Welcome to Part 4 of this review of the Pluralsight course Android for .NET Developers: 1 Getting Started by Jim Wilson
Jim has over 30 years of software engineering experience, with the past 15 years heavily focused on creating mobile device and location-based solutions. He has co-founded multiple software-related startups and has served in a consulting role at several more.
After nearly a decade as a Microsoft Device Application Development MVP, Jim now focuses on developing Android and iOS device applications. Jim’s passion is mentoring software developers. He blogs at hedgehogjim.wordpress.com.
Also in this series:
Part 1 – Series Overview
Part 2 – Setting up your environment
Part 3 – Android Toolset Fundamentals
Part 4 – Dalvik Debug Monitor Server
Part 5 – Understanding Android Projects
Part 6 – Android Studio
Part 7 – Understanding Android Versioning
Dalvik Debug Monitor Server (DDMS)
What is DDMS?
DDMS is a tool that provides a wide variety of debugging features, and its layout features three main sections:
1. List of connected devices and AVDs
2. Tools tab
3. Logcat View
For processes to be visible, debugging must be enabled.
We see the tools architecture diagram from the beginning of the last module again, and Jim explains the relationship and interaction between DDMS and our App.
Like .NET, Java runs a virtual machine. Each process gets its own copy of the Dalvik virtual machine. ADB connects to each virtual machine individually.
DDMS can reach inside of each virtual machine and see everything that’s going on. Jim says the ADB environment actually connects into the Android OS itself, allowing it to work very closely with the operating system.
DDMS is a set of tools. They give us visibility of:
– Memory usage
– Thread activity
– Network activity
– Access device.AVD file system
– Screen capture
– AVD control
In this we look at the most important, or commonly used, tools
To learn them all see https://developer.android.com/studio/profile/ddms.html
Jim explains that two primary memory usage tools that DDMS provides:
1. The heap view for a high-level view of the ap’s general memory usage
2. Allocation Tracker for a detailed object by object memory allocation information
Jim likes to use the allocation tracker more often than the heap view.
He demonstrates using them from Eclipse by switching to the DDMS perspective.
We see tabs for Thread, Heap, Allocation Tracker, Network, File Explorer and others.
To see the heap information we click the Update Heap button. Jim warns that this has a big negative effect on your application performance.
He turns it off and moves to the Allocation Tracker tab and we see the effect of clicking the “Get Allocations” button.
We also learn about the Include trace checkbox.
The threads viewer shows the threads running in your app ach each thread’s current call stack. Jim demonstrates how to use it. We click Update threads and it monitors the threads and their activity.
Jim says Method Profiling is outside the scope of this course but it is explained in the DDMS documentation.
DDMS allows us to see our network statistics, i.e. data sent and received by the app. Jim demonstrates this in Eclipse.
We see there is a speed dropdown with “Medium (250ms)” selected. This means it updates four times a second. We can click the start button and see a graph rendering our network activity.
The file explorer allows us to view and navigate the file system. At the top right corner of the file explorer there are some buttons.
These allow us to transfer files to and from our device, delete a file or folder, and create a new folder.
Screen capture creates a static image of the selected device.
We can refresh to get a new screen capture, rotate by 90 degrees, save to file, and copy an image to the clipboard.
Jim says there are some things that we can test with an emulator even more easily than with a real device. We can do things such as:
– change cellular radio behavior
– simulate radio transfer rate and delay
– simulate phone calls and text messaging
– set the current GPS coordinates
– use GPX or KML file formats to simulate GPS feed