1. 1
ANDROID NÂNG CAOANDROID NÂNG CAO
Bài 9:
Debugging inDebugging in
Android Application DevelopmentAndroid Application Development

2. Debug Environment
Dev Tools Android application
Hierarchy Viewer & layoutopt
Traceview & Method profiling
ANR & StrictMode
Agenda
jhat & Heap Profiling

3. Debug Environment

4. Android Debug Bridge
Model:
 Client
 Server
Components
A client
A server
A daemon
Important commands:
-d/-e/-s
devices.
install/uninstall.
pull/push
forward
shell
logcat
kill-server
Client
1
Client
2
Server
Daemon
1
Daemon
2
Daemon
31
5037
5037
5555/5554
5585/5584
5557/5556

5. UI/Application Exercise Monkey
The Monkey: generates pseudo-random streams of user events
Application: stress-test applications
Detect application crashes or receives any sort of unhandled
exception.
ANR error.
Basic usage:
$ adb shell monkey [options] <event-count>
 Sample:
$ adb shell monkey -p your.package.name -v 500
 Reference:
http://developer.android.com/guide/developing/tools/monkey.html

6. Dalvik Debug Monitor Server
 2 ways to start DDMS:
 Command line.
 Show DDMS perspective in Eclipse.
 Using:
 Monitoring:
 Viewing heap usage for a process.
 Tracking memory allocation of objects.
 Examining thread information.
 Starting method profiling.
 Using LogCat.
 File operation
 Work with emulator or device’s file system.
 Emulating phone operations and location
 Changing network state, speed, latency.
 Spoofing calls or SMS text messages.
 Setting the location of phone.
 Process Management
 Execute garbage collection
 Interrupt process
 Reference:
http://developer.android.com/guide/developing/debugging/ddms.html

7. adb logcat command
Use to view & follow the content of system log’s buffer.
Filter log output:
Using filter expression: tag:priority … tag:priority
Controll log output format:
Using –v switch: brief, process, tag, thread, raw, time, long.
Viewing Alternative Log Buffers :
Using –b switch: radio, event, main.
Viewing stdout and stderr:
setprop log.redirect-stdio true or edit /data/local.prop
Reference:
http://developer.android.com/guide/developing/tools/adb.html

8. Device
DDMS & Debuggers
DDMS adb
Connect
VM monitoring service
VM
JDWP
Debugger
(jdb)
VM start/stop
adbd
VM’s PID
Monitor
8700
8600

9. Hierarchy Viewer & layoutopt
Purpose: Debugging & profiling user interface
Tools:
Hierarchy Viewer.
layoutopt
Reference:
http://developer.android.com/guide/developing/debugging/debugging-ui.html

10. Hierarchy Viewer
Purpose: Debugging &optimize user interface
Running HV:
Connect your device or launch an emulator.
Install the application you want to work with.
Run the application, and ensure that its UI is visible.
Launch hierarchyviewer
The first window you see displays a list of devices and emulators.
Select the name of your Activity from the list. You can now look at
its view hierarchy using the View Hierarchy window, or look at a
magnified image of the UI using the Pixel Perfect window

11. Hierarchy Viewer
•TreeView:

12. Hierarchy Viewer
•Pixel Perfect window:

13. layoutopt
Purpose: analyze XML layout file to find inefficiences.
Running layoutopt: layoutopt <xmlfile>
Information display when effect is detected:
The filename
 The line number.
 The description.

14. TraceView & Method Profiling
 TraceView: a graphical viewer for execution logs that you create by using the Debug
class to log tracing information in your code.
 Application:
 Method profiling to find the bottle neck in your code execution.
 Usage:
 Create trace file:
 Using Debug class:
// start tracing to "/sdcard/xml.trace"
Debug.startMethodTracing(“xml");
//Call to the method you want to trace.
// stop tracing
Debug.stopMethodTracing();
 Using method profiling feature of DDMS to generate trace file.
 Copy file to host machine.
 Viewing trace file in Traceview.
 Limitation:
 Thread name is not emitted if thread exits during profiling.
 Reuses thread ID of VM.
 Reference:
http://developer.android.com/guide/developing/debugging/debugging-tracing.html

15. TraceView & Method Profiling
 Timeline Panel:
 Profile Panel:

16. dmtracedump
 Generate graphical call-stack diagram from trace log file.
Call reference number Inclusive elapsed time Exclusive elapsed time
Number of calls
dmtracedump [-ho] [-s sortable] [-d trace-base-name] [-g outfile] <trace-base-name>

17. jhat & Heap Profiling
 Heap Profiling helps to find the leak memory, speed up the program:
 How many instances of a class.
 How much memory usage.
 Usage:
 Set the break point:
 Exception break point.
 Conditional break point.
 Dump HPROF file from DDMS.
 Using jhat (java heap analysis tool) to parse hprof file.
 Open the favorite web browser and visit: http://localhost:7000

18. jhat & Heap Profiling
 Exception breakpoint:
 Run > Add Java Exception Breakpoint …
 Conditional breakpoint:
 Right click on breakpoint > Properties > Check Conditional checkbox > Enter the
condition.
Read more about MAT: http://10.1.6.46/mediawiki/index.php/Dectect_memory_leak_using_MAT

19. jhat & Heap Profiling
 Using DDMS dump hprof file:
 Click on “Show heap histogram”:

20. ANR & StrictMode
 ANR.
 Causes
 Activity
 BroadcastReceiver
 StrictMode:
public void onCreate() {
if (DEVELOPER_MODE) {
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectDiskReads()
.detectDiskWrites()
.detectNetwork() // or .detectAll() for all detectable problems
.penaltyLog()
.build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
.detectLeakedSqlLiteObjects()
.detectLeakedClosableObjects()
.penaltyLog()
.penaltyDeath()
.build());
}
super.onCreate();
}
 Reference:
http://developer.android.com/guide/practices/design/responsiveness.html

21. Dev Tools Application
 Get it from emulator & install into real device.
 Application:
 Enable some settings in your device for testing & debugging.
 Usage:
 Launch it > Development Settings
 Debug app
 Wait for debugger
 Show screen updates
 Immediately destroy activities
 Show CPU usage
 Show background
 Reference:
http://developer.android.com/guide/developing/debugging/debugging-devtools.html

22. Debug Tips
 Dump the stack trace:
adb shell > ps > kill -3
 Display useful info on the emulator screen:
View Dev Tools App
 Get application and system state information from the emulator:
View dumpsys and dumpstate
 Get wireless connectivity information:
DDMS > Device menu > Dump radio state
 Log trace data:
Call startMethodTracing()
 Log radio data:
adb shell>logcat –b radio
 Capture screenshots:
DDMS> Select device >Screen Capture
 Use debugging helper classes:
Log, Debug, StrictMode
 Garbage collection:
Any object the debugger is aware of is not garbage collected until after the debugger disconnects

23. Nguyen Huu Phuoc, MEng.
●  Blog:http://folami.nghelong.com
●  Website http://phuocnh.nghelong.com