android 实现两个数字的乘法，页面之间的传值 以及菜单下拉列表的使用

package com.example.test1;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
	private EditText factorOne;
	private EditText factorTwo;
	private Button calculate;
	private TextView symbol;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		// 根据空间ID 取得代表控件的对象
		factorOne = (EditText) findViewById(R.id.factone);
		factorTwo = (EditText) findViewById(R.id.facttwo);
		symbol = (TextView) findViewById(R.id.symbol);
		calculate = (Button) findViewById(R.id.calculate);

		// 为symbol和calculate设置显示的值
		symbol.setText(R.string.symbol);
		calculate.setText(R.string.calculator);

		// 给calculate设置绑定事件
		calculate.setOnClickListener(new CalculateListener());
	}

	// 编写一个监听器

	class CalculateListener implements OnClickListener {

		@Override
		public void onClick(View arg0) {
			// 1.取得两个EditText的值
			String factorOneStr = factorOne.getText().toString();
			String factorTwoStr = factorTwo.getText().toString();
			// 2.将这两个值存放到Intent对象当中
			Intent it = new Intent();
			it.putExtra("one", factorOneStr);
			it.putExtra("two", factorTwoStr);
			it.setClass(MainActivity.this, ResultActivity.class);
			// 使用这个Intent对象来启动ResultActivity
			MainActivity.this.startActivity(it);

		}
	}

	// 添加回调函数,当客户点击menu按钮时调用该方法
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		menu.add(0, 1, 1, R.string.exit);
		menu.add(0, 2, 2, R.string.about);
		return super.onCreateOptionsMenu(menu);
	}

	// 为menu添加动作,也是一个回调函数,当客户点击菜单当中的某一个选项时调用该方法
	public boolean onOptionsItemSelected(MenuItem item) {
		if (item.getItemId() == 1) {
			finish();
		}
		return super.onOptionsItemSelected(item);

	}

}

补充：给按钮添加监听事件：注意是new(View.OnClickListener())不要把View 丢了

		nextpage.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				
				
			}
		});

package com.example.test1;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

 
public class ResultActivity extends Activity{
	private TextView resultView;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.result);
		resultView= (TextView) findViewById(R.id.result);
		//得到Intent对象的值
		Intent it = getIntent();
		String factorOneStr =it.getStringExtra("one");
		String factorTwoStr =it.getStringExtra("two");
		int factorOneInt=Integer.parseInt(factorOneStr);
		int factorTwoInt=Integer.parseInt(factorTwoStr);
		int result =factorOneInt*factorTwoInt;
		resultView.setText(result+"");
	}

}

页面布局：

<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="fill_parent"
    android:orientation="vertical"
    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=".MainActivity" >

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

    <TextView
        android:id="@+id/symbol"
        android:layout_width="987dp"
        android:layout_height="124dp"
        android:text="@string/hello" />

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

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/calculate"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
         />

</LinearLayout>

<?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="fill_parent"
    android:orientation="vertical"
    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=".MainActivity" >
    
    <TextView
        android:id="@+id/result"
        android:layout_width="987dp"
        android:layout_height="77dp" />
    
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, MainActivity</string>
 
    <string name="app_name">test1</string>
    <string name="action_settings">Settings</string>
    <string name="calculator">计算</string>
    <string name="symbol">乘以</string>
     <string name="exit">退出</string>
     <string name="about">关于</string>

</resources>

AndroidManifest.xml文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.test1"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.test1.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.test1.ResultActivity"
            android:theme="@style/AppTheme" >
        </activity>
    </application>

</manifest>