我是一个编程初学者,请耐心等待,我正在尝试使用KeyListener制作计算器,以下是我得到的代码(已剪切)
public void keyPressed(KeyEvent e){
int code = e.getKeyCode();
System.out.println(" Code: " + KeyEvent.getKeyText(code));
if(KeyEvent.VK_ADD == e.getKeyCode()){
tmp = Double.parseDouble(txtDisplay.getText());
txtDisplay.setText(display);
add = true;
}
if(KeyEvent.VK_DIVIDE == e.getKeyCode()){
tmp = Double.parseDouble(txtDisplay.getText());
txtDisplay.setText(display);
div = true;
}
if(KeyEvent.VK_SUBTRACT == e.getKeyCode()){
tmp = Double.parseDouble(txtDisplay.getText());
txtDisplay.setText(display);
sub = true;
}
if(KeyEvent.VK_MULTIPLY == e.getKeyCode()){
tmp = Double.parseDouble(txtDisplay.getText());
txtDisplay.setText(display);
mul = true;
}
if(e.getKeyCode()==KeyEvent.VK_BACK_SPACE){
txtDisplay.setText("");
tmp = 0;
toSolve = 0;
}
if(e.getKeyCode() == KeyEvent.VK_ENTER){
toSolve = Double.parseDouble(txtDisplay.getText());
if( add == true ){
toSolve = tmp + toSolve;}
else if ( sub == true ){
toSolve = tmp - toSolve;}
else if ( mul == true ){
toSolve = tmp * toSolve;}
else if ( div == true ){
toSolve = tmp / toSolve;}
txtDisplay.setText(Double.toString( toSolve ));
add = false ;
sub = false ;
mul = false ;
div = false ;
}
}
我希望它执行所有操作,但当我运行它时,似乎只做了加法。我认为这可能是我的编程逻辑问题。另外,如何从文本字段中删除操作符号,因为它也会转换符号,导致抛出异常。
VK_SLASH
代替VK_DIVIDE
,并使用VK_MINUS
代替VK_SUBTRACT
。 - Sergiy MedvynskyyScriptEngine
来评估文本字段中的表达式。