写个简单的安卓计算器
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <EditText android:id="@+id/result" android:cursorVisible="false" android:editable = "false" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="2"/> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="16px" android:layout_marginRight="16px" android:orientation="horizontal"> <Button android:id="@+id/C" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/C" android:textColor="#ffff6970" android:layout_weight="1"/> <Button android:id="@+id/addition" android:text="@string/addition" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1"/> <Button android:id="@+id/Multiplication" android:text="@string/Multiplication" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1"/> <Button android:id="@+id/del" android:text="@string/del" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="16px" android:layout_marginRight="16px"> <Button android:id="@+id/seven" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/seven" android:layout_weight="1"/> <Button android:id="@+id/eight" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/eight" android:layout_weight="1"/> <Button android:id="@+id/nine" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/nine" android:layout_weight="1"/> <Button android:id="@+id/add" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/add" android:layout_weight="1"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="16px" android:layout_marginRight="16px"> <Button android:id="@+id/four" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/four" android:layout_weight="1"/> <Button android:id="@+id/five" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/five" android:layout_weight="1"/> <Button android:id="@+id/six" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/six" android:layout_weight="1"/> <Button android:id="@+id/Reduction" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/Reduction" android:layout_weight="1"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_marginLeft="16px" android:layout_marginRight="16px"> <LinearLayout android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="3" android:orientation="vertical" > <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <Button android:id="@+id/one" android:layout_width="0dp" android:layout_weight="1" android:layout_height="wrap_content" android:text="@string/one"/> <Button android:id="@+id/two" android:layout_width="0dp" android:layout_weight="1" android:layout_height="wrap_content" android:text="@string/two"/> <Button android:id="@+id/three" android:layout_width="0dp" android:layout_weight="1" android:layout_height="wrap_content" android:text="@string/three"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <Button android:id="@+id/zero" android:layout_width="0dp" android:layout_height="wrap_content" android:text="@string/zero" android:layout_weight="2"/> <Button android:id="@+id/point" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:text="@string/point"/> </LinearLayout> </LinearLayout> <LinearLayout android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1"> <Button android:id="@+id/equal" android:text="@string/equal" android:textColor="#ffff6970" android:layout_width="match_parent" android:layout_height="match_parent"/> </LinearLayout> </LinearLayout> </LinearLayout>
strings.xml
<resources> <string name="app_name">Calculator</string> <string name="hello_world">Hello world!</string> <string name="action_settings">Settings</string> <string name="C">C</string> <string name="addition">/</string> <string name="Multiplication">x</string> <string name="del">del</string> <string name="seven">7</string> <string name="eight">8</string> <string name="nine">9</string> <string name="add">+</string> <string name="six">6</string> <string name="five">5</string> <string name="four">4</string> <string name="Reduction">-</string> <string name="three">3</string> <string name="two">2</string> <string name="one">1</string> <string name="equal">=</string> <string name="zero">0</string> <string name="point">.</string> </resources>
MainActivity.java
package wuxiaocheng.cn.calculator;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.TextView;
import android.view.View.OnClickListener;
public class MainActivity extends Activity implements OnClickListener {
//定义两个参数，接受result前后的值
double num1 = 0, num2 = 0;
//计算结果
double Result = 0;
//判断是否按了“=”按钮
boolean isClickEqu = false;
//判断操作数
int op = 0;
TextView result = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
//从布局中查找按钮
Button C = (Button) this.findViewById(R.id.C);
Button addition = (Button)this.findViewById(R.id.addition);
Button Multiplication = (Button)this.findViewById(R.id.Multiplication);
Button del = (Button) this.findViewById(R.id.del);
Button seven = (Button) this.findViewById(R.id.seven);
Button eight = (Button) this.findViewById(R.id.eight);
Button nine = (Button) this.findViewById(R.id.nine);
Button add = (Button) this.findViewById(R.id.add);
Button four = (Button) this.findViewById(R.id.four);
Button five = (Button) this.findViewById(R.id.five);
Button six = (Button) this.findViewById(R.id.six);
Button Reduction = (Button) this.findViewById(R.id.Reduction);
Button one = (Button) this.findViewById(R.id.one);
Button two = (Button) this.findViewById(R.id.two);
Button three = (Button) this.findViewById(R.id.three);
Button zero = (Button) this.findViewById(R.id.zero);
Button point = (Button) this.findViewById(R.id.point);
Button equal = (Button) this.findViewById(R.id.equal);
result = (TextView) this.findViewById(R.id.result);
//让activity实现点击事件的接口
C.setOnClickListener(this);
addition.setOnClickListener(this);
Multiplication.setOnClickListener(this);
del.setOnClickListener(this);
seven.setOnClickListener(this);
eight.setOnClickListener(this);
nine.setOnClickListener(this);
add.setOnClickListener(this);
four.setOnClickListener(this);
five.setOnClickListener(this);
six.setOnClickListener(this);
Reduction.setOnClickListener(this);
one.setOnClickListener(this);
two.setOnClickListener(this);
three.setOnClickListener(this);
zero.setOnClickListener(this);
point.setOnClickListener(this);
equal.setOnClickListener(this);
}
//接口里面未实现的方法
public void onClick(View v){
switch (v.getId()){
//清零键
case R.id.C:
result.setText(null);
break;
//删除键
case R.id.del:
String myStr = result.getText().toString();
{
try {
result.setText(myStr.substring(0,myStr.length()-1));
}catch (Exception e){
result.setText("");
}
}
break;
//按钮0-9
case R.id.zero:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString0=result.getText().toString();
myString0+="0";
result.setText(myString0);
break;
case R.id.one:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString1=result.getText().toString();
myString1+="1";
result.setText(myString1);
break;
case R.id.two:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString2=result.getText().toString();
myString2+="2";
result.setText(myString2);
break;
case R.id.three:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString3=result.getText().toString();
myString3+="3";
result.setText(myString3);
break;
case R.id.four:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString4=result.getText().toString();
myString4+="4";
result.setText(myString4);
break;
case R.id.five:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString5=result.getText().toString();
myString5+="5";
result.setText(myString5);
break;
case R.id.six:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString6=result.getText().toString();
myString6+="6";
result.setText(myString6);
break;
case R.id.seven:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString7=result.getText().toString();
myString7+="7";
result.setText(myString7);
break;
case R.id.eight:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString8=result.getText().toString();
myString8+="8";
result.setText(myString8);
break;
case R.id.nine:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myString9=result.getText().toString();
myString9+="9";
result.setText(myString9);
break;
//点
case R.id.point:
if(isClickEqu)
{
result.setText(null);
isClickEqu=false;
}
String myStringp=result.getText().toString();
myStringp+=".";
result.setText(myStringp);
break;
//加
case R.id.add:
String mystringadd = result.getText().toString();
if(mystringadd.equals(null))
{
return;
}
num1 = Double.valueOf(mystringadd);
result.setText(null);
op = 1;
isClickEqu = false;
break;
//减
case R.id.Reduction:
String mystringred = result.getText().toString();
if(mystringred.equals(null))
{
return;
}
num1 = Double.valueOf(mystringred);
result.setText(null);
op = 2;
isClickEqu = false;
break;
//乘
case R.id.Multiplication:
String mystringmul = result.getText().toString();
if(mystringmul.equals(null))
{
return;
}
num1 = Double.valueOf(mystringmul);
result.setText(null);
op = 3;
isClickEqu = false;
break;
//除
case R.id.addition:
String mystringat = result.getText().toString();
if(mystringat.equals(null))
{
return;
}
num1 = Double.valueOf(mystringat);
result.setText(null);
op = 4;
isClickEqu = false;
break;
//等于
case R.id.equal:
String myStringeq=result.getText().toString();
if (myStringeq.equals(null)){
return;
}
num2 = Double.valueOf(myStringeq);
result.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;
}
result.setText(String.valueOf(Result));
isClickEqu = true;
break;
}
}
}
原文：http://my.oschina.net/u/2264427/blog/479998