项目移植中，遇到需要区分不同系统版本的问题。于是查找相关方法如下：
android.os.Build类提供了当前系统信息。
可用if (Build.VERSION.SDK_INT < Build.VERSION_CODES.GINGERBREAD)这样来判断。
有人用这样一个函数来获取版本号：
public static int getAndroidSDKVersion() {
int version;
try {
version = Integer.valueOf(android.os.Build.VERSION.SDK);
} catch (NumberFormatException e) {
Log.e(e.toString());
}
return version;
}
android.os.Build.VERSION_CODES 值有如下，其中第二列的值就是API LEVEL编号：
| int | 1 (0x00000001) | BASE | October 2008: The original, first, version of Android. |
| int | 2 (0x00000001) | BASE_1_1 | February 2009: First Android update, officially called 1.1. |
| int | 3 (0x00000001) | CUPCAKE | May 2009: Android 1.5. |
| int | 10000 (0x00002710) | CUR_DEVELOPMENT | Magic version number for a current development build, which has not yet turned into an official release. |
| int | 5 (0x00000001) | DONUT | September 2009: Android 1.6. |
| int | ECLAIR | November 2009: Android 2.0 | |
| Applications targeting this or a later release will get these new changes in behavior: | |||
| 5 (0x00000008) | The Service.onStartCommand function will return the new START_STICKY behavior instead of the old compatibility START_STICKY_COMPATIBILITY. | ||
| int | 6 (0x00000008) | ECLAIR_0_1 | December 2009: Android 2.0.1 |
| int | 7 (0x00000008) | ECLAIR_MR1 | January 2010: Android 2.1 |
| int | 8 (0x00000008) | FROYO | June 2010: Android 2.2 |
| int | GINGERBREAD | November 2010: Android 2.3 | |
| Applications targeting this or a later release will get these new changes in behavior: | |||
| 9 (0x00000009) | The application's notification icons will be shown on the new dark status bar background, so must be visible in this situation. | ||
| int | 10 (0x0000000a) | GINGERBREAD_MR1 | February 2011: Android 2.3.3. |
| int | 11 (0x0000000b) | HONEYCOMB | February 2011: Android 3.0. |
| int | 12 (0x0000000c) | HONEYCOMB_MR1 | May 2011: Android 3.1. |
| int | 13 (0x0000000d) | HONEYCOMB_MR2 | June 2011: Android 3.2. |
| int | 14 (0x0000000e) | ICE_CREAM_SANDWICH | October 2011: Android 4.0. |
| int | 15 (0x0000000f) | ICE_CREAM_SANDWICH_MR1 | December 2011: Android 4.0.3. |
| int | 16 (0x00000010) | JELLY_BEAN | Android 4.1. |