我的Google-API活动存在问题。我使用了Google的示例代码并更改了一些行来填写创建一个带有我的总邮件数量的静态int。到目前为止一切顺利，这很好。每次我必须更新我的mail_count值时，我执行以下代码：
Intent intent2 = new Intent(getBaseContext(), MainActivity.class);
intent2.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED | Intent.FLAG_ACTIVITY_CLEAR_TOP);
startService(intent2);
这很好用，但问题是每次我开始活动时它都会显示几秒钟。我真的知道这是活动的重点，但我没有得到如何在我的项目中使用GOOGLE-API活动在背景中与API进行通信，并且不会每次都显示（用户确认访问后。）
这是我的Google-API活动代码（MainActivity）：
.widgetNew;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.api.client.extensions.android.http.AndroidHttp;
import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential;
import com.google.api.client.googleapis.extensions.android.gms.auth.GooglePlayServicesAvailabilityIOException;
import com.google.api.client.googleapis.extensions.android.gms.auth.UserRecoverableAuthIOException;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.ExponentialBackOff;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.gmail.model.*;
import android.Manifest;
import android.accounts.AccountManager;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.text.TextUtils;
import android.text.method.ScrollingMovementMethod;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RemoteViews;
import android.widget.TextView;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import pub.devrel.easypermissions.AfterPermissionGranted;
import pub.devrel.easypermissions.EasyPermissions;
public class MainActivity extends Activity
implements EasyPermissions.PermissionCallbacks {
GoogleAccountCredential mCredential;
private TextView mOutputText;
private Button mCallApiButton;
//ProgressDialog mProgress;
static final int REQUEST_ACCOUNT_PICKER = 1000;
static final int REQUEST_AUTHORIZATION = 1001;
static final int REQUEST_GOOGLE_PLAY_SERVICES = 1002;
static final int REQUEST_PERMISSION_GET_ACCOUNTS = 1003;
static int EMAIL_COUNT = 0;
private static final String BUTTON_TEXT = "Call Gmail API";
private static final String PREF_ACCOUNT_NAME = "accountName";
private static final String[] SCOPES = { GmailScopes.GMAIL_LABELS, GmailScopes.GMAIL_READONLY , GmailScopes.MAIL_GOOGLE_COM};
/**
* Create the main activity.
* @param savedInstanceState previously saved instance data.
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// LinearLayout activityLayout = new LinearLayout(this);
// LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
// LinearLayout.LayoutParams.MATCH_PARENT,
// LinearLayout.LayoutParams.MATCH_PARENT);
// activityLayout.setLayoutParams(lp);
// activityLayout.setOrientation(LinearLayout.VERTICAL);
// activityLayout.setPadding(16, 16, 16, 16);
// ViewGroup.LayoutParams tlp = new ViewGroup.LayoutParams(
// ViewGroup.LayoutParams.WRAP_CONTENT,
// ViewGroup.LayoutParams.WRAP_CONTENT);
// mCallApiButton = new Button(this);
// mCallApiButton.setText(BUTTON_TEXT);
// mCallApiButton.setOnClickListener(new View.OnClickListener() {
// @Override
// public void onClick(View v) {
// mCallApiButton.setEnabled(false);
// mOutputText.setText("");
// mCallApiButton.setEnabled(true);
// }
// });
//activityLayout.addView(mCallApiButton);
// mOutputText = new TextView(this);
//mOutputText.setLayoutParams(tlp);
// mOutputText.setPadding(16, 16, 16, 16);
// mOutputText.setVerticalScrollBarEnabled(true);
// mOutputText.setMovementMethod(new ScrollingMovementMethod());
// mOutputText.setText(
// "Click the \'" + BUTTON_TEXT +"\' button to test the API.");
//activityLayout.addView(mOutputText);
// mProgress = new ProgressDialog(this);
// mProgress.setMessage("Calling Gmail API ...");
//setContentView(activityLayout);
// Initialize credentials and service object.
mCredential = GoogleAccountCredential.usingOAuth2(
getApplicationContext(), Arrays.asList(SCOPES))
.setBackOff(new ExponentialBackOff());
getResultsFromApi();
finish();
}
/**
* Attempt to call the API, after verifying that all the preconditions are
* satisfied. The preconditions are: Google Play Services installed, an
* account was selected and the device currently has online access. If any
* of the preconditions are not satisfied, the app will prompt the user as
* appropriate.
*/
private void getResultsFromApi() {
if (! isGooglePlayServicesAvailable()) {
acquireGooglePlayServices();
} else if (mCredential.getSelectedAccountName() == null) {
chooseAccount();
} else if (! isDeviceOnline()) {
//mOutputText.setText("No network connection available.");
} else {
new MakeRequestTask(mCredential).execute();
}
}
/**
* Attempts to set the account used with the API credentials. If an account
* name was previously saved it will use that one; otherwise an account
* picker dialog will be shown to the user. Note that the setting the
* account to use with the credentials object requires the app to have the
* GET_ACCOUNTS permission, which is requested here if it is not already
* present. The AfterPermissionGranted annotation indicates that this
* function will be rerun automatically whenever the GET_ACCOUNTS permission
* is granted.
*/
@AfterPermissionGranted(REQUEST_PERMISSION_GET_ACCOUNTS)
private void chooseAccount() {
if (EasyPermissions.hasPermissions(
this, Manifest.permission.GET_ACCOUNTS)) {
String accountName = getPreferences(Context.MODE_PRIVATE)
.getString(PREF_ACCOUNT_NAME, null);
if (accountName != null) {
mCredential.setSelectedAccountName(accountName);
getResultsFromApi();
} else {
// Start a dialog from which the user can choose an account
startActivityForResult(
mCredential.newChooseAccountIntent(),
REQUEST_ACCOUNT_PICKER);
}
} else {
// Request the GET_ACCOUNTS permission via a user dialog
EasyPermissions.requestPermissions(
this,
"This app needs to access your Google account (via Contacts).",
REQUEST_PERMISSION_GET_ACCOUNTS,
Manifest.permission.GET_ACCOUNTS);
}
}
/**
* Called when an activity launched here (specifically, AccountPicker
* and authorization) exits, giving you the requestCode you started it with,
* the resultCode it returned, and any additional data from it.
* @param requestCode code indicating which activity result is incoming.
* @param resultCode code indicating the result of the incoming
* activity result.
* @param data Intent (containing result data) returned by incoming
* activity result.
*/
@Override
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch(requestCode) {
case REQUEST_GOOGLE_PLAY_SERVICES:
if (resultCode != RESULT_OK) {
//mOutputText.setText(
// "This app requires Google Play Services. Please install " +
// "Google Play Services on your device and relaunch this app.");
} else {
getResultsFromApi();
}
break;
case REQUEST_ACCOUNT_PICKER:
if (resultCode == RESULT_OK && data != null &&
data.getExtras() != null) {
String accountName =
data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
if (accountName != null) {
SharedPreferences settings =
getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = settings.edit();
editor.putString(PREF_ACCOUNT_NAME, accountName);
editor.apply();
mCredential.setSelectedAccountName(accountName);
getResultsFromApi();
}
}
break;
case REQUEST_AUTHORIZATION:
if (resultCode == RESULT_OK) {
getResultsFromApi();
}
break;
}
}
/**
* Respond to requests for permissions at runtime for API 23 and above.
* @param requestCode The request code passed in
* requestPermissions(android.app.Activity, String, int, String[])
* @param permissions The requested permissions. Never null.
* @param grantResults The grant results for the corresponding permissions
* which is either PERMISSION_GRANTED or PERMISSION_DENIED. Never null.
*/
@Override
public void onRequestPermissionsResult(int requestCode,
@NonNull String[] permissions,
@NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
EasyPermissions.onRequestPermissionsResult(
requestCode, permissions, grantResults, this);
}
/**
* Callback for when a permission is granted using the EasyPermissions
* library.
* @param requestCode The request code associated with the requested
* permission
* @param list The requested permission list. Never null.
*/
@Override
public void onPermissionsGranted(int requestCode, List<String> list) {
// Do nothing.
}
/**
* Callback for when a permission is denied using the EasyPermissions
* library.
* @param requestCode The request code associated with the requested
* permission
* @param list The requested permission list. Never null.
*/
@Override
public void onPermissionsDenied(int requestCode, List<String> list) {
// Do nothing.
}
/**
* Checks whether the device currently has a network connection.
* @return true if the device has a network connection, false otherwise.
*/
private boolean isDeviceOnline() {
ConnectivityManager connMgr =
(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
return (networkInfo != null && networkInfo.isConnected());
}
/**
* Check that Google Play services APK is installed and up to date.
* @return true if Google Play Services is available and up to
* date on this device; false otherwise.
*/
private boolean isGooglePlayServicesAvailable() {
GoogleApiAvailability apiAvailability =
GoogleApiAvailability.getInstance();
final int connectionStatusCode =
apiAvailability.isGooglePlayServicesAvailable(this);
return connectionStatusCode == ConnectionResult.SUCCESS;
}
/**
* Attempt to resolve a missing, out-of-date, invalid or disabled Google
* Play Services installation via a user dialog, if possible.
*/
private void acquireGooglePlayServices() {
GoogleApiAvailability apiAvailability =
GoogleApiAvailability.getInstance();
final int connectionStatusCode =
apiAvailability.isGooglePlayServicesAvailable(this);
if (apiAvailability.isUserResolvableError(connectionStatusCode)) {
showGooglePlayServicesAvailabilityErrorDialog(connectionStatusCode);
}
}
/**
* Display an error dialog showing that Google Play Services is missing
* or out of date.
* @param connectionStatusCode code describing the presence (or lack of)
* Google Play Services on this device.
*/
void showGooglePlayServicesAvailabilityErrorDialog(
final int connectionStatusCode) {
GoogleApiAvailability apiAvailability = GoogleApiAvailability.getInstance();
Dialog dialog = apiAvailability.getErrorDialog(
MainActivity.this,
connectionStatusCode,
REQUEST_GOOGLE_PLAY_SERVICES);
dialog.show();
}
/**
* An asynchronous task that handles the Gmail API call.
* Placing the API calls in their own task ensures the UI stays responsive.
*/
private class MakeRequestTask extends AsyncTask<Void, Void, List<String>> {
private com.google.api.services.gmail.Gmail mService = null;
private Exception mLastError = null;
public MakeRequestTask(GoogleAccountCredential credential) {
HttpTransport transport = AndroidHttp.newCompatibleTransport();
JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
mService = new com.google.api.services.gmail.Gmail.Builder(
transport, jsonFactory, credential)
.setApplicationName("Gmail API Android Quickstart")
.build();
}
/**
* Background task to call Gmail API.
* @param params no parameters needed for this task.
*/
@Override
protected List<String> doInBackground(Void... params) {
try {
return getDataFromApi();
} catch (Exception e) {
mLastError = e;
cancel(true);
return null;
}
}
/**
* Fetch a list of Gmail labels attached to the specified account.
* @return List of Strings labels.
* @throws IOException
*/
private List<String> getDataFromApi() throws IOException {
// Get the labels in the user's account.
String user = "me";
List<String> labels = new ArrayList<String>();
Profile profile = mService.users().getProfile("me").execute();
labels.add("E-Mails: " + profile.getMessagesTotal());
EMAIL_COUNT = profile.getMessagesTotal();
//tv.setText("TEST");
return labels;
}
@Override
protected void onPreExecute() {
// mOutputText.setText("");
// mProgress.show();
}
@Override
protected void onPostExecute(List<String> output) {
//mProgress.hide();
if (output == null || output.size() == 0) {
// mOutputText.setText("No results returned.");
} else {
//output.add(0, "Data retrieved using the Gmail API:");
//mOutputText.setText(TextUtils.join("\n", output));
finish();
}
}
@Override
protected void onCancelled() {
// mProgress.hide();
if (mLastError != null) {
if (mLastError instanceof GooglePlayServicesAvailabilityIOException) {
showGooglePlayServicesAvailabilityErrorDialog(
((GooglePlayServicesAvailabilityIOException) mLastError)
.getConnectionStatusCode());
} else if (mLastError instanceof UserRecoverableAuthIOException) {
startActivityForResult(
((UserRecoverableAuthIOException) mLastError).getIntent(),
MainActivity.REQUEST_AUTHORIZATION);
} else {
// mOutputText.setText("The following error occurred:\n"
// + mLastError.getMessage());
}
} else {
// mOutputText.setText("Request cancelled.");
}
}
}
}