ERROR/dalvikvm-heap(4204): 691456-byte external allocation too large for this process.
01-25 22:13:18.694: ERROR/(4204): VM won't let us allocate 691456 bytes 01-25 22:13:18.694

If you have ever got the message above, you are at the right place.

First of all the reason:
Heap size != External Memory size
Dalvik's external memory is limited to ~ 4MBs for each process (That is the Ugly Truth). If it overflows, you get the BitmapFactory.DecodeFile Error.
That's why even if you have like 2MB-s heap memory free, VM won't let you allocate ~700KB.
Since you can't modify external memory's size, you have to reduce your memory usage. This is the only solution I have, but it really works at least.

The solution:
Let say you have a nice big Gallery with lots of large images. An ImageAdapter class will provide all of the images that you are going to use. Therefore you'll need a List of ImageViews.

If you want to include a database with initial data in your apk, you have to insert the database file into the projects assets folder, then programmatically check if the database, and if it does not exists copy the one from the assets.

You will need a function to check if the database exists, fox example:

If the check shows that the the database does not exist, a function like this will copy it:

How to display a custom dialog in your Android application

Yesterday Jozsi showed you, how to make an alert dialog, today I'm going to show you, how to make a custom dialog/popup window.
Sometimes, it's better to make your own dialog, because this way, you can display whatewer you want., the way you want it.
First, make your own layout, with the needed elements. Here, I'm going to use two buttons, a textview inside a scrollview, and an imageview...

Here is an example of an applacation, that illustrates how you can create a simple AlertDialog. The dialog can display maximum three buttons.

The most spread method to connect to a remote MySQL database from an android device, is to put some kind of service into the middle. Since MySQL is usually used together with PHP, the easiest and most obvious way to write a PHP script to manage the database and run this script using HTTP protocol from the android system.

We can code the data in JSON format, between Android and PHP with the easy to use built in JSON functions in both languages.

I present some sample code, which selects data from a database depending on a given condition and creates a log message on the android side with the received data.

Lets suppose that we have a MySQL database named PeopleData, and a table int created, with the following SQL:

There is more than one way, to play media files on an Android phone, let me show you two of them.

Audio:
MediaPlayer is the easier way, if you just want to play an audio file in the background, somewhere in an appliaction. There are no ui controls here, but of course you can use MediaPlayer.stop(), play(), seekTo() ,etc. Just bind the needed functions to a button, gesture, or event. As you can see, it also throws a lot of exceptions, which you need to catch.

Step 1.
First thing I want you to think about is that do You really need to use Bitmaps?
If the answer is No, go to step 2. :) Otherwise, think again.
Ok, Let me explain it. I needed Bitmaps to get the width of the images, to create an ImageAdapter for my Gallery. As far as I know, there's no other way to do that. So I used Bitmaps, and even if I recycled them, once in a while it stopped with the message: DDMS: OutOfMemory .. Phone: Force Close..
Not to speak about how laggy your app will be if you are using Bitmaps..
I've spent 2 weeks to find a solution for this problem, but I couldn't find any usable of them. Then I thought, I try not using Bitmaps anymore. So I have to find another way to get the width of images. Unfortunately, it's just a workaround, but it works so who cares, right?
I can determine widths with a PHP script, store it in my existing database. After I did that, everything was working properly.

Hoever the practice is to store them normally and save the access route (Uri), sometimes it can be handy to store files/images completely in database.
In sqlite database there are only a few data types, so its easy to choose: files can be stored in a text as a ByteArray.

Lets see a sample code, where we download an image from the Internet then store it in the local database:

Accessing the sensor data of a phone, is not too complicated, but since API level 3, a lot of things got deprecated. Using only the emulator, you have only a few (here is one) options, to simulate sensor data. I would recommend the use of a physical phone. Keep in mind, that not all phones have the same sensors integrated! Cheaper phones might not have a temperature sensor, or a gyroscope, but I'm pretty sure, that all Android phones have at least an accelerometer, and an orientation sensor.

Here is an example, how to access acceleration and orientation sensor data (in API level 3 and above), without using any deprecated methods.