Question

我目前正在学习JavaFX。我正在构建一个应用程序，它将文件作为输入，连接到外部服务器，并将解析后的结果返回到MySQL数据库。核心功能工作正常，但我希望对用户进行JavaFX更新，以便他们知道他们正在等待连接到服务器等。但是，当调用该方法时，文本更新在方法之前是不可见的已完成执行 - 我希望更新实时发生。违规方法如下：

public void doBlast(){

    //this line is not updated until completion of the program - not straight away
    status.setText("Connecting to NCBI servers..NCBI" + "\n");

//Biojava API details extracted as it is not relevant

    BufferedReader bufferedFileReader = null;
    Scanner bufferedScanner = null;
    BufferedWriter bufferedWriterXML = null;
    String rid = null;
    int count = 0;
    try {

        //this.getFasta() represents the input file
        bufferedScanner 
                = new Scanner(new BufferedReader(new FileReader (this.getFasta())));

        //this.getTempXML() is a temporary file for temporary storage of xml output from the server
        bufferedWriterXML
                = new BufferedWriter (new FileWriter (this.getTempXML(), true));
        String line, nextline, query, xmlLine;

        //Loops for a specified number of times
        while (count < alignmentLimit) {
            this.setSequence_id(bufferedScanner.nextLine());

            //newline here
            bufferedScanner.nextLine();

            //this line from the file is used to search a database in the server
            query = bufferedScanner.nextLine();

            //this line is not updated until completion of the program - not straight away
            status.setText("Connecting to NCBI servers.." + "\n");

            //below service connects to server
            rid = service.sendAlignmentRequest(query, props);

            //results 
            InputStream in = service.getAlignmentResults(rid, outputProps);

            //this line is not updated until completion of the program - not straight away
            status.setText("Connected to NCBI." + "\n");                
            bufferedFileReader = new BufferedReader(new InputStreamReader(in));                
            xmlLine = bufferedFileReader.readLine();
            while (xmlLine != null) {
                bufferedWriterXML.write("\n" + xmlLine);
                xmlLine = bufferedFileReader.readLine();

                //  have to flush here so that it prints to file; 
                //  the file can then be deleted each loop
                bufferedWriterXML.flush();
            }                   
            count++;

            //this method removes specific strings
            this.removeAll("<?xml", "<!DOCTYPE", this.getTempXML(), this.getXML()); 

            //this method fills a database with the data from server
            this.xml2mysql();

            //file cleaning
            this.eraseData(this.getTempXML());
            this.eraseData(this.getXML());

            bufferedScanner.nextLine();

            //this line is not updated until completion of the program - not straight away
            numberOfRecords.setText(Integer.toString(count));
        }    
    }
    catch (Exception anException){
                anException.printStackTrace();
    }
    finally {
        try {
            bufferedWriterXML.close();
            bufferedScanner.close();
            bufferedFileReader.close();    
        }
        catch (Exception anException){
            System.out.println("Error: " + anException);
        }
    }
}

setText（）方法使用FXML定义的fx：id变量，上面的方法在控制器中。

非常感谢有人能帮助我。我到处寻找解决方案。感谢。

Answer 1

您应该查看使用将文件加载到后台线程的任务或服务。

您可以挂钩执行期间调用的方法：

来自Oracle文档：

在call方法中，你可以使用updateProgress，updateMessage， updateTitle方法，用于更新相应的值 JavaFX应用程序线程上的属性。但是，如果任务是取消后，将忽略来自call方法的返回值

如果在JavaFX线程上执行长进程，UI将被阻止并显示为冻结。

JavaFX - SetText（）到TextArea在程序完成之前不会执行

1 个答案: