android实现简易计算器

本文实例为大家分享了android实现简易计算器展示的具体代码，供大家参考，具体内容如下

效果图：

一、如图，首先布局计算器主页显示

activity_main.xml

<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" >

  <EditText
    android:id="@+id/num1"
    android:layout_width="80dp"
    android:layout_height="wrap_content"
    android:inputType="number" />

  <TextView
    android:id="@+id/type"
    android:layout_width="40dp"
    android:layout_height="50dp"
    android:layout_toRightOf="@id/num1"
    android:gravity="center" />

  <EditText
    android:id="@+id/num2"
    android:layout_width="80dp"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/num1"
    android:layout_marginLeft="50dp"
    android:inputType="number" />

  <TextView
    android:id="@+id/equal"
    android:layout_width="80dp"
    android:layout_height="50dp"
    android:layout_toRightOf="@id/num2"
    android:gravity="center" />

  <Button
    android:id="@+id/add"
    android:layout_width="70dp"
    android:layout_height="wrap_content"
    android:layout_below="@id/num1"
    android:text="@string/add" />

  <Button
    android:id="@+id/sub"
    android:layout_width="70dp"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/add"
    android:layout_alignTop="@id/add"
    android:text="@string/sub" />

  <Button
    android:id="@+id/mul"
    android:layout_width="70dp"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/sub"
    android:layout_alignTop="@id/sub"
    android:text="@string/mul" />

  <Button
    android:id="@+id/div"
    android:layout_width="70dp"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/mul"
    android:layout_alignTop="@id/mul"
    android:text="@string/div" />
</RelativeLayout>

二、计算器实现的方法

public class CalculatorBiz {

 public float add(float num1,float num2){
 return num1+num2;
 }

 public float sub(float num1,float num2){
 return num1-num2;
 }

 public float mul(float num1,float num2){
 return num1*num2;
 }

 public float div(float num1,float num2){
 return num1/num2;
 }

}

三、MainActivity主要方法

public class MainActivity extends Activity {
  //定义组件
 private EditText inputnum1;
 private EditText inputnum2;
 private TextView type;
 private TextView equal;
 private Button add;
 private Button sub;
 private Button mul;
 private Button div;
 CalculatorBiz calculator=new CalculatorBiz();

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //查找组件
    inputnum1=(EditText) findViewById(R.id.num1);
    inputnum2=(EditText) findViewById(R.id.num2);
    type=(TextView) findViewById(R.id.type);
    equal=(TextView) findViewById(R.id.equal);
    add=(Button) findViewById(R.id.add);
    sub=(Button) findViewById(R.id.sub);
    mul=(Button) findViewById(R.id.mul);
    div=(Button) findViewById(R.id.div);

    type.setTextColor(Color.WHITE);
    equal.setTextColor(Color.WHITE);

    add.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
  String num1=inputnum1.getText().toString();
  String num2=inputnum2.getText().toString();
  float a=Float.parseFloat(num1);
  float b=Float.parseFloat(num2);
  type.setText("+");
  equal.setText("="+calculator.add(a, b));

  }});
    sub.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
  String num1=inputnum1.getText().toString();
  String num2=inputnum2.getText().toString();
  float a=Float.parseFloat(num1);
  float b=Float.parseFloat(num2);
  type.setText("-");
  equal.setText("="+calculator.sub(a, b));

  }});
    mul.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
  String num1=inputnum1.getText().toString();
  String num2=inputnum2.getText().toString();
  float a=Float.parseFloat(num1);
  float b=Float.parseFloat(num2);
  type.setText("*");
  equal.setText("="+calculator.mul(a, b));

  }});
    div.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
  String num1=inputnum1.getText().toString();
  String num2=inputnum2.getText().toString();
  float a=Float.parseFloat(num1);
  float b=Float.parseFloat(num2);
  type.setText("/");
  equal.setText("="+calculator.div(a, b));

  }});

  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
   super.onCreateOptionsMenu(menu);
   menu.add(0, 1, 0, "关于");
   menu.add(0, 2, 1, "退出");
   menu.findItem(2);
    return true;
  }
  public boolean onOptionsItemSelected(MenuItem item){
   if(item.getItemId() == 1){
   Toast.makeText(this, "详细内容\n"+"作者：dyp\n"+"版本：version1", Toast.LENGTH_LONG).show();
   }else if(item.getItemId() == 2){
   Toast.makeText(this, "退出\n"+"你确定退出程序？", Toast.LENGTH_LONG).show();
   }
   return super.onOptionsItemSelected(item);
  }

}

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