如何在条件下启用 JButton？

Question

我正在尝试创建一个在满足特定条件时启用的 JButton。程序初始值为setEnabled(false)，更新后应该是setEnabled(true).

我尝试了几件事。这里有一些代码：

public class SwimAction extends AbstractAction {
    private final PoolModel poolModel;
    private final Swimmer swimmer;

    public SwimAction(PoolModel poolModel, Swimmer swimmer) {
        super("GO!");
        this.poolModel = poolModel;
        this.swimmer = swimmer;
        // default
        setEnabled(false);
    }

我尝试了以下方法：

// Replaced the setEnabled(false) by setEnabled(checkGo())
public boolean checkGo(){
        return(pool.isNotOccupied());
    }

// Overwrite setEnabled
@Overwrite
public void setEnabled(boolean bool){
        boolean oldBool = this.enabled;
        if (oldBool != bool && pool.isNotOccupied()) {
            this.enabled = bool;
            this.firePropertyChange("enabled", oldBool, bool);
        }
    }

但是，其中 none 有效。任何人都知道如何在满足特定条件 (pool.isNotOccupied()) 时启用按钮？

Answer 1

似乎您需要侦听池对象占用状态的变化属性，最好的方法是为其提供某种侦听器。这可以像 ChangeListener 一样简单，或者更好的是 PropertyChangeListener。最佳解决方案的细节可能在很大程度上取决于您的程序的结构，以及我们看不到的其余代码，但是，如果 PoolModel 是您正在收听的内容，如果您给它...

public class PoolModel {
    public static final String OCCUPIED = "occupied";
    private PropertyChangeSupport propChangeSupport = new PropertyChangeSupport(this);
    private boolean occupied;
    
    public void addPropertyChangeListener(PropertyChangeListener l) {
        propChangeSupport.addPropertyChangeListener(l);
    }
    
    // also have a remove listener
    
    public boolean isOccupied() {
        return occupied;
    }
    
    public void setOccupied(boolean occupied) {
        boolean oldValue = this.occupied;
        boolean newValue = occupied;
        this.occupied = occupied;
        propChangeSupport.firePropertyChange(OCCUPIED, oldValue, newValue);
    }
    
    // ......

然后在使用它的代码中：

poolModel.addPropertyChangeListener(pcEvent -> {
    if (pcEvent.getPropertyName().equals(OCCUPIED)) {
        setEnabled((boolean) pcEvent.getNewValue());
    }
});

如何在条件下启用 JButton？

How to enable a JButton on a condition?

java

swing

components

jbutton

isenabled