AndroidStudio实现简易计算器（表格布局TableLayout）

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>


 
 
 

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>

  // 圆角
  //颜色

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>



 
 
 

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>



  //默认颜色
  //按下的改变的颜色

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>



 


 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 
 

 

 

 

 

 

 


 

 

 

 


 

package com.example.calculator;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

 Button btn_clean,btn_del,btn_divide,btn_0,btn_1,btn_2,btn_3,btn_4,btn_5,btn_6,btn_7,btn_8,btn_9,
 btn_multiply,btn_add,btn_minus,btn_point,btn_equal;
 TextView textView;
 boolean clear_flag;  //清空标识
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate (savedInstanceState);
 setContentView (R.layout.activity_main);
 btn_0 = findViewById(R.id.btn_0); //初始化
 btn_1 = findViewById(R.id.btn_1);
 btn_2 = findViewById(R.id.btn_2);
 btn_3 = findViewById(R.id.btn_3);
 btn_4 = findViewById(R.id.btn_4);
 btn_5 = findViewById(R.id.btn_5);
 btn_6 = findViewById(R.id.btn_6);
 btn_7 = findViewById(R.id.btn_7);
 btn_8 = findViewById(R.id.btn_8);
 btn_9 = findViewById(R.id.btn_9);
 btn_multiply = findViewById(R.id.btn_multiply);
 btn_divide = findViewById(R.id.btn_divide);
 btn_add = findViewById(R.id.btn_add);
 btn_minus = findViewById(R.id.btn_minus);
 btn_point = findViewById(R.id.btn_point);
 btn_del =findViewById(R.id.btn_del);
 btn_equal = findViewById(R.id.btn_equal);
 btn_clean = findViewById(R.id.btn_clean);

 textView = findViewById(R.id.textView);

 btn_0.setOnClickListener(this); //设置按钮的点击事件
 btn_1.setOnClickListener(this);
 btn_2.setOnClickListener(this);
 btn_3.setOnClickListener(this);
 btn_4.setOnClickListener(this);
 btn_5.setOnClickListener(this);
 btn_6.setOnClickListener(this);
 btn_7.setOnClickListener(this);
 btn_8.setOnClickListener(this);
 btn_9.setOnClickListener(this);
 btn_minus.setOnClickListener(this);
 btn_multiply.setOnClickListener(this);
 btn_del.setOnClickListener(this);
 btn_divide.setOnClickListener(this);
 btn_point.setOnClickListener(this);
 btn_add.setOnClickListener(this);
 btn_equal.setOnClickListener(this);
 btn_clean.setOnClickListener(this);
 }

 public void onClick(View v) {
 String str = textView.getText().toString();
 switch(v.getId ()){
 case R.id.btn_0:
 case R.id.btn_1:
 case R.id.btn_2:
 case R.id.btn_3:
 case R.id.btn_4:
 case R.id.btn_5:
 case R.id.btn_6:
 case R.id.btn_7:
 case R.id.btn_8:
 case R.id.btn_9:
 case R.id.btn_point:
 if(clear_flag){
  clear_flag=false;
  str="";
  textView.setText ("");
 }
 textView.setText(str+((Button)v).getText ());
 break;

 case R.id.btn_add:
 case R.id.btn_minus:
 case R.id.btn_multiply:
 case R.id.btn_divide:
 if(clear_flag){
  clear_flag=false;
  textView.setText("");
 }
 textView.setText(str+" "+((Button)v).getText()+" ");
 break;
 case R.id.btn_del:
 if(clear_flag){
  clear_flag=false;
  textView.setText ("");
 }else if (str != null && !str.equals ("")){
  textView.setText(str.substring(0,str.length()-1)); //删除一个字符
 }
 break;
 case R.id.btn_clean:
 clear_flag=false;
 str = "";
 textView.setText(""); //清空文本内容
 break;
 case R.id.btn_equal:
 getResult(); //获取结果
 break;
 }
 }

 private void getResult() {  //算法
 String s = textView.getText().toString();
 if(s == null || s.equals ("")){
 return;
 }
 if (!s.contains ("")){
 return;
 }
 if (clear_flag){
 clear_flag=false;
 return;
 }
 clear_flag=true;

 String str1 = s.substring(0,s.indexOf(" "));  // 获取到运算符前面的字符
 String str_y = s.substring(s.indexOf(" ")+1,s.indexOf(" ")+2); //获取到运算符
 String str2 = s.substring(s.indexOf(" ")+ 3);  //获取到运算符后面的字符

 double result = 0;
 if (!str1.equals ("") && !str2.equals ("")){
 double num1 = Double.parseDouble(str1); //将str1、str2强制转化为double类型
 double num2 = Double.parseDouble(str2);

 if (str_y.equals ("+")){
 result = num1 + num2;
 }else if (str_y.equals ("-")){
 result = num1 - num2;
 }else if (str_y.equals ("÷")){
 if (num2 == 0){
  result = 0;
 }else {
  result = num1/num2;
 }
 }else if (str_y.equals ("*")){
 result = num1*num2;
 }
 if (!str1.contains (".") && !str2.contains (".") && !s.equals ("÷")){
 int k = (int) result; //强制转换
 textView.setText (k);
 }else{
 textView.setText (result+"");
 }
 }else if (!str1.equals ("") && str2.equals ("")){
 textView.setText (s);
 }else if (str1.equals ("") && !str2.equals ("")){
 double num2 = Double.parseDouble(str2);
 if (s.equals ("+")){
 result = 0 + num2;
 }else if (s.equals("-")){
 result = 0 - num2;
 }else if (s.equals("×")){
 result = 0;
 }else if (s.equals("÷")){
 result = 0;
 }
 if (!str2.contains (".")) {
 int r = (int) result;
 textView.setText (r + "");
 } else {
 textView.setText (result + "");
 }
 } else {
 textView.setText ("");
 }
 }
}