (comboEmpf.getValue()) {
            case "A": System.out.println("A");break;
            case "B":
            File fTEST = new File("C:\\B\\");
            File[] fpathTEST = fTEST.listFiles();
            String[] fnameTEST = fTEST.list();

        for (int i=0; i<fpathTEST.length; i++) {
            SendenTask sendTEST = new SendenTask([e-mail],
                    "bodycontent",
                    "subject", 
                    fpathTEST[i].toString(),    
                    fnameTEST[i],               
                    i,                      //count
                    fpathTEST.length);      //max

              lblStatus1.textProperty().bind(sendTEST.messageProperty());
              thread = new Thread(sendTEST);
              thread.start();   
              }
              break;
            }
        }

         public class SendenTask extends Task<Void> {
                private String adr;
                private String body;
                private String subj;
                private String fp;
                private String fn;
                private int count;
                private int max;

             public SendenTask(String adr, String body, String subj, String fp, String fn, int count, int max) {
                this.adr = adr;
                this.body = body;
                this.subj = subj;
                this.fp = fp;
                this.fn = fn;
                this.count = count;
                this.max = max;

             }

             @Override 
             protected Void call() throws Exception {

             while(!sending) {
             sending = true

             updateMessage("connecting");
             //doing connectionAction


             updateMessage("sending");
             //doing sendingthingys


             //sending complete
             updateMessage("done");
                 }
                 return null;
             }
     @Override
     protected void succeeded() {
         super.succeeded();
         lblStatus1.textProperty().unbind();
         sending = false;
         }
       }

    }

//edit3最大的问题是，我将lblStatus1.textProperty()放在哪里。bind(send test . message property())；其中lblStatus1.textProperty()。unbind()；?

Answer 1

您必须使用任务类。

这是一个小演示。让我们通过for循环模拟耗时的任务：

import javafx.application.Application;
import javafx.application.Platform;
import javafx.concurrent.Task;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.stage.Stage;


public class TaskDemo extends Application {


    @Override
    public void start(Stage stage) throws Exception {
        final Label label = new Label();

        Task<Void> task = new Task<Void>() {
            @Override
            protected Void call() throws Exception {
                boolean fxApplicationThread = Platform.isFxApplicationThread();
                System.out.println("Is call on FXApplicationThread: " + fxApplicationThread);
                // Run your time consuming task here!
                for (int i = 0; i < 10; i++) {
                    Thread.sleep(1000);
                    updateMessage("Time elapsed: " + i);
                }
                return null;
            }

            @Override
            protected void succeeded() {
                boolean fxApplicationThread = Platform.isFxApplicationThread();
                System.out.println("Is call on FXApplicationThread: " + fxApplicationThread);
                super.succeeded();
                label.textProperty().unbind();
                label.setText("Task done");
            }
        };
        // Bind messageProperty of task for textProperty of Label
        label.textProperty().bind(task.messageProperty());
        stage.setScene(new Scene(label, 300, 200));
        stage.show();
        new Thread(task).start();

    }
}

事情很简单。你的耗时任务将冻结用户界面，直到它完成。通过使用< code>Task类，您的耗时任务在后台线程上运行，让JavaFX线程响应。有时，您可以从< code>call方法“发布”任务的结果。不要在后台线程上更新JavaFX UI(在< code>call方法中)。通过调用< code > platform . isfxaapplicationthread()，可以检查代码是否在< code > fxaapplicationthread 上运行。如果您的代码没有在那个线程上运行，不要从那里更新您的JavaFX UI！