Android简单计算器

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/editText1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10" >

        <requestFocus />
    </EditText>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="buttonClick"
            android:text="+"
            android:textColor="#000fff"
            android:textSize="20dp" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="buttonClick1"
            android:text="-" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="buttonClick2"
            android:text="*" />

        <Button
            android:id="@+id/button4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="buttonClick3"
            android:text="/" />

    </LinearLayout>

    <EditText
        android:id="@+id/editText2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40dp"
        android:text="=" />

    <EditText
        android:id="@+id/editText3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="#ff0000"
        android:ems="10" />

</LinearLayout>

package com.example.jisuanqi;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {
    Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //加法
        Button button=(Button)findViewById(R.id.button1);
        button.setOnClickListener(new OnClickListener() {        
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                EditText ed1=(EditText)findViewById(R.id.editText1);
                EditText ed2=(EditText)findViewById(R.id.editText2);
                EditText ed3=(EditText)findViewById(R.id.editText3);
                int num1=Integer.parseInt(ed1.getText().toString());
                int num2=Integer.parseInt(ed2.getText().toString());
                int num3=num1+num2;
                ed3.setText(String.valueOf(num3));
            }
        });
        //减法
        Button button2=(Button)findViewById(R.id.button2);
        button2.setOnClickListener(new OnClickListener() {        
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                EditText ed1=(EditText)findViewById(R.id.editText1);
                EditText ed2=(EditText)findViewById(R.id.editText2);
                EditText ed3=(EditText)findViewById(R.id.editText3);
                int num1=Integer.parseInt(ed1.getText().toString());
                int num2=Integer.parseInt(ed2.getText().toString());
                int num3=num1-num2;
                ed3.setText(String.valueOf(num3));
            }
        });
        //乘法
        Button button3=(Button)findViewById(R.id.button3);
        button3.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                EditText ed1=(EditText)findViewById(R.id.editText1);
                EditText ed2=(EditText)findViewById(R.id.editText2);
                EditText ed3=(EditText)findViewById(R.id.editText3);
                int num1=Integer.parseInt(ed1.getText().toString());
                int num2=Integer.parseInt(ed2.getText().toString());
                int num3=num1*num2;
                ed3.setText(String.valueOf(num3));
            }
        });
        //除法
       Button button4=(Button)findViewById(R.id.button4);
       button4.setOnClickListener(new OnClickListener() {        
        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            EditText ed1=(EditText)findViewById(R.id.editText1);
            EditText ed2=(EditText)findViewById(R.id.editText2);
            EditText ed3=(EditText)findViewById(R.id.editText3);
            int num1=Integer.parseInt(ed1.getText().toString());
            int num2=Integer.parseInt(ed2.getText().toString());
            int num3=num1/num2;
            ed3.setText(String.valueOf(num3));
        }
    });
       
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
}