登录facebook按钮打开一个新活动

Question

我尝试在用户点击按钮后登录Facebook，然后成功登录后，就会创建新活动。

这是迄今为止主要活动的代码！

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.Toast;

import com.facebook.LoggingBehavior;
import com.facebook.Session;
import com.facebook.SessionState;
import com.facebook.Settings;

public class MainActivity extends Activity {

    @SuppressWarnings("unused")
    private static final String URL_PREFIX_FRIENDS = "https://graph.facebook.com/me/friends?access_token=";
    private Session.StatusCallback statusCallback = new SessionStatusCallback();
    private ImageButton fbImgButton;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        fbImgButton = (ImageButton)findViewById(R.id.imageView2);

        Settings.addLoggingBehavior(LoggingBehavior.INCLUDE_ACCESS_TOKENS);

        Session session = Session.getActiveSession();
        if(session == null) {
            if(savedInstanceState != null) {
                session = Session.restoreSession(this, null, statusCallback, savedInstanceState);
            }
            if(session== null) {
                session = new Session(this);
            }
            Session.setActiveSession(session);
            if (session.getState().equals(SessionState.CREATED_TOKEN_LOADED)) {
                session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
            }
        }
        updateView();

    }

    @Override
    public void onStart() {
        super.onStart();
        Session.getActiveSession().addCallback(statusCallback);
    }

    @Override
    public void onStop() {
        super.onStop();
        Session.getActiveSession().removeCallback(statusCallback);
    }

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

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        Session session = Session.getActiveSession();
        Session.saveSession(session, outState);
    }

    private void updateView() {
        Session session = Session.getActiveSession();
        if(session.isOpened()) {
            Toast.makeText(getApplicationContext(), "Logged in....", Toast.LENGTH_LONG).show();
            fbImgButton.setOnClickListener(new OnClickListener() {
                public void onClick(View view) { loginfb(); }
            });
        } else {
            fbImgButton.setOnClickListener(new OnClickListener() {
                public void onClick(View view) { onClickLogin(); }
            });
        }
    }

    public void loginfb() {
        //start the new activity here
        //Toast.makeText(getApplicationContext(), "Works first", Toast.LENGTH_LONG).show();
        Intent intent = new Intent(MainActivity.this, SelectionFragment.class);
        MainActivity.this.startActivity(intent);

    }

    private void onClickLogin() {
        Session session = Session.getActiveSession();
        if (!session.isOpened() && !session.isClosed()) {
            session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
        } else {
            Session.openActiveSession(this, true, statusCallback);
        }
        Intent intent = new Intent(MainActivity.this, SelectionFragment.class);
        MainActivity.this.startActivity(intent);
    }

    public void shareOnTwitter(View v) {
        EditText widget40 = (EditText)findViewById(R.id.widget40);
        Uri uri = Uri.parse("https://twitter.com/intent/tweet?text=" + " @coolfacts_fb " + widget40.getText());
        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
        startActivity(intent);
    }

    public void nofb(View v) {
        Intent intent = new Intent(v.getContext(), shareTw.class);
        startActivityForResult(intent, 0);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;

    }

    private class SessionStatusCallback implements Session.StatusCallback {
        @Override
        public void call(Session session, SessionState state, Exception exception) {
            updateView();
        }
    }
}

问题是，无论用户当前的状态是什么，如果我点击facebook登录按钮就进入新活动！

有人可以帮帮我吗？

Answer 1

试试这个：

public class MainActivity extends Activity {

    @SuppressWarnings("unused")
    private static final String URL_PREFIX_FRIENDS = "https://graph.facebook.com/me/friends?access_token=";
    private Session.StatusCallback statusCallback = new SessionStatusCallback();
    private ImageButton fbImgButton;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        fbImgButton = (ImageButton)findViewById(R.id.imageView2);

        Settings.addLoggingBehavior(LoggingBehavior.INCLUDE_ACCESS_TOKENS);

        // Add Session Callback Here
        Session.getActiveSession().addCallback(statusCallback);

        Session session = Session.getActiveSession();
        if(session == null) {
            if(savedInstanceState != null) {
                session = Session.restoreSession(this, null, statusCallback, savedInstanceState);
            }
            if(session== null) {
                session = new Session(this);
            }
            Session.setActiveSession(session);
            if (session.getState().equals(SessionState.CREATED_TOKEN_LOADED)) {
                session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
            }

            // Get Avtive Session again in case of session is null  
            Session session = Session.getActiveSession();
        }

    // Dont call updateView() here as we have called this from session callback already.
    // updateView();

    }

    @Override
    public void onStart() {
        super.onStart();
        Session.getActiveSession().addCallback(statusCallback);
    }

    @Override
    public void onStop() {
        super.onStop();
        Session.getActiveSession().removeCallback(statusCallback);
    }

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

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        Session session = Session.getActiveSession();
        Session.saveSession(session, outState);
    }

    // Minor changes made with updateView() Method flow
    private void updateView() {
        Session session = Session.getActiveSession();    
        fbImgButton.setOnClickListener(new OnClickListener() {
          public void onClick(View view) {      
           if(session.isOpened()){
              Toast.makeText(getApplicationContext(), "loginfb...", Toast.LENGTH_LONG).show();   
              loginfb(); 
           }
           else{
              Toast.makeText(getApplicationContext(), "onClickLogin...", Toast.LENGTH_LONG).show();
              onClickLogin();
           }
          }
       });
    }

    public void loginfb() {
        //start the new activity here
        //Toast.makeText(getApplicationContext(), "Works first", Toast.LENGTH_LONG).show();
        Intent intent = new Intent(MainActivity.this, SelectionFragment.class);
        MainActivity.this.startActivity(intent);

    }

    private void onClickLogin() {
        Session session = Session.getActiveSession();
        if (!session.isOpened() && !session.isClosed()) {
            session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
        } else {
            Session.openActiveSession(this, true, statusCallback);
        }
        Intent intent = new Intent(MainActivity.this, SelectionFragment.class);
        MainActivity.this.startActivity(intent);
    }

    public void shareOnTwitter(View v) {
        EditText widget40 = (EditText)findViewById(R.id.widget40);
        Uri uri = Uri.parse("https://twitter.com/intent/tweet?text=" + " @coolfacts_fb " + widget40.getText());
        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
        startActivity(intent);
    }

    public void nofb(View v) {
        Intent intent = new Intent(v.getContext(), shareTw.class);
        startActivityForResult(intent, 0);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;

    }

    private class SessionStatusCallback implements Session.StatusCallback {
        @Override
        public void call(Session session, SessionState state, Exception exception) {
            updateView();
        }
    }
}

检查此onCreate（）和onStart（）的区别。它清楚地显示onCreate（）在onStart（）之前首先调用，因此我们还需要从onCreate（）方法添加会话回调。

Difference between onCreate() and onStart()

注意：你可以保持你的updateView（）方法，逻辑上也没有错。

希望这会对你有所帮助。

感谢。

Answer 2

在“onClickLogin（）”方法结束时，在Session有机会打开之前调用startActivity（）。会话开始在后台打开，但新的活动将弹出顶部。

在您的代码中，看起来您的updateView（）方法是对已打开的Session作出反应的正确位置。如果Session状态为OPENED，请考虑调用startActivity（）。