小编bla*_*ack的帖子

作为新的Android和Facebook sdk但尝试通过链接登录

正如他们所说,它会用facebook进行登录过程,但没有任何事情发生,并且每次显示已注销状态.这是活动类.

 public class MYFaceLoginActivity extends FragmentActivity {

        private LoginFragment loginfragment; 

        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            // TODO Auto-generated method stub
            if(savedInstanceState==null)
            {
                loginfragment=new LoginFragment();
                getSupportFragmentManager().beginTransaction().add(android.R.id.content, loginfragment).commit();

            }
            else
            {
                loginfragment=(LoginFragment) getSupportFragmentManager().findFragmentById(android.R.id.content);
            }


        }

        @Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            // TODO Auto-generated method stub
            super.onActivityResult(requestCode, resultCode, data);
            //loginfragment.onActivityResult(requestCode, resultCode, data);
        }

    }

接下来是片段类

public class LoginFragment extends Fragment 
{
    private View …

String key = Collections.max(countMap.entrySet(), (entry1, entry2) -> entry1.getValue() - entry2.getValue()).getKey();
System.out.println(key);
Set<Entry<String,Integer>> entrySet = countMap.entrySet();
Collections.max(countMap.entrySet());

这里第一行代码" Collections.max(Collection<?extends T>, Comparator<? super T>)"将两个参数作为Set和比较器,工作正常.

但是最后一行代码" Collections.max(countMap.entrySet());"给出了编译时错误,说" 类型集合中的方法max(Collection)不适用于参数(Set>) ".需要对上述代码进行解释.