Tag: programming - Page 4 - Catzie.net Blog

Android RecyclerView notifyItemChanged() IllegalStateException “Cannot call this method while RecyclerView is computing a layout or scrolling”

If your Android app is crashing with error IllegalStateException “Cannot call this method while RecyclerView is computing a layout or scrolling”, you may try placing your notifyitemchanged inside a Runnable.

Assuming you have a call to notifyItemChanged() inside onBindViewHolder() that is making your app crash with IllegalStateException, you may try something like this:

                                        myRecyclerView.post(new Runnable() {
                                            @Override
                                            public void run() {
                                                myArrayList.remove(position);
                                                myArrayList.add(something);

                                                recyclerViewMainScreenHeader.getAdapter().<code>notifyItemChanged</code>();
                                            }
                                        });

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myRecyclerView.post(new Runnable() {

@Override

public void run() {

myArrayList.remove(position);

myArrayList.add(something);

recyclerViewMainScreenHeader.getAdapter().<code>notifyItemChanged</code>();

}

});

October 20, 2017

Setup/update Ruby on OS X El Capitan 10.11.5

I need to learn Ruby on Rails for my new job. I’m a little thrilled about this chance to learn a new language, and I’m trying to get started with it on my Macbook which runs OS X El Capitan 10.11.5. I already have Ruby here, I don’t remember if pre-installed though. It’s out of date and I wanted to upgrade, as this resource Getting Started with Rails recommends version 2.2.2 or higher.

First step I took was to get RVM (Ruby Version Manager):
curl -sSL https://get.rvm.io | bash -s stable --ruby

Then I received this message:

” * To start using RVM you need to run source /Users/catzie/.rvm/scripts/rvm
in all your open shell windows, in rare cases you need to reopen all shell windows.”

And so I ran:
source /Users/catzie/.rvm/scripts/rvm

Then:
rvm install 2.4

Which returned this message:

Already installed ruby-2.4.0.
To reinstall use:

rvm reinstall ruby-2.4.0

Finally, I ran this:
rvm use 2.4 --default

My next step was to install SQLite3 on my OS X as per instructions found here on SQLite – Installation.

I got this message after following the instructions:

SQLite version 3.17.0 2017-02-13 16:02:40
Enter “.help” for usage hints.
Connected to a transient in-memory database.
Use “.open FILENAME” to reopen on a persistent database.
sqlite>

Simple SMS Reader app in Android using BroadcastReceiver class

Before I began coding Android apps, I was amazed how verification processes go like this: The Android app tells you they’ll send you an SMS containing verification code, and that you need to enter such code into a text field on the Android app. But when you receive the SMS, the verification code appears on the text field before you even type! I was like, whoa, how do they do that?

Now that I am able to develop simple Android apps, I already have an idea how it’s done.

We extend a class called BroadcastReceiver and implement its onReceive() method. This receiver is then registered either in the AndroidManifest.xml file, or registered as needed in a .java file (e.g., Activity)

I’m registering mine in my MainActivity file. I’ll provide the link to my project files on Github later on this page, but for now here’s what it looks like:

public class MainActivity extends AppCompatActivity {

    private SmsReceiver receiver;

    private TextView tv_sms_from;
    private TextView tv_sms_message;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tv_sms_from = (TextView) findViewById(R.id.tv_sms_from);
        tv_sms_message = (TextView) findViewById(R.id.tv_sms_message);

        receiver = new SmsReceiver(new Handler()); // create receiver
        registerReceiver(receiver, new IntentFilter(“android.provider.Telephony.SMS_RECEIVED”));

    }

    public class SmsReceiver extends BroadcastReceiver {

        private SharedPreferences preferences;
        private String TAG = “SmsReceiver”;

        private final Handler handler; // for executing code on UI thread

        public SmsReceiver(Handler handler){
            this.handler = handler;
        }

        @Override
        public void onReceive(Context context, Intent intent) {
            // TODO Auto-generated method stub

            if(intent.getAction().equals(“android.provider.Telephony.SMS_RECEIVED”)){
                Bundle bundle = intent.getExtras();

                //—get the SMS message passed in—
                SmsMessage[] msgs = null;
                if (bundle != null){
                    //—retrieve the SMS message received—
                    try{
                        Object[] pdus = (Object[]) bundle.get(“pdus”);
                        msgs = new SmsMessage[pdus.length];
                        for(int i=0; i<msgs.length; i++){
                            msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
                            final String msgFrom = msgs[i].getOriginatingAddress();
                            final String msgBody = msgs[i].getMessageBody();

                            Log.d(TAG, “SMS Received! From: ” + msgFrom + “, Message: ” + msgBody);

                            // post the UI-updating code to our Handler
                            handler.post(new Runnable() {
                                @Override
                                public void run() {
                                    Toast.makeText(MainActivity.this, “SMS Received!”, Toast.LENGTH_LONG).show();
                                    tv_sms_from.setText(“From: ” + msgFrom);
                                    tv_sms_message.setText(“Message: ” + msgBody);
                                }
                            });

                        }
                    } catch(Exception e){
                            Log.d(“Exception caught”,e.getMessage());
                    }
                }
            }
        }
    }

}

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public class MainActivity extends AppCompatActivity {

private SmsReceiver receiver;

private TextView tv_sms_from;

private TextView tv_sms_message;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

tv_sms_from = (TextView) findViewById(R.id.tv_sms_from);

tv_sms_message = (TextView) findViewById(R.id.tv_sms_message);

receiver = new SmsReceiver(new Handler()); // create receiver

registerReceiver(receiver, new IntentFilter(“android.provider.Telephony.SMS_RECEIVED”));

}

public class SmsReceiver extends BroadcastReceiver {

private SharedPreferences preferences;

private String TAG = “SmsReceiver”;

private final Handler handler; // for executing code on UI thread

public SmsReceiver(Handler handler){

this.handler = handler;

}

@Override

public void onReceive(Context context, Intent intent) {

// TODO Auto-generated method stub

if(intent.getAction().equals(“android.provider.Telephony.SMS_RECEIVED”)){

Bundle bundle = intent.getExtras();

//—get the SMS message passed in—

SmsMessage[] msgs = null;

if (bundle != null){

//—retrieve the SMS message received—

try{

Object[] pdus = (Object[]) bundle.get(“pdus”);

msgs = new SmsMessage[pdus.length];

for(int i=0; i<msgs.length; i++){

msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);

final String msgFrom = msgs[i].getOriginatingAddress();

final String msgBody = msgs[i].getMessageBody();

Log.d(TAG, “SMS Received! From: “ + msgFrom + “, Message: “ + msgBody);

// post the UI-updating code to our Handler

handler.post(new Runnable() {

@Override

public void run() {

Toast.makeText(MainActivity.this, “SMS Received!”, Toast.LENGTH_LONG).show();

tv_sms_from.setText(“From: “ + msgFrom);

tv_sms_message.setText(“Message: “ + msgBody);

}

});

}

} catch(Exception e){

Log.d(“Exception caught”,e.getMessage());

}

I first created a class called SmsReceiver which extends the BroadcastReceiver class that I mentioned earlier. Inside it, there’s an implemented method onReceive(), where we first check if the Intent’s action is android.provider.Telephony.SMS_RECEIVED, otherwise we do nothing. We read message(s) that the Android devices just received and get the originating address (e.g. phone number of sender) and message body. Then lastly, the TextViews in the XML file are updated with the originating address and message body so you could see that thea app works.

By the way, I used a Handler in this app so that I could set the values of TextViews inside the MainActivity’s XML file. A new Handler object is passed from MainActivity.onCreate() to the SmsReceiver constructor. And later on once the message originating address and message body are available in BroadcastReceiver.onReceive(), we use the handler to “post” and set the TextView values.

Now, for the source files of this Android app…

Feel free to download my Android project files here: Android-Incoming-SMS-Reader

Resource:
http://stackoverflow.com/a/14648933

January 3, 2017

Android app dev: Add ActionBar to Preference Activity

When I converted an activity into PreferenceActivity, I noticed that its ActionBar disappeared. I’ll show you how I brought the ActionBar back to my PreferenceActivity.

In this guide I will assume that the name of the file that contains your is SettingsActivity.java, and that the view assigned to your SettingsActivity.java is named .

First, create settings_toolbar.xml under /app/src/main/res/layout/ and place the following code into it:

<?xml version=”1.0″ encoding=”utf-8″?>
<android.support.v7.widget.Toolbar
    xmlns:android=”http://schemas.android.com/apk/res/android”
    xmlns:app=”http://schemas.android.com/apk/res-auto”
    android:id=”@+id/toolbar”
    app:theme=”@style/ThemeOverlay.AppCompat.Dark.ActionBar”
    android:layout_width=”match_parent”
    android:layout_height=”wrap_content”
    android:minHeight=”?attr/actionBarSize”
    app:navigationContentDescription=”@string/abc_action_bar_up_description”
    android:background=”?attr/colorPrimary”
    app:navigationIcon=”?attr/homeAsUpIndicator”
    app:title=”@string/action_settings”
    />

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<?xml version=“1.0” encoding=“utf-8”?>

<android.support.v7.widget.Toolbar

xmlns:android=“http://schemas.android.com/apk/res/android”

xmlns:app=“http://schemas.android.com/apk/res-auto”

android:id=“@+id/toolbar”

app:theme=“@style/ThemeOverlay.AppCompat.Dark.ActionBar”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:minHeight=“?attr/actionBarSize”

app:navigationContentDescription=“@string/abc_action_bar_up_description”

android:background=“?attr/colorPrimary”

app:navigationIcon=“?attr/homeAsUpIndicator”

app:title=“@string/action_settings”

/>

Then add the following overridden method to SettingsActivity.java:

 @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);

        LinearLayout root = (LinearLayout)findViewById(android.R.id.list).getParent().getParent().getParent();
        Toolbar bar = (Toolbar) LayoutInflater.from(this).inflate(R.layout.settings_toolbar, root, false);
        root.addView(bar, 0); // insert at top
        bar.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });
    }

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@Override

protected void onPostCreate(Bundle savedInstanceState) {

super.onPostCreate(savedInstanceState);

LinearLayout root = (LinearLayout)findViewById(android.R.id.list).getParent().getParent().getParent();

Toolbar bar = (Toolbar) LayoutInflater.from(this).inflate(R.layout.settings_toolbar, root, false);

root.addView(bar, 0); // insert at top

bar.setNavigationOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

finish();

}

});

}

The Java method programmatically creates a Toolbar object from the XML toolbar at settings_toolbar.xml.

Reference(s): Creating a Preference Screen with support (v21) Toolbar

September 14, 2016

Laravel 5: activate API token guard and print “Unauthorized” instead of login redirect

In Laravel 5, I wrap my API routes in a route group like this:

Route::group([‘middleware’ => [‘auth:api’,’throttle’]], function() {
    // API routes here
});

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Route::group([‘middleware’ => [‘auth:api’,‘throttle’]], function() {

// API routes here

});

Notice that I use auth:api and throttle on my middleware array.

auth:api turns on the auth middleware with API token as guard, while throttle activates rate limiter for APIs.

To get started with API token authentication, you may read https://gistlog.co/JacobBennett/090369fbab0b31130b51.

I followed the same tutorial to set mine up, but had this issue: Upon using invalid api_token or no token at all, I am redirected to the /login route, which in my case is a currently nonexistent route.

As instructed by the guide, I already edited my app/Http/Middleware/Authenticate.php file to add the || $request->wantsJson() condition, but my API routes still redirected to /login route upon detection of invalid api_token.

The solution

What I did was add another condition: || $guard == "api"

And now, my app/Http/Middleware/Authenticate.php file looks like this:

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Support\Facades\Auth;

class Authenticate
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @param  string|null  $guard
     * @return mixed
     */
    public function handle($request, Closure $next, $guard = null)
    {
        if (Auth::guard($guard)->guest()) {
            if ($request->ajax() || $request->wantsJson() || $guard == “api”) {
                return response(‘Unauthorized.’, 401);
            } else {
                return redirect()->guest(‘login’);

            }
        }

        return $next($request);
    }
}

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<?php

namespace App\Http\Middleware;

use Closure;

use Illuminate\Support\Facades\Auth;

class Authenticate

{

/**

* Handle an incoming request.

*

* @param \Illuminate\Http\Request $request

* @param \Closure $next

* @param string|null $guard

* @return mixed

*/

public function handle($request, Closure $next, $guard = null)

{

if (Auth::guard($guard)->guest()) {

if ($request->ajax() || $request->wantsJson() || $guard == “api”) {

return response(‘Unauthorized.’, 401);

} else {

return redirect()->guest(‘login’);

}

return $next($request);

}

July 21, 2016

Android app dev: ShareActionProvider in Activity & Fragment

I’ve been taking the Developing Android Apps course on Udacity, and yesterday I encountered a difficulty in solving the Quiz: Share Intent.

One of the course’s goal is to build the Sunshine App – an Android app with weather forecast.

In that quiz I had to implement ShareActionProvider on my DetailsFragment so that a share icon becomes available on my app’s ActionBar.

One of the main difficulties was the error that stated ActionProvider cannot be cast into ShareActionProvider. And at some point there was also an error saying that the methods/classes I’m using require API 14, while my minimum supported API is 9. The Udacity course required that I set it to 9 so I couldn’t change that.

Now, the sharing in my app is working file, and I will share how I did it via Gist. I actually ended up taking a peek at the code provided by Developing Android Apps course on Udacity because I didn’t want to waste any more time doing trial-and-error (I have another project to work on! lol), but I still had to edit their code for ShareActionProvider here and there to make it bug-free.

And so, take a look at how my Sunshine app codes ended up:

July 21, 2016

Laravel 5 RESTful API with Basic Auth: PHPUnit Testing

I’ve been using PHPUnit to test my RESTful API. PHPUnit is ready to use in Laravel.

In my Laravel-based RESTful API, I have an endpoint /api/users which returns JSON data when you send a GET request. The API will only return such data if the client sends the corrent username and password (Basic Authentication). The JSON data looks like this:

{“success”:true,”users”:[{“id”:1,”name”:”default”,”email”:”def@def.def”,”created_at”:”2016-07-08 20:23:47″,”updated_at”:”2016-07-08 20:23:47″},{“id”:2,”name”:”Eddard Stark”,”email”:”winter@westeros.org”,”created_at”:”2016-07-08 20:23:47″,”updated_at”:”2016-07-08 20:23:47″},{“id”:3,”name”:”Jon Snow”,”email”:”lorcommander@nightswatch.org”,”created_at”:”2016-07-08 20:23:47″,”updated_at”:”2016-07-08 20:23:47″},{“id”:4,”name”:”Sansa Stark”,”email”:”wholetthedogsout@winterfell.com”,”created_at”:”2016-07-08 20:23:48″,”updated_at”:”2016-07-08 20:23:48″},{“id”:5,”name”:”Tyrion Lanniter”,”email”:”ilikedragons@westeros.org”,”created_at”:”2016-07-08 20:23:48″,”updated_at”:”2016-07-08 20:23:48″},{“id”:6,”name”:”Lyanna Mormont”,”email”:”lyanna@bearisland.org”,”created_at”:”2016-07-08 20:23:48″,”updated_at”:”2016-07-08 20:23:48″},{“id”:7,”name”:”Davos Seaworth”,”email”:”seaworth@westeros.org”,”created_at”:”2016-07-08 20:23:48″,”updated_at”:”2016-07-08 20:23:48″},{“id”:8,”name”:”Daenerys Targaryen”,”email”:”queen@westeros.org”,”created_at”:”2016-07-08 20:23:48″,”updated_at”:”2016-07-08 20:23:48″},{“id”:9,”name”:”Cersei Lannister”,”email”:”longmayshereign@westeros.org”,”created_at”:”2016-07-08 20:23:48″,”updated_at”:”2016-07-08 20:23:48″},{“id”:10,”name”:”Gregor Clegane”,”email”:”hound@westeros.org”,”created_at”:”2016-07-08 20:23:48″,”updated_at”:”2016-07-08 20:23:48″}],”status_code”:200}

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{“success”:true,“users”:[{“id”:1,“name”:“default”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:47”,“updated_at”:“2016-07-08 20:23:47”},{“id”:2,“name”:“Eddard Stark”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:47”,“updated_at”:“2016-07-08 20:23:47”},{“id”:3,“name”:“Jon Snow”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:47”,“updated_at”:“2016-07-08 20:23:47”},{“id”:4,“name”:“Sansa Stark”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:48”,“updated_at”:“2016-07-08 20:23:48”},{“id”:5,“name”:“Tyrion Lanniter”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:48”,“updated_at”:“2016-07-08 20:23:48”},{“id”:6,“name”:“Lyanna Mormont”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:48”,“updated_at”:“2016-07-08 20:23:48”},{“id”:7,“name”:“Davos Seaworth”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:48”,“updated_at”:“2016-07-08 20:23:48”},{“id”:8,“name”:“Daenerys Targaryen”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:48”,“updated_at”:“2016-07-08 20:23:48”},{“id”:9,“name”:“Cersei Lannister”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:48”,“updated_at”:“2016-07-08 20:23:48”},{“id”:10,“name”:“Gregor Clegane”,“email”:“[email protected]”,“created_at”:“2016-07-08 20:23:48”,“updated_at”:“2016-07-08 20:23:48”}],“status_code”:200}

I’m gonna show you how to create a PHPUnit test for this kind of JSON API data in Laravel 5.

To create a test case, use this command:

 php artisan make:test ApiUsersTest

1	php artisan make:test ApiUsersTest

This will create a new test case named ApiUsersTest.php in your directory /tests

Paste the following code in it.

<?php

use Illuminate\Foundation\Testing\WithoutMiddleware;
use Illuminate\Foundation\Testing\DatabaseMigrations;
use Illuminate\Foundation\Testing\DatabaseTransactions;

class ApiUsersTest extends TestCase
{
    use DatabaseTransactions; 

    public function testGetAllUsersNoAuth()
    {
		$content = $this->call(‘GET’, ‘/api/users’)->getContent();
		$this->assertEquals($content, “Invalid credentials.”);
    }

    public function testGetAllUsersWithBasicAuth()
    {
	    $content = $this->call(‘GET’, ‘/api/users’,[],[], [], [
            “HTTP_Authorization” => “Basic ” . base64_encode(“username” . “:” . “password”),
            “PHP_AUTH_USER” => “username”, // must add this header since PHP won’t set it correctly
            “PHP_AUTH_PW” => “password” // must add this header since PHP won’t set it correctly as well
        ])->getContent();

		$json_content = json_decode($content);

        if(!empty($json_content->success)){
        	$this->assertTrue($json_content->success); // this test expects the JSON key “success” to have value of Boolean true
        }
        
	}

}

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<?php

use Illuminate\Foundation\Testing\WithoutMiddleware;

use Illuminate\Foundation\Testing\DatabaseMigrations;

use Illuminate\Foundation\Testing\DatabaseTransactions;

class ApiUsersTest extends TestCase

{

use DatabaseTransactions;

public function testGetAllUsersNoAuth()

{

$content = $this->call(‘GET’, ‘/api/users’)->getContent();

$this->assertEquals($content, “Invalid credentials.”);

}

public function testGetAllUsersWithBasicAuth()

{

$content = $this->call(‘GET’, ‘/api/users’,[],[], [], [

“HTTP_Authorization” => “Basic “ . base64_encode(“username” . “:” . “password”),

“PHP_AUTH_USER” => “username”, // must add this header since PHP won’t set it correctly

“PHP_AUTH_PW” => “password” // must add this header since PHP won’t set it correctly as well

])->getContent();

$json_content = json_decode($content);

if(!empty($json_content->success)){

$this->assertTrue($json_content->success); // this test expects the JSON key “success” to have value of Boolean true

}

Edit the test case as needed.

July 9, 2016