Java ComponentPeer.isFocusable方法代码示例

import java.awt.peer.ComponentPeer; //导入方法依赖的package包/类
public static boolean shouldFocusOnClick(Component component) {
    boolean acceptFocusOnClick = false;

    // A component is generally allowed to accept focus on click
    // if its peer is focusable. There're some exceptions though.


    // CANVAS & SCROLLBAR accept focus on click
    final ComponentAccessor acc = AWTAccessor.getComponentAccessor();
    if (component instanceof Canvas ||
        component instanceof Scrollbar)
    {
        acceptFocusOnClick = true;

    // PANEL, empty only, accepts focus on click
    } else if (component instanceof Panel) {
        acceptFocusOnClick = (((Panel)component).getComponentCount() == 0);


    // Other components
    } else {
        ComponentPeer peer = (component != null ? acc.getPeer(component) : null);
        acceptFocusOnClick = (peer != null ? peer.isFocusable() : false);
    }
    return acceptFocusOnClick && acc.canBeFocusOwner(component);
}
 

import java.awt.peer.ComponentPeer; //导入方法依赖的package包/类
/**
 * Determines whether a Component is an acceptable choice as the new
 * focus owner. The Component must be visible, displayable, and enabled
 * to be accepted. If client code has explicitly set the focusability
 * of the Component by either overriding
 * <code>Component.isFocusTraversable()</code> or
 * <code>Component.isFocusable()</code>, or by calling
 * <code>Component.setFocusable()</code>, then the Component will be
 * accepted if and only if it is focusable. If, however, the Component is
 * relying on default focusability, then all Canvases, Labels, Panels,
 * Scrollbars, ScrollPanes, Windows, and lightweight Components will be
 * rejected.
 *
 * @param aComponent the Component whose fitness as a focus owner is to
 *        be tested
 * @return <code>true</code> if aComponent meets the above requirements;
 *         <code>false</code> otherwise
 */
protected boolean accept(Component aComponent) {
    if (!(aComponent.isVisible() && aComponent.isDisplayable() &&
          aComponent.isEnabled()))
    {
        return false;
    }

    // Verify that the Component is recursively enabled. Disabling a
    // heavyweight Container disables its children, whereas disabling
    // a lightweight Container does not.
    if (!(aComponent instanceof Window)) {
        for (Container enableTest = aComponent.getParent();
             enableTest != null;
             enableTest = enableTest.getParent())
        {
            if (!(enableTest.isEnabled() || enableTest.isLightweight())) {
                return false;
            }
            if (enableTest instanceof Window) {
                break;
            }
        }
    }

    boolean focusable = aComponent.isFocusable();
    if (aComponent.isFocusTraversableOverridden()) {
        return focusable;
    }

    ComponentPeer peer = aComponent.getPeer();
    return (peer != null && peer.isFocusable());
}
 

import java.awt.peer.ComponentPeer; //导入方法依赖的package包/类
@SuppressWarnings("deprecation")
public static boolean shouldFocusOnClick(Component component) {
    boolean acceptFocusOnClick = false;

    // A component is generally allowed to accept focus on click
    // if its peer is focusable. There're some exceptions though.


    // CANVAS & SCROLLBAR accept focus on click
    if (component instanceof Canvas ||
        component instanceof Scrollbar)
    {
        acceptFocusOnClick = true;

    // PANEL, empty only, accepts focus on click
    } else if (component instanceof Panel) {
        acceptFocusOnClick = (((Panel)component).getComponentCount() == 0);


    // Other components
    } else {
        ComponentPeer peer = (component != null ? component.getPeer() : null);
        acceptFocusOnClick = (peer != null ? peer.isFocusable() : false);
    }
    return acceptFocusOnClick &&
           AWTAccessor.getComponentAccessor().canBeFocusOwner(component);
}
 

import java.awt.peer.ComponentPeer; //导入方法依赖的package包/类
/**
 * Determines whether a Component is an acceptable choice as the new
 * focus owner. The Component must be visible, displayable, and enabled
 * to be accepted. If client code has explicitly set the focusability
 * of the Component by either overriding
 * {@code Component.isFocusTraversable()} or
 * {@code Component.isFocusable()}, or by calling
 * {@code Component.setFocusable()}, then the Component will be
 * accepted if and only if it is focusable. If, however, the Component is
 * relying on default focusability, then all Canvases, Labels, Panels,
 * Scrollbars, ScrollPanes, Windows, and lightweight Components will be
 * rejected.
 *
 * @param aComponent the Component whose fitness as a focus owner is to
 *        be tested
 * @return {@code true} if aComponent meets the above requirements;
 *         {@code false} otherwise
 */
protected boolean accept(Component aComponent) {
    if (!(aComponent.isVisible() && aComponent.isDisplayable() &&
          aComponent.isEnabled()))
    {
        return false;
    }

    // Verify that the Component is recursively enabled. Disabling a
    // heavyweight Container disables its children, whereas disabling
    // a lightweight Container does not.
    if (!(aComponent instanceof Window)) {
        for (Container enableTest = aComponent.getParent();
             enableTest != null;
             enableTest = enableTest.getParent())
        {
            if (!(enableTest.isEnabled() || enableTest.isLightweight())) {
                return false;
            }
            if (enableTest instanceof Window) {
                break;
            }
        }
    }

    boolean focusable = aComponent.isFocusable();
    if (aComponent.isFocusTraversableOverridden()) {
        return focusable;
    }

    ComponentPeer peer = aComponent.peer;
    return (peer != null && peer.isFocusable());
}