我按照本教程http://www.androidhive.info/2012/03/android-facebook-connect-tutorial/将 Facebook 连接到我的 Android 应用程序。我没有很多按钮，而是有一个用于登录和注销的按钮。
1）我第一次运行课程时，我可以登录然后成功注销。当我点击同一个按钮再次登录时，登录页面不会出现，但是会出现 Toast 文本“LOGGING IN”，这是loginToFacebook()我的if-else函数之后。因此，我认为，它应该像我第一次运行课程一样运行 facebook 登录页面。但是没有出现登录页面。
我做错了什么？我该怎么办？
2）以及如何String fbLoggedIn在登录后显示用户名而不是文本“CONNECTED!!” ?
public class FacebookActivity extends Activity{
private static String APP_ID = "";
private Facebook facebook;
private AsyncFacebookRunner mAsyncRunner;
String FILENAME = "AndroidSSO_data";
private SharedPreferences mPrefs;
private Button backButton;
private String name = "CONNECTED!!";
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.settings_share);
facebook = new Facebook(APP_ID);
mAsyncRunner = new AsyncFacebookRunner(facebook);
RelativeLayout fbButton = (RelativeLayout) findViewById(R.id.fbLayout);
fbButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (!facebook.isSessionValid())
{
System.out.println("Not Connected. Clicked and Login.");
loginToFacebook();
Toast.makeText(getApplicationContext(), "LOGGING IN", Toast.LENGTH_LONG).show();}
else
{
System.out.println("Connected. Logged Out.");
logoutFromFacebook();
Toast.makeText(getApplicationContext(), "LOGGED OUT", Toast.LENGTH_LONG).show();}
}
});
}
public void loginToFacebook() {
mPrefs = getPreferences(MODE_PRIVATE);
String access_token = mPrefs.getString("access_token", null);
long expires = mPrefs.getLong("access_expires", 0);
if (access_token != null) {
facebook.setAccessToken(access_token);
}
if (expires != 0) {
facebook.setAccessExpires(expires);
}
if (!facebook.isSessionValid()) {
facebook.authorize(this, new String[] { "email", "publish_stream" }, new DialogListener() {
@Override
public void onCancel() {
// Function to handle cancel event
}
@Override
public void onComplete(Bundle values) {
// Function to handle complete event
// Edit Preferences and update facebook acess_token
SharedPreferences.Editor editor = mPrefs.edit();
editor.putString("access_token", facebook.getAccessToken());
editor.putLong("access_expires", facebook.getAccessExpires());
editor.commit();
TextView fbUser = (TextView) findViewById(R.id.fbUser);
fbUser.setVisibility(View.VISIBLE);
String fbLoggedIn = name;
fbUser.setText(fbLoggedIn);
Toast.makeText(getApplicationContext(), "LOGGED IN AS " + name, Toast.LENGTH_LONG).show();
}
@Override
public void onError(DialogError error) {
// Function to handle error
}
@Override
public void onFacebookError(FacebookError fberror) {
// Function to handle Facebook errors
}
});
}
}
public void getProfileInformation() {
mAsyncRunner.request("me", new RequestListener() {
@Override
public void onComplete(String response, Object state) {
Log.d("Profile", response);
String json = response;
try {
JSONObject profile = new JSONObject(json);
// getting name of the user
final String name = profile.getString("name");
// getting email of the user
final String email = profile.getString("email");
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(), "Name: " + name + "\nEmail: " + email, Toast.LENGTH_LONG).show();
}
});
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void onIOException(IOException e, Object state) { }
@Override
public void onFileNotFoundException(FileNotFoundException e, Object state) { }
@Override
public void onMalformedURLException(MalformedURLException e, Object state) { }
@Override
public void onFacebookError(FacebookError e, Object state) { }
});
}
//logout from Facebook
public void logoutFromFacebook() {
mAsyncRunner.logout(this, new RequestListener() {
@Override
public void onComplete(String response, Object state) {
Log.d("Logout from Facebook", response);
if (Boolean.parseBoolean(response) == true) {
// User successfully Logged out
}
}
@Override
public void onIOException(IOException e, Object state) { }
@Override
public void onFileNotFoundException(FileNotFoundException e, Object state) { }
@Override
public void onMalformedURLException(MalformedURLException e, Object state) { }
@Override
public void onFacebookError(FacebookError e, Object state) { }
});
}
为了更清楚起见，我将我的 if-else 设置为这样（从上面的完整代码中提取）。
RelativeLayout fbButton = (RelativeLayout) findViewById(R.id.fbLayout);
fbButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (!facebook.isSessionValid())
{
System.out.println("Not Connected. Clicked and Login.");
loginToFacebook();
Toast.makeText(getApplicationContext(), "LOGGING IN", Toast.LENGTH_LONG).show();}
else
{
System.out.println("Connected. Logged Out.");
logoutFromFacebook();
Toast.makeText(getApplicationContext(), "LOGGED OUT", Toast.LENGTH_LONG).show();}
}
});