android - 如何检查用户已经登录 android (Facebook SDK 4.0)

Question

这是我的代码:

public class LocationDetailActivity extends ActionBarActivity {

private CallbackManager mCallBackManager;
private FacebookCallback<LoginResult> mCallBack;
private ImageView mBtnBack;
AccessToken token;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.location_detail_layout);
    FacebookSdk.sdkInitialize(getApplicationContext());
    share = (ImageButton) findViewById(R.id.imageShare);
    token  = AccessToken.getCurrentAccessToken();

 share.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(token == null) {
                    final Dialog dialog = new Dialog(LocationDetailActivity.this);
                    dialog.setContentView(R.layout.share_custom_dialog);
                    dialog.setTitle("Login as:");
                    dialog.show();
                    mCallBackManager = CallbackManager.Factory.create();
                    mCallBack = new FacebookCallback<LoginResult>() {
                        @Override
                        public void onSuccess(LoginResult loginResult) {

                            Profile profile = Profile.getCurrentProfile();
                            if(profile!=null){
                                dialog.cancel();
                                ShareDialog shareDialog = new ShareDialog(LocationDetailActivity.this);
                                if(shareDialog.canShow(ShareLinkContent.class)){
                                ShareLinkContent content = new ShareLinkContent.Builder()
                                        .setContentUrl(Uri.parse("https://developers.facebook.com"))
                                        .build();
                                    shareDialog.show(content);
                                }
                            }
                        }

                        @Override
                        public void onCancel() {

                        }

                        @Override
                        public void onError(FacebookException e) {

                        }
                    };
                    LoginButton loginButton = (LoginButton)dialog.findViewById(R.id.login_button);
                    loginButton.setReadPermissions("user_friends");
                    loginButton.registerCallback(mCallBackManager, mCallBack);
                }
                else if(token != null){
                    ShareDialog shareDialog = new ShareDialog(LocationDetailActivity.this);
                    if(shareDialog.canShow(ShareLinkContent.class)){
                        ShareLinkContent content = new ShareLinkContent.Builder()
                                .setContentUrl(Uri.parse("https://developers.facebook.com"))
                                .build();
                        shareDialog.show(content);
                    }
                }
            }
        });

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    mCallBackManager.onActivityResult(requestCode, resultCode, data);
}
}

我想检查用户是否已经从 Facebook 的应用程序登录。如果他们不这样做，我的应用程序将显示带有登录按钮的自定义对话框。否则，我的应用程序将显示共享对话框，但当我点击我的按钮时，即使我登录了 Facebook，也会始终显示自定义对话框。

更多信息: AccessToken token = AccessToken.getCurrentAccessToken();

Answer 1

检查登录状态

boolean isLoggedIn = accessToken != null && !accessToken.isExpired();

然后您可以稍后执行实际登录，例如在自定义按钮的 OnClickListener 中:

LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("public_profile"));