Gui 程序递增但不递减

Question

此代码应该根据按下的按钮来增加或减少，但是，只有增加才有效。这是代码的花絮，因为我不允许发布整个代码：

作者哈里斯·伊尔沙德：

   Listener listenNow = new Listener();
    decrement.addActionListener(listenNow);
    increment.addActionListener(listenNow);
    panel.add(decrement);
    panel.add(increment);
    panel.add(label);
    frame.add(panel);
    frame.pack();

}

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

private class Listener implements ActionListener {

    public void actionPerformed(ActionEvent anyEvent) {
        if (anyEvent.getSource() == decrement) {
            info = label.getText();
            dec = Integer.parseInt(info);
            dec = dec - 1;
            info = Integer.toString(dec);
            label.setText(info);
        } else if (anyEvent.getSource() == increment) {
            info = label.getText();
        }
        dec = Integer.parseInt(info);
        dec = dec + 1;
        info = Integer.toString(dec);
        label.setText(info);
    }
}

}

Answer 1

花点时间看看你的逻辑......

// If decrement action...
if (anyEvent.getSource() == decrement) {
    // Decrement value...
    info = label.getText();
    dec = Integer.parseInt(info);
    dec = dec - 1;
    info = Integer.toString(dec);
    label.setText(info);
// If increment action...
} else if (anyEvent.getSource() == increment) {
    // Get the text...???
    info = label.getText();
}

// And then increment the value when all else is done...
dec = Integer.parseInt(info);
dec = dec + 1;
info = Integer.toString(dec);
label.setText(info);

所以基本上，当您尝试减少值时，实际上确实会减少它，但会立即再次增加它......

尝试将最后一段代码移到else-if 语句中，例如...

if (anyEvent.getSource() == decrement) {
    info = label.getText();
    dec = Integer.parseInt(info);
    dec = dec - 1;
    info = Integer.toString(dec);
    label.setText(info);
} else if (anyEvent.getSource() == increment) {
    info = label.getText();
    dec = Integer.parseInt(info);
    dec = dec + 1;
    info = Integer.toString(dec);
    label.setText(info);
}

Answer 2

尝试关注

            public void actionPerformed(ActionEvent anyEvent) {
        if (anyEvent.getSource() == decrement) {
            info = label.getText();
            dec = Integer.parseInt(info);
            dec = dec - 1;
            info = Integer.toString(dec);
            label.setText(info);
        } else if (anyEvent.getSource() == increment) {
            info = label.getText();
            dec = Integer.parseInt(info);
            dec = dec + 1;
            info = Integer.toString(dec);
            label.setText(info);

        }
        // These are causing the issue. These should be part of else if (anyEvent.getSource() == increment) { 
        /*dec = Integer.parseInt(info);
        dec = dec + 1;
        info = Integer.toString(dec);
        label.setText(info);*/
        // Coz of above every time this method is called it will result in increment.
    }