Android学习笔记——menu

该工程的功能是实现两个数相乘，并在另外一个Activity中显示计算的结果

以下的代码是MainActivity.java中的代码

package com.example.menu;

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 TextView symbol;
    private Button calculate;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        factorOne = (EditText)findViewById(R.id.factorOne);
        factorTwo = (EditText)findViewById(R.id.factorTwo);
        symbol = (TextView)findViewById(R.id.symbol);
        calculate = (Button)findViewById(R.id.calculate);

        //symbol.setText("乘以");
        //calculate.setText("计算");

        //为symbol和calculate设置显示的值
        symbol.setText(R.string.symbol);
        calculate.setText(R.string.calculate);
        //将监听器的对象绑定到按钮对象上面
        calculate.setOnClickListener(new CalculateListener());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // TODO Auto-generated method stub
        menu.add(0,1,1,R.string.exit);
        menu.add(0,2,2,R.string.about);
        return super.onCreateOptionsMenu(menu);
    }

    //当客户点击MENU按钮的时候，调用该方法
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        if(item.getItemId() == 1){
            finish();
        }
        return super.onOptionsItemSelected(item);
    }

    class CalculateListener implements OnClickListener{

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            //取得两个EditText控件的值
            String factorOneStr = factorOne.getText().toString();
            String factorTwoStr = factorTwo.getText().toString();
            //将这两个值存放到Intent对象当中
            Intent intent = new Intent();
            intent.putExtra("one",factorOneStr);
            intent.putExtra("two",factorTwoStr);
            intent.setClass(MainActivity.this,ResultActivity.class );
            //使用这个Intent对象来启动ResultActivity
            MainActivity.this.startActivity(intent);
        }

    }
}

以下的代码是ResultActivity.java中的代码

package com.example.menu;

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.activity_result);
        resultView = (TextView)findViewById(R.id.result);
        //得到Intent对象当中的值
        Intent intent = getIntent();
        String factorOneStr = intent.getStringExtra("one");
        String factorTwoStr = intent.getStringExtra("two");
        int factorOneInt = Integer.parseInt(factorOneStr);
        int factorTwoInt = Integer.parseInt(factorTwoStr);
        //计算两个值的积
        int result = factorOneInt * factorTwoInt;
        resultView.setText(result + "");
    }
}

以下的代码是activity_main.xml中的代码

<?xml version="1.0" encoding="utf-8"?>
<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/factorOne"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
      />  

    <TextView
        android:id="@+id/symbol"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />

     <EditText
        android:id="@+id/factorTwo"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
      /> 

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

</LinearLayout>

以下的代码是activity_result.xml中的代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

    <TextView
        android:id="@+id/result"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />

</LinearLayout>

以下的代码是string.xml中的代码

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">menu</string>
    <string name="hello_world">Hello world!</string>
    <string name="resultLabel">result</string>
    <string name="symbol">乘法</string>
    <string name="calculate">计算</string>
    <string name="exit">退出</string>
    <string name="about">关于</string>
</resources>

以下的代码是AndroidManifest.xml中的代码

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

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="21" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".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 = ".ResultActivity">
        </activity>
    </application>

</manifest>