java计算器 图形用户界面 升级版v2.0 （限制位数显示+四舍五入的处理）(五)
ase 1:
num_record = num_record + Double.parseDouble(str);break;
case 2:
num_record = num_record - Double.parseDouble(str);break;
case 3:
num_record = num_record * Double.parseDouble(str);break;
case 4:
num_record = num_record / Double.parseDouble(str);break;
case 5:break;
}
show_str=show_str+text_show.getText()+"-";
text_show1.setText(show_str);
str="";
count_point=0;
text_show.setText("");
operator=2;
}
}
}
});
button_multiplication.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (str.equals("")) {}
else {
switch (operator) {
case 0:
num_record = Double.parseDouble(str);break;
case 1:
num_record = num_record + Double.parseDouble(str);break;
case 2:
num_record = num_record - Double.parseDouble(str);break;
case 3:
num_record = num_record * Double.parseDouble(str);break;
case 4:
num_record = num_record / Double.parseDouble(str);break;
case 5:break;
}
show_str = show_str + text_show.getText() + "*";
text_show1.setText(show_str);
str="";
count_point=0;
text_show.setText("");
operator=3;
}
}
});
button_division.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (str.equals("")) {}
else {
switch (operator) {
case 0:
num_record = Double.parseDouble(str);break;
case 1:
num_record = num_record + Double.parseDouble(str);break;
case 2:
num_record = num_record - Double.parseDouble(str);break;
case 3:
num_record = num_record * Double.parseDouble(str);break;
case 4:
num_record = num_record / Double.parseDouble(str);break;
case 5:break;
}
}
show_str = show_str + text_show.getText()+"/";
text_show1.setText(show_str);
str="";
count_point=0;
text_show.setText("");
operator=4;
}
});
button_equal.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (str.equals("")) {}
else {
switch (operator) {
case 0:
num_record = Double.parseDouble(str);break;
case 1:
num_record = num_record + Double.parseDouble(str);break;
case 2:
num_record = num_record - Double.parseDouble(str);break;
case 3:
num_record = num_record * Double.parseDouble(str);break;
case 4:
num_record = num_record / Double.parseDouble(str);break;
case 5:break;
}
}
show_str="";
count_point=0;
//输出显示
text_show1.setText("");
if(num_record-(int)num_record==0){
text_show.setText(""+(int)num_record);
}
else{//保留总共15位数字，确保显示框能装下
if((""+num_record).length()>
16){
String s=(""+num_record).substring(0,16);
text_show.setText(round(s));//四舍五入处理
}
else{
text_show.setText(""+num_record);
}
}
operator=5;
}
});
}
public String round(String s){//四舍五入
double k;
String s1;
int len;//小数的位数（15位以内）
k=Double.parseDouble(s);
s1=""+(i