效果圖：

資原始檔：
color.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
    <color name="white">#FFFFFF</color
 
>
    <color name="black">#000000</color>
    <color name="zi">#FFFFFF</color>
    <color name="gray">#BEBEBE</color>
    <color name="green">#9AFF9A</color>
    <color name="littlegreen">#F0FFFF</color>
</resources>

white.xml

設定input text的填充色為白色

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

selector.xml

點選按鈕時產生陰影效果

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

equeal.xml
同理，等號的陰影效果

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

佈局檔案

<?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"
    android:background="@drawable/jisuanqi"

    tools:context="com.example.administrator.calculate.MainActivity"
    >

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="30dp"
        android:paddingLeft="20dp"
        android:paddingRight="20dp"
        android:paddingTop="20dp">

        <EditText
            android:id="@+id/input"
            android:layout_width="fill_parent"
            android:layout_height="60dp"
            android:background="@drawable/white"
            android:editable="false"
            android:gravity="right|bottom"
            />
    </LinearLayout>
    <LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    android:orientation="horizontal"
    android:gravity="center">
    <Button
        android:layout_width="65dp"
        android:layout_height="65dp"
        android:text="C"
        android:background="@drawable/selector"
        android:gravity="center"
        android:textSize="25sp"
        android:id="@+id/clear"
        />
    <Button
        android:layout_width="65dp"
        android:layout_height="65dp"
        android:text="←"
        android:background="@drawable/selector"
        android:gravity="center"
        android:layout_marginLeft="10dp"
        android:textSize="23sp"
        android:id="@+id/delete"
        />
    <Button
        android:layout_width="65dp"
        android:layout_height="65dp"
        android:text="×"
        android:background="@drawable/selector"
        android:gravity="center"
        android:layout_marginLeft="10dp"
        android:textSize="25sp"
        android:id="@+id/cheng"
        />
    <Button
        android:layout_width="65dp"
        android:layout_height="65dp"
        android:text="÷"
        android:background="@drawable/selector"
        android:gravity="center"
        android:layout_marginLeft="10dp"
        android:textSize="25sp"
        android:id="@+id/clu"
        />

</LinearLayout>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:orientation="horizontal"
        android:gravity="center">
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="7"
            android:background="@drawable/selector"
            android:gravity="center"
            android:textSize="25sp"
            android:id="@+id/num7"
            />
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="8"
            android:background="@drawable/selector"
            android:gravity="center"
            android:layout_marginLeft="10dp"
            android:textSize="25sp"
            android:id="@+id/num8"
            />
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="9"
            android:background="@drawable/selector"
            android:gravity="center"
            android:layout_marginLeft="10dp"
            android:textSize="25sp"
            android:id="@+id/num9"
            />
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="－"
            android:background="@drawable/selector"
            android:gravity="center"
            android:layout_marginLeft="10dp"
            android:textSize="25sp"
            android:id="@+id/charjian"
            />

    </LinearLayout>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:orientation="horizontal"
        android:gravity="center">
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="4"
            android:background="@drawable/selector"
            android:gravity="center"
            android:textSize="25sp"
            android:id="@+id/num4"
            />
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="5"
            android:background="@drawable/selector"
            android:gravity="center"
            android:layout_marginLeft="10dp"
            android:textSize="25sp"
            android:id="@+id/num5"
            />
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="6"
            android:background="@drawable/selector"
            android:gravity="center"
            android:layout_marginLeft="10dp"
            android:textSize="25sp"
            android:id="@+id/num6"
            />
        <Button
            android:layout_width="65dp"
            android:layout_height="65dp"
            android:text="＋"
            android:background="@drawable/selector"
            android:gravity="center"
            android:layout_marginLeft="10dp"
            android:textSize="25sp"
            android:id="@+id/charadd"
            />

    </LinearLayout>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:gravity="center_horizontal"
        android:layout_marginTop="10dp"
        >
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"

            >
            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                >
                <Button
                    android:layout_width="65dp"
                    android:layout_height="65dp"
                    android:background="@drawable/selector"
                    android:text="1"
                    android:gravity="center"
                    android:textSize="25sp"
                    android:id="@+id/num1"
                    />
                <Button
                    android:layout_width="65dp"
                    android:layout_height="65dp"
                    android:text="2"
                    android:background="@drawable/selector"
                    android:gravity="center"
                    android:layout_marginLeft="10dp"
                    android:textSize="25sp"
                    android:id="@+id/num2"/>
                <Button
                    android:layout_width="65dp"
                    android:layout_height="65dp"
                    android:text="3"
                    android:background="@drawable/selector"
                    android:gravity="center"
                    android:layout_marginLeft="10dp"
                    android:textSize="25sp"
                    android:id="@+id/num3"/>
            </LinearLayout>

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:layout_marginTop="10dp">

                <Button
                    android:id="@+id/num0"
                    android:layout_width="140dp"
                    android:layout_height="65dp"
                    android:text="0"
                    android:background="@drawable/selector"
                    android:gravity="center"
                    android:textSize="25sp" />

                <Button
                    android:id="@+id/dian"
                    android:layout_width="65dp"
                    android:layout_height="65dp"
                    android:layout_marginLeft="10dp"
                    android:background="@drawable/selector"
                    android:gravity="center"
                    android:text="."
                    android:textSize="25sp" />

            </LinearLayout>

        </LinearLayout>

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <Button
                android:layout_width="65dp"
                android:layout_height="140dp"
                android:text="="
                android:background="@drawable/equal"
                android:gravity="center"
                android:layout_marginLeft="10dp"
                android:textSize="25sp"
                android:id="@+id/equai"/>
        </LinearLayout>

    </LinearLayout>

</LinearLayout>

java程式碼

package com.example.administrator.calculate;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.Toast;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.input)
    EditText input;
    @BindView(R.id.clear)
    Button clear;
    @BindView(R.id.delete)
    Button delete;
    @BindView(R.id.cheng)
    Button cheng;
    @BindView(R.id.clu)
    Button chu;
    @BindView(R.id.num7)
    Button num7;
    @BindView(R.id.num8)
    Button num8;
    @BindView(R.id.num9)
    Button num9;
    @BindView(R.id.charjian)
    Button charjian;
    @BindView(R.id.num4)
    Button num4;
    @BindView(R.id.num5)
    Button num5;
    @BindView(R.id.num6)
    Button num6;
    @BindView(R.id.charadd)
    Button charadd;
    @BindView(R.id.num1)
    Button num1;
    @BindView(R.id.num2)
    Button num2;
    @BindView(R.id.num3)
    Button num3;
    @BindView(R.id.num0)
    Button num0;
    @BindView(R.id.dian)
    Button dian;
    @BindView(R.id.equai)
    Button equal;

    private  String ss="";
    private  boolean fu=false;
    private  boolean num=false;
    private  boolean point=false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);


    }

    @OnClick({R.id.clear, R.id.delete, R.id.cheng, R.id.clu, R.id.num7, R.id.num8, R.id.num9, R.id.charjian, R.id.num4, R.id.num5, R.id.num6, R.id.charadd, R.id.num1, R.id.num2, R.id.num3, R.id.num0, R.id.dian, R.id.equai})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.clear:
            {
                ss="";
                input.setText(ss);
            }
                break;
            case R.id.delete:
            {
                if(ss.indexOf(" ")==ss.length()-3)
                {
                    ss= ss.substring(0,ss.length() - 2);
                }
                if(ss.length()>0)
                {
                    ss= ss.substring(0,ss.length() - 1);
                }
                input.setText(ss);
            }
                break;
            case R.id.cheng:
            {
                if(ss.length()==0)
                {
                    break;
                }
                if(ss.contains(" "))
                {
                    if(ss.indexOf(" ")==ss.length()-3||ss.indexOf(" ")==ss.length()-2||ss.indexOf(" ")==ss.length()-1) break;
                    getResult();
                }
                fu=true;
                ss+=" × ";
                input.setText(ss);
            }
                break;
            case R.id.clu:
            {
                if(ss.length()==0)
                {
                    break;
                }
                if(ss.contains(" "))
                {
                    if(ss.indexOf(" ")==ss.length()-3||ss.indexOf(" ")==ss.length()-2||ss.indexOf(" ")==ss.length()-1) break;
                    getResult();
                }
                fu=true;
                ss+=" ÷ ";
                input.setText(ss);
            }
                break;
            case R.id.num7:
            {
                ss+="7";
                input.setText(ss);
            }
                break;
            case R.id.num8:
            {
                ss+="8";
                input.setText(ss);
            }
                break;
            case R.id.num9:
            {
                ss+="9";
                input.setText(ss);
            }
                break;
            case R.id.charjian:
            {
                if(ss.length()==0)
                {
                    break;
                }
                if(ss.contains(" "))
                {
                    if(ss.indexOf(" ")==ss.length()-3||ss.indexOf(" ")==ss.length()-2||ss.indexOf(" ")==ss.length()-1) break;
                    getResult();
                }
                fu=true;
                ss+=" － ";
                input.setText(ss);
            }
                break;
            case R.id.num4:
            {
                ss+="4";
                input.setText(ss);
            }
                break;
            case R.id.num5:
            {
                ss+="5";
                input.setText(ss);
            }
                break;
            case R.id.num6:
            {
                ss+="6";
                input.setText(ss);
            }
                break;
            case R.id.charadd:
            {
                if(ss.length()==0)
                {
                    break;
                }
                if(ss.contains(" "))
                {
                    if(ss.indexOf(" ")==ss.length()-3||ss.indexOf(" ")==ss.length()-2||ss.indexOf(" ")==ss.length()-1) break;
                    getResult();
                }
                fu=true;
                ss+=" ＋ ";
                input.setText(ss);
            }
                break;
            case R.id.num1:
            {
                ss+="1";
                input.setText(ss);
            }
                break;
            case R.id.num2:
            {
                ss+="2";
                input.setText(ss);
            }
                break;
            case R.id.num3:
            {
                ss+="3";
                input.setText(ss);
            }
                break;
            case R.id.num0:
            {
                ss+="0";
                input.setText(ss);
            }
                break;
            case R.id.dian:
            {
                if(ss.length()==0||ss.indexOf(" ")==ss.length()-3||ss.lastIndexOf(".")>ss.indexOf(" "))
                {
                    break;
                }
                else
                {
                    ss+=".";
                    input.setText(ss);
                }
            }
                break;
            case R.id.equai:
                getResult();
                break;
        }
    }
    private void getResult()
    {
        double result=0;
        if(ss==null||ss.equals("")) return;
        if(!ss.contains(" "))  return;
        String s1=ss.substring(0,ss.indexOf(" "));
        String op=ss.substring(ss.indexOf(" ")+1,ss.indexOf(" ")+2);
        String s2=ss.substring(ss.indexOf(" ")+3);
        if(!s1.equals("")&&!s2.equals(""))
        {
            double d1=Double.parseDouble(s1);
            double d2=Double.parseDouble(s2 );
            switch (op)
            {
                case "＋": result=d1+d2;break;
                case "－": result=d1-d2;break;
                case "×": result=d1*d2;break;
                case "÷":
                {
                    if(d2==0)
                    {
                        Toast.makeText(this, "不能除以零", Toast.LENGTH_SHORT).show();
                        break;
                    }
                    result=d1/d2*1.0;
                }
                break;
            }

            int r = (int)  result;
            if(r==result)
            {
                input.setText(""+r);
                ss=""+r;
            }
            else
            {
                input.setText(result+"");
                ss=""+result;
            }

        }
    }
}

在AndroidManifest.xml檔案中activity 後面新增

android:theme=”@style/Theme.AppCompat.DayNight.NoActionBar”