为Android中的所有已安装应用程序设置密码

Question

首先，我尝试仅为一个应用程序设置密码。我为Instagram设置了密码。但它不起作用。我使用了以下代码。

LockAppMainActivity.java

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_lock_app_main);
    startService(new Intent(this, CreatedWith.class));
}

CreatedWith.java

public class CreatedWith extends IntentService {
    public CreatedWith() {
        super("CreatedWith");
        // TODO Auto-generated constructor stub
    }

    @Override
    protected void onHandleIntent(Intent arg0) {
        // TODO Auto-generated method stub
        ActivityManager mActivityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.RunningTaskInfo> RunningTask = mActivityManager.getRunningTasks(1);
        ActivityManager.RunningTaskInfo ar = RunningTask.get(0);
        String activityOnTop = ar.topActivity.getClassName();
        if(activityOnTop.equals("com.instagram.android")){
            Intent lockIntent = new Intent(this, LockScreen.class);
            lockIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            this.startActivity(lockIntent);
        }
    }
}

LockScreen.java //包含解锁的代码

但是这段代码不起作用。当我打开Instagram时，它正常打开。没有显示锁屏。

谢谢