Question

我正在使用JavaFX（使用场景构建器），我正在尝试使用progressIndicator构建一个progressBar，它将显示后台文件上传状态。

这是我的javafx控制器（一些初始化）：

@FXML
private Pane uploadsStatuses;
@FXML
private ProgressBar uploadBar;
@FXML
private ProgressIndicator uploadProgressIndicator;
...
@Override
@FXML
public void initialize(URL url, ResourceBundle rb) {
    ...
    assert uploadsStatuses != null : "fx:id=\"uploadsStatuses\" was not injected: check your FXML file 'FXMLDocument.fxml'.";
    assert uploadBar != null : "fx:id=\"uploadBar\" was not injected: check your FXML file 'FXMLDocument.fxml'.";
    assert uploadProgressIndicator != null : "fx:id=\"uploadProgressIndicator\" was not injected: check your FXML file 'FXMLDocument.fxml'.";
    ...

为了上传文件，我正在使用FTP4J库，我已经实现了一种计算文件上传百分比的方法：

public class Ftp4jListener implements FTPDataTransferListener {
    private int transfBytes=0;
    private int totalBytes=0;
    private long fileSize = -1;
    private String fileName;
    ...
    @Override
    public void transferred(int length)
    {
        transfBytes+=length;
        float percent = (float) transfBytes / this.fileSize;
        float fPercent = percent*100;
        log.info("File: " + this.fileName + " | Bytes transfered "+ transfBytes + " Percentage: " + fPercent + "%");
    }

问题是如何将FTP4J监听器绑定到我的progressBar＆amp; progressIndicator？

Answer 1

要么：

重写您的侦听器类以使用JavaFX属性：

public class Ftp4jListener implements FTPDataTransferListener {
    private final ReadOnlyIntegerWrapper transfBytes = new ReadOnlyIntegerWrapper();
    private final ReadOnlyIntegerWrapper totalBytes = new ReadOnlyIntegerWrapper();
    private final ReadOnlyLongWrapper fileSize = new ReadOnlyLongWrapper(-1);

    public ReadOnlyIntegerProperty transfBytesProperty() {
        return transfBytes.getReadOnlyProperty() ;
    }

    public int getTransfBytes() {
        return transfBytesProperty().get();
    }

    // etc. for other two properties...

    private String fileName;
    ...
    @Override
    public void transferred(int length)
    {
        transfBytes.set(tranfBytes.get()+length);
        float percent = (float) transfBytes.get() / this.fileSize.get();
        float fPercent = percent*100;
        log.info("File: " + this.fileName + " | Bytes transfered "+ transfBytes.get() + " Percentage: " + fPercent + "%");
    }

}

然后，您可以使用一个或多个属性注册侦听器并更新进度条：

ftp4jListener.transfBytesProperty().addListener((obs, oldValue, newValue) -> 

    uploadBar.setProgress(((double)ftp4jListener.getTransfBytes())/ftp4jListener.getFileSize()));

如果您要在后台线程中传输数据（您应该这样做），请务必更新FX应用程序线程上的进度条：

ftp4jListener.transfBytesProperty().addListener((obs, oldValue, newValue) -> 
    Platform.runLater(() -> 
        uploadBar.setProgress(((double)ftp4jListener.getTransfBytes())/ftp4jListener.getFileSize())));

或来自Task调用updateProgress(...)，并将进度条的progress属性绑定到任务的progress属性。

或者：

编写您的侦听器以接受回调：

public class Ftp4jListener implements FTPDataTransferListener {
    private int transfBytes=0;
    private int totalBytes=0;
    private long fileSize = -1;
    private String fileName;

    private final DoubleConsumer percentageCallback ;

    public Ftp4jListener(DoubleConsumer percentageCallback) {
        this.percentageCallback = percentageCallback ;
    }
    ...
    @Override
    public void transferred(int length)
    {
        transfBytes+=length;
        float percent = (float) transfBytes / this.fileSize;
        float fPercent = percent*100;

        percentageCallback.accept(fPercent);

        log.info("File: " + this.fileName + " | Bytes transfered "+ transfBytes + " Percentage: " + fPercent + "%");
    }
}

然后您可以将侦听器创建为

Ftp4jListener ftp4jListener = new Ftp4jListener(percent -> 
    Platform.runLater(() -> uploadBar.setProgress(percent)));

JavaFX进度条显示文件上传状态

1 个答案: