安卓（Android studio）编写一个计算器，可以连续加减乘除，可加小数点，不包含括号以及加减乘除优先算法。
安卓（Android studio）编写一个计算器，可以累加，可加小数点，不包含括号以及加减乘除优先算法。
首先需要在res目录下的layout文件下创建一个xml文件进行界面的布局设计，接着在Java目录下创建一个Java的class类文件，然后在AndroidManifest.xml设置启动Java的class类文件。具体实现如下：（部分代码可以封装处理，时间不够处理的有点繁琐）
1. 布局设计（各个控件的ID，大小等设计）
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/txtResult"
android:text="显示结果"
android:gravity="right"
android:textSize="24dp"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/btnCls"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="C"/>
<Button
android:id="@+id/btnDel"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:onClick="myClick"
android:text="DEL"/>
<Button
android:id="@+id/btnchu"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="÷"/>
LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/btn1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="1"/>
<Button
android:id="@+id/btn2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="2"/>
<Button
android:id="@+id/btn3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="3"/>
<Button
android:id="@+id/btnAdd"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="+"/>
LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/btn4"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="4"/>
<Button
android:id="@+id/btn5"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="5"/>
<Button
android:id="@+id/btn6"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="6"/>
<Button
android:id="@+id/btnobs"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="-"/>
LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/btn7"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="7"/>
<Button
android:id="@+id/btn8"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="8"/>
<Button
android:id="@+id/btn9"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="9"/>
<Button
android:id="@+id/btncheng"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="×"/>
LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/btn0"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="0"/>
<Button
android:id="@+id/btndot"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="myClick"
android:text="."/>
<Button
android:id="@+id/btneql"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:onClick="myClick"
android:text="="/>
LinearLayout>
LinearLayout>
2. 激活设置
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.demo">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".Lsn0">//Lsn0是Java类
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
intent-filter>
activity>
<activity android:name=".MainActivity">activity>
application>
manifest>
3.Java实现具体功能
package com.example.demo;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
public class Lsn0 extends AppCompatActivity {
//Button btn1,btn2,btn3;
private TextView txtResult;
//Button[] btn=new Button[10];
private Button btnAdd, btncheng, btnchu, btnDel, btnCls, btnobs, btneql, btndot;
private StringBuffer digitalA = new StringBuffer(), digitalB = new StringBuffer();
private boolean isChar = false, isDot = false;
private int operate = 0;
Button[] btn = new Button[10];
int[] btnId = {R.id.btn0, R.id.btn1, R.id.btn2, R.id.btn3, R.id.btn4, R.id.btn5, R.id.btn6, R.id.btn7, R.id.btn8, R.id.btn9};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.main_layout);
txtResult = (TextView) this.findViewById(R.id.txtResult);
//btn1 = (Button) this.findViewById(R.id.btn1);
//btn2 = (Button) this.findViewById(R.id.btn2);
//btn3 = (Button) this.findViewById(R.id.btn3);
//txtResult = (TextView) this.findViewById(R.id.txtResult);
initView();
btnAdd = (Button) this.findViewById(R.id.btnAdd);
btnobs = (Button) this.findViewById(R.id.btnobs);
btncheng = (Button) this.findViewById(R.id.btncheng);
btnchu = (Button) this.findViewById(R.id.btnchu);
btnDel = (Button) this.findViewById(R.id.btnDel);
btnCls = (Button) this.findViewById(R.id.btnCls);
btneql = (Button) this.findViewById(R.id.btneql);
btndot = (Button) this.findViewById(R.id.btndot);
btnAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
operate = 1;
isChar = true;
if (digitalA.length()!=0&&digitalB.length()!=0) {
//txtResult.setText("0");
float a = Float.parseFloat(digitalA.toString());
float b = Float.parseFloat(digitalB.toString());
float c=0;
c=a+b;
digitalA=new StringBuffer();
digitalA.append(c);
digitalB=new StringBuffer();
}
txtResult.setText(digitalA);
//float a = Float.parseFloat(digitalA.toString());
//float b = Float.parseFloat(digitalB.toString());
//if (digitalB.length()!=0&&digitalA.length()!=0){
// }
}
});
btnobs.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
operate = 2;
isChar = true;
txtResult.setText("0");
if (digitalA.length()!=0&&digitalB.length()!=0) {
//txtResult.setText("0");
float a = Float.parseFloat(digitalA.toString());
float b = Float.parseFloat(digitalB.toString());
float c=0;
c=a-b;
digitalA=new StringBuffer();
digitalA.append(c);
digitalB=new StringBuffer();
}
}
});
btncheng.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
operate = 3;
isChar = true;
txtResult.setText("0");
if (digitalA.length()!=0&&digitalB.length()!=0) {
//txtResult.setText("0");
float a = Float.parseFloat(digitalA.toString());
float b = Float.parseFloat(digitalB.toString());
float c=0;
c=a*b;
digitalA=new StringBuffer();
digitalA.append(c);
digitalB=new StringBuffer();
}
}
});
btnchu.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
operate = 4;
isChar = true;
txtResult.setText("0");
if (digitalA.length()!=0&&digitalB.length()!=0) {
//txtResult.setText("0");
float a = Float.parseFloat(digitalA.toString());
float b = Float.parseFloat(digitalB.toString());
float c=0;
c=a/b;
digitalA=new StringBuffer();
digitalA.append(c);
digitalB=new StringBuffer();
}
}
});
/*btndot.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//operate=5;
isChar=true;
float a=Float.parseFloat(digitalA.toString());
float b=Float.parseFloat(digitalB.toString());
if (a!=null){
}
//txtResult.setText(c+"");
//digitalA=new StringBuffer();
//digitalB=new StringBuffer();
//txtResult.setText(null);
}
});*/
btnCls.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
digitalB = new StringBuffer();
digitalA = new StringBuffer();
txtResult.setText("请输入");
}
});
btnDel.setOnClickListener(new MyClick());
btndot.setOnClickListener(new MyClick());
btneql.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
float a = Float.parseFloat(digitalA.toString());
float b = Float.parseFloat(digitalB.toString());
float c = 0;
switch (operate) {
case 1:
c = a + b;
break;
case 2:
c = a - b;
break;
case 3:
c = a * b;
break;
case 4:
c = a / b;
break;
}
txtResult.setText(c + "");
digitalA = new StringBuffer();
digitalB = new StringBuffer();
}
});
MyClick myClick = new MyClick();
for (int i = 0; i < btn.length; i++) {
btn[i].setOnClickListener(myClick);
}
//btndot.setOnClickListener(myClick);
// btnCls.setOnClickListener(myClick);
}
class MyClick implements View.OnClickListener {
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.btnDel:
if (isChar) {
String temp = digitalB.substring(0, digitalB.length() - 1);
digitalB = new StringBuffer();
digitalB.append(temp);
txtResult.setText(digitalB.toString());
break;
} else {
String temp = digitalA.substring(0, digitalA.length() - 1);
digitalA = new StringBuffer();
digitalA.append(temp);
txtResult.setText(digitalA.toString());
break;
}
case R.id.btndot:
if (isChar) {
if (!isDot) {
if (digitalB.length() > 0) {
digitalB.append(".");
isDot = true;
break;
} else {
digitalB.append("0");
digitalB.append(".");
isDot = true;
break;
}
}
break;
} else {
if (!isDot) {
if (digitalA.length() > 0) {
digitalA.append(".");
isDot = true;
break;
} else {
digitalA.append("0");
digitalA.append(".");
isDot = true;
break;
}
}
break;
}
// case R.id.btnCls:{
//
//
// break;
// //digitalA.delete(0,9);
// //digitalB.delete(0,9);
// }
case R.id.btn1:
if (isChar) {
digitalB.append('1');
break;
} else {
digitalA.append("1");
break;
}
case R.id.btn2:
if (isChar) {
digitalB.append('2');
break;
} else {
digitalA.append("2");
break;
}
case R.id.btn3:
if (isChar) {
digitalB.append('3');
break;
} else {
digitalA.append("3");
break;
}
case R.id.btn4:
if (isChar) {
digitalB.append('4');
break;
} else {
digitalA.append("4");
break;
}
case R.id.btn5:
if (isChar) {
digitalB.append('5');
break;
} else {
digitalA.append("5");
break;
}
case R.id.btn6:
if (isChar) {
digitalB.append('6');
break;
} else {
digitalA.append("6");
break;
}
case R.id.btn7:
if (isChar) {
digitalB.append('7');
break;
} else {
digitalA.append("7");
break;
}
case R.id.btn8:
if (isChar) {
digitalB.append('8');
break;
} else {
digitalA.append("8");
break;
}
case R.id.btn9:
if (isChar) {
digitalB.append('9');
break;
} else {
digitalA.append("9");
break;
}
case R.id.btn0:
if (isChar) {
digitalB.append('0');
break;
} else {
digitalA.append("0");
break;
}
/* case R.id.btndot:
if (isChar) {
digitalB.append(".");
break;
}else {
digitalA.append(".");
break;
}*/
}
if (isChar) {
txtResult.setText(digitalB.toString());
} else {
txtResult.setText(digitalA.toString());
}
}
}
void initView() {
for (int i = 0; i < btn.length; i++) {
btn[i] = (Button) this.findViewById(btnId[i]);
}
//btn1.setOnClickListener(new MyClick());
}
}
4.截图展示效果
