android的简单计算器的实现

来源：互联网发布：sqlmap mssql 编辑：程序博客网时间：2024/06/05 20:08

终于放假了，不过是没有暑假的暑假了。

好久以前就就有接触过安卓，过了这么久还是没有相当于没有入门状态。昨天有空又做了一个简单的计算器练一下手，如有大神看到请绕行了，因为代码实在写得比较烂。嘿嘿。废话不说了，先上图：

首先看一下这个计算器的结构很简单，包含两各Activity：一个是标准类型（标准Activity），只包含简单的加减乘除，另一个加上了更多的功能（科学Activity），如sin，cos等。

看一下标准Activity的布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context=".MainActivity" >        <TextView        android:id="@+id/textview"        android:layout_width="337dp"        android:layout_height="50dp"        android:gravity="right|bottom"        android:textSize="30dp" />        <EditText            android:id="@+id/edittext1"            android:layout_width="355dp"            android:layout_height="70dp"             android:inputType="textMultiLine"    android:gravity="right|bottom"    android:minLines="2"    android:textSize="40dp"/>       <RelativeLayout           android:layout_width="match_parent"           android:layout_height="90dp" >           <Button               android:id="@+id/qiehuan"               android:layout_width="100dp"               android:layout_height="35dp"               android:layout_alignParentLeft="true"               android:layout_centerVertical="true"               android:layout_marginLeft="3dp"               android:text="标准"               android:textSize="15dp"               android:background="@drawable/btneffect" />       </RelativeLayout>       <RelativeLayout           android:layout_width="360dp"           android:layout_height="80dp" >           <Button               android:id="@+id/del"               android:layout_width="85dp"               android:layout_height="75dp"               android:layout_marginLeft="93dp"               android:background="@drawable/btneffect2"               android:text="DEL" />           <Button               android:id="@+id/cheng"               android:layout_width="85dp"               android:layout_height="75dp"               android:layout_marginLeft="182dp"               android:background="@drawable/btneffect2"               android:text="×" />           <Button               android:id="@+id/clear"               android:layout_width="85dp"               android:layout_height="75dp"               android:layout_marginLeft="4dp"               android:background="@drawable/btneffect1"               android:text="C" />           <Button               android:id="@+id/chu"               android:layout_width="85dp"               android:layout_height="75dp"               android:layout_alignParentTop="true"               android:layout_toRightOf="@+id/cheng"               android:layout_marginLeft="3dp"               android:background="@drawable/btneffect2"               android:text="÷" />       </RelativeLayout>        <RelativeLayout            android:layout_width="360dp"            android:layout_height="80dp"            android:orientation="horizontal" >    <Button        android:id="@+id/btn7"        android:layout_width="85dp"        android:layout_height="75dp"        android:layout_marginLeft="4dp"        android:background="@drawable/btneffect"        android:text="7" />    <Button        android:id="@+id/btn9"        android:layout_width="85dp"        android:layout_height="75dp"      android:layout_marginLeft="182dp"        android:background="@drawable/btneffect"        android:text="9" />    <Button        android:id="@+id/btn8"        android:layout_width="85dp"        android:layout_height="75dp"android:layout_marginLeft="93dp"        android:background="@drawable/btneffect"        android:text="8" />    <Button        android:id="@+id/jian"        android:layout_width="85dp"        android:layout_height="75dp"android:layout_toRightOf="@+id/btn9"        android:layout_alignParentTop="true"        android:layout_marginLeft="3dp"        android:background="@drawable/btneffect2"        android:text="-" /></RelativeLayout>        <RelativeLayout            android:layout_width="354dp"            android:layout_height="80dp"            android:orientation="horizontal" >        <Button    android:id="@+id/btn4"    android:layout_width="85dp"    android:layout_height="75dp"    android:text="4"     android:layout_marginLeft="4dp"    android:background="@drawable/btneffect"/>    <Button        android:id="@+id/btn6"        android:layout_width="85dp"        android:layout_height="75dp"android:layout_marginLeft="182dp"        android:background="@drawable/btneffect"        android:text="6" />    <Button        android:id="@+id/btn5"        android:layout_width="85dp"        android:layout_height="75dp"       android:layout_marginLeft="93dp"        android:background="@drawable/btneffect"        android:text="5" />    <Button        android:id="@+id/jia"        android:layout_width="85dp"        android:layout_height="75dp"       android:layout_toRightOf="@+id/btn6"        android:layout_alignParentTop="true"        android:layout_marginLeft="3dp"        android:background="@drawable/btneffect2"        android:text="+" /></RelativeLayout>        <RelativeLayout    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="horizontal">        <Button    android:id="@+id/btn1"    android:layout_width="85dp"    android:layout_height="75dp"    android:text="1"        android:layout_marginLeft="3dp"    android:background="@drawable/btneffect" />    <Button        android:id="@+id/deng"        android:layout_width="85dp"        android:layout_height="155dp"android:layout_toRightOf="@+id/btn3"        android:layout_alignParentTop="true"        android:layout_marginLeft="3dp"        android:text="="         android:background="@drawable/btneffect1"/>    <Button        android:id="@+id/btn3"        android:layout_width="85dp"        android:layout_height="75dp"android:layout_marginLeft="182dp"        android:text="3"        android:background="@drawable/btneffect" />    <Button        android:id="@+id/btn2"        android:layout_width="85dp"        android:layout_height="75dp"        android:text="2"         android:layout_marginLeft="93dp"        android:background="@drawable/btneffect"/><Button    android:id="@+id/btn0"    android:layout_width="wrap_content"    android:layout_height="75dp"    android:layout_alignParentLeft="true"    android:layout_alignRight="@+id/btn2"    android:layout_below="@+id/btn1"    android:text="0"        android:layout_marginLeft="3dp"        android:layout_marginTop="5dp"    android:background="@drawable/btneffect" /><Button    android:id="@+id/dian"    android:layout_width="85dp"    android:layout_height="75dp"    android:layout_alignLeft="@+id/btn3"    android:layout_alignTop="@+id/btn0"    android:text="."    android:background="@drawable/btneffect" /></RelativeLayout>   </LinearLayout>

MainActivity.java如下：

import android.R.string;import android.os.Bundle;import android.app.Activity;import android.content.Intent;import android.text.InputType;import android.view.KeyEvent;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.view.Window;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity {private long exitTime = 0;protected static final float NaN = 0;private Button[] btnNum = new Button[11];// 数值按钮private Button clear,del,cheng,chu,jian,jia,deng,qiehuan;private EditText edittext;private TextView textview;int flag;String num1,nan="NaN",max="∞",zero="0";float result,zo=0;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main); btnNum[0] = (Button) findViewById(R.id.btn0);          btnNum[1] = (Button) findViewById(R.id.btn1);          btnNum[2] = (Button) findViewById(R.id.btn2);          btnNum[3] = (Button) findViewById(R.id.btn3);          btnNum[4] = (Button) findViewById(R.id.btn4);          btnNum[5] = (Button) findViewById(R.id.btn5);          btnNum[6] = (Button) findViewById(R.id.btn6);          btnNum[7] = (Button) findViewById(R.id.btn7);          btnNum[8] = (Button) findViewById(R.id.btn8);          btnNum[9] = (Button) findViewById(R.id.btn9);          btnNum[10] = (Button) findViewById(R.id.dian);        qiehuan = (Button) findViewById(R.id.qiehuan);        edittext = (EditText) findViewById(R.id.edittext1);        clear = (Button) findViewById(R.id.clear);        del = (Button) findViewById(R.id.del);        cheng = (Button) findViewById(R.id.cheng);        chu = (Button) findViewById(R.id.chu);        jian = (Button) findViewById(R.id.jian);        jia = (Button) findViewById(R.id.jia);        deng = (Button) findViewById(R.id.deng);        textview = (TextView) findViewById(R.id.textview);                edittext.setCursorVisible(false);    //隐藏光标        edittext.setInputType(InputType.TYPE_NULL); // 关闭软键盘         edittext.setText("0");   //初始值                        for(int i=0;i<=10;i++){//数字输入显示        btnNum[i].setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubButton btn = (Button) v;              String input = btn.getText().toString();            String edittext_Value = edittext.getText().toString();              String textview_Value = textview.getText().toString();            if( edittext_Value.equals(nan) || edittext_Value.equals(max) || edittext_Value.equals(zero)){            edittext.setText("");            }            edittext.setText(edittext.getText().toString() + input);// 设置显示区域的值}});         }                clear.setOnClickListener(new OnClickListener() {    //清除键@Overridepublic void onClick(View v) {// TODO Auto-generated method stubedittext.setText("0");textview.setText("");}});                del.setOnClickListener(new OnClickListener() {//删除键@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString show = edittext.getText().toString();int L = show.length();if(L == 0){}else if(L != 0){edittext.setText(show.substring(0, L-1));}}});                jia.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubflag=1;num1 = edittext.getText().toString();edittext.setText(edittext.getText().toString() + "+");}});                jian.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubflag=2;num1 = edittext.getText().toString();edittext.setText(edittext.getText().toString() + "-");}});                cheng.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubflag=3;num1 = edittext.getText().toString();edittext.setText(edittext.getText().toString() + "×");}});        chu.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubflag=4;num1 = edittext.getText().toString();edittext.setText(edittext.getText().toString() + "÷");}});/*public void dengdown(){String num = edittext.getText().toString(); if (num.indexOf("+") <= 0 && num.indexOf("-") <= 0 && num.indexOf("×") <= 0 && num.indexOf("÷") <= 0)        { flag=5;        }}*/deng.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString num = edittext.getText().toString();String num2 = num.substring(num1.length()+1,num.length());float numa = Float.parseFloat(num1);float numb = Float.parseFloat(num2);if(num.length()>0) {System.out.println("11111111");}switch (flag) {case 1:result = numa+numb;break;case 2:result = numa-numb;break;case 3:result = numa*numb;break;case 4:if(numa == 0 && numb == 0){edittext.setText(nan);}else if (numb == 0){edittext.setText(max);}else  result = numa/numb;break;/*case 5:*/default://dengdown();break;}textview.setText(num+"=");int re = (int)result;float xiaoshu = result-re;if(xiaoshu == zo){edittext.setText(String.valueOf(re));}else edittext.setText(String.valueOf(result));}});qiehuan.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubIntent it = new Intent(MainActivity.this,ScienceActivity.class);startActivity(it);}});}@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {// TODO Auto-generated method stubif(keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN){ if((System.currentTimeMillis()-exitTime) > 2000){ Toast.makeText(getApplicationContext(), "再按一次退出程序", Toast.LENGTH_SHORT).show(); exitTime = System.currentTimeMillis(); } else { finish(); System.exit(0); } return true; } return super.onKeyDown(keyCode, event); } @Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}

为了给Button加入以下效果使界面更美观，又写了三个XML文件：

其中btneffect.xml如下，其他两个类似，如下：

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="http://schemas.android.com/apk/res/android" >    <item android:state_pressed="false">        <shape >            <gradient android:startColor="#FAF0E6" android:endColor="#FAF0E6"android:angle="270" /><stroke android:width="1dip" android:color="#696969" /><corners android:radius="10dp" /><padding android:left="1dp" android:top="1dp"android:right="1dp" android:bottom="1dp" />        </shape>    </item>    <item android:state_pressed="true">        <shape >            <gradient android:startColor="#DCDCDC" android:endColor="#DCDCDC"android:angle="270" /><stroke android:width="1dip" android:color="#000000" /><corners android:radius="10dp" /><padding android:left="1dp" android:top="1dp"android:right="1dp" android:bottom="1dp" />        </shape>    </item></selector>

这就是简单计算器基本实现了，关于另外一个Activity的实现和这个基本类似，就不贴代码了。如有哪里写得不好或者有更好的想法，希望大家指正，本文仅作为新手们的交流。

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