android studio 项目 :UI设计 实现简单计算器(实现高精度)
实验二 UI设计(一)
实验目的:
自主完成一个简单APP的设计工作,综合应用已经学到的Android UI设计技巧,重点注意合理使用布局。
实验要求:
1.完成一个计算器的设计,可以以手机自带的计算器为参考。设计过程中,注意考虑界面的美观性,不同机型的适应性,以及功能的完备性。
2.注意结合Activity的生命周期,考虑不同情况下计算器的界面状态。
3.如有余力,可以考虑实现一个高精度科学计算型的计算器。
实现效果:
整数和浮点数的加减乘除、取余、开根号,异号、清零 计算结果全部实现。
精度保留到小数点后100位,比如下面是√3的计算结果。(可以自行修改精度)
完全满足日常使用,可以取代手机自带的计算器软件。。。
程序主要包含Mainactivity.java、Calculator.java 和 activity_main.xml三个文件,分别用于控制、逻辑和视图。符合MVC框架。
文件结构:
代码:
MainActivity.java
package com.example.calculator;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
TextView textView1,textView2,textView_op,textView_res;
Calculator calculator;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView1=(TextView) findViewById(R.id.textview_num1);
textView2=(TextView)findViewById(R.id.textview_num2);
textView_op=(TextView)findViewById(R.id.textview_op);
textView_res=(TextView)findViewById(R.id.textview_res);
Button t_C=(Button) findViewById(R.id.C);
Button t_genhao=(Button) findViewById(R.id.genhao);
Button t_quyu=(Button) findViewById(R.id.quyu);
Button t_add=(Button) findViewById(R.id.add);
Button t_num7=(Button) findViewById(R.id.num7);
Button t_num8=(Button) findViewById(R.id.num8);
Button t_num9=(Button) findViewById(R.id.num9);
Button t_sub=(Button) findViewById(R.id.sub);
Button t_num4=(Button) findViewById(R.id.num4);
Button t_num5=(Button) findViewById(R.id.num5);
Button t_num6=(Button) findViewById(R.id.num6);
Button t_xinghao=(Button) findViewById(R.id.xinghao);
Button t_num1=(Button) findViewById(R.id.num1);
Button t_num2=(Button) findViewById(R.id.num2);
Button t_num3=(Button) findViewById(R.id.num3);
Button t_chuhao=(Button) findViewById(R.id.chuhao);
Button t_jiahuojian=(Button) findViewById(R.id.jiahuojian);
Button t_num0=(Button) findViewById(R.id.num0);
Button t_dian=(Button) findViewById(R.id.dian);
Button t_denhao=(Button) findViewById(R.id.denhao);
calculator=new Calculator();
View.OnClickListener buttonlistener=new View.OnClickListener() {
@Override
public void onClick(View view) {
String show=((Button)view).getText().toString();
calculator.process(show);
textView1.setText(calculator.getSnum1());
textView_op.setText(calculator.getSop());
textView2.setText(calculator.getSnum2());
textView_res.setText(calculator.getSres());
}
};
t_num0.setOnClickListener(buttonlistener);
t_num1.setOnClickListener(buttonlistener);
t_num2.setOnClickListener(buttonlistener);
t_num3.setOnClickListener(buttonlistener);
t_num4.setOnClickListener(buttonlistener);
t_num5.setOnClickListener(buttonlistener);
t_num6.setOnClickListener(buttonlistener);
t_num7.setOnClickListener(buttonlistener);
t_num8.setOnClickListener(buttonlistener);
t_num9.setOnClickListener(buttonlistener);
t_C.setOnClickListener(buttonlistener);
t_genhao.setOnClickListener(buttonlistener);
t_quyu.setOnClickListener(buttonlistener);
t_jiahuojian.setOnClickListener(buttonlistener);
t_add.setOnClickListener(buttonlistener);
t_sub.setOnClickListener(buttonlistener);
t_xinghao.setOnClickListener(buttonlistener);
t_chuhao.setOnClickListener(buttonlistener);
t_dian.setOnClickListener(buttonlistener);
t_denhao.setOnClickListener(buttonlistener);
}
}
Calculator.java
package com.example.calculator;
import static java.math.BigDecimal.ROUND_HALF_UP;
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
public class Calculator {
BigDecimal b1,b2,bres;
boolean floatflag1,floatflag2;
int scale;
String snum1,snum2,sop,sres;
enum state{state_i1,state_i2,state_init,state_res};
state s;
//enum operator{op_add,op_sub,op_mul,op_div,op_none}
//operator op;
public Calculator(){
scale=100;
floatflag1=false;
floatflag2=false;
clear();
}
public void process(String show)
{
if(show.charAt(0)>='0'&& show.charAt(0)<='9')//输入数字
{
switch (s)
{
case state_init:
if(show.charAt(0)=='0')break;
snum1=show;
s=state.state_i1;
break;
case state_i1:
snum1+=show;
break;
case state_i2:
snum2+=show;
break;
case state_res:
clear();
process(show);
break;
}
}
else//输入操作符
{
switch (show)
{
case "C":
clear();
break;
case "+":
switch (s)
{
case state_init: sop=show;s=state.state_i2;
break;
case state_i1: sop=show;s=state.state_i2;
break;
case state_i2:
if(snum2=="")
{
sop=show;
break;
}
snum1=getres(2);snum2="";sres="";sop=show;
break;
case state_res:
if(sres.contains("error"))
{
clear();
break;
}
sop=show;snum1=sres;snum2="";sres="";s=state.state_i2;
break;
}
break;
case "=":
switch (s)
{
case state_i1:
if(snum1.charAt(snum1.length()-1)=='.')snum1+="0";
sres=snum1;
snum1="";
snum2="";
sop="";
s=state.state_res;
break;
case state_i2:
if(snum2=="")break;
if(snum2.charAt(snum2.length()-1)=='.')break;
sres=getres(2);
snum1="";
snum2="";
sop="";
s=state.state_res;
break;
default:break;
}
break;
case "-":
switch (s)
{
case state_init: sop=show;s=state.state_i2;
break;
case state_i1: sop=show;s=state.state_i2;
break;
case state_i2:
if(snum2=="")
{
sop=show;
break;
}
snum1=getres(2);snum2="";sres="";sop=show;
break;
case state_res:
if(sres.contains("error"))
{
clear();
break;
}
sop=show;snum1=sres;snum2="";sres="";s=state.state_i2;
break;
}
break;
case "*":
switch (s)
{
case state_init: sop=show;s=state.state_i2;
break;
case state_i1: sop=show;s=state.state_i2;
break;
case state_i2:
if(snum2=="")
{
sop=show;
break;
}
snum1=getres(2);snum2="";sres="";sop=show;
break;
case state_res:
if(sres.contains("error"))
{
clear();
break;
}
sop=show;snum1=sres;snum2="";sres="";s=state.state_i2;
break;
}
break;
case "/":
switch (s)
{
case state_init: sop=show;s=state.state_i2;
break;
case state_i1: sop=show;s=state.state_i2;
break;
case state_i2:
if(snum2=="")
{
sop=show;
break;
}
snum1=getres(2);snum2="";sres="";sop=show;
break;
case state_res:
if(sres.contains("error"))
{
clear();
break;
}
sop=show;snum1=sres;snum2="";sres="";s=state.state_i2;
break;
}
break;
case "√":
switch (s)
{
case state_init: snum1="";snum2="";sop="";sres="0";s=state.state_res;
break;
case state_i1: sop=show;sres=getres(1);snum1="";snum2="";sop="";s=state.state_res;
break;
case state_i2:
if(snum2=="")break;
String t=snum1;snum1=snum2;
String t_op=sop;sop=show;
snum2=getres(1);
snum1=t;
sop=t_op;
sres="";
break;
case state_res:
if(sres.contains("error"))
{
clear();
break;
}
sop=show;
snum1=sres;
sres=getres(1);
snum1="";
sop="";
break;
}
break;
case "%":
switch (s)
{
case state_init:
break;
case state_i1:
if(snum1.contains("."))break;
sop=show;s=state.state_i2;
break;
case state_i2:
if(snum2=="")
{
if(!snum1.contains("."))
sop=show;
break;
}
snum1=getres(2);snum2="";sres="";sop=show;
break;
case state_res:
if(sres.contains("error"))
{
clear();
break;
}
if(sres.contains("."))break;
sop=show;snum1=sres;snum2="";sres="";s=state.state_i2;
break;
}
break;
case "+/-":
switch (s)
{
case state_init:
break;
case state_i1:
if(snum1.charAt(0)!='-')
snum1="-"+snum1;
else snum1=snum1.substring(1);
break;
case state_i2:
if(snum2=="")break;
if(snum2.charAt(0)!='-')
snum2="-"+snum2;
else snum2=snum2.substring(1);
break;
case state_res:
if(sres.contains("error"))
{
clear();
break;
}
if(sres.charAt(0)!='-'&& !sres.equals(0))
sres="-"+sres;
else sres=sres.substring(1);
snum1=sres;
snum2="";
sres="";
sop="";
if(snum1.equals("0"))
s=state.state_init;
else
s=state.state_i1;
break;
}
break;
case ".":
switch (s)
{
case state_init:
snum1+=show;
s=state.state_i1;
break;
case state_i1:
if(snum1.contains("."))break;
else snum1+=show;
break;
case state_i2:
if(snum2.equals("")){
if(sop.equals("%"))break;
snum2="0.";
break;
}
if(sop.equals("%")||snum2.contains("."))break;
else snum2+=show;
break;
case state_res:
break;
}
break;
}
}
}
public String getSnum1()
{
return snum1;
}
public String getSnum2()
{
return snum2;
}
public String getSop()
{
return sop;
}
public String getSres()
{
return sres;
}
public void clear()
{
snum1="0";
snum2="";
sop="";
sres="";
s=state.state_init;
b1=BigDecimal.valueOf(0);
b2=BigDecimal.valueOf(0);
bres=BigDecimal.valueOf(0);
}
public String getres(int flag)
{
String t="null";
if(flag==1)
{
b1=new BigDecimal(snum1);
if(snum1.equals("0"))return t="0";
if(sop.equals("√"))
{
bres=sqrt(b1,scale);
t=bres.toString();
return t;
}
else if(sop.equals("+/-"))
{
//略了,直接字符串处理
}
}
else if(flag==2)
{
b1=new BigDecimal(snum1);
b2=new BigDecimal(snum2);
switch (sop)
{
case "+":
bres=b1.add(b2);
t=bres.toString();
break;
case "-":
bres=b1.subtract(b2);
t=bres.toString();
break;
case "*":
bres=b1.multiply(b2);
t=bres.toString();
break;
case "/":
if(b2.equals(BigDecimal.valueOf(0)))return t="error: / by zero";
bres=b1.divide(b2,scale,RoundingMode.HALF_UP);
t=bres.toString();
break;
case "%":
if(b2.equals(BigDecimal.valueOf(0)))return t="error: / by zero";
bres=b1.remainder(b2);
t=bres.toString();
break;
}
}
return t;
}
public static BigDecimal sqrt(BigDecimal value, int scale){ //高精度浮点数开根号
BigDecimal num2 = BigDecimal.valueOf(2);
int precision = 100;
MathContext mc = new MathContext(precision, RoundingMode.HALF_UP);
BigDecimal deviation = value;
int cnt = 0;
while (cnt < precision) {
deviation = (deviation.add(value.divide(deviation, mc))).divide(num2, mc);
cnt++;
}
deviation = deviation.setScale(scale, BigDecimal.ROUND_HALF_UP);
return deviation;
}
}
布局文件:activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/textview_num1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="0"
android:textAlignment="textEnd"
android:textColor="#009688"
android:textSize="24sp"
android:textStyle="bold" />
<TextView
android:id="@+id/textview_op"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text=""
android:textAlignment="textEnd"
android:textColor="#009688"
android:textSize="24sp"
android:textStyle="bold" />
<TextView
android:id="@+id/textview_num2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text=""
android:textAlignment="textEnd"
android:textColor="#009688"
android:textSize="24sp"
android:textStyle="bold" />
<TextView
android:id="@+id/textview_res"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text=""
android:textAlignment="textEnd"
android:textColor="#009688"
android:textSize="24sp"
android:textStyle="bold" />
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
<Button
android:id="@+id/C"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="C" />
<Button
android:id="@+id/genhao"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="√" />
<Button
android:id="@+id/quyu"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="%" />
<Button
android:id="@+id/add"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="+" />
</LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
<Button
android:id="@+id/num7"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="7" />
<Button
android:id="@+id/num8"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="8" />
<Button
android:id="@+id/num9"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="9" />
<Button
android:id="@+id/sub"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="-" />
</LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
<Button
android:id="@+id/num4"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="4" />
<Button
android:id="@+id/num5"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="5" />
<Button
android:id="@+id/num6"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="6" />
<Button
android:id="@+id/xinghao"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="*" />
</LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
<Button
android:id="@+id/num1"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="1" />
<Button
android:id="@+id/num2"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="2" />
<Button
android:id="@+id/num3"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="3" />
<Button
android:id="@+id/chuhao"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="/" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
<Button
android:id="@+id/jiahuojian"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="+/-" />
<Button
android:id="@+id/num0"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="0" />
<Button
android:id="@+id/dian"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="." />
<Button
android:id="@+id/denhao"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="=" />
</LinearLayout>
</LinearLayout>