Android studio设计简易计算器

<?xml version="1.0" encoding="utf-8"?>
<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"
 android:background="#000000">
 
 <TextView
 android:id="@+id/text1"
 android:layout_width="match_parent"
 android:layout_height="170dp"
 android:layout_marginLeft="10dp"
 android:layout_marginTop="10dp"
 android:layout_marginRight="10dp"
 android:background="#ffffff"
 android:gravity="right|bottom"
 android:hint="0"
 android:paddingRight="5dp"
 android:textColor="#000000"
 android:textSize="40sp" />
 <LinearLayout
 android:id="@+id/relative"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:layout_marginTop="10dp"
 android:layout_marginRight="10dp"
 android:layout_marginLeft="10dp"
 android:orientation="vertical">
 
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content">
 <Button
 android:id="@+id/btn_7"
 style="@style/ButtonStyle"
 android:text="@string/btn_7" />
 <Button
 android:id="@+id/btn_8"
 style="@style/ButtonStyle"
 android:text="@string/btn_8" />
 <Button
 android:id="@+id/btn_9"
 style="@style/ButtonStyle"
 android:text="@string/btn_9" />
 <Button
 android:id="@+id/btn_clear"
 style="@style/ButtonStyle"
 android:text="@string/btn_clear"/>
 </LinearLayout>
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content">
 <Button
 android:id="@+id/btn_4"
 style="@style/ButtonStyle"
 android:text="@string/btn_4" />
 <Button
 android:id="@+id/btn_5"
 style="@style/ButtonStyle"
 android:text="@string/btn_5" />
 <Button
 android:id="@+id/btn_6"
 style="@style/ButtonStyle"
 android:text="@string/btn_6" />
 <Button
 android:id="@+id/btn_plus"
 style="@style/ButtonStyle"
 android:text="@string/btn_plus"/>
 </LinearLayout>
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content">
 <Button
 android:id="@+id/btn_1"
 style="@style/ButtonStyle"
 android:text="@string/btn_1" />
 <Button
 android:id="@+id/btn_2"
 style="@style/ButtonStyle"
 android:text="@string/btn_2" />
 <Button
 android:id="@+id/btn_3"
 style="@style/ButtonStyle"
 android:text="@string/btn_3" />
 <Button
 android:id="@+id/btn_minus"
 style="@style/ButtonStyle"
 android:text="@string/btn_minus"/>
 </LinearLayout>
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content">
 <Button
 android:id="@+id/btn_0"
 style="@style/ButtonStyle"
 android:text="@string/btn_0" />
 <Button
 android:id="@+id/btn_equal"
 style="@style/ButtonEqualStyle"
 android:text="@string/btn_equal" />
 <Button
 android:id="@+id/btn_divide"
 style="@style/ButtonStyle"
 android:text="@string/btn_divide" />
 <Button
 android:id="@+id/btn_multiply"
 style="@style/ButtonStyle"
 android:text="@string/btn_multiply"/>
 </LinearLayout>
 </LinearLayout>
 
</LinearLayout>

<resources>
 <string name="app_name">计算器</string>
 <string name="text1">显示文本框</string>
 <string name="relative">布局</string>
 <string name="btn_1">1</string>
 <string name="btn_2">2</string>
 <string name="btn_3">3</string>
 <string name="btn_4">4</string>
 <string name="btn_5">5</string>
 <string name="btn_6">6</string>
 <string name="btn_7">7</string>
 <string name="btn_8">8</string>
 <string name="btn_9">9</string>
 <string name="btn_0">0</string>
 <string name="btn_clear">C</string>
 <string name="btn_plus">+</string>
 <string name="btn_minus">-</string>
 <string name="btn_multiply">×</string>
 <string name="btn_divide">÷</string>
 <string name="btn_equal">=</string>
</resources>

<resources>
 <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
 <!-- Customize your theme here. -->
 <item name="colorPrimary">@color/colorPrimary</item>
 <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
 <item name="colorAccent">@color/colorAccent</item>
 </style>
 <style name="ButtonBaseStyle">
 <item name="android:layout_width">40dp</item>
 <item name="android:layout_height">70dp</item>
 <item name="android:layout_margin">10dp</item>
 <item name="android:padding">10dp</item>
 <item name="android:textColor">@android:color/black</item>
 <item name="android:textSize">30sp</item>
 </style>
 <style name="ButtonStyle" parent="ButtonBaseStyle">
 <item name="android:background">@drawable/bg_selector</item>
 <item name="android:layout_weight">1</item>
 </style>
 <style name="ButtonEqualStyle" parent="ButtonBaseStyle">
 <item name="android:background">@drawable/ping_bg</item>
 <item name="android:layout_weight">1</item>
 </style>
</resources>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="5dp"/>
 <solid android:color="#ffffff"/>
</shape>

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="5dp"></corners>
 <solid android:color="#ee82ee"></solid>
</shape>

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
 <item android:drawable="@drawable/white_bg" android:state_pressed="false"></item>
 <item android:drawable="@drawable/ping_bg"
 android:state_pressed="true"></item>
</selector>

package com.example.exp3;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 int[] ids = {R.id.btn_0, R.id.btn_1, R.id.btn_2, R.id.btn_3, R.id.btn_4, R.id.btn_4,
 R.id.btn_5, R.id.btn_6, R.id.btn_7, R.id.btn_8, R.id.btn_9, R.id.btn_equal,
 R.id.btn_clear, R.id.btn_multiply, R.id.btn_minus, R.id.btn_divide, R.id.btn_plus};
 //将所有按钮整合成一个数组
 for (int i = 0; i < ids.length; i++)
 findViewById(ids[i]).setOnClickListener(this);//给每个按钮设置一个监听事件
 }
 @Override
 public void onClick(View v) {
 TextView tv_input = (TextView) findViewById(R.id.text1);
 Button btn = (Button)v;
 String str=tv_input.getText().toString();//获取xml那里的输入
 String strButton =btn.getText().toString();//点击按钮得到的文本
 switch (v.getId()){
 case R.id.btn_0:
 case R.id.btn_1:
 case R.id.btn_2:
 case R.id.btn_3:
 case R.id.btn_4:
 case R.id.btn_5:
 case R.id.btn_6:
 case R.id.btn_7:
 case R.id.btn_8:
 case R.id.btn_9:
 if (str.equals("0"))
  tv_input.setText(strButton);
 else
  tv_input.setText(str+strButton);
 break;
 case R.id.btn_clear:
 tv_input.setText("0");
 break;
 case R.id.btn_plus:
 case R.id.btn_minus:
 case R.id.btn_multiply:
 case R.id.btn_divide:
 tv_input.setText(str+strButton);
 break;
 case R.id.btn_equal:
 MyCalc obj=new MyCalc(str);
 double ret = obj.Calc();
 int Ret = (int)ret;
 if (ret == Ret)
  tv_input.setText(String.valueOf(Ret));
 else
  tv_input.setText(String.valueOf(ret));
 break;
 }
 }
 
 class MyCalc {
 private String input;
 
 public MyCalc(String input) {
 this.input = input;
 }
 
 public double Calc() {
 if (TextUtils.isEmpty(input))
 return 0;
 Pattern pattern = Pattern.compile("[+(×)(÷)/-]");
 String[] nums = pattern.split(input);
 Matcher matcher = pattern.matcher(input);
 if (matcher.find() == false)
 return 0;
 String op = matcher.group(0);
 double first = Double.parseDouble(nums[0]);
 double second = Double.parseDouble(nums[1]);
 double sum = 0;
 try {
 switch (op) {
  case "+":
  sum = first + second;
  break;
  case "-":
  sum = first - second;
  break;
  case "×":
  sum = first * second;
  break;
  case "÷":
  sum = first / second;
  break;
 }
 } catch (Exception e) {
 Toast.makeText(MainActivity.this, "出错", Toast.LENGTH_LONG).show();
 }
 return sum;
 }
 }
}