ExpandableListView with dynamic images

ExpandableListViews are great, but less great without images within them, particularly dynamic images (set at the time of creation for the list). The examples (here's one that was a reasonable starting point) and snippets on the Web left a lot to be desired, but what I was aiming for was this:


Note the color 'indicator' (in this case) changes based on variables for the child row. Very useful. This is a key feature of a health attribute (eg. weight) and a color indicator (eg. red for overweight).

To accomplish such a thing one needs to do a number of things in concert within the project, the instantiation of the ExpandableListView and the project's resources, hence the difficulties of trying to grok this solely from one code snippet or another. As an added bonus my example includes a ClickListener to detect clicks within the list.

The sample Eclipse project can be downloaded here. Enjoy.

Rendering an ExpandableListActivity

Most Android code snippets are about one Activity class or other derivative, like ExpandableListActivity. But what if you have multiple classes that you want to render in some orchestrated fashion?

If you have an ExpandableListActivity called healthProfile, and you need to render it from a main class called KeasDroid, this will get it done:

Intent myIntent = new Intent(KeasDroid.this, healthProfile.class); KeasDroid.this.startActivity(myIntent);

But remember you have to add the activity in the manifest file, as shown below:

Keas API documentation

Reference materials can be found here...

Android threads - the basics

Often you have a need to spawn a thread in which to do something useful, like load data from an external API.

You can handle events from the spawned thread and alert the user. In this case we'll use a ProgressDialog while at work...

Here are the basics. First your class must implement Runnable:
public class FooClass extends Activity implements Runnable {

When you are ready to create the thread:

public void loadData() {
pd = ProgressDialog.show(this, "Working..", "Accessing data...", true,
false);
Thread thread = new Thread(this);
thread.start();
}

Then your code is in the run() method:

public void run() {
// do something time intensive or asynchronous
handler.sendEmptyMessage(0);
}

private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
pd.dismiss(); // dismiss the progress dialog
}
};

The Handler override method handles the end of the thread.
That's it.

Accessing Keas API and data from Android

An Eclipse project "KeasAPI" that accesses data from Keas' API for a given test user and specified namespace. Download the project here.


NOTE: the API works with a "test" partner ID against test data. Real patient data is not accessible without consent from user and a legitimate Keas approved partner ID.

Using the "labs.*" namespace (all lab data), reply from API appears as follows within Eclipse's LogCat window:

Icons on Android

Using an icon with your Android app isn't intuitive within the current eclipse environment, there are a few steps to follow and here they are:

- make sure your icon is in .png image format
- copy (drag & drop) your icon(s) to each of the /res/drawable folders (hdpi, ldpi, mdpi) in eclipse
- make sure its name is in lower case (there's no rename, need to copy then rename w/paste)
- refer to an icon ("icon") in the project manifest as: android:src="@drawable/icon"

The icon will be available for ImageView UI components and will be the iconic representation for the application within the Android application picker.

Using LogCat with filters

You can manage your application output logs nicely within Eclipse and the Android extensions.

Open the "LogCat" view alongside Properties, Console, etc. as shown below. Set filters to capture Log.i() calls. Now your runtime logging is organized and not crowded within the usual SysOut stream...