从零开始学android实现计算器功能示例分享(计算器源码)

<?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" >

    <linearlayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
 <textview 
     android:id="@+id/tvresult"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:height="50dp"
     android:text="@string/tvresult"
     />
</linearlayout>
<linearlayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
    <button
        android:id="@+id/btnbackspace"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:width="150dp"
        android:layout_marginleft="10dp"
             android:text="@string/btnbackspace"/>
      <button
        android:id="@+id/btnce"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="150dp"
             android:text="@string/btnce"/>
</linearlayout>
<linearlayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
      <button
        android:id="@+id/btn7"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginleft="10dp"
         android:width="75dp"
             android:text="@string/btn7"/>
         <button
        android:id="@+id/btn8"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btn8"/>
               <button
        android:id="@+id/btn9"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btn9"/>
                     <button
        android:id="@+id/btndiv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btndiv"/>
</linearlayout>
<linearlayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
      <button
        android:id="@+id/btn4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginleft="10dp"
         android:width="75dp"
             android:text="@string/btn4"/>
         <button
        android:id="@+id/btn5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btn5"/>
               <button
        android:id="@+id/btn6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btn6"/>
                     <button
        android:id="@+id/btnmul"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btnmul"/>
</linearlayout>
<linearlayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
      <button
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginleft="10dp"
         android:width="75dp"
             android:text="@string/btn1"/>
         <button
        android:id="@+id/btn2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btn2"/>
               <button
        android:id="@+id/btn3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btn3"/>
                     <button
        android:id="@+id/btnadd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btnadd"/>
</linearlayout>
<linearlayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
      <button
        android:id="@+id/btn0"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginleft="10dp"
         android:width="75dp"
             android:text="@string/btn0"/>
         <button
        android:id="@+id/btnc"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btnc"/>
               <button
        android:id="@+id/btnequ"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btnequ"/>
                     <button
        android:id="@+id/btnsub"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         android:width="75dp"
             android:text="@string/btnsub"/>
</linearlayout>
</linearlayout>

package com.example.week2;

import android.os.bundle;
import android.view.view;
import android.view.view.onclicklistener;
import android.widget.button;
import android.widget.textview;
import android.app.activity;

public class mainactivity extends activity  implements onclicklistener{

    //声明一些控件
    button btn0=null;
    button btn1=null;
    button btn2=null;
    button btn3=null;
    button btn4=null;
    button btn5=null;
    button btn6=null;
    button btn7=null;
    button btn8=null;
    button btn9=null;
    button btnbackspace=null;
    button btnce=null;
    button btnc=null;
    button btnadd=null;
    button btnsub=null;
    button btnmul=null;
    button btndiv=null;
    button btnequ=null;
    textview tvresult=null;
    //声明两个参数。接收tvresult前后的值
    double num1=0,num2=0;
    double result=0;//计算结果
    int op=0;//判断操作数，
    boolean isclickequ=false;//判断是否按了“=”按钮

    @override
    protected void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.main);
        //从布局文件中获取控件，
        btn0=(button)findviewbyid(r.id.btn0);
        btn1=(button)findviewbyid(r.id.btn1);
        btn2=(button)findviewbyid(r.id.btn2);
        btn3=(button)findviewbyid(r.id.btn3);
        btn4=(button)findviewbyid(r.id.btn4);
        btn5=(button)findviewbyid(r.id.btn5);
        btn6=(button)findviewbyid(r.id.btn6);
        btn7=(button)findviewbyid(r.id.btn7);
        btn8=(button)findviewbyid(r.id.btn8);
        btn9=(button)findviewbyid(r.id.btn9);
        btnbackspace=(button)findviewbyid(r.id.btnbackspace);
        btnce=(button)findviewbyid(r.id.btnce);
        btnc=(button)findviewbyid(r.id.btnc);
        btnequ=(button)findviewbyid(r.id.btnequ);
        btnadd=(button)findviewbyid(r.id.btnadd);
        btnsub=(button)findviewbyid(r.id.btnsub);
        btnmul=(button)findviewbyid(r.id.btnmul);
        btndiv=(button)findviewbyid(r.id.btndiv);
        tvresult=(textview)findviewbyid(r.id.tvresult);

        //添加监听\
        btnbackspace.setonclicklistener(this);
        btnce.setonclicklistener(this);

        btn0.setonclicklistener(this);
        btn1.setonclicklistener(this);
        btn2.setonclicklistener(this);
        btn3.setonclicklistener(this);
        btn4.setonclicklistener(this);
        btn5.setonclicklistener(this);
        btn6.setonclicklistener(this);
        btn7.setonclicklistener(this);
        btn8.setonclicklistener(this);
        btn9.setonclicklistener(this);

       
        btnadd.setonclicklistener(this);
        btnsub.setonclicklistener(this);
        btnmul.setonclicklistener(this);
        btndiv.setonclicklistener(this);
        btnequ.setonclicklistener(this);
    }
    @override
    public void onclick(view v) {
        switch (v.getid()) {
        //btnbackspace和ce--------------------
        case r.id.btnbackspace:
            string mystr=tvresult.gettext().tostring();
            try {
                tvresult.settext(mystr.substring(0, mystr.length()-1));
            } catch (exception e) {
                tvresult.settext("");
            }

            break;
        case r.id.btnce:
            tvresult.settext(null);
            break;

            //btn0--9---------------------------
        case r.id.btn0:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring=tvresult.gettext().tostring();
            mystring+="0";
            tvresult.settext(mystring);
            break;
        case r.id.btn1:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring1=tvresult.gettext().tostring();
            mystring1+="1";
            tvresult.settext(mystring1);
            break;
        case r.id.btn2:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring2=tvresult.gettext().tostring();
            mystring2+="2";
            tvresult.settext(mystring2);
            break;
        case r.id.btn3:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring3=tvresult.gettext().tostring();
            mystring3+="3";
            tvresult.settext(mystring3);
            break;
        case r.id.btn4:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring4=tvresult.gettext().tostring();
            mystring4+="4";
            tvresult.settext(mystring4);
            break;
        case r.id.btn5:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring5=tvresult.gettext().tostring();
            mystring5+="5";
            tvresult.settext(mystring5);
            break;
        case r.id.btn6:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring6=tvresult.gettext().tostring();
            mystring6+="6";
            tvresult.settext(mystring6);
            break;
        case r.id.btn7:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring7=tvresult.gettext().tostring();
            mystring7+="7";
            tvresult.settext(mystring7);
            break;
        case r.id.btn8:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring8=tvresult.gettext().tostring();
            mystring8+="8";
            tvresult.settext(mystring8);
            break;
        case r.id.btn9:
            if(isclickequ)
            {
                tvresult.settext(null);
                isclickequ=false;
            }
            string mystring9=tvresult.gettext().tostring();
            mystring9+="9";
            tvresult.settext(mystring9);
            break;

            //btn+-*/=--------------------------------
        case r.id.btnadd:           
            string mystringadd=tvresult.gettext().tostring();
            if(mystringadd.equals(null))
            {
                return;
            }
            num1=double.valueof(mystringadd);
            tvresult.settext(null);
            op=1;
            isclickequ=false;
            break;

        case r.id.btnsub:
            string mystringsub=tvresult.gettext().tostring();
            if(mystringsub.equals(null))
            {
                return;
            }
            num1=double.valueof(mystringsub);
            tvresult.settext(null);
            op=2;
            isclickequ=false;
            break;
        case r.id.btnmul:
            string mystringmul=tvresult.gettext().tostring();
            if(mystringmul.equals(null))
            {
                return;
            }
            num1=double.valueof(mystringmul);
            tvresult.settext(null);
            op=3;
            isclickequ=false;
            break;
        case r.id.btndiv:
            string mystringdiv=tvresult.gettext().tostring();
            if(mystringdiv.equals(null))
            {
                return;
            }
            num1=double.valueof(mystringdiv);
            tvresult.settext(null);
            op=4;
            isclickequ=false;
            break;
        case r.id.btnequ:
            string mystringequ=tvresult.gettext().tostring();
            if(mystringequ.equals(null))
            {
                return;
            }
            num2=double.valueof(mystringequ);
            tvresult.settext(null);
            switch (op) {
            case 0:
                result=num2;
                break;
            case 1:
                result=num1+num2;
                break;
            case 2:
                result=num1-num2;
                break;
            case 3:
                result=num1*num2;
                break;
            case 4:
                result=num1/num2;
                break;
            default:
                result=0;
                break;
            }
            tvresult.settext(string.valueof(result));
            isclickequ=true;
            break;

        default:
            break;
        }
    }
}