Activity中ConfigChanges属性的用法

通过设置这个属性可以使Activity捕捉设备状态变化，以下是可以被识别的内容： 
CONFIG_FONT_SCALE
CONFIG_MCC
CONFIG_MNC
CONFIG_LOCALE
CONFIG_TOUCHSCREEN
CONFIG_KEYBOARD
CONFIG_NAVIGATION
CONFIG_ORIENTATION

设置方法：将下列字段用“|”符号分隔开，例如：“locale|navigation|orientation
”
Value Description
“mcc“ The IMSI mobile country code (MCC) has changed — that is, a SIM hasbeen detected and updated the MCC.移动国家号码，由三位数字组成，每个国家都有自己独立的MCC，可以识别手机用户所属国家。
“mnc“ The IMSI mobile network code (MNC) has changed — that is, a SIM hasbeen detected and updated the MNC.移动网号，在一个国家或者地区中，用于区分手机用户的服务商。
“locale“ The locale has changed — for example, the user has selected a new language that text should be displayed in.用户所在地区发生变化。
“touchscreen“ The touchscreen has changed. (This should never normally happen.)
“keyboard“ The keyboard type has changed — for example, the user has plugged in an external keyboard.键盘模式发生变化，例如：用户接入外部键盘输入。
“keyboardHidden“ The keyboard accessibility has changed — for example, the user has slid the keyboard out to expose it.用户打开手机硬件键盘
“navigation“ The navigation type has changed. (This should never normally happen.)
“orientation“ The screen orientation has changed — that is, the user has rotated the device.设备旋转，横向显示和竖向显示模式切换。
“fontScale“ The font scaling factor has changed — that is, the user has selected a new global font size.全局字体大小缩放发生改变
通过一个例子介绍这个属性的用法： 首先需要修改项目的manifest:
?View Code XML
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.androidres.ConfigChangedTesting"
      android:versionCode="1"
      android:versionName="1.0.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".ConfigChangedTesting"
                  android:label="@string/app_name"
                  android:configChanges="keyboardHidden|orientation">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

在Activity中添加了 android:configChanges属性，目的是当所指定属性(Configuration Changes)发生改变时，通知程序调用 onConfigurationChanged()函数。 创建一个Layout UI:
?View Code XML
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<Button
        android:id="@+id/pick"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Pick"
    />
<Button
        android:id="@+id/view"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="View"
    />
</LinearLayout>

这个简单的UI包含两个按钮，其中一个是通过Contact列表选择一个联系人，另外一个是查看当前选择联系人的详细内容

项目的Java源代码：

import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.net.Uri;
import android.os.Bundle;
import android.provider.Contacts.People;
import android.view.View;
import android.widget.Button;


public class ConfigChangedTesting extends Activity {
    /** Called when the activity is first created. */
    static final int PICK_REQUEST = 1337;
    Button viewButton=null;
    Uri contact = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);

        setupViews();
    }


    public void onConfigurationChanged(Configuration newConfig) {
                 super.onConfigurationChanged(newConfig);  


                 setupViews();
    }  

    /* (non-Javadoc)
     * @see android.app.Activity#onActivityResult(int, int, android.content.Intent)
     */
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        //super.onActivityResult(requestCode, resultCode, data);


        if(requestCode == PICK_REQUEST){


            if(resultCode==RESULT_OK){


                contact = data.getData();
                viewButton.setEnabled(true);
            }


        }


    }


    private void setupViews(){


        setContentView(R.layout.main);


        Button pickBtn = (Button)findViewById(R.id.pick);


        pickBtn.setOnClickListener(new View.OnClickListener(){


            public void onClick(View v) {
                // TODO Auto-generated method stub


                Intent i=new Intent(Intent.ACTION_PICK,People.CONTENT_URI);
                startActivityForResult(i,PICK_REQUEST);
            }
         });
 

         viewButton =(Button)findViewById(R.id.view);  
 

         viewButton.setOnClickListener(new View.OnClickListener() {
                    public void onClick(View view) {
                         startActivity(new Intent(Intent.ACTION_VIEW, contact));
                     }
         });  
 

         viewButton.setEnabled(contact!=null);
     }
 }