我在我的 Android 应用程序中使用 Google plus 登录，工作正常。
从任何其他意图单击注销按钮时显示空指针异常。
也当点击登录按钮时直接进入我的下一页。不在登录页面。
但从演示应用程序注销它工作正常。
我搜索了相关答案，没有发现任何解决方案仍然保持不变。
帮我解决它
link 1 http://examples.javacodegeeks.com/android/android-google-plus-login-example/
link 2 http://www.androidhive.info/2014/02/android-login-with-google-plus-account-1/
我已经引用了 2 个链接，但从下一个意图注销时仍然显示空指针异常。
我的注销代码：
public void googlePlusLogout()
{
if (mGoogleApiClient.isConnected())
{
Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
mGoogleApiClient.disconnect();
mGoogleApiClient.connect();
updateProfile(false);
}
}
这里从另一个意图调用方法来登录类
otherintent.java
session.logoutUser();// here i am clearing the shared pref
sign_in Signinclass = new sign_in();
Signinclass.googlePlusLogout();
finish();
这是我的演示代码，它工作正常，我在应用程序登录中使用的相同代码工作正常，但从另一个页面调用注销不起作用。显示空指针异常。
AndroidGooglePlus示例 .java
public class AndroidGooglePlusExample extends Activity implements OnClickListener, ConnectionCallbacks, OnConnectionFailedListener {
private static final int RC_SIGN_IN = 0;
// Google client to communicate with Google
private GoogleApiClient mGoogleApiClient;
private boolean mIntentInProgress;
private boolean signedInUser;
private ConnectionResult mConnectionResult;
private SignInButton signinButton;
private ImageView image;
private TextView username, emailLabel;
private LinearLayout profileFrame, signinFrame;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
signinButton = (SignInButton) findViewById(R.id.signin);
signinButton.setOnClickListener(this);
image = (ImageView) findViewById(R.id.image);
username = (TextView) findViewById(R.id.username);
emailLabel = (TextView) findViewById(R.id.email);
profileFrame = (LinearLayout) findViewById(R.id.profileFrame);
signinFrame = (LinearLayout) findViewById(R.id.signinFrame);
mGoogleApiClient = new GoogleApiClient.Builder(this).addConnectionCallbacks(this).addOnConnectionFailedListener(this).addApi(Plus.API, Plus.PlusOptions.builder().build()).addScope(Plus.SCOPE_PLUS_LOGIN).build();
}
protected void onStart() {
super.onStart();
mGoogleApiClient.connect();
}
protected void onStop() {
super.onStop();
if (mGoogleApiClient.isConnected()) {
mGoogleApiClient.disconnect();
}
}
private void resolveSignInError() {
if (mConnectionResult.hasResolution()) {
try {
mIntentInProgress = true;
mConnectionResult.startResolutionForResult(this, RC_SIGN_IN);
} catch (SendIntentException e) {
mIntentInProgress = false;
mGoogleApiClient.connect();
}
}
}
@Override
public void onConnectionFailed(ConnectionResult result) {
if (!result.hasResolution()) {
GooglePlayServicesUtil.getErrorDialog(result.getErrorCode(), this, 0).show();
return;
}
if (!mIntentInProgress) {
// store mConnectionResult
mConnectionResult = result;
if (signedInUser) {
resolveSignInError();
}
}
}
@Override
protected void onActivityResult(int requestCode, int responseCode, Intent intent) {
switch (requestCode) {
case RC_SIGN_IN:
if (responseCode == RESULT_OK) {
signedInUser = false;
}
mIntentInProgress = false;
if (!mGoogleApiClient.isConnecting()) {
mGoogleApiClient.connect();
}
break;
}
}
@Override
public void onConnected(Bundle arg0) {
signedInUser = false;
Toast.makeText(this, "Connected", Toast.LENGTH_LONG).show();
getProfileInformation();
}
private void updateProfile(boolean isSignedIn) {
if (isSignedIn) {
signinFrame.setVisibility(View.GONE);
profileFrame.setVisibility(View.VISIBLE);
} else {
signinFrame.setVisibility(View.VISIBLE);
profileFrame.setVisibility(View.GONE);
}
}
private void getProfileInformation() {
try {
if (Plus.PeopleApi.getCurrentPerson(mGoogleApiClient) != null) {
Person currentPerson = Plus.PeopleApi.getCurrentPerson(mGoogleApiClient);
String personName = currentPerson.getDisplayName();
String personPhotoUrl = currentPerson.getImage().getUrl();
String email = Plus.AccountApi.getAccountName(mGoogleApiClient);
username.setText(personName);
emailLabel.setText(email);
new LoadProfileImage(image).execute(personPhotoUrl);
// update profile frame with new info about Google Account
// profile
updateProfile(true);
}
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onConnectionSuspended(int cause) {
mGoogleApiClient.connect();
updateProfile(false);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.signin:
googlePlusLogin();
break;
}
}
public void signIn(View v) {
googlePlusLogin();
}
public void logout(View v) {
googlePlusLogout();
}
private void googlePlusLogin() {
if (!mGoogleApiClient.isConnecting()) {
signedInUser = true;
resolveSignInError();
}
}
private void googlePlusLogout() {
if (mGoogleApiClient.isConnected()) {
Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
mGoogleApiClient.disconnect();
mGoogleApiClient.connect();
updateProfile(false);
}
}
// download Google Account profile image, to complete profile
private class LoadProfileImage extends AsyncTask<String, Void, Bitmap> {
ImageView downloadedImage;
public LoadProfileImage(ImageView image) {
this.downloadedImage = image;
}
protected Bitmap doInBackground(String... urls) {
String url = urls[0];
Bitmap icon = null;
try {
InputStream in = new java.net.URL(url).openStream();
icon = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return icon;
}
protected void onPostExecute(Bitmap result) {
downloadedImage.setImageBitmap(result);
}
}
