Develop Reference

Android Monitor logcat not displaying any messages - studio version 2.2.1

I am new to app development and have come across an issue my course hasn't yet covered but requires.
I have created a simple app that generates a log entry using Log.i after clicking a button - see screenshot below.
link to screenshot
As you may well see, no logs have been generated at all for the running emulator. This happened on an earlier app and after searching for an answer, found that going to the terminal and finding the appropriate directory, I could restart the adb using the 'kill-server' and 'start-server' commands. As this didn't work, I found the file in windows explorer and double clicked the adb.exe file. This seemed to fix the problem.
Having started another project (the one linked in the screenshot), the same problem has arisen but the same steps do not correct the issue and as such have nothing being generated in the logcat.
*beneath the emulator you see, I have nothing in the search box, the logcat is set to verbose and regex(?) is ticked.
Any help with this would be greatly appreciated as i'm reluctant to proceed with the course material before sorting out this issue.
Thanks.
some additional information I have found in the 'AVD' section of the 'Run' Window :
libpng warnings
adb successful start?
EDIT - requested code
EDIT 2 - It's a bit of a bodge but it seems the adb operator command 'logcat' used in the Terminal, turns the terminal into the logcat i.e. c:..\sdk\adb logcat' - all my missing logs, including the ones generated by the buttonClicked function appear in the terminal and new logs also appear there.
Terminal as logcat
Thank you for your responses but maybe someone knows a way to fix the logcat itself, i'd appreciate the answer. Thanks again.

I have managed to resolve the issue by closing all related software, rebooting my laptop and running the adb.exe file in the ..\android\sdk\platform-tools\ directory before launching the android studio.
Hope this helps if anyone else has the same issue.

Stitches S, I think you are not calling the buttonclicked method anywhere as I haven't seen it calling in the screenshot. But if you are calling it somewhere else then try log.d() to print that. It always works for me.

if you want to see log on button click set the buttonClick method inside the oncreate(), may be its doing nothing that's why not showing any log
this code is working in my case:
public class About_us extends AppCompatActivity {
TextView header, address;
private String Info="Info";
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.contact);
header=findViewById(R.id.head);
address= findViewById(R.id.tv_address);
}
public void buttonClick(View view){
Log.d( Info,"button is clickd" );
}
}
and this is my xml view
<TextView android:id="#+id/head"
android:onClick="buttonClick"
android:layout_width="match_parent"
android:background="#color/third"
android:text="#string/app_name"
android:gravity="center"
android:textSize="20sp"
android:textColor="#color/first"
android:layout_height="30dp"/>

How to take off a PX4 autopilot using mavlink message?

I follow the following link's sample code
http://android.dronekit.io/first_app.html
and when I set API VehicleApi.getApi(this.drone).arm(true);
vehicleState.isFlying() automatically becomes true.
Can anybody tell me what this problem is?
What I need is:
1. take off, land
I read from some website that the dronekit-android does not support the mode changing. If so, how should I send the mavlink message to take off and land?
So far, I can sucessfully send the mavlink message to the PX4 board.
Thanks for replying.
Thank you for replying.
BR
SeanH

If you trace though some of the code in dronekit-android, you can see that isFlying is set here with the code below.
boolean isFlying = systemStatus == MAV_STATE.MAV_STATE_ACTIVE || ...;
MAV_STATE_ACTIVE, defined here states
System is active and might be already airborne. Motors are engaged.
So isFlying doesn't mean it's airborne but just that the motors are turned on. That occurs when you call VehicleApi.getApi(this.drone).arm(true); because you are literally arming the vehicle at that point.
For takeoff, you want to use the ControlApi. ControlApi.getApi(drone).takeOff(desired_altitude, listener) and for land you need to use VehicleApi.getApi(drone).setVehicleMode(VehicleMode.COPTER_LAND, listener)
The sample code you're looking at is very old. I suggest you follow the sample app from github.

I have not tried android-dronekit before and I noticed that the src folder have not been updated for more than two years on github.
I advice you to use python-dronekit because there is a powerful library called pymavlink in python and used in python-dronekit. You can build hyper application if you want but first try to takeoff and land in python.

play-games-plugin-for-unity - show specific Leaderboard

I'm trying to integrate the google play Leaderboard with help of the play-games-plugin-for-unity plugin into my game.
It works fine, committing to Leaderboard an all, only one thing is not working. When I call the Leaderboard
//LEADERBOARD
if (GUI.Button(leaderboardButton, "Leaderboard"))
{
((PlayGamesPlatform)Social.Active).ShowLeaderboardUI(Constants.LEADERBOARDID);
// Social.ShowLeaderboardUI();
}
it opens the window where I see all leaderboards. But I'm giving a specific id. This would be the behaviour I expect from the line Social.ShowLeaderboardUI(); which is commented out. The overload with a given Id (hid behind Constants.LEADERBOARDID) should start the specific Leaderboard UI according to the doc. Someone knows if this is an issue (haven't seen any report on GitHub) and how to solve it? It isn't that that big of an issue, but one click is better than two.
I tried something interesting. I changed the Id to some wrong value. Still the same behavior (opening the window with all leaderboards). Of course committing the score doesn't work anymore.

Okay, i found the error in the sourcecode of the Plugin, fixed it and resolved the problem. So here I present the fix if someone needs it. It's in the LeaderboardManager class.
This is how ShowUI is called:
internal void ShowUI(string leaderboardId, Action callback) {
Misc.CheckNotNull(callback);
C.LeaderboardManager_ShowAllUI(mServices.AsHandle(), Callbacks.InternalShowUICallback,
Callbacks.ToIntPtr(callback));
}
This should be the correct version
internal void ShowUI(string leaderboardId, Action callback) {
Misc.CheckNotNull(callback);
C.LeaderboardManager_ShowUI(mServices.AsHandle(),leaderboardId, Callbacks.InternalShowUICallback,
Callbacks.ToIntPtr(callback));
}
}
See the difference? C.LeaderboardManager_ShowAllUI instead of C.LeaderboardManager_ShowUI is called.

android phonegap if timeout fallback

i'm trying to do a fallback on a timeout event!
ive set super.setingeterproperty("loadurltimeoutvalue", 60") so i can simulate it. Been searching around and havent found alot of answers to this.
I'm trying to do this: if timeout event -> load page from assets folder.
this so i can hide the error message that occurs on timeout. that error message contains the address to the site being loaded, and i dont want that at all to show up anywhere.
if (mWebView.loadUrlTimeout == currentLoadUrlTimeout) {
//super.loadurl("android_assets bla bla")
}
Found that code here, but cant get it to work. i think there are lots of parts missing, to the code, as i tried stripping it.
I am still pretty fresh to this, so there might be really logical flaws which i just dont see.
Any help greatly appreciated :)

Try setting following property in the activity before loading the page, it should work:
super.setStringProperty("errorUrl", "file:///android_asset/www/error_page.html");

setStringProperty has been deprecated in 3.0. Use config.xml instead:
<preference name="ErrorUrl" value="myErrorPage.html"/>

Android Debugging, how?

Ok so I've finally cobbled enough working parts into my app that its just plain old refusing to do anything now. I understand how to use logcat, but that is about it.
The main problem at the moment is that I get the error
Activity Idle Timeout for HistoryRecord then my package
I need to learn how to do better debugging. Plus if anyone can suggest things I should do for this error please let me know.
I think its something to do with the interactions with the database.
Cheers
EDIT:
What IDE are you using, if any?
Eclipse with Android tool has
moderately good debugging facilities;
set a breakpoint and debug away.
I am using Eclipse
And I know of breakpoints, but not their real use. Where would I set them for this error?
I am used to PHP where errors tell you a specific line to look at is there a way to do this in Eclipse?

In Eclipse if you right click in the margin next to your code - easy place to start is probably in your onCreate method - you can choose to Toggle Breakpoint. This will set a breakpoint at that location.
Now, in Eclipse choose Run->Debug As->Android Application.
This will run your app in the emulator and your app with stop running at your breakpoint. At this point you can step thru your code line by line using F6 I believe.
Once you've hit the breakpoint and your code is paused, use a guide like this http://www.ibm.com/developerworks/library/os-ecbug/ which will highlight all the different things you can do at that point.

Max... If you can wrap the offending line of code in try catch you can log the exception or set a breakpoint at the exception. So for the code below that will throw an exception:
String test= null;
try {
test.length();
}
catch (Exception e) {
Log.d(TAG,"test",e);
}
LogCat will display test,java.lang.NullPointerException blah, blah, blah
OR you can set a breakpoint at the Log.d line and if hit in DEBUG mode the app will pause and the variable window in the DEBUG view will show:
this:MyApp e:NullPointerException
BUT it does not sound like your app is throwing an exception, rather it is timing out on a database call. I would stub out the call to the database and see if the timeout goes away. Then slowly add back code until it times out.
JAL