JavaFX - 布局锚点

• 

  简述

  锚窗格允许将子节点的边缘锚定到与锚窗格边缘的偏移量。如果锚点窗格设置了边框和/或填充，则将从这些插图的内边缘开始测量偏移量。

  如果我们在应用程序中使用 Anchor 窗格，其中的节点将锚定在距窗格特定距离的位置。

  类名为 AnchorPane 包裹的 javafx.scene.layout代表锚窗格。添加节点后，您需要从窗格的所有方向（顶部、底部、右侧和左侧）为其设置一个锚点。为了设置锚点，这个类提供了四种方法，它们是——setBottomAnchor(), setTopAnchor(), setLeftAnchor(), setRightAnchor(). 对于这些方法，您需要传递一个表示锚点的双精度值。
• 

  例子

  以下程序是 Anchor Pane 布局的示例。在这里，我们在锚定窗格中插入一个旋转圆柱体。同时，我们将其设置为从各个方向（顶部、左侧、右侧、底部）距窗格 50 个单位的距离。

  将此代码保存在名称为的文件中 AnchorPaneExample.java.

  
  import javafx.animation.RotateTransition; 
  import javafx.collections.ObservableList; 
  import javafx.scene.Scene;
  import javafx.scene.layout.AnchorPane; 
  import javafx.scene.paint.Color; 
  import javafx.scene.paint.PhongMaterial; 
  import javafx.scene.shape.Cylinder; 
  import javafx.scene.transform.Rotate; 
  import javafx.stage.Stage; 
  import javafx.util.Duration;          
  public class AnchorPaneExample extends Application { 
     @Override 
     public void start(Stage stage) {                     
        //Drawing a Cylinder 
        Cylinder cylinder = new Cylinder();        
        
        //Setting the properties of the Cylinder 
        cylinder.setHeight(180.0f); 
        cylinder.setRadius(100.0f);     
        
        //Preparing the phong material of type diffuse color 
        PhongMaterial material = new PhongMaterial();  
        material.setDiffuseColor(Color.BLANCHEDALMOND); 
        
        //Setting the diffuse color material to Cylinder5 
        cylinder.setMaterial(material);  
         
        //Setting rotation transition for the cylinder 
        RotateTransition rotateTransition = new RotateTransition(); 
        
        //Setting the duration for the transition 
        rotateTransition.setDuration(Duration.millis(1000)); 
        
        //Setting the node for the transition 
        rotateTransition.setNode(cylinder);       
        
        //Setting the axis of the rotation 
        rotateTransition.setAxis(Rotate.X_AXIS);  
        
        //Setting the angle of the rotation 
        rotateTransition.setByAngle(360);
        
        //Setting the cycle count for the transition 
        rotateTransition.setCycleCount(RotateTransition.INDEFINITE); 
        
        //Setting auto reverse value to false 
        rotateTransition.setAutoReverse(false); 
        
        //playing the animation 
        rotateTransition.play(); 
        
        //Creating an Anchor Pane  
        AnchorPane anchorPane = new AnchorPane();  
         
        //Setting the anchor to the cylinder      
        AnchorPane.setTopAnchor(cylinder, 50.0); 
        AnchorPane.setLeftAnchor(cylinder, 50.0); 
        AnchorPane.setRightAnchor(cylinder, 50.0); 
        AnchorPane.setBottomAnchor(cylinder, 50.0); 
         
        //Retrieving the observable list of the Anchor Pane 
        ObservableList list = anchorPane.getChildren();  
        
        //Adding cylinder to the pane 
        list.addAll(cylinder);        
           
        //Creating a scene object 
        Scene scene = new Scene(anchorPane);  
        
        //Setting title to the Stage 
        stage.setTitle("Anchor Pane Example"); 
           
        //Adding scene to the stage 
        stage.setScene(scene); 
            
        //Displaying the contents of the stage 
        stage.show(); 
     } 
     public static void main(String args[]){ 
        launch(args); 
     } 
  }
  

  使用以下命令从命令提示符编译并执行保存的 java 文件。

  
  javac AnchorPaneExample.java 
  java AnchorPaneExample
  

  执行时，上述程序会生成一个 JavaFX 窗口，如下所示。