Android简单计算器

不念不忘少年蓝@ 2022-08-23 09:57 248阅读 0赞

layout：

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context="com.test.sj_pc.test.MainActivity">
    
    
    
        <EditText
            android:id="@+id/print"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1"
            android:id="@+id/value1"
            android:layout_marginTop="51dp"
            android:layout_alignParentTop="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="2"
            android:id="@+id/value2"
            android:layout_above="@+id/value4"
            android:layout_toRightOf="@+id/value1"
            android:layout_toEndOf="@+id/value1" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="3"
            android:id="@+id/value3"
            android:layout_alignTop="@+id/value2"
            android:layout_alignLeft="@+id/value6"
            android:layout_alignStart="@+id/value6" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="4"
            android:id="@+id/value4"
            android:layout_below="@+id/value1"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="5"
            android:id="@+id/value5"
            android:layout_alignTop="@+id/value4"
            android:layout_toRightOf="@+id/value4"
            android:layout_toEndOf="@+id/value4" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="6"
            android:id="@+id/value6"
            android:layout_above="@+id/value9"
            android:layout_alignLeft="@+id/value9"
            android:layout_alignStart="@+id/value9" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="7"
            android:id="@+id/value7"
            android:layout_below="@+id/value4"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="8"
            android:id="@+id/value8"
            android:layout_alignBottom="@+id/value7"
            android:layout_toRightOf="@+id/value7"
            android:layout_toEndOf="@+id/value7" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="9"
            android:id="@+id/value9"
            android:layout_below="@+id/value5"
            android:layout_toRightOf="@+id/value5"
            android:layout_toEndOf="@+id/value5" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="0"
            android:id="@+id/value0"
            android:layout_below="@+id/value7"
            android:layout_toRightOf="@+id/value7"
            android:layout_toEndOf="@+id/value7" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="+"
            android:id="@+id/add"
    
    
            android:layout_above="@+id/value6"
            android:layout_toRightOf="@+id/value3"
            android:layout_toEndOf="@+id/value3" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="-"
            android:id="@+id/minus"
    
            android:layout_alignTop="@+id/value6"
            android:layout_toRightOf="@+id/value6"
            android:layout_toEndOf="@+id/value6" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="*"
            android:id="@+id/mul"
    
            android:layout_below="@+id/value9"
            android:layout_toRightOf="@+id/value9"
            android:layout_toEndOf="@+id/value9" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="/"
            android:id="@+id/divide"
    
            android:layout_below="@+id/value6"
            android:layout_toRightOf="@+id/value6"
            android:layout_toEndOf="@+id/value6" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="="
            android:id="@+id/result"
            android:layout_below="@+id/value9"
            android:layout_alignLeft="@+id/value9"
            android:layout_alignStart="@+id/value9" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="."
            android:id="@+id/point"
            android:layout_alignBottom="@+id/value0"
            android:layout_toLeftOf="@+id/value0"
            android:layout_toStartOf="@+id/value0" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="退出"
            android:id="@+id/quit"
            android:layout_marginTop="44dp"
            android:layout_below="@+id/mul"
            android:layout_alignParentRight="true"
            android:layout_alignParentEnd="true" />
    
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="回退"
            android:id="@+id/delete"
            android:layout_alignTop="@+id/quit"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />
    </RelativeLayout>

此处可以自行拖动控件进行布局

大概样子直接上图

![Image 1][]

Java代码：

package com.test.sj_pc.test;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    
    public class MainActivity extends Activity {
        private double prevalue =0.0;   //前一个数
        private double lastvalue=0.0;   //后一个数
        private int optionnum;          //操作码 1为加2为减3为乘4为除
        private StringBuffer sb=new StringBuffer(); //采用stringbuffer类存储信息
    
        private EditText print;
    
        private Button btn1 ;
        private Button btn2;
        private Button btn3 ;
        private Button btn4 ;
        private Button btn5 ;
        private Button btn6 ;
        private Button btn7 ;
        private Button btn8 ;
        private Button btn9 ;
        private Button btn0 ;
        private Button btnpoint;
    
        private Button btnadd ;
        private Button btnminus ;
        private Button btnmul ;
        private Button btndivide ;
        private Button btnresult;
    
        private Button btnquit ;
        private Button btndetelte ;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            findbuttonbyid();
    
    
            setnumberlistener();   //自定义函数 为数字按钮添加监听
            setoptionmethod();     //自定义函数 为运算按钮添加监听
            btndetelte.setOnClickListener(btndeteltelistener); //自定义函数 为回退按钮添加监听
            btnquit.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    MainActivity.this.finish();
                }
            });                                             //退出函数
    
            btnresult.setOnClickListener(resultOnclickLisener);//获得结果
    
        }
    
        private void findbuttonbyid() {
            btn1=(Button)findViewById(R.id.value1);
            btn2=(Button)findViewById(R.id.value2);
            btn3=(Button)findViewById(R.id.value3);
            btn4=(Button)findViewById(R.id.value4);
            btn5=(Button)findViewById(R.id.value5);
            btn6=(Button)findViewById(R.id.value6);
            btn7=(Button)findViewById(R.id.value7);
            btn8=(Button)findViewById(R.id.value8);
            btn9=(Button)findViewById(R.id.value9);
            btn0=(Button)findViewById(R.id.value0);
            btnpoint=(Button)findViewById(R.id.point);
    
            btnadd=(Button)findViewById(R.id.add);
            btnminus=(Button)findViewById(R.id.minus);
            btnmul=(Button)findViewById(R.id.mul);
            btndivide=(Button)findViewById(R.id.divide);
            btnresult=(Button)findViewById(R.id.result);
    
            btndetelte=(Button)findViewById(R.id.delete);
            btnquit=(Button)findViewById(R.id.quit);
    
            print =(EditText)findViewById(R.id.print);
            print.setEnabled(false);               //显示框不可输入
        }
    
        public  void setoptionmethod() {
            btnadd.setOnClickListener(listeneroption);
            btnminus.setOnClickListener(listeneroption);
            btnmul.setOnClickListener(listeneroption);
            btndivide.setOnClickListener(listeneroption);
        }
    
        public View.OnClickListener listeneroption= new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                prevalue=getNumberFromButton(sb);
                Button Boption=(Button)v;
                switch (Boption.getText().toString()){
                    case "+":
                        print.setText("");
                        sb.delete(0,sb.length());
                        optionnum=1;
                        break;
                    case "-":
                        print.setText("");
                        sb.delete(0,sb.length());
                        optionnum=2;
                        break;
                    case "*":
                        print.setText("");
                        sb.delete(0,sb.length());
                        optionnum=3;
                        break;
                    case "/":
                        print.setText("");
                        sb.delete(0,sb.length());
                        optionnum=4;
                        break;
                       default:
                           break;
                }
            }
        };
    
        public void setnumberlistener(){
           btn1.setOnClickListener(listenernum);
           btn2.setOnClickListener(listenernum);
           btn3.setOnClickListener(listenernum);
           btn4.setOnClickListener(listenernum);
           btn5.setOnClickListener(listenernum);
           btn6.setOnClickListener(listenernum);
           btn7.setOnClickListener(listenernum);
           btn8.setOnClickListener(listenernum);
           btn9.setOnClickListener(listenernum);
           btn0.setOnClickListener(listenernum);
           btnpoint.setOnClickListener(listenernum);
        }
        View.OnClickListener listenernum =new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Button b1=(Button)v;
                switch(b1.getText().toString()){
                    case "1":
                        sb.append("1");
                        print.setText(sb.toString());
                        break;
                    case "2":
                        sb.append("2");
                        print.setText(sb.toString());
                        break;
                    case "3":
                        sb.append("3");
                        print.setText(sb.toString());
                        break;
                    case "4":
                        sb.append("4");
                        print.setText(sb.toString());
                        break;
    
                    case "5":
                        sb.append("5");
                        print.setText(sb.toString());
                        break;
                    case "6":
                        sb.append("6");
                        print.setText(sb.toString());
                        break;
    
                    case "7":
                        sb.append("7");
                        print.setText(sb.toString());
                        break;
    
                    case "8":
                        sb.append("8");
                        print.setText(sb.toString());
                        break;
    
                    case "9":
                        sb.append("9");
                        print.setText(sb.toString());
                        break;
    
                    case "0":
                        sb.append("0");
                        print.setText(sb.toString());
                        break;
                    case ".":
                        sb.append(".");
                        print.setText(sb.toString());
                        break;
    
                    default:
                        print.setText("");
                        break;
                }
            }
        };
        View.OnClickListener btndeteltelistener =new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int length=sb.length();
                if(length>0) {
                    sb.deleteCharAt(length - 1);
                    print.setText(sb.toString());
                }
            }
        };
        public double getNumberFromButton(StringBuffer sb){
            double numbervalue=0.0;
            if("".equals(sb.toString()))
            {
    
            }else {
                numbervalue = Double.valueOf(sb.toString());
            }
    
            return  numbervalue;
        }
        View.OnClickListener resultOnclickLisener= new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                double result;
                switch (optionnum){
                    case 1:
                        lastvalue=getNumberFromButton(sb);
                        result=prevalue+lastvalue;
                        print.setText(result+"");
                        break;
                    case 2:
                        lastvalue=getNumberFromButton(sb);
                        result=prevalue-lastvalue;
                        print.setText(result+"");
                        break;
                    case 3:
                        lastvalue=getNumberFromButton(sb);
                        result=prevalue*lastvalue;
                        print.setText(result+"");
                        break;
                    case 4:
                        lastvalue=getNumberFromButton(sb);
                        if(lastvalue!=0) {
                            result = prevalue / lastvalue;
                            print.setText(result + "");
                        }else {
                            print.setText("error");
                        }
                        break;
    
                }
            }
        };
    
    }

[Image 1]: