eclipse完成Android计算器界面开发，并且实现基本的功能(加减乘除、清零)
先布局好计算器的结构样式，再编写java文件，如下：
activity_main.xml代码
<LinearLayout xmlns:android="/apk/res/android"xmlns:tools="/tools"android:id="@+id/LinearLayout1"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"android:paddingBottom="10dp"android:paddingLeft="10dp"android:paddingRight="10dp"android:paddingTop="10dp"tools:context="com.example.calculator2.MainActivity" ><EditTextandroid:id="@+id/input"android:layout_width="match_parent"android:layout_height="60dp"android:inputType="none"android:gravity="center|right"android:textSize="30sp" /><LinearLayoutandroid:id="@+id/LinearLayout11"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal" ><Buttonandroid:id="@+id/clear"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="2"android:text="@string/b1" /><Buttonandroid:id="@+id/negative"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b2" /><Buttonandroid:id="@+id/del"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b3" /></LinearLayout><LinearLayoutandroid:id="@+id/LinearLayout12"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal" ><Buttonandroid:id="@+id/btn7"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b4" /><Buttonandroid:id="@+id/btn8"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b5" /><Buttonandroid:id="@+id/btn9"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b6" /><Buttonandroid:id="@+id/divide"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b7" /></LinearLayout><LinearLayoutandroid:id="@+id/LinearLayout13"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal" ><Buttonandroid:id="@+id/btn4"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b8" /><Buttonandroid:id="@+id/btn5"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b9" /><Buttonandroid:id="@+id/btn6"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b10" /><Buttonandroid:id="@+id/multply"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b11" /></LinearLayout><LinearLayoutandroid:id="@+id/LinearLayout14"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal" ><Buttonandroid:id="@+id/btn1"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b12" /><Buttonandroid:id="@+id/btn2"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b13" /><Buttonandroid:id="@+id/btn3"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b14" /><Buttonandroid:id="@+id/minus"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b15" /></LinearLayout><LinearLayoutandroid:id="@+id/LinearLayout15"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal" ><Buttonandroid:id="@+id/btn0"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b16" /><Buttonandroid:id="@+id/plus"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="3"android:text="@string/b17" /></LinearLayout><LinearLayoutandroid:id="@+id/LinearLayout16"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal" ><Buttonandroid:id="@+id/point"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="1"android:text="@string/b18" /><Buttonandroid:id="@+id/equal"android:onClick="cal"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_weight="3"android:text="@string/b19" /></LinearLayout></LinearLayout>
MainActivity.java代码块
package com.example.calculator2;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;public class MainActivity extends Activity {//创建计算机类所有属性private EditText input;private Button btn0,btn1,btn2,btn3,btn4,btn5,btn6,btn7,btn8,btn9,plus,minus,divide,multply,equal,point,clear;//将先后输入的数转到num1，num2private double num1,num2;//num1，num2进行的加减乘除操作optionprivate int option;private String opd = " ";//显示操作符@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);//界面加载代码setContentView(R.layout.activity_main);//获取所有button对应的值input = (EditText) findViewById(R.id.input);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);point = (Button) findViewById(R.id.point);plus = (Button) findViewById(R.id.plus);minus = (Button) findViewById(R.id.minus);multply = (Button) findViewById(R.id.multply);divide = (Button) findViewById(R.id.divide);clear = (Button) findViewById(R.id.clear);equal = (Button) findViewById(R.id.equal);//创建数字按钮点击事件btn0.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();//创建str变量str = str + "0";//str新增点击的数字input.setText(str);//输出最后的字符串}});btn1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "1";input.setText(str);}});btn2.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "2";input.setText(str);}});btn3.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "3";input.setText(str);}});btn4.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "4";input.setText(str);}});btn5.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "5";input.setText(str);}});btn6.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "6";input.setText(str);}});btn7.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "7";input.setText(str);}});btn8.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "8";input.setText(str);}});btn9.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + "9";input.setText(str);}});point.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();str = str + ".";input.setText(str);}});//清除按钮clear.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {input.setText("");}});//四则运算按钮plus.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();num1 = Double.parseDouble(str);option = 1;opd = "+";input.setText("");}});minus.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();num1 = Double.parseDouble(str);option = 2;opd = "-";input.setText("");}});multply.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();num1 = Double.parseDouble(str);option = 3;opd = "×";input.setText("");}});divide.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();num1 = Double.parseDouble(str);option = 4;opd = "÷";input.setText("");}});//等号按钮equal.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {String str = input.getText().toString();num2 = Double.parseDouble(str);double result = 0;if(option == 1){result = num1 + num2;} else if(option == 2){result = num1 - num2;} else if(option == 3){result = num1 * num2;} else if(option == 4){result = num1 / num2;}//将完整结果输出input.setText(String.valueOf(num1) + opd + String.valueOf(num2) +"="+String.valueOf(result));}});}}
