Android简单计算机APP的开发

工具：android studio

纯手写，简单语法。

布局用网格布局：

 

功能实现：

package com.example.jisuanji;

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 {
    Button b1, b2, b3, b4, b5, b6, b7, b8, b9, b0, badd, bless, bcheng, bchu, bdian, bdengyu,bclean;
    TextView txt;
    String str="",str1="";
    double num1,num2;
    double result;
    int op;
    String opd="";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b1 = (Button) findViewById(R.id.one);
        b2 = (Button) findViewById(R.id.two);
        b3 = (Button) findViewById(R.id.three);
        b4 = (Button) findViewById(R.id.four);
        b5 = (Button) findViewById(R.id.five);
        b6 = (Button) findViewById(R.id.six);
        b7 = (Button) findViewById(R.id.seven);
        b8 = (Button) findViewById(R.id.eight);
        b9 = (Button) findViewById(R.id.nine);
        b0 = (Button) findViewById(R.id.zero);
        badd = (Button) findViewById(R.id.add);
        bless = (Button) findViewById(R.id.less);
        bcheng = (Button) findViewById(R.id.cheng);
        bchu = (Button) findViewById(R.id.chu);
        bdian=(Button)findViewById(R.id.dian);
        bdengyu=(Button)findViewById(R.id.dengyu);
        bclean=(Button)findViewById(R.id.clean);
        txt=(TextView)findViewById(R.id.txt);
        b1.setOnClickListener(new click1());
        b2.setOnClickListener(new click2());
        b3.setOnClickListener(new click3());
        b4.setOnClickListener(new click4());
        b5.setOnClickListener(new click5());
        b6.setOnClickListener(new click6());
        b7.setOnClickListener(new click7());
        b8.setOnClickListener(new click8());
        b9.setOnClickListener(new click9());
        b0.setOnClickListener(new click0());
        badd.setOnClickListener(new clickadd());
        bless.setOnClickListener(new clickless());
        bcheng.setOnClickListener(new clickcheng());
        bchu.setOnClickListener(new clickchu());
        bdengyu.setOnClickListener(new clickdengyu());
        bdian.setOnClickListener(new clickdian());
        bclean.setOnClickListener(new clickclean());
    }
    class clickclean implements View.OnClickListener{
        public void onClick(View v)
        {
            txt.setText("0");
            str="";
        }
    }
    class click1 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str += "1";
            str1=str;
            txt.setText(str1);
        }
    }
    class click2 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str += "2";str1=str;txt.setText(str1);
        }
    }
    class click3 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str += "3";str1=str;txt.setText(str1);
        }
    }
    class click4 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+"4";str1=str;txt.setText(str1);
        }
    }
    class click5 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+"5";str1=str;txt.setText(str1);
        }
    }
    class click6 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+"6";str1=str;txt.setText(str1);
        }
    }
    class click7 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+"7";str1=str;txt.setText(str1);
        }
    }
    class click8 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+"8";str1=str;txt.setText(str1);
        }
    }
    class click9 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+"9";str1=str;txt.setText(str1);
        }
    }
    class click0 implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+"0";str1=str;txt.setText(str1);
        }
    }
    class clickadd implements View.OnClickListener
    {
        public void onClick(View v)
        {
            op=1;
            num1=Double.parseDouble(str);
            str1=str+"+";
            str="";
            txt.setText(str1);
        }
    }
    class clickless implements View.OnClickListener
    {
        public void onClick(View v)
        {
            op=2;
            num1=Double.parseDouble(str);
            str1=str+"-";
            str="";txt.setText(str1);
        }
    }
    class clickcheng implements View.OnClickListener
    {
        public void onClick(View v)
        {
            op=3;
            num1=Double.parseDouble(str);
            str1=str+"*";
            str="";txt.setText(str1);
        }
    }
    class clickchu implements View.OnClickListener
    {
        public void onClick(View v)
        {
            op=4;
            num1=Double.parseDouble(str);
            str1=str+"/";
            str="";
            txt.setText(str1);
        }
    }
    class clickdengyu implements View.OnClickListener
    {
        public void onClick(View v)
        {
            if(op==1){
                num2=Double.parseDouble(str);
                result=num1+num2;
                opd=Double.toString(result);
                txt.setText(opd);
            }
            if (op==2){
                num2=Double.parseDouble(str);
                result=num1-num2;
                opd=Double.toString(result);
                txt.setText(opd);
            }
            if (op==3){
                num2=Double.parseDouble(str);
                result=num1*num2;
                opd=Double.toString(result);
                txt.setText(opd);
            }
            if (op==4){
                num2=Double.parseDouble(str);
                result=num1/num2;
                opd=Double.toString(result);
                txt.setText(opd);
            }
        }
    }
    class clickdian implements View.OnClickListener
    {
        public void onClick(View v)
        {
            str=str+".";str1=str;txt.setText(str1);
        }
    }
}