安卓如何获取安卓系统版本的号及安卓4.0以下如何屏蔽home键

Platform Version	API Level	VERSION_CODE	Notes
Android 4.2	17	JELLY_BEAN_MR1	Platform Highlights
Android 4.1, 4.1.1	16	JELLY_BEAN	Platform Highlights
Android 4.0.3, 4.0.4	15	ICE_CREAM_SANDWICH_MR1	Platform Highlights
Android 4.0, 4.0.1, 4.0.2	14	ICE_CREAM_SANDWICH
Android 3.2	13	HONEYCOMB_MR2
Android 3.1.x	12	HONEYCOMB_MR1	Platform Highlights
Android 3.0.x	11	HONEYCOMB	Platform Highlights
Android 2.3.4 Android 2.3.3	10	GINGERBREAD_MR1	Platform Highlights
Android 2.3.2 Android 2.3.1 Android 2.3	9	GINGERBREAD
Android 2.2.x	8	FROYO	Platform Highlights
Android 2.1.x	7	ECLAIR_MR1	Platform Highlights
Android 2.0.1	6	ECLAIR_0_1
Android 2.0	5	ECLAIR
Android 1.6	4	DONUT	Platform Highlights
Android 1.5	3	CUPCAKE	Platform Highlights
Android 1.1	2	BASE_1_1
Android 1.0	1	BASE

public class hello extends Activity {
 int currentapiVersion=1;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO 自动生成的方法存根
  super.onCreate(savedInstanceState);
  setContentView(R.layout.hello);
  currentapiVersion=android.os.Build.VERSION.SDK_INT;//获取安卓系统的版本号
  
 }

 //屏蔽home键
public void onAttachedToWindow() { 
 if( currentapiVersion<14)
 {
     this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD); 
     super.onAttachedToWindow(); 
 }
}
}