java - JavaFX View:add和setConstraints之间有区别吗？

add（）或setConstraints之间是否有区别，是的，Preference还是真正的大区别？

public class example extends Application {


    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("Example");
        GridPane grid = new GridPane();

        Label label = new Label("Example A");
        Label label2 = new Label("Example B");

        grid.add(label, 0,0);

        GridPane.setConstraints(label2, 1, 0);
        grid.getChildren().add(label2);

        Scene scene = new Scene(grid, 300,200);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

最佳答案

GridPane类中两个方法的实现：

/**
 * Adds a child to the gridpane at the specified column,row position.
 * This convenience method will set the gridpane column and row constraints
 * on the child.
 * @param child the node being added to the gridpane
 * @param columnIndex the column index position for the child within the gridpane, counting from 0
 * @param rowIndex the row index position for the child within the gridpane, counting from 0
 */
public void add(Node child, int columnIndex, int rowIndex) {
    setConstraints(child, columnIndex, rowIndex);
    getChildren().add(child);
}

/**
 * Sets the column,row indeces for the child when contained in a gridpane.
 * @param child the child node of a gridpane
 * @param columnIndex the column index position for the child
 * @param rowIndex the row index position for the child
 */
public static void setConstraints(Node child, int columnIndex, int rowIndex) {
    setRowIndex(child, rowIndex);
    setColumnIndex(child, columnIndex);
}

add方法在指定的列，行位置将一个子项添加到网格窗格中。
setConstraints设置包含在网格窗格中的子项的列，行索引。

setConstraints不会添加子项，但指定在GridPane中如何显示子项。