XCode Interface Builder开发——2
XCode Interface Builder开发——2app
简单的练手项目--仿苹果自备的计算器
简介
制做一个简易功能的计算器并不是难事，可是其中要考虑的不一样状况却仍有许多，稍不留神就会踩坑。
例如：ide
- 在输入完运算符后若是直接输入负号或者小数点的状况
- 连续运算的状况
- 在输入等号后继续运算或直接输入数字进行下一轮的计算的状况
- 小数状况下，精度带来的问题
- ... ...
设计思想
按照编译原理中的三元式的思想，为了区分输入的第一运算对象和第二运算对象，我分别将其命名为firstNum和secondNum，并将它们做为ViewController的属性。而且为了区分计算器当前处于何种模式下（点击小数点后的小数模式、点击负号的负号模式、待第二个数输入的模式等等），我又将各类不一样的BOOL型变量设置为其属性供各类方法下调用。网站
话很少说，看代码：ui
//
// ViewController.m
// MyFirstApp
//
// Created by solist on 2019/1/31.
// Copyright © 2019 solist. All rights reserved.
//
#import "ViewController.h"
@interface ViewController ()
@property(nonatomic) double firstNum;
@property(nonatomic) double secondNum;
@property(nonatomic) BOOL fistNumIsActive;
@property(nonatomic) BOOL isWaitingForSecondNum;
@property(nonatomic) BOOL isTappingSecondNum;
@property(nonatomic) BOOL isNegativeNum;
@property(nonatomic) BOOL isBeginNegativeNum;
@property(nonatomic) BOOL isAfterEqual;
@property(nonatomic) BOOL isTappingDecimals;
@property(nonatomic) float decimalRecord;
@property(nonatomic,weak) NSString *operation;
@property (weak, nonatomic) IBOutlet UITextField *result;
@end
@implementation ViewController
//初始化属性
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
_firstNum=0.0;
_secondNum=0.0;
_fistNumIsActive=YES;
_isTappingSecondNum=NO;
_isWaitingForSecondNum=NO;
_isNegativeNum=NO;
_isBeginNegativeNum=NO;
_isAfterEqual=NO;
_isTappingDecimals=NO;
_decimalRecord=0.1;
[self updateScreen:0.0];
}
//更新屏幕数据（对象方法，在不一样的按钮响应事件中调用）
-(void)updateScreen:(double) num{
_result.text=[NSString stringWithFormat:@"%f", num];
}
//清空（与清空“AC”的Btn链接）
- (IBAction)AC {
_result.text=@"0";
_firstNum=0.0;
_secondNum=0.0;
//更新数据
[self updateScreen:_firstNum];
_fistNumIsActive=YES;
_isWaitingForSecondNum=NO;
_isTappingSecondNum=NO;
_isNegativeNum=NO;
_isBeginNegativeNum=NO;
_isAfterEqual=NO;
_isTappingDecimals=NO;
_decimalRecord=0.1;
_operation=@"nil";
}
//正负数转换（与负号“-”的Btn链接）
- (IBAction)pnConversion{
if(_isWaitingForSecondNum||_firstNum==0){
_isBeginNegativeNum=!_isBeginNegativeNum;
_isNegativeNum=!_isNegativeNum;
//_secondNum=0;
_isWaitingForSecondNum=NO;
if(_isBeginNegativeNum&&!_isAfterEqual){
[self updateScreen:-0.0];
}
else if(_isAfterEqual){
_firstNum=-_firstNum;
[self updateScreen:_firstNum];
}
else{
[self updateScreen:+0.f];
}
}
else{
_isNegativeNum=!_isNegativeNum;
if(!_isTappingSecondNum){
//修改第一个数的符号位
_firstNum=0-_firstNum;
[self updateScreen:_firstNum];
}
else{
if(_fistNumIsActive){
//当修改数为结果时
//修改第一个数的符号位
_firstNum=0-_firstNum;
[self updateScreen:_firstNum];
}
else{
//修改第二个数的符号位
_secondNum=0-_secondNum;
if(_firstNum==0){
_firstNum=-0.0;
}
[self updateScreen:_secondNum];
}
}
}
}
//百分号转换（与百分号“%”的Btn链接）
- (IBAction)percentageConversion {
if(!_isTappingSecondNum)
{
//将第一个数改成百分数
_firstNum=_firstNum/100.0;
[self updateScreen:_firstNum];
}
else{
if(_fistNumIsActive){
//当修改数为结果时
//将第一个数改成百分数
_firstNum=_firstNum/100.0;
[self updateScreen:_firstNum];
}
else{
//将第二个数改成百分数
_secondNum=_secondNum/100.0;
[self updateScreen:_secondNum];
}
}
}
//除法（与乘号“x”的Btn链接）
- (IBAction)divide {
//取消小数功能
_decimalRecord=0.1;
//一、输入等号后继续输入的状况
if(_isAfterEqual){
_isAfterEqual=!_isAfterEqual;
}
_isNegativeNum=NO;
_isBeginNegativeNum=NO;
//二、连续输入的状况
if(_isTappingSecondNum){
NSArray *operationsArray = @[@"add", @"sub", @"multi",@"divide"];
//得到上次的运算符
NSUInteger item = [operationsArray indexOfObject:_operation];
float theResult;
switch (item) {
case 0:
theResult=_firstNum+_secondNum;
break;
case 1:
theResult=_firstNum-_secondNum;
break;
case 2:
theResult=_firstNum*_secondNum;
break;
case 3:
theResult=_firstNum/_secondNum;
default:
break;
}
//在屏幕上输出结果
[self updateScreen:theResult];
//更新firstNum
_firstNum=theResult;
}
//更新firstNum
_firstNum=[_result.text floatValue];
//修改运算符号，并通知下一步为输入secondNum
_isWaitingForSecondNum=YES;
_fistNumIsActive=NO;
_secondNum=0;
_operation=@"divide";
_isTappingSecondNum=NO;
_isTappingDecimals=NO;
}
//乘法（与乘号“✖️”的Btn链接）
- (IBAction)multi {
//取消小数功能
_decimalRecord=0.1;
if(_isAfterEqual){
_isAfterEqual=!_isAfterEqual;
}
_isNegativeNum=NO;
_isBeginNegativeNum=NO;
//连续输入的状况
if(_isTappingSecondNum){
NSArray *operationsArray = @[@"add", @"sub", @"multi",@"divide"];
//得到上次的运算符
NSUInteger item = [operationsArray indexOfObject:_operation];
float theResult;
switch (item) {
case 0:
theResult=_firstNum+_secondNum;
break;
case 1:
theResult=_firstNum-_secondNum;
break;
case 2:
theResult=_firstNum*_secondNum;
break;
case 3:
theResult=_firstNum/_secondNum;
default:
break;
}
//在屏幕上输出结果
[self updateScreen:theResult];
//更新firstNum
_firstNum=theResult;
}
//更新firstNum
_firstNum=[_result.text floatValue];
//修改运算符号，并通知下一步为输入secondNum
_isWaitingForSecondNum=YES;
_fistNumIsActive=NO;
_secondNum=0;
_operation=@"multi";
_isTappingSecondNum=NO;
_isTappingDecimals=NO;
}
//减法（与减号“-”的Btn链接）
- (IBAction)sub {
//取消小数功能
_decimalRecord=0.1;
if(_isAfterEqual){
_isAfterEqual=!_isAfterEqual;
}
_isNegativeNum=NO;
_isBeginNegativeNum=NO;
//连续输入的状况
if(_isTappingSecondNum){
NSArray *operationsArray = @[@"add", @"sub", @"multi",@"divide"];
//得到上次的运算符
NSUInteger item = [operationsArray indexOfObject:_operation];
float theResult;
switch (item) {
case 0:
theResult=_firstNum+_secondNum;
break;
case 1:
theResult=_firstNum-_secondNum;
break;
case 2:
theResult=_firstNum*_secondNum;
break;
case 3:
theResult=_firstNum/_secondNum;
default:
break;
}
//在屏幕上输出结果
[self updateScreen:theResult];
//更新firstNum
_firstNum=theResult;
}
//更新firstNum
_firstNum=[_result.text floatValue];
//修改运算符号，并通知下一步为输入secondNum
_isWaitingForSecondNum=YES;
_fistNumIsActive=NO;
_secondNum=0;
_operation=@"sub";
_isTappingSecondNum=NO;
_isTappingDecimals=NO;
}
//加法（与“+”的Btn链接）
- (IBAction)add {
//取消小数功能
_decimalRecord=0.1;
if(_isAfterEqual){
_isAfterEqual=!_isAfterEqual;
}
_isNegativeNum=NO;
_isBeginNegativeNum=NO;
//连续输入的状况
if(_isTappingSecondNum){
NSArray *operationsArray = @[@"add", @"sub", @"multi",@"divide"];
//得到上次的运算符
NSUInteger item = [operationsArray indexOfObject:_operation];
float theResult;
switch (item) {
case 0:
theResult=_firstNum+_secondNum;
break;
case 1:
theResult=_firstNum-_secondNum;
break;
case 2:
theResult=_firstNum*_secondNum;
break;
case 3:
theResult=_firstNum/_secondNum;
default:
break;
}
//在屏幕上输出结果
[self updateScreen:theResult];
//更新firstNum
_firstNum=theResult;
}
//更新firstNum
_firstNum=[_result.text floatValue];
//修改运算符号，并通知下一步为输入secondNum
_isWaitingForSecondNum=YES;
_fistNumIsActive=NO;
_secondNum=0;
_operation=@"add";
_isTappingSecondNum=NO;
_isTappingDecimals=NO;
}
//等号（与等号的Btn链接）
- (IBAction)equal {
//取消小数功能
_decimalRecord=0.1;
_isNegativeNum=NO;
_isBeginNegativeNum=NO;
_isTappingSecondNum=NO;
NSArray *operationsArray = @[@"add", @"sub", @"multi",@"divide"];
NSUInteger item = [operationsArray indexOfObject:_operation];
//特殊状况:secondNum未输入，按secondNum=firstNum
if(_isWaitingForSecondNum){
_secondNum=_firstNum;
}
//进行计算
float theResult;
BOOL error=NO;
switch (item) {
case 0:
theResult=_firstNum+_secondNum;
break;
case 1:
theResult=_firstNum-_secondNum;
break;
case 2:
theResult=_firstNum*_secondNum;
break;
case 3:
if(_secondNum==0.0){
error=YES;
}else{
theResult=_firstNum/_secondNum;
}
break;
default:
//当无运算符时，即清空后只输入了firstNum
theResult=_firstNum;
break;
}
//在屏幕上输出结果
if(error){
//输出错误提示
_result.text=@"错误";
_firstNum=0.0;
}
else{
[self updateScreen:theResult];
}
//为下一次计算作准备
_firstNum=theResult;
_secondNum=0.0;
_fistNumIsActive=YES;
_isWaitingForSecondNum=YES;
_isTappingSecondNum=NO;
_isBeginNegativeNum=NO;
_isNegativeNum=NO;
_isAfterEqual=YES;
}
//点击数字1（与数字1的Btn链接）
- (IBAction)_1 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-1.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-1.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+1.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+1.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-1.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-1.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+1.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+1.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_2 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-2.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-2.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+2.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+2.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-2.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-2.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+2.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+2.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_3 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-3.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-3.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+3.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+3.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-3.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-3.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+3.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+3.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_4 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-4.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-4.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+4.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+4.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-4.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-4.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+4.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+4.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_5 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-5.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-5.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+5.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+5.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-5.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-5.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+5.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+5.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_6 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-6.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-6.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+6.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+6.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-6.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-6.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+6.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+6.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_7 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-7.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-7.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+7.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+7.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-7.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-7.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+7.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+7.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_8 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-8.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-8.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+8.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+8.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-8.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-8.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+8.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+8.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_9 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-9.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-9.0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+9.0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+9.0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-9.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-9.f;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+9.f*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+9.f;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
- (IBAction)_0 {
//进行下一轮的计算
if(_isAfterEqual){
[self AC];
}
if(_fistNumIsActive){
//正在输入第一个数
if(_isNegativeNum){
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum-0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0-0;
}
}
else{
if(_isTappingDecimals){
//输入了小数点模式后
_firstNum=_firstNum+0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_firstNum=_firstNum*10.0+0;
}
}
//更新屏幕
[self updateScreen:_firstNum];
_isWaitingForSecondNum=NO;
}
else{
//正在输入第二个数
_isTappingSecondNum=YES;
if(_isNegativeNum){
//_secondNum=_secondNum*10.f-1.f;
if(_isTappingDecimals){
_secondNum=_secondNum-0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f-0;
}
}
else{
//_secondNum=_secondNum*10.f+1.f;
if(_isTappingDecimals){
_secondNum=_secondNum+0*_decimalRecord;
_decimalRecord*=0.1;
}
else{
_secondNum=_secondNum*10.f+0;
}
}
//更新屏幕
[self updateScreen:_secondNum];
_isWaitingForSecondNum=NO;
}
}
//小数点（与小数点“.”的Btn链接）
- (IBAction)decimalPoint {
//当输入完小数点再输入数字后再次输入小数点则无效
if(_decimalRecord==0.1f){
_isTappingDecimals=!_isTappingDecimals;
}
//判断当前数字是否为整数
double tmp=[_result.text doubleValue];
double eps = 1e-10;
BOOL isInteger = tmp - floor(tmp) < eps;
if(_isTappingDecimals&&isInteger){
NSString*content =_result.text;
NSMutableAttributedString*attributeString = [[NSMutableAttributedString alloc]initWithString:content];
NSUInteger Loc = [[attributeString string] rangeOfString:@"."].location;
// 须要改变的区间
NSRange range = NSMakeRange(Loc, 1);
// 改变小数点颜色
[attributeString addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:range];
// 为label添加Attributed
[_result setAttributedText:attributeString];
}
else{
NSString*content =_result.text;
NSMutableAttributedString*attributeString = [[NSMutableAttributedString alloc]initWithString:content];
NSUInteger Loc = [[attributeString string] rangeOfString:@"."].location;
// 须要改变的区间
NSRange range = NSMakeRange(Loc, 1);
// 改变小数点颜色
[attributeString addAttribute:NSForegroundColorAttributeName value:[UIColor blackColor] range:range];
// 为label添加Attributed
[_result setAttributedText:attributeString];
}
//若按完j运算符再点击小数点时，更新屏幕显示（+0或-0）
if(_isWaitingForSecondNum&&_isTappingDecimals){
[self updateScreen:0.0];
NSString*content =_result.text;
NSMutableAttributedString*attributeString = [[NSMutableAttributedString alloc]initWithString:content];
NSUInteger Loc = [[attributeString string] rangeOfString:@"."].location;
// 须要改变的区间
NSRange range = NSMakeRange(Loc, 1);
// 改变小数点颜色
[attributeString addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:range];
// 为label添加Attributed
[_result setAttributedText:attributeString];
}
}
@end
成品图
遇到的坑
以前我将firstNum和secondNum的类型设置的是float，在一开始的调试过程当中一直未出现问题，可是当写小数功能时发现了问题，当我利用nsLog打印出结果时发现：111.01+0.001的结果不等于111.011而是等于111.01098......，后来发现是由于float自身的精度问题（7位有效数字），在将float修改成double（16位有效数字）后有所改善，但遇到位数更多的小数仍会出现该问题。
关于精度的问题，我以为这个网站讲的不错，能够参考这个网站：https://www.jianshu.com/p/9cbed21f37fe
对于须要更多精确计算的方法，也能够试试封装的NSDecimalNumber类，在这里由于没怎么用过，就不说了。
整体来讲，此次设计遇到的问题主要集中在逻辑设计，须要考虑到用户的误操做（被除数为0等状况）以及数字精度问题，其余来讲没有难度，能够看成IOS的初学练手。atom
按钮的圆形设计
我主要是经过修改按钮的layer.cornerRadius属性来实现的，这里我提供一个简单的方法，直接经过storyBoard来进行设置，以下图所示：
设计
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相关文章
- 1. iOS interface builder + AutoLayout 高效开发
- 2. Unknown Class **** in Interface Builder file
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- 10. iOS之界面开发屏幕适配Interface Builder、Storyboard、Xib、Nib、AutoSizing、AutoLayout、Masonry