Facebook Android SDK 3.0, how to share content without the LoginButton

I am now doing a little project that want to have a share button(dialog), when users click it, it will auto-login to his/her fb account and share the content they want.

After the tutorial from fb dev, my app can share content to wall, but need to login with a fblogin button before sharing.

I have read a post from stackoverflow: Android - Facebook SDK 3 - How to login programmatically without LoginButton

UPDATE: I have implement the feedDialog with onActivityResult in my project, I found that i can login and share with one button. HOWEVER, when i rebuild the app/restart my phone, i have to press the button twice to share at the first time, but become normal(press once) later.

P.S.I have implement it with shareActionProvider

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getSupportMenuInflater().inflate(R.menu.content_main, menu);
    /** Getting the actionprovider associated with the menu item whose id is share */
    mShareActionProvider = (ShareActionProvider) menu.findItem(R.id.share).getActionProvider();

    /** Getting the target intent */
    Intent intent = getDefaultShareIntent();

    /** Setting a share intent */       
    if(intent!=null){
        mShareActionProvider.setShareIntent(intent);
        mShareActionProvider.setOnShareTargetSelectedListener(new OnShareTargetSelectedListener(){
            @Override
            public boolean onShareTargetSelected(ShareActionProvider source, Intent intent) {
                if ("com.facebook.katana".equals(intent.getComponent().getPackageName())){
                    if (Session.getActiveSession() == null || Session.getActiveSession().isClosed()) {
                        Se