Question

我的代码中出现了这个编译错误：

方法add（UComponent comp，KopiAlignment约束）;对于DBlock类型来说是不明确的......

我想创建UBlock接口来为现有的类DBlock进行抽象

以下是代码：

界面UBlock：

public interface UBlock extends UComponent, BlockListener {
   public void add(UComponent comp, KopiAlignment constraints);
}

类DBlock：

public class DBlock extends JPanel implements  UBlock {
    public void add(UComponent comp, KopiAlignment constraints) {
    } 
}

我在另一个类中调用add方法：

private DBlock blockView;

blockView.add(displays[i], new KopiAlignment(chartPos + leftOffset, i + 1, 1, false));

当我从DBlock中删除UBlock的实现时错误不再存在，这里是被调用的方法：

/**
 * Adds the specified component to the end of this container.
 * Also notifies the layout manager to add the component to 
 * this container's layout using the specified constraints object.
 * This is a convenience method for {@link #addImpl}.
 * <p>
 * Note: If a component has been added to a container that
 * has been displayed, <code>validate</code> must be
 * called on that container to display the new component.
 * If multiple components are being added, you can improve
 * efficiency by calling <code>validate</code> only once,
 * after all the components have been added.
 *
 * @param     comp the component to be added
 * @param     constraints an object expressing 
 *                  layout contraints for this component
 * @exception NullPointerException if {@code comp} is {@code null}
 * @see #addImpl
 * @see #validate
 * @see javax.swing.JComponent#revalidate()
 * @see       LayoutManager
 * @since     JDK1.1
 */
public void add(Component comp, Object constraints) {
    addImpl(comp, constraints, -1);
}

那我怎么解决这个问题呢？

Answer 1

问题是您继承了另一个add方法。这意味着在DBlock课程中您同时拥有

public void add(UComponent comp, KopiAlignment constraints)

和

public void add(Component comp, Object constraints)

随时为您服务。

现在KopiAlignment是Object的子类型，我猜UComponent是Component的子类型。这意味着当您使用add和UComponent作为参数调用KopiAlignment时，参数类型适合这两种方法，尽管它们正式具有不同的签名。

据我所知，没有真正的方法可以解决这个问题。

方法“XXX”对于类型是不明确的

1 个答案: