Idea intellij “USB device not found” Android problem

Lately I’ve been really frustrated with this message. I don’t know when it has started to pop up, but every time I’m in the middle of important debugging, and want to restart the app I get this message when starting the app:

USB device not found

I’ve read bunch of blogs and stackoverflow questions and answers but nothing helped. Then I tried one very simple trick:

adb kill-server
adb devices

After that I’ve got this response:

* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached
37329B0B96FD00EC    device

After that intellij worked without problems.

Passing objects from one Activity to another

When you want to transfer some parameters (String, int, whatever) in Android you can pass it via one of the Intent.putExtra methods. It’s simple as that. You can say:

int parameter = 42; // just an example

Intent intent = new Intent(currentActivity, newActivity.class);
intent.putExtra("myParameter", parameter);
startActivity(intent);

But what happens when you want a pass your custom made class instance? You can pass:

  1. it’s id and gather it from db or web service for example. That’s OK, but it’s a bummer if you have already have it, why do the same thing again?
  2. your class could implement Serializable interface. This is a perfectly working solution, but as many people said, it’s not an optimal solution (just take a look at stackoverflow)
  3. or use android’s Parcelable interface :)

Just to be clear, I don’t like implementing additional serializing/deserializing code, but as it turns out, it’s pretty simple to implement it, and it improves performance. So why not? :)

To make your class Parcelable, you have to implement the following methods:

int describeContents();
void writeToParcel(Parcel dest, int flags);

And you have to define a public static field named CREATOR (that implements Parcelable.Creator<T>)

Just take a look this example:

import android.os.Parcel;
import android.os.Parcelable;

import java.util.Date;

public class ExampleParcelable implements Parcelable {

   private String stringValue;
   private Integer integerValue;
   private char charValue;
   private boolean boolValue;
   private Date dateValue;

   @Override
   public int describeContents() {
      return 0;
   }

   @Override
   public void writeToParcel(Parcel dest, int flags) {
      dest.writeString(stringValue);
      dest.writeInt(integerValue);
      dest.writeInt(charValue); // yup, it's actually a char
      dest.writeInt(boolValue ? 1 : 0); // can't store bools, but we can do it this way
      dest.writeLong(dateValue.getTime()); // same here, can't write date's, but we can get time in long
    }

    // Added this default constructor in case you are using some JSON/XML whatever parsers that require no-arg constructor
    public ExampleParcelable() { }

    /**
    Just to make life easier, I've added a constructor that creates our ExampleParcelable from a Parcel (of course, you don't have to do it that way)
    */
   public ExampleParcelable(Parcel parcel) {
       // The only important thing is to read them in the same
       // order as you wrote them (take a look at writeToParcel)
       stringValue = parcel.readString();
       integerValue = parcel.readInt();
       charValue = (char) parcel.readInt();
       dateValue = new Date(parcel.readLong());
   }

   public static final Parcelable.Creator CREATOR = new Creator<UserContentInfo>() {

    @Override
    public ExampleParcelable createFromParcel(Parcel source) {
       return new ExampleParcelable(source);
    }

   @Override
   public ExampleParcelable[] newArray(int size) {
      return new ExampleParcelable[0];
   }
};

}

It’s pretty much straight forward. In writeToParcel method you need to write fields that you need (in case you don’t want to pass every field), and later in CREATOR’s createFromParcel read every field in the same order you’ve written to Parcel in the first place.

I’ve added an example how can you write, and later read char and date types. Because can’t write everything (but it can write other Parcelables in case you need it).

Using it is the same thing as in the first example

ExampleParcelable test = new ExampleParcelable(); // just an example, set fields you need

Intent intent = new Intent(currentActivity, newActivity.class);
intent.putExtra("myParameter", test);
startActivity(intent);

Also, in case you are super-lazy to implement your own Parcelables, I’ve found this awesome project (source code: https://github.com/dallasgutauckis/parcelabler).
It creates them for you :)

Mavenizing android projects

I must confess, I like building my java apps with maven because I really hate managing all the dependencies, and on the other side I can use great tools like sonar and jenkins/hudson out of the box.

So the goal was to build my android project with maven.  First stop was of course the official android-maven url: http://code.google.com/p/maven-android-plugin/

In the getting started it was pretty clear to install jdk, android sdk, maven and that’s about it. I’ve created my pom file like they said:

<dependency>
   <groupId>com.google.android</groupId>
   <artifactId>android</artifactId>
   <version>1.6_r2</version>
   <scope>provided</scope>
</dependency>

In the project I’m talking about, I’m using android 1.6. After mvn clean install I had my first problem.

1. Maps not found

package com.google.android.maps does not exist

So that was pretty clear that I only have “clean” android installed (or at least in my mvn repo). After a quick google search, I’ve found out about mvn android sdk deployer (https://github.com/mosabua/maven-android-sdk-deployer). That seemed to be the answer to my problems. Yup, just clone the repo, mvn clean install it and you’re ready to go. But after running mvn clean install (for maven android sdk deployer) I’ve got the following error:

2. addon-google_apis-google-3/source.properties not found

Failed to execute goal org.codehaus.mojo:properties-maven-plugin:1.0-alpha-2:read-project-properties (default) on project google-apis-3: Properties file not found: /Users/vuknikolic/dev/android-sdk-mac_x86/add-ons/addon-google_apis-google-3/source.properties -> 

This one confused me, I knew that I had google add-on installed for v3, I’ve checked the path, but it wasn’t there. Then I saw on maven-android-sdk-deployer’s github page:

Platforms and Add on folder names changes in SDK

When updating an existing android sdk install the add-ons subfolder can sometimes be reused and their contents be updates so you could end up with e.g. the google maps-4r2 in a folder named google_apis-4_r01. To work around this just uninstall the affected add-on and reinstall it with the android sdk tool.

After that android mvn deployer worked like a charm, great works guys. So I’ve returned to my project, started mvn clean install… and…

3. JSON not found?

package org.json does not exist

This one seemed weird, cause why on earth would I miss something inside of android sdk? If it is installed already… My good friend Google saved me again (http://code.google.com/p/maven-android-plugin/issues/detail?id=77), there seems to be a problem with 1.6_r2 package as well, so I had to upgrade it to 2.1.2 as advised in that issue.

After that I was finally building my android project with maven. So here are the five easy steps to start building your android project (that uses google maps) with maven:

  1. Create pom.xml and set version to 2.1.2 or above in maven dependency
  2. Clone maven-android-sdk-deployer
  3. Uninstall old installed versions with Android SDK manager and install them again (just to make your life easier)
  4. Start mvn clean install in maven-android-sdk-deployer
  5. Start mvn clean install in your project

Android presentation, prezi and general impression

This is my first post without any code, but I just had to express myself :)

Today I had my first non-JavaSvet presentation (for those who don’t know JavaSvet is the first serbian Java user group). It was organized by the great people in SEE ICT organization. I wasn’t the only speaker,  a friend of mine Vladan Petrović  was in it as well, and he made this awesome presentation in prezi (I’ve helped with the content, not that much with the overall design). You can find the presentation here.

Photo by Vladimir Trkulja

I must say that I am pretty impressed how fast it was to make a presentation, and how effective it looks like. I saw that some people in the audience were impressed. And also, this was my first time presenting something that is inside a browser, and not powerpoint/open(libre)office. So it was all pretty new for me.

The goal was to first explain android basics, and later give them some small exercises that they can work on. We decided to test them with a little bit of tic-tac-toe. We’ve showed all the basics with this little example that I have made (github link). In case you need it, you can find there some basic examples of activities, services, broadcast receivers and content provider. Basically all-in-one example. It’s a small, but functional mp3 player (actual song isn’t hosted @ github). To make things more geeky, I’ve selected Paranoid Android by Radiohead (OK Computer album), cool eh?

The thing that totally blew me away was that when I got back home, I’ve already had some facebook invites, and tweets, that people continued working on the example as their first project.

I would be the luckiest man if any of those guys keep on working, and if they can make some cash out of it, that would be more than amazing. So thumbs up for everybody :)

UPDATE: Great guys from start it uploaded the video to youtube.

Cepelin

Cepelin is an android app that I’ve worked on with my colleges from my (now ex) firm youngculture.  There was believe it or not, eight of us willing to learning something, create an app and have a lot of fun. Couple of meetings with beer, few days working on an “ueberly awesome” idea (cafe, restaurant and event guide) we actually won the golden award on VIP mobile’s Android Challenge.

Members of the awesome team are: Saša Slavnić, Dragan Marjanović, Marko Simić, Željko Gavrilović, Žarko Šušnjar, Igor Popov, Igor Spasić and yours truly.

You can see our icon in the official VIP mobile commercial (27-28th second) :)

And here are the screenshots:

Gradski Prevoz – android app

My third application for VIP Android Challenge 1.0. I’ve created this application with great friend of mine Milan Delibašić.

Gradski Prevoz (Public Transport) helps user in using public transport by providing information on lines, schedules and other useful stuff. Currently supports several lines of public transport in Belgrade, Serbia.

This application (although not fully finished, because we didn’t map all the lines and buses) won the bronze award (HTC Hero)

This application was featured in VIP mobile’s commercial :)

klopaj! for android

My second application for VIP Android Challenge 1.0. Klopaj! lets you search entire Belgrade for the best restaurants. Just enter type of food, or restaurant’s name or whatever you would like and let klopaj show you where it is. You can comment restaurants, added them to your favorites, love them or not. App is powered by klopaj.com website.

This application also won a HTC Tattoo phone, that I’m currently using :)

988 Helper

988 Helper (originally 988 Pomoćnik) is my first Android application it was created for the VIP Android Challenge 1.0 . I’ve worked on it together with my great friend Milan Delibašić

The point is that somebody calls you, and you don’t have that person/number in your phonebook, 988 Helper will find out who is that person using Telekom Srbija’s 988 service. Simple as that :)

Application won HTC Tattoo phone :D

UPDATE: 988 Pomoćnik has been removed from the android market, because Telekom Srbija’s site has changed. Before taking it off this application had more than 3000 downloads. I’ve very proud of that detail :)