AppBrain published statistics on library usage on Android. This list of libraries is very interesting and to me quite surprising. These stats are presented on three tabs: “Ad networks”, “Social SDKs” and “Development tools”. Here I care about development tools only. For example the two most-used libraries are those of the leading analytics providers, Google […]  Continue Reading  “Surprising Statistics on Library Usage in Android Apps”

AutoCompleteTextView is a nice widget Android provides. It helps the user enter text by presenting him possible selections based on what he has entered so far. Nicolas Klein has written a nice introduction of AutoCompleteTextView. As a short recap: You have to provide a ListAdapter that also must implement the Filterable interface. The filterable adapter […]  Continue Reading  “How Android’s AutoCompleteTextView Nearly Drove me Nuts”

The class ContentProviderOperation.Builder has a method named withValueBackReference(String key, int previousResult). The API states ominously “Add a ContentValues back reference. A column value from the back references takes precedence over a value specified in withValues(ContentValues)”. Now, thank you, Google! That about explains everything! Android’s documentation is never short of surprises. A lot of stuff is […]  Continue Reading  “Android’s ContentProviderOperation: “withBackReference” explained”

This is the last part of a three part tutorial on content providers. In this post I am going to show you how to write your own content provider. I covered the common concepts of content providers in my first post of this series. And in the second part I’ve covered how to use content […]  Continue Reading  “Android Tutorial: Writing your own Content Provider”

For an app I am working on I needed a MergeCursor to use search in a meaningful way. I needed to use two combine two cursors from different sources and I was going to merge them. The only major difference between the code for both cursors was the projection map I used to transform the […]  Continue Reading  “Weird error message in Android’s MergeCursor”

In a previous posting I have explained how you can check the device’s current connectivity status. But this is only a temporary snapshot of the status. It might change anytime – and it probably will, given the volatility of a mobile environment. Thus you want to know whenever the connectivity state changes. Thankfully Android’s ConnectivityManager […]  Continue Reading  “Android: Getting Notified of Connectivity Changes”

Displaying error messages in forms on Android is really simple. Most widgets have a setError(CharSequence text) method that can be used to indicate problems. Say you have a form where you have to enter a product. Now while entering more data into the form the app might check the product number and some backend service […]  Continue Reading  “Displaying Error Hints in Forms on Android”

In this tutorial I am going to show you how to make use of existing content providers. It’s the second part of a three part tutorial on content providers. In the first part I covered the common concepts of content providers and in the next part I am going to deal with how to write […]  Continue Reading  “Android Tutorial: Using Content Providers”

Recently I stumbled upon a NullPointerException caused by using findViewById(R.id.whatever) which returned null for this id. But the id was in the layout file. And I didn’t change the layout programmatically. Furthermore other widgets were found without any problem. Hmm – what’s going on? To analyze the problem I thought about a way to find […]  Continue Reading  “Finding all View-IDs of an Android UI”

ContentProviders are one of Android’s core building blocks. They represent a relational interface to data – either in databases or (cached) data from the cloud. Sometimes you want to use them for multiple operations in a row. Like updating different sources and so on. In those cases you could call the respective ContentResolver methods multiple […]  Continue Reading  “Android: Better Performance with ContentProviderOperation”