android新手上路（三）--- 關於onConfigurationChange旋屏時沒有觸發

自從Android 3.2，screen size也開始跟着設備的橫豎切換而改變。
所以，在AndroidManifest.xml裏設置的MiniSdkVersion和 TargetSdkVersion屬性大於等於13的情況下，
如果你想阻止程序在運行時重新加載Activity，除了設置"orientation"，你還必須設置"ScreenSize"。
解決方法：

AndroidManifest.xml中設置android:configChanges="orientation|screenSize"

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

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="14" />
    <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"
            android:configChanges="orientation|screenSize"
            >       
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

MainActivity.java

package com.rilihong.listener;

import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
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.Toast;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button bt = (Button)findViewById(R.id.bt);
        bt.setOnClickListener(new OnClickListener()
        {
        	public void onClick(View view)
        	{
        		Configuration config = getResources().getConfiguration();
        		if(config.orientation == Configuration.ORIENTATION_LANDSCAPE)
        		{
        			MainActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        		}
        		else
        		{
        			MainActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        		}
        	}
        });
    }


    @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;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
    
    public void onConfigurationChanged(Configuration config)
    {
    	super.onConfigurationChanged(config);
    	String screen = config.orientation == Configuration.ORIENTATION_LANDSCAPE?"橫向屏幕":"縱向屏幕";
    	Toast.makeText(this, "系統的屏幕方向發生改變"+"\n修改後的屏幕方向爲："+screen, Toast.LENGTH_LONG).show();
    }
    
}