Android 锁屏

public class Locker extends Activity {

private DevicePolicyManager policyManager;
private ComponentName componentName;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        policyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
        componentName = new ComponentName(this, LockScreenAdmin.class);
        
        mylock();
        android.os.Process.killProcess(android.os.Process.myPid());
    }
    
    private void mylock() {
     boolean active = policyManager.isAdminActive(componentName);
     if (!active) {
     activeManage();
     policyManager.lockNow();
     }
     if (active) {
     policyManager.lockNow();
     }
    }
    
    private void activeManage() {
     Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
     intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);
     intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "other description");   
     startActivity(intent);
    }
}