从参数类示例化新对象

0x6upsns  于 2021-06-27  发布在  Java
关注(0)|答案(1)|浏览(325)

我正在用几个顺序创建的jframes构建一个游戏。对于其中的两个框架（大厅和实际的游戏框架），我采用了像f11一样的全屏模式的用户输入。要进入或离开这个全屏模式，我显然必须处理当前帧并创建一个新的帧作为设置 setUndecorated() 只能在使框架可见之前进行设置。
由于jframes中的其他ui元素将成为关注的焦点，因此我必须使用键绑定。因此，我做了一个进入或离开全屏模式的类。为了明确jframe是否应该在全屏模式下创建，我传递了一个int windowState 作为参数。由于可以示例化两个不同的屏幕，我不能简单地调用类本身，而是需要查看传递给动作事件的帧。
到目前为止，我试着这么做：

public class EnterFullscreen extends AbstractAction{

    private static final long serialVersionUID = 1773898497666165938L;

    private JFrame frame;
    private Class<?> frameType;
    private Constructor<?> c;

    public EnterFullscreen(JFrame frame) {

        this.frame = frame;

        try {
            frameType = frame.getClass();
            c = frameType.getConstructor(String.class);
        } catch (NoSuchMethodException | SecurityException e) {
            e.printStackTrace();
        }

    }

    @Override
    public void actionPerformed(ActionEvent e) {

        try {

            frame.setVisible(false);
            if (frame.isUndecorated()) {
                c.newInstance(0);
            } else {
                c.newInstance(1);
            }

            frame.dispose();

        } catch (InstantiationException | IllegalAccessException | IllegalArgumentException
                | InvocationTargetException e1) {
            e1.printStackTrace();
        }

    }

}

错误消息：

java.lang.NoSuchMethodException: de.munchkin.frontend.Lobby.<init>(java.lang.String)
    at java.lang.Class.getConstructor0(Class.java:3082)
    at java.lang.Class.getConstructor(Class.java:1825)
    at de.munchkin.keybindings.EnterFullscreen.<init>(EnterFullscreen.java:24)
    at de.munchkin.frontend.Lobby.<init>(Lobby.java:45)
    at de.munchkin.frontend.MatchCreation.lambda$1(MatchCreation.java:169)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6539)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
    at java.awt.Component.processEvent(Component.java:6304)
    at java.awt.Container.processEvent(Container.java:2239)
    at java.awt.Component.dispatchEventImpl(Component.java:4889)
    at java.awt.Container.dispatchEventImpl(Container.java:2297)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4904)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4535)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4476)
    at java.awt.Container.dispatchEventImpl(Container.java:2283)
    at java.awt.Window.dispatchEventImpl(Window.java:2746)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
    at java.awt.EventQueue$4.run(EventQueue.java:733)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at de.munchkin.keybindings.EnterFullscreen.actionPerformed(EnterFullscreen.java:40)
    at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1668)
    at javax.swing.JComponent.processKeyBinding(JComponent.java:2882)
    at javax.swing.JComponent.processKeyBindings(JComponent.java:2943)
    at javax.swing.JComponent.processKeyEvent(JComponent.java:2845)
    at java.awt.Component.processEvent(Component.java:6316)
    at java.awt.Container.processEvent(Container.java:2239)
    at java.awt.Component.dispatchEventImpl(Component.java:4889)
    at java.awt.Container.dispatchEventImpl(Container.java:2297)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1954)
    at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:835)
    at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1103)
    at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:974)
    at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:800)
    at java.awt.Component.dispatchEventImpl(Component.java:4760)
    at java.awt.Container.dispatchEventImpl(Container.java:2297)
    at java.awt.Window.dispatchEventImpl(Window.java:2746)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
    at java.awt.EventQueue$4.run(EventQueue.java:733)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

问题是，我得到了这个错误，但找不到问题是什么，因为我认为我正在做的是大多数关于这个主题的so文章所描述的：第1条第2条等等。
这些文章中描述的是，我需要获取构造函数并调用 newInstance() 如果我没有错的话，我就是这么做的。
那么，我需要做些什么不同的事情才能让它发挥作用呢？我真的没有看到任何不同的解决方案中提出的其他so职位以上链接。

JavaClassGenericsInstanceinstantiation

1条答案

按热度按时间
34gzjxbg

34gzjxbg1#

堆栈跟踪显示你的类 Lobby 没有包含一个类型为的参数的构造函数 String .
从你的习惯中 c.newInstance(0) ，我假设构造函数采用int/整数。所以，你应该写：

c = frameType.getConstructor(Integer.class);
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