I have very old Siemens CX70 in working state and just don't want to throw it out. My idea is to use its math power and peripherals (GSM module, USB, Camera and screen) to build some simple applications for home use (multichannel termometer, timer and cheap security system - for examples).
I know I should use Java ME and IDE (I love Netbeans, for example). Can you tell me what I need more to start developing? I know Java well, I just need to make an environment to developing, debug and deploy. Mobile library documentation will be very helpful too.
Thanks.
There are so many online tutorials about this topic that the only right thing to do is to refer you to google.com
Search after "getting started with j2me".
However, there's something else you should know upfront before getting too excited.
The security model in JavaME will prevent you from doing much useful stuff, in relation to some of the things you mention.
Every time you try to access certain things in the phone, like e.g. the camera, or send SMS, or read/write a file on SD card, etc etc - the phone will show a popup "This app is trying to access camera. Allow this?". And the app will only continue after a manual click on Yes.
As you can imagine, this of course renders a lot of ideas useless.
In order to prevent these popups, you can sign your app with a certificate you buy from Thawte or Verisign. But as that'll cost you $300 a year, it's not the way most sparetime hobby developers chooses.
Personally, I found another way, but it requires you to use a phone from Sony Ericsson.
Because the old Sony Ericsson phones can be patched in order to remove the Java security. After doing this on one of my old phones, I've been having fun making apps like the ones you mention. For example, an app that keeps an eye on my home when we're out, by taking a picture every second. If it detects a difference in the picture, it sends me an MMS with the picture. :-)
I have searched a long time for patching options for other brands, but I just can't find anything useful. Nokia should supposedly also be patchable, but I just can't find anything useful about it.
So in short: If you'd like to make some sparetime hobby apps on a phone like that, you should either find a Sony Ericsson phone and patch it - or go dig up an old used Android device.
Good luck.
Related
im creating an Android app and i want to put it on Google Play. I want the users to download it, use and test it for about 7 days and then, the app will be blocked and the user has to buy it to continue using it.
I've tried with Backup Manager but it didnt work.
Then i read about Licensing (i have a good tutorial already) but i dont know if its what i need.
Other option is to make a subscrition payment to use, but with a free trial, however this is a bad option because the user has to put the payment method and data to use the app.
What do you think guys? can i use Licensing for what i need or better other tecnology?
EDIT:
Maybe i didnt explain myself very good, i want to know if with the Licensing system i can do a trial version of an app for like 7 days. I've tried the other solutions and didnt work for me (Backup Manager, SharedPreferences...) and want to know if Licensing can help me or if its another technology i can use.
There is no direct solutions for what you want.
Google provides a Subscriptions trial with their Subscriptions library, but then the users should pay "regularly" for the content of your app. (weekly, monthly or yearly etc..)
The best option for your use case in my opinion should be this:
You setup your app as FREE on the store
When the user download the app the first time, you create some sort of key which identify your installation on that device
After trial period ends, you can block the app usage until the user purchase an In-App item which re-enable the app functionality.
This is some sort of FREE/PRO version logic which a lot of developers already use in the store.
So, I have been exploring many similar questions across website (this, this and this and many more). People wanting to implement their own custom lock screen (not talking about widgets). So far there have been two implementation techniques which users are using.
Home Screen Replacement. In this technique its suggested to create a home screen application, where after unlock logic the default screen shows up. I believe that in this situation developer has to disable Home, Search, Menu and Back button when the lock screen is visible and to implement the Screen off-on logic.
An application. In this technique a normal app is made where after unlock logic the default screen shows up. I believe that in this situation developer has to disable Home, Search, Menu and Back button when the lock screen is visible and to implement the Screen off-on logic.
Now, I don't understand that what is the difference between two approaches? StackOverflow community seems to stress more on the home screen replacement technique. I am very new to Android development so I might be missing some aspect about it. Please suggest that which approach should I use and why? (also, which is easy?).
Thanks so much!
I would use the first method, but only for usability reasons. Because it gives the user a choice to easily revert back to the original homescreen/lockscreen if he chooses not to make the new one a default choice yet.
I'm afraid both strategies you described are quite difficult (depending on the api level range you want it to work on). The difficulty is not in their difference, the difficulty is in overriding the buttons (as Google makes it more difficult by closing down security loopholes for the newer api levels).
PS: Please note that Jellybean has a new Daydream functionality. If customizing the lockscreen is all you need. That may be the way to go since Jellybean is much more secure in that respect and more difficult to work with than the previous api levels otherwise.
Also, consider using the HTC screenlock api for HTC devices. This way, your solution won't be too hacky at least for their newer devices. And perhaps, do a version for rooted devices as well, since that too should be easy, for users who already have obtained root on their device. Don't discount the rooted market, users with root access do spend a disproportionate amount of money on applications in Google Play. That much is obvious if you just take a look at some of the rough numbers of downloads for paid applications that say (for root only) that Google Play gives you.
I want to make a security app for Android phones. Basically, I don't want anyone to be able to un-install it without having to enter a specific password first.
Also, is there a way to prevent the app from being stopped manually (like being closed via. Taskmanager) etc?
This sounds more akin to Malware-like behaviour than that of a regular Android application, anyway:
For a regular Android application, I'd imagine that making it 'uninstallable' is near enough impossible to achieve - try to contemplate what the state of the Android app market would be like right now if this were possible!
On the other hand, if privileged control (root access) was available then this might be a possibility - an example of that could be like how wireless carriers implement bundled software. However, like I mentioned, there is no regular avenue available for applications released via. the Android market to achieve what you've asked, it should be pretty clear to you why...
Here's my requirement:
I often receive calls from unidentified numbers on my mobile phones. I would like an application which would use a reference list like this, and show me the carrier name and the area of origin along with the number on screen.
Mobile make : Sony Ericsson
Model : C902
Operating System: Propreitary
J2ME: MIDP 2.0
Here are my questions:
Is it possible to do something like this? I have installed a lot of java apps on my mobile, and all of them have to be launched seperately, can be run in the background, but they never seem to access anything native.
If it is possible, which area of J2Me should I start with, for creating an application that achieves the above requirement?
If it is not possbile, what are my alternatives?
I'm pretty sure this isn't possible. I dabbled in J2ME for a while, and came to the conclusion that it's basically just a big joke hard to do anything meaningful. Sorry.
can be run in the background? yes using Push Registry. access anything native? it depends on which native thing you want to access.
It is not possible.
On this model, you don't have alternatives, but on Symbian you can try Qt with help of Qt Mobility Project
I am looking to create a video training program which records videos - via webcam, user screen capture and captures sound. Now the main problem is that I need a cross-platform (mac and windows) solutions.
I know its possible to use flash to record webcam + audio. But its not possible to record the user's screen via flash.
So am wonder if I should use Java (which i believe will work on mac & windows). I do not want to develop to separate versions because of the cost involved in developing two versions.
Please guide me as I am new to this.
Thank you.
UPDATE
Hello again,
I had a look at the following site: www.screencast-o-matic.com or www.screentoaster.com. I see that they have developed a java applet which helps interact with Windows/Mac to record the screen.
I am wondering how to go about developing something like that and integrating it with Flash (for webcam and audio recording).
Is this a better idea?
This is not an answer to your question, but I strongly recommend against using video for educational programmes. Our company delivers university courses on-line, and we long ago learned that video feeds are only effective under particular scenarios. In general, a talking head is a waste of bandwidth. You're much better off to put together a well designed powerpoint presentation, record a voice-over (and edit it!) and then assemble the whole thing as a flash presentation. This is a non-trivial amount of work, but it provides a much more interesting product for the student.
When to use video:
1) When you are demonstrating something dynamic - Mechanics or Chemistry for example.
2) When you are acting out a scenario or case as an illustration -- For example, threat de-escalation techniques for high school teachers.
When you solve the screen recording problem, seriously consider whether you need full motion or if you can get away with stills. Often the motion is distracting, and a still with good voice over can be more effective. (Hint: Replace mouse pointers with something HUGE before recording -- Like Fox did with hockey pucks)
Try CamStudio. I don't know, if it works on Mac, but on windows, it's the best solution I know. It's open source, so you can use it's source code, if you want to :)
If you're looking to build an application that does all of the recording and screen capture itself, then you might consider using Adobe AIR (essentially, Flash running on the desktop) in combination with Merapi. Merapi is essentially a bridge between Adobe AIR and Java. So for example, for your project, you might use Java to handle the lower-level (but still cross-platform) stuff you can't do natively in AIR, and use Merapi to wire the Java application to your AIR UI.
This is by no means a simple project. Lets get that said and out the way. There are open source (and cross-platform) options for each element, but nothing (I know of) that will do everything for you.
I think the "cleanest" option would be to use Flash for webcam and audio, as you said, and run a VNC server to send the screen video... The only closed-platform code will be the VNC launching code. That should be pretty simple to maintain!
That raises a problem because most people are behind NAT firewalls these days. Setting up port forwarding is a pain in the behind. I've used an app called Gitso before which allows people to connect to me and send their desktop to my screen (for tech support). Its VNC-based and all it really does is add another layer on top of the VNC connection so rather than me connecting to them, they connect to me. That makes the whole business of port forwarding a non-issue.
And once you've recorded everything, there's the final issue of syncing it all back together... Might not be so hard.
Well, Camtasia provides the solution to get your problem done. It can record the onscreen activity and also the webcam video and put them in the same player template. Another screen recorder DemoCreator can publish the screen recording as Flash movie, but can not record the webcam.