我想要一个在 onAction
block 内更新的进度条。由于以下代码中的某种原因,进度条在退出 onAction
block 之前不会更新。我在 9 秒内没有任何进展,然后就达到了 90%。 System.out
打印得很好。
package net.snortum.play;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.text.Text;
import javafx.stage.Stage;
public class ProgressBarTester extends Application {
public static void main( String[] args ) {
launch( ProgressBarTester.class, args );
}
@Override
public void start( final Stage stage ) throws Exception {
final GridPane grid = new GridPane();
grid.setAlignment( Pos.CENTER );
grid.setHgap( 10 );
grid.setVgap( 10 );
grid.setPadding( new Insets( 25, 25, 25, 25 ) );
final Text title = new Text( "Test Progress Bar" );
int col = 0, row = 0, colSpan = 2, rowSpan = 1;
grid.add( title, col, row, colSpan, rowSpan );
col = 0;
row++;
grid.add( new Label( "Progress:" ), col, row );
col = 1;
final ProgressBar progress = new ProgressBar( 0.0 );
grid.add( progress, col, row );
final HBox hbox = new HBox();
hbox.setAlignment( Pos.BASELINE_RIGHT );
final Button submit = new Button( "Go" );
hbox.getChildren().add( submit );
col = 1;
row++;
grid.add( hbox, col, row );
submit.setOnAction( new EventHandler<ActionEvent>() {
@Override
public void handle( ActionEvent event ) {
double size = 10.0;
for (double i = 0.0; i < size; i++){
progress.setProgress( i / size );
System.out.printf("Complete: %02.2f%n", i * 10);
try {
Thread.sleep(1000);
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
} );
final Scene scene = new Scene( grid );
stage.setScene( scene );
stage.setTitle( "Test Progress Bar" );
stage.show();
}
}
最佳答案
tomsomtom 精确答案的长形式:
如果您使用 JavaFX 线程来做这种长期工作,您会阻止 UI 更新等。因此您必须在独立的线程中运行您的工作线程。如果您在单独的线程中运行,则必须使用 runLater() 将所有 GUI 操作(如 Progress.setProgress())传回 JavaFX 线程,因为 JavaFX 不是多线程的。
在您的操作中尝试一下:
submit.setOnAction( new EventHandler<ActionEvent>() {
@Override
public void handle( ActionEvent event ) {
double size = 10.0;
new Thread(){
public void run() {
for (double i = 0.0; i < size; i++){
final double step = i;
Platform.runLater(() -> progress.setProgress( step / size ));
System.out.printf("Complete: %02.2f%n", i * 10);
try {
Thread.sleep(1000);
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
}.start();
}
} );
关于user-interface - Javafx 中的 ProgressBar 不会在 onAction block 中更新,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/54706646/