Selecting Multiple Tickets in Open Event Android

Open Event Android allows the user to select multiple tickets for an event this blog post will guide you on how its done. Ticket Id and quantity of ticket selected is stored in the form of List of pair. The first element of the List is the Id of the ticket and the second element is its quantity.

private var tickeIdAndQty = ArrayList<Pair<Int, Int>>()

Whenever the user selects any ticket using the dropdown the following snippet of code is executed. handleTicketSelect takes id and quantity of the selected ticket and search if any pair with passed id as the first element exists in the ticketIdAndQty list, if exists it updates that record else it inserts a new pair with given id and quantity into the list.

private fun handleTicketSelect(id: Int, quantity: Int) {
       val pos = ticketIdAndQty.map { it.first }.indexOf(id)
       if (pos == –1) {
           ticketIdAndQty.add(Pair(id, quantity))
       } else {
           ticketIdAndQty[pos] = Pair(id, quantity)
       }

When the user selects register the ticketIdAndQty list which contains details of selected tickets is added to the bundle along with the event id and are passed to attendee fragment. Attendee fragment allows the user to fill in other details such as country, payment option, first name etc.

Later attendee fragment with the help of attendee view model creates individual attendee on the server

rootView.register.setOnClickListener {
           if (!ticketsViewModel.totalTicketsEmpty(ticketIdAndQty)) {
               val fragment = AttendeeFragment()
               val bundle = Bundle()
               bundle.putLong(EVENT_ID, id)
               bundle.putSerializable(TICKET_ID_AND_QTY, ticketIdAndQty)
               fragment.arguments = bundle
               activity?.supportFragmentManager
                       ?.beginTransaction()
                       ?.replace(R.id.rootLayout, fragment)
                       ?.addToBackStack(null)
                       ?.commit()
           } else {
               handleNoTicketsSelected()
           }
       }

When the register is selected an attendee is created for every ticket id inside ticketIdandQty list wherever the second element of the pair that is quantity is greater than zero. FFirst name last name, email and other information is taken from the text views populated on the screen and attendee object is created using these data. Lastly, createAttendee view model function is called passing the generated attendee, country, and selected payment option. The former calls service layer function and created an attendee by making a post request to the server.

 ticketIdAndQty?.forEach {
                   if (it.second > 0) {
                       val attendee = Attendee(id = attendeeFragmentViewModel.getId(),
                               firstname = firstName.text.toString(),
                               lastname = lastName.text.toString(),
                               email = email.text.toString(),
                               ticket = TicketId(it.first.toLong()),
                               event = eventId)
                       val country = if (country.text.isEmpty()) country.text.toString() else null
                       attendeeFragmentViewModel.createAttendee(attendee, id, country, selectedPaymentOption)
                   }
               }

The above-discussed procedure creates one attendee for every ticket quantity which means if a user select ticket id 1 with 3 quantity and ticket id 2 with 5 as quantity total 8 attendees will be generated. Later after successfully generating the attendee’s order is created. Every order has an array of attendees along with other other related information.

Resources

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Updating User information in Open Event Android

A user can update its information such as first name, last name from the Edit Profile Fragment in Open Event Android. Edit Profile Fragment can be accessed from the menu inside the Profile page. On opening Edit Profile Fragment user can interact with the simple UI to update his/her information. This blog post will guide you on how its implemented in Open Event Android.

To update a User we send a patch request to Open Event Server. The patch request contains the Updated User as body and auth token as header and it returns the updated user in response. Following it what the interface method looks like

@PATCH(“users/{id}”)
fun updateUser(@Body user: User, @Path(“id”) id: Long): Single<User>

This method is exposed to the View Model using a service layer function which calls the above function and also inserts the returned user in the database.

fun updateUser(user: User, id: Long): Single<User> {
       return authApi.updateUser(user, id).map {
           userDao.insertUser(it)
           it
       }
   }

On using map on Single<User> returned by updateUser we can access the user inside the scope which is then inserted into the database using the DAO method insert user and the same user object is returned by the function.

This service layer method is then used in updateUser method of EditProfileViewModel class which specifies how it is subscribed and on which thread observer should be set etc. The Edit Profile Fragment fragment calls this method whenever the user clicks on the Update button.

fun updateUser(firstName: String, lastName: String) {
       val id = authHolder.getId()
       if (firstName.isEmpty() || lastName.isEmpty()) {
           message.value = “Please provide first name and last name!”
           return
       }
       compositeDisposable.add(authService.updateUser(User(id = id,          firstName = firstName, lastName = lastName), id)
               .subscribeOn(Schedulers.io())
               .observeOn(AndroidSchedulers.mainThread())
               .doOnSubscribe {
                   progress.value = true
               }
               .doFinally {
                   progress.value = false
               }
               .subscribe({
                   message.value = “User updated successfully!”
                   Timber.d(“User updated”)
               }) {
                   message.value = “Error updating user!”
                   Timber.e(it, “Error updating user!”)
               })
   }

UpdateUser takes two parameters first name and last name if any of these parameters is empty the function returns with an error message which is displayed on the UI else service layer update user function is called with argument a User object with first name and last name as provided to view model function and an id which is accessed using authHolder’s getId method. Whenever this is subscribed we set progress.value true which displays spinner on the UI this is set false after the operation is complete. If the patch request results in success then toast message is shown on screen and a success message is logged similar to this in case of error, an error toast is displayed and an error is logged.

This goes for the logic to update user we also need UI and menu item which launches this fragment.

Inside Menu.xml add the following snippet of code

<item
  android:id=“@+id/edit_profile”
  android:title=“@string/edit_profile” />

This will create a menu item inside the ProfileFragment. The next step is to wire this logic which tells what happens when the user selects this menu item. The following code wires it to EditProfileFragment.

R.id.edit_profile -> {
               val fragment = EditProfileFragment()              activity?.supportFragmentManager?.beginTransaction()?.replace(R.id.frameContainer, fragment)?.addToBackStack(null)?.commit()
               return true

Resources

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Attendee Form Builder in Open Event Frontend

The Open-Event-Frontend allows the event organiser to create tickets for his or her event. Other uses can buy these tickets in order to attend the event. When buying a ticket we ask for certain information from the buyer. Ideally the event organizer should get to choose what information they want to ask from the buyer. This blog post goes over the implementation of the attendee form builder in the Open Event Frontend.

Information to Collect

The event organizer can choose what details to ask from the order buyer. In order to specify the choices, we present a table with the entries of allowed fields that the organizer can ask for. Moreover there is an option to mark the field as required and hence making it compulsory for the order buyer to add that information in order to buy the tickets.

Route

The route is mainly responsible for fetching the required custom forms.

async model() {
    let filterOptions = [{
      name : 'form',
      op   : 'eq',
      val  : 'attendee'
    }];

    let data = {
      event: this.modelFor('events.view')
    };
    data.customForms = await data.event.query('customForms', {
      filter       : filterOptions,
      sort         : 'id',
      'page[size]' : 50
    });

    return data;
  }

If they don’t exist then we create them in afterModel hook. We check if the size of the list of custom forms sent from the server is 3 or not. If it is 3 then we create the additional custom forms for the builder. Upon creating an event, the server automatically creates 3 custom forms for the builder. These 3 forms are firstName, lastName and email.

afterModel(data) {
    /**
     * Create the additional custom forms if only the compulsory forms exist.
     */
    if (data.customForms.length === 3) {
      let customForms = A();
      for (const customForm of data.customForms ? data.customForms.toArray() : []) {
        customForms.pushObject(customForm);
      }

      const createdCustomForms = this.getCustomAttendeeForm(data.event);

      for (const customForm of createdCustomForms ? createdCustomForms : []) {
        customForms.pushObject(customForm);
      }

      data.customForms = customForms;
    }
  }

Complete source code for reference can be found here.

Component Template

The component template for the form builder is supposed to show the forms and other options to the user in a presentable manner. Due to pre-existing components for handling custom forms, the template is extremely simple. We just loop over the list of custom forms and present the event organizer with a table comprising of the forms. Apart from the forms the organizer can specify the order expiry time. Lastly we present a save button in order to save the changes.

<form class="ui form {{if isLoading 'loading'}}"  {{action 'submit' data on='submit'}} autocomplete="off">
  <h3 class="ui dividing header">
    <i class="checkmark box icon"></i>
    <div class="content">
      {{t 'Information to Collect'}}
    </div>
  </h3>
  <div class="ui two column stackable grid">
    <div class="column">
      <table class="ui selectable celled table">
        <thead>
          <tr>
            {{#if device.isMobile}}
              <th class="center aligned">
                {{t 'Options'}}
              </th>
            {{else}}
              <th class="right aligned">
                {{t 'Option'}}
              </th>
              <th class="center aligned">
                {{t 'Include'}}
              </th>
              <th class="center aligned">
                {{t 'Require'}}
              </th>
            {{/if}}
          </tr>
        </thead>
        <tbody>
          {{#each data.customForms as |field|}}
            <tr class="{{if field.isIncluded 'positive'}}">
              <td class="{{if device.isMobile 'center' 'right'}} aligned">
                <label class="{{if field.isFixed 'required'}}">
                  {{field.name}}
                </label>
              </td>
              <td class="center aligned">
                {{ui-checkbox class='slider'
                              checked=field.isIncluded
                              disabled=field.isFixed
                              onChange=(action (mut field.isIncluded))
                              label=(if device.isMobile (t 'Include'))}}
              </td>
              <td class="center aligned">
                {{ui-checkbox class='slider'
                              checked=field.isRequired
                              disabled=field.isFixed
                              onChange=(action (mut field.isRequired))
                              label=(if device.isMobile (t 'Require'))}}
              </td>
            </tr>
          {{/each}}
        </tbody>
      </table>
    </div>
  </div>
  <h3 class="ui dividing header">
    <i class="options box icon"></i>
    <div class="content">
      {{t 'Registration Options'}}
    </div>
  </h3>
  <div class="field">
    <label>{{t 'REGISTRATION TIME LIMIT'}}</label>
    <div class="{{unless device.isMobile 'two wide'}} field">
      {{input type='number' id='orderExpiryTime' value=data.event.orderExpiryTime min="1" max="60" step="1"}}
    </div>
  </div>
  <div class="ui hidden divider"></div>
  <button type="submit" class="ui teal submit button" name="submit">{{t 'Save'}}</button>
</form>

 

Component

The component is responsible for saving the form. It also provides runtime validations to ensure that the entries entered in the fields of the form are valid.

import Component from '@ember/component';
import FormMixin from 'open-event-frontend/mixins/form';

export default Component.extend(FormMixin, {
  getValidationRules() {
    return {
      inline : true,
      delay  : false,
      on     : 'blur',
      fields : {
        orderExpiryTime: {
          identifier : 'orderExpiryTime',
          rules      : [
            {
              type   : 'integer[1..60]',
              prompt : this.get('l10n').t('Please enter a valid registration time limit between 1 to 60 minutes.')
            }
          ]
        }
      }
    };
  },
  actions: {
    submit(data) {
      this.onValid(() => {
        this.save(data);
      });
    }
  }
});

References

 

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Redirecting to Previous Route in Ember

The Open-Event-Frontend allows the event organiser to create tickets for his or her event. Other uses can buy these tickets in order to attend the event. In order to make the user experience smooth, we redirect the user to their previous route when they successfully login into their account. This blog explains how we have achieved this functionality in the project.

Insight

We have two different cases to handle in order to solve this problem:

  1. The user was in route A and wanted to move to route B. Here route A doesn’t require authorization and route B requires authorization. In this case, we would like to direct the user to the login route and once they are done, redirect them back to route B.
  2. The user was in route A and directly entered the login route using the login button. In this case we want to direct them back to the route A after successful login.

We use Ember-simple-auth in order to manage authentication in the project. Not only does it make it easy to manage authentication, it also handles the case 1 for us out of the box. So now the simplified problem is to redirect the user back to the previous route if they entered the login route directly using the web address or the login button.

Approach

If we can somehow store the previous route visited by a user, then we can easily redirect them back once they are logged in.

We will add a custom property in the session service called previousRouteName which will store the URL of the previous route visited by the user. We will make use of the willTransition hook in the application.js file. This hook is called everytime the user transitions from one route to another which makes it suitable for us to update the previousRouteName.

actions: {
    willTransition(transition) {
      transition.then(() => {
        let params = this._mergeParams(transition.params);
        let url;

        // generate doesn't like empty params.
        if (isEmpty(params)) {
          url = transition.router.generate(transition.targetName);
        } else {
          url = transition.router.generate(transition.targetName, params);
        }
        // Do not save the url of the transition to login route.
        if (!url.includes('login')) {
          this.set('session.previousRouteName', url);
        }
      });
    }
  }

_mergeParams is a helper function which makes use of merge function of the Lodash library.

/**
   * Merge all params into one param.
   * @param params
   * @return {*}
   * @private
   */
  _mergeParams(params) {
    return merge({}, ...values(params));
  },

Now we’re done with saving the URL of the previous route. All that remains is to trigger the redirect once the user has successfully logged in. We will use the sessionAuthenticated hook which is triggered everytime the user logs in.

sessionAuthenticated() {
    if (this.get('session.previousRouteName')) {
      this.transitionTo(this.get('session.previousRouteName'));
    } else {
      this._super(...arguments);
    }
  },

If the previous route variable is set, we redirect to it otherwise we can the super method and let Ember-simple-auth handle case 1 mentioned earlier for us.

References

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My Tickets in Open Event Frontend

The Open-Event-Frontend allows the event organiser to create tickets for his or her event. Other uses can buy these tickets in order to attend the event. The My tickets section lists all the tickets that have been bought by a user. This blog post explains how it has been implemented in the project.

Route

The My-Tickets list route has three responsibilities:

  1. Showing appropriate title according to the current tab.
  2. Setting the filter options according to the tab.
  3. Fetching the data from the store according to the filter options.

The title of the route is decided by the following snippet:

titleToken() {
    switch (this.get('params.ticket_status')) {
      case 'upcoming':
        return this.get('l10n').t('Upcoming');
      case 'past':
        return this.get('l10n').t('Past');
      case 'saved':
        return this.get('l10n').t('Saved');
    }
  },

The second and the third requirement is satisfied inside the model hook. We define the filterOptions according to the current tab and then make the request to fetch the data accordingly. The following code snippet is responsible for this:

model(params) {
    this.set('params', params);
    let filterOptions = [{
      name : 'completed-at',
      op   : 'ne',
      val  : null
    }];
    if (params.ticket_status === 'upcoming') {
      filterOptions.push(
        {
          name : 'event',
          op   : 'has',
          val  : {
            name : 'starts-at',
            op   : 'ge',
            val  : moment().toISOString()
          }
        });
    } else if (params.ticket_status === 'past') {
      filterOptions.push(
        {
          name : 'event',
          op   : 'has',
          val  : {
            name : 'ends-at',
            op   : 'lt',
            val  : moment().toISOString()
          }
        }
      );
    }

    return this.get('authManager.currentUser').query('orders', {
      include : 'event',
      filter  : filterOptions
    });
  }

Template

The template of the My tickets list is extremely simple. We simply loop over all the orders and use the order-card component to display each of them. The order-card component is discussed in detail later. If there are no orders under the user, we show the appropriate message.

<div class="row">
  <div class="sixteen wide column">
    {{#if model}}
      {{#each model as |order|}}
        {{#order-card order=order}}
        {{/order-card}}
        <div class="ui hidden divider"></div>
      {{/each}}
    {{else}}
      <div class="ui disabled header">{{t 'No tickets found'}}</div>
    {{/if}}
  </div>
</div>

Order-card Component

The order card component is responsible for handling a single order and showing its details in as a card. In order to decide whether the order is a paid order or not, we have defined a computed property inside the order-card.js file.

import Component from '@ember/component';
import { computed } from '@ember/object';
import { isEqual } from '@ember/utils';

export default Component.extend({
  isFreeOrder: computed('order', function() {
    const amount = this.get('order.amount');
    return amount === null || isEqual(amount, '0');
  })
});

The template for the component contains the event logo aligned to the left in the card. We show the event details such as the name, location and start date on the right. Below the event details we show the order details such as the order amount, currency, the identifier and the date and time on which the order was completed. Below is the full code for reference:

<div class="event wide ui grid row">
  {{#unless device.isMobile}}
    <div class="ui card three wide computer six wide tablet column">
      <a class="image" href="#">
        {{widgets/safe-image src=(if order.event.originalImageUrl order.event.originalImageUrl order.event.originalImageUrl)}}
      </a>
    </div>
  {{/unless}}
  <div class="ui card thirteen wide computer ten wide tablet sixteen wide mobile column">
    <a class="main content" href="#">
      {{#smart-overflow class='header'}}
        {{order.event.name}}
      {{/smart-overflow}}
      <div class="meta">
        <span class="date">
          {{moment-format order.event.startsAt 'ddd, DD MMMM YYYY, h:mm A'}}
        </span>
      </div>
      {{#smart-overflow class='description'}}
        {{order.event.shortLocationName}}
      {{/smart-overflow}}
    </a>
    <div class="extra content small text">
      <span>
        <span>
          {{#if isFreeOrder}}
            {{t 'Free'}}
          {{else}}
            {{order.event.paymentCurrency}}{{order.amount}}
          {{/if}}
          {{t 'order'}}
        </span>
        <span>#{{order.identifier}}</span>
        <span>{{t 'on'}} {{moment-format order.completedAt 'MMMM DD, YYYY h:mm A'}}</span>
      </span>
    </div>
  </div>
</div>

References

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Automating Play Store releases in Open Event Android with Fastlane

In Open Event Android we are using fastlane to automate the process of releasing the app to the Play Store, otherwise without this tool we would have to sign the release apk everytime before making a release but with fastlane all we need to do is just merge the development branch with the master branch and the updated app is released in Play Store.

The first thing that we need to do is encrypt the signing keys and upload it to the repository so we will create an encrypted tar file of the signing keys and upload it to the repository.

Now we want to decrypt the tar file everytime we merge our development branch into the master branch. We will create a bash script which does the above task which looks like this.

#!/bin/sh
set -e

export DEPLOY_BRANCH=${DEPLOY_BRANCH:-master}

if [ "$TRAVIS_PULL_REQUEST" != "false" -o "$TRAVIS_REPO_SLUG" != "fossasia/open-event-android" -o "$TRAVIS_BRANCH" != "$DEPLOY_BRANCH" ]; then
 echo "We decrypt key only for pushes to the master branch and not PRs. So, skip."
exit 0
fi

# Decrypt keys
openssl aes-256-cbc -K $encrypted_59a1db41ee4d_key -iv $encrypted_59a1db41ee4d_iv -in ./scripts/secrets.tar.enc -out ./scripts/secrets.tar -d
tar xvf ./scripts/secrets.tar -C scripts/

 

We need to define all these variables written after the $ sign as our Travis environment variables.

Next thing that we need to do is sign the apk so first thing that we check in the update-apk script is if we are on the master branch. We take the unsigned apk and sign it with the following commands.

 cp open-event-master-app-playStore-release-unsigned.apk open-event-master-app-playStore-release-unaligned.apk
jarsigner -verbose -tsa http://timestamp.comodoca.com/rfc3161 -sigalg SHA1withRSA -digestalg SHA1 -keystore ../scripts/key.jks -storepass $STORE_PASS -keypass $KEY_PASS open-event-master-app-playStore-release-unaligned.apk $ALIAS

 

The following command zipaligns the app

 ${ANDROID_HOME}/build-tools/27.0.3/zipalign -v -p 4 open-event-master-app-playStore-release-unaligned.apk open-event-master-app-playStore-release.apk

 

After signing the release apk, the final step is to publish the app to the playstore. The following command will install fastlane.

gem install fastlane

 

This command will take the signed apk and upload it in alpha channel of the playstore.

fastlane supply --apk open-event-master-app-playStore-release.apk --track alpha --json_key ../scripts/fastlane.json --package_name $PACKAGE_NAME

 

That’s it! Now releasing an update to the playstore is as simple as sending a pull request to the master branch. A process that would have otherwise required few minutes has been reduced to just seconds.

Resources

  1. Fastlane Official Site: https://fastlane.tools/
  2. Fastlane Android Documentaion: https://docs.fastlane.tools/getting-started/android/release-deployment/
  3. Fastlane Repository: https://github.com/fastlane/fastlane
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Building Open Event Android for F-Droid

According to the official website F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. Only apps that are open source and use only open source libraries are accepted in F-Droid. Let’s see what steps were taken to publish Open Event Android in F-Droid.

We need to build a different app for F-Droid because it cannot use any proprietary  libraries so instead of making a new app we made two flavors of the same app. One that would be published in playstore and the other for F-Droid. It is really easy to make different flavors of the same app. Just add the following lines in the build.gradle

flavorDimensions "default"

productFlavors {
fdroid {
dimension "default"
}

playStore {
dimension "default"
}
}

 

We specify the flavor dimension in the first line because all product flavors must have a flavor dimension and then we specify the name of our product flavors. That’s all that is required to make various flavors of an app after that we just need to remove the proprietary libraries from the F-Droid build.

When we have finished building the app we can start with the process of submitting the app to F-Droid. We need to send a Merge Request to the F-droid repository. Let’s see what all steps are required before we could submit our Merge Request to include our app in F-Droid

We need to clone the fdroid server directly from the source so that we have all the latest changes and set the path.

git clone https://gitlab.com/fdroid/fdroidserver.git
export PATH="$PATH:$PWD/fdroidserver"

 

Then clone your fork of the fdroiddata repository and open the directory. You need to write your own username here.

git clone https://gitlab.com/nikit19/fdroiddata.git
cd fdroiddata

 

The following command will make a template for you in the metadata directory, the name of the file is our application id. If you open the metadata folder you will see text files of all the apps that are published in F-Droid. If you want to publish an app in F-droid it is this file that needs to be sent in merge request. There are no other changes that needs to be done, we just have to fill the fields in the meta file correctly.

cp templates/app-minimal metadata/com.eventyay.attendee.txt

 

After filling all the details in the meta file we need to commit those changes. The following command will check if there are any syntax errors in the meta file.

fdroid readmeta

 

Finally we need to build the app. The following command builds the app from the source repository so if we have followed all the steps correctly, the app would build successfully and then we can send the merge request.

fdroid build -v -l com.eventyay.attendee

 

Resources

  1. Quick Start: https://gitlab.com/fdroid/fdroiddata/blob/master/README.md#quickstart
  2. Making merge requests: https://gitlab.com/fdroid/fdroiddata/blob/master/CONTRIBUTING.md#merge-requests

 

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Implement Charges Endpoint in the Open Event Android App

In the Open Event Android App we first create an attendee and then the order when a user tries to buy a ticket but the end user will only know that the transaction is successful when money gets deducted from his account. This is where we use the charges endpoint of the Open Event Server to complete the payment. Let’s see how this is being done in the Open Event Android App.

We are sending a POST request from the app to the following endpoint. The order identifier is added in the url to uniquely identify the order for which we are charging the user. The body of the POST request contains the Charge object with the required information.

@POST("orders/{orderIdentifier}/charge")
fun chargeOrder(@Path("orderIdentifier") orderIdentifier: String, @Body charge: Charge): Single<Charge>

 

This is how the model class Charge looks like. We specify the type at the top. Then we can either send a stripe or paypal token to the server which contains all the details of the payment. Message and status fields are returned from the server after the getting a success response. The status is true if the payment has been successfully made otherwise it is false. The message field gives us the feedback about what kind of error we got if the payment was not successful otherwise we get a success response.

@Type("charge")
data class Charge(
@Id(IntegerIdHandler::class)
val id: Int,
val stripe: String? = null,
val paypal: String? = null,
val message: String? = null,
val status: Boolean? = null
)

 

This is how we send the stripe token to the server. If the card details are correct then we receive the stripe token in the onSuccess method and send it to the server using the Charges endpoint.

override fun onSuccess(token: Token) {
//Send this token to server
val charge = Charge(attendeeFragmentViewModel.getId().toInt(), token.id, null)
attendeeFragmentViewModel.completeOrder(charge)

}

 

This is the function that is being used to send the POST request. It takes a charge object as an argument and then we use that in the chargeOrder method. The orderIdentifier variable that we see in the chargeOrder function is a lateinit variable that gets initialized when an order has been returned from the server. When this request is being made in the background thread we show user the progress bar. When we receive a success response from the server, we update the value of the message variable with the value returned from the server and show it to the user. If the value of the status is true that means that the payment has been successfully completed.

fun completeOrder(charge: Charge) {
compositeDisposable.add(orderService.chargeOrder(orderIdentifier.toString(), charge)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.doOnSubscribe {
progress.value = true
}.doFinally {
progress.value = false
}.subscribe({
message.value = it.message
paymentCompleted.value = it.status

if (it.status != null && it.status) {
Timber.d("Successfully charged for the order!")
} else {
Timber.d("Failed charging the user")
}
}, {
message.value = "Payment not completed!"
Timber.d(it, "Failed charging the user")
}))
}

Resources

  1. ReactiveX official documentation: http://reactivex.io/
  2. Vogella RxJava 2 – Tutorial: http://www.vogella.com/tutorials/RxJava/article.html
  3. Androidhive RxJava Tutorial: https://www.androidhive.info/RxJava/
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Ticket Details in the Open Event Android App

It is important to show the user the ticket details before he makes the payment so that he is aware how much does each ticket costs. Let’s see how this is being done in the Open Event Android App.

This function will query the database with a list of ids and return the tickets with the matching ids.

@Query("SELECT * from Ticket WHERE id in (:ids)")
fun getTicketsWithIds(ids: List<Int>): Single<List<Ticket>>

 

To use the above function we first need the ids of the tickets that needs to be shown so we loop through the ticketIdAndQty variable and everytime the quantity is greater than 0 we add the id of the ticket to the array list.

val ticketIds = ArrayList<Int>()
ticketIdAndQty?.forEach {
if (it.second > 0) {
ticketIds.add(it.first)
}
}

 

The next step is to call getTicketsWithIds function in a background thread because it is a database operation and we don’t make calls to the database in the main thread. If the call to the database is successful we store the list of tickets in a variable otherwise an error message is shown to the user.

compositeDisposable.add(ticketService.getTicketsWithIds(ticketIds)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({
tickets.value = it
}, {
Timber.e(it, "Error Loading tickets!")
}))

 

To display the values to the user we just have to use the ticket variable and use its various fields but subtotal is not present in the variable so we have to calculate it. We just multiply the price of the ticket  with its quantity. So we pass the adapter position in the qty array to get the quantity of the current ticket and multiply it with the price.

val subTotal: Float? = ticket.price?.toFloat()?.times(qty[adapterPosition])

 

Ticket details are only shown if the user clicks on the textview which says view so we adjust the visibility of the ticket details in this simple if else statements and also update the textview value accordingly.

if (rootView.view.text == "(view)") {
rootView.ticketDetails.visibility = View.VISIBLE
rootView.view.text = "(hide)"
} else {
rootView.ticketDetails.visibility = View.GONE
rootView.view.text = "(view)"
}

 

Resources

  1. Room official documentation :https://developer.android.com/topic/libraries/architecture/room
  2. Vogella RxJava 2 – Tutorial : http://www.vogella.com/tutorials/RxJava/article.html
  3. Androidhive RxJava Tutorial : https://www.androidhive.info/RxJava/
Continue Reading

Tickets fragment in the Open Event Android App

Ticketing is one of the most important part of any event management system. In the Open Event Android App you can view all the ticket details of any event. Let’s see how this was accomplished.

This is how our TicketApi class looks. We are sending a GET request to get the list of all tickets associated with an event. Id here is the event id which is used to uniquely identify an event.

interface TicketApi {

@GET("events/{id}/tickets?include=event&fields[event]=id&page[size]=0")
fun getTickets(@Path("id") id: Long): Flowable<List<Ticket>>

}

 

In the ticket details screen we see the event details on top. We are loading these details from the event which is stored in the database, we use the event id to query the database and load these details.

This is how the events are loaded from the database. We are observing the live data variable event and calling the loadEventDetails methods as soon as the value of the variable changes.

ticketsViewModel.event.observe(this, Observer {
it?.let { loadEventDetails(it) }
})

ticketsViewModel.loadEvent(id)

 

Let’s have a look at the loadEvent function that is there in our ViewModel. It only requires one parameter that is our event id. We first check if the id is correct or not then load the events in a background thread and report the error if there is any.

fun loadEvent(id: Long) {
if (id.equals(-1)) {
throw IllegalStateException("ID should never be -1")
}
compositeDisposable.add(eventService.getEvent(id)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe({
event.value = it
}, {
Timber.e(it, "Error fetching event %d", id)
error.value = "Error fetching event"
}))
}

 

The following function is used to load the event details with the date formatted in the appropriate manner. We first use the function getLocalizedDateTime to get the localized date in string and then format the date according to our needs.

private fun loadEventDetails(event: Event) {
rootView.eventName.text = event.name
rootView.organizerName.text = "by ${event.organizerName.nullToEmpty()}"
val dateString = StringBuilder()
val startsAt = EventUtils.getLocalizedDateTime(event.startsAt)
val endsAt = EventUtils.getLocalizedDateTime(event.endsAt)
rootView.time.text = dateString.append(EventUtils.getFormattedDate(startsAt))
.append(" - ")
.append(EventUtils.getFormattedDate(endsAt))
.append(" • ")
.append(EventUtils.getFormattedTime(startsAt))
}

 

That’s all that is needed to make the tickets screen. This how the fragment looks in the app.

Resources

  1. ReactiveX official documentation : http://reactivex.io/
  2. Vogella RxJava 2 – Tutorial : http://www.vogella.com/tutorials/RxJava/article.html
  3. Androidhive RxJava Tutorial : https://www.androidhive.info/RxJava/
Continue Reading
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