惟一标识码这东西在网络应用中很是有用,例如检测是否重复注册之类的。
import android.provider.Settings.Secure;
private String android_id = Secure.getString(getContext().getContentResolver(), Secure.ANDROID_ID);
咱们在项目过程当中或多或少会使用到设备的惟一识别码,咱们但愿可以获得一个稳定、可靠的设备惟一识别码。今天咱们将介绍几种方式。
1. DEVICE_ID
假设咱们确实须要用到真实设备的标识,可能就须要用到DEVICE_ID。在之前,咱们的Android设备是手机,这个DEVICE_ID能够同经过TelephonyManager.getDeviceId()获取,它根据不一样的手机设备返回IMEI,MEID或者ESN码,但它在使用的过程当中会遇到不少问题:
- 非手机设备: 若是只带有Wifi的设备或者音乐播放器没有通话的硬件功能的话就没有这个DEVICE_ID
- 权限: 获取DEVICE_ID须要READ_PHONE_STATE权限,但若是咱们只为了获取它,没有用到其余的通话功能,那这个权限有点大才小用
- bug:在少数的一些手机设备上,该实现有漏洞,会返回垃圾,如:zeros或者asterisks的产品
2. MAC ADDRESS
咱们也能够经过手机的Wifi或者蓝牙设备获取MAC ADDRESS做为DEVICE ID,可是并不建议这么作,由于并非全部的设备都有Wifi,而且,若是Wifi没有打开,那硬件设备没法返回MAC ADDRESS.
3. Serial Number
在Android 2.3能够经过android.os.Build.SERIAL获取,非手机设备能够经过该接口获取。
4. ANDROID_IDANDROID_ID是设备第一次启动时产生和存储的64bit的一个数,当设备被wipe后该数重置
ANDROID_ID彷佛是获取Device ID的一个好选择,但它也有缺陷:
- 它在Android <=2.1 or Android >=2.3的版本是可靠、稳定的,但在2.2的版本并非100%可靠的
- 在主流厂商生产的设备上,有一个很常常的bug,就是每一个设备都会产生相同的ANDROID_ID:9774d56d682e549c
5. Installtion ID : UUID
以上四种方式都有或多或少存在的必定的局限性或者bug,在这里,有另一种方式解决,就是使用UUID,该方法无需访问设备的资源,也跟设备类型无关。
这种方式是经过在程序安装后第一次运行后生成一个ID实现的,但该方式跟设备惟一标识不同,它会由于不一样的应用程序而产生不一样的ID,而不是设备惟一ID。所以常常用来标识在某个应用中的惟一ID(即Installtion ID),或者跟踪应用的安装数量。很幸运的,Google Developer Blog提供了这样的一个框架:
public class Installation {
private static String sID = null;
private static final String INSTALLATION = "INSTALLATION";
public synchronized static String id(Context context) {
if (sID == null) {
File installation = new File(context.getFilesDir(), INSTALLATION);
try {
if (!installation.exists())
writeInstallationFile(installation);
sID = readInstallationFile(installation);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
return sID;
}
private static String readInstallationFile(File installation) throws IOException {
RandomAccessFile f = new RandomAccessFile(installation, "r");
byte[] bytes = new byte[(int) f.length()];
f.readFully(bytes);
f.close();
return new String(bytes);
}
private static void writeInstallationFile(File installation) throws IOException {
FileOutputStream out = new FileOutputStream(installation);
String id = UUID.randomUUID().toString();
out.write(id.getBytes());
out.close();
}
}
总结
综合以上所述,为了实如今设备上更通用的获取设备惟一标识,咱们能够实现这样的一个类,为每一个设备产生惟一的UUID,以ANDROID_ID为基础,在获取失败时以TelephonyManager.getDeviceId()为备选方法,若是再失败,使用UUID的生成策略。
重申下,如下方法是生成Device ID,在大多数状况下Installtion ID可以知足咱们的需求,可是若是确实须要用到Device ID,那能够经过如下方式实现:
import android.content.Context;
import android.content.SharedPreferences;
import android.provider.Settings.Secure;
import android.telephony.TelephonyManager;
import java.io.UnsupportedEncodingException;
import java.util.UUID;
public class DeviceUuidFactory {
protected static final String PREFS_FILE = "device_id.xml";
protected static final String PREFS_DEVICE_ID = "device_id";
protected static UUID uuid;
public DeviceUuidFactory(Context context) {
if( uuid ==null ) {
synchronized (DeviceUuidFactory.class) {
if( uuid == null) {
final SharedPreferences prefs = context.getSharedPreferences( PREFS_FILE, 0);
final String id = prefs.getString(PREFS_DEVICE_ID, null );
if (id != null) {
// Use the ids previously computed and stored in the prefs file
uuid = UUID.fromString(id);
} else {
final String androidId = Secure.getString(context.getContentResolver(), Secure.ANDROID_ID);
// Use the Android ID unless it's broken, in which case fallback on deviceId,
// unless it's not available, then fallback on a random number which we store
// to a prefs file
try {
if (!"9774d56d682e549c".equals(androidId)) {
uuid = UUID.nameUUIDFromBytes(androidId.getBytes("utf8"));
} else {
final String deviceId = ((TelephonyManager) context.getSystemService( Context.TELEPHONY_SERVICE )).getDeviceId();
uuid = deviceId!=null ? UUID.nameUUIDFromBytes(deviceId.getBytes("utf8")) : UUID.randomUUID();
}
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
// Write the value out to the prefs file
prefs.edit().putString(PREFS_DEVICE_ID, uuid.toString() ).commit();
}
}
}
}
}
/**
* Returns a unique UUID for the current android device. As with all UUIDs, this unique ID is "very highly likely"
* to be unique across all Android devices. Much more so than ANDROID_ID is.
*
* The UUID is generated by using ANDROID_ID as the base key if appropriate, falling back on
* TelephonyManager.getDeviceID() if ANDROID_ID is known to be incorrect, and finally falling back
* on a random UUID that's persisted to SharedPreferences if getDeviceID() does not return a
* usable value.
*
* In some rare circumstances, this ID may change. In particular, if the device is factory reset a new device ID
* may be generated. In addition, if a user upgrades their phone from certain buggy implementations of Android 2.2
* to a newer, non-buggy version of Android, the device ID may change. Or, if a user uninstalls your app on
* a device that has neither a proper Android ID nor a Device ID, this ID may change on reinstallation.
*
* Note that if the code falls back on using TelephonyManager.getDeviceId(), the resulting ID will NOT
* change after a factory reset. Something to be aware of.
*
* Works around a bug in Android 2.2 for many devices when using ANDROID_ID directly.
*
* @see http://code.google.com/p/android/issues/detail?id=10603
*
* @return a UUID that may be used to uniquely identify your device for most purposes.
*/
public UUID getDeviceUuid() {
return uuid;
}
}
代码: 这里是你在Android里读出 惟一的 IMSI-ID / IMEI-ID 的方法。 Java: String myIMSI = android.os.SystemProperties.get(android.telephony.TelephonyProperties.PROPERTY_IMSI); // within my emulator it returns: 310995000000000 String myIMEI = android.os.SystemProperties.get(android.telephony.TelephonyProperties.PROPERTY_IMEI); // within my emulator it returns: 000000000000000
注:android.os.SystemProperties的标签被打上@hide了,因此sdk中并不会存在。若是须要使用,须要有android的source code支持。