How do android developers obtain information to put into their apps?

Q. If an android developer were to create a GPS system or a Weather App, how do they get the information fed into the application? Obviously i wouldn't have my own sattelite or weather station so how do i put information into the application?

A. For GPS you'd use the Android core libraries, like this class: http://developer.android.com/reference/android/location/LocationManager.html

For a weather app you'd use some weather API, the most obvious probably being the Google Weather API, but you could really use any one you want. http://blog.programmableweb.com/2010/02/08/googles-secret-weather-api/

How to download android apps from my pc and transfer the apps to my android device later?

Q. I'm planning to buy a WiFi only Honeycomb tablet(say xoom or acer a500). But I don't have any wifi router now, though I'm planning to buy one later. So, for the moment, how can I download android apps from the android market and install it to my android device?

A. I think the easyest is to scan the app code.Just save the code images, and install by scanning later.

How to find the android application that crashes and reboots my android phone?

Q. I have an android HTC phone, I put custom ICS on my phone, from the beginning it worked flawlessly,after installing few Certified applications from Google play and moving the applications from phone memory to SD-Card, my phone starts to crashes and reboot every few minutes.

I want to figure out what application has destroyed my phone and remove that application for ever.
I am wondering if there is any way to monitor and log all the applications activities and crashes on the my Android phone,even capturing the services which are running in the background before system bootsup to user interface those services that are causing my phone crashes.

Is there any application to debug the running processes on the phone or fix the faulty applications on my phone?
:-(
Thanks

A. Ideally, there should be an option in SETTINGS > DEVELOPER OPTIONS > Show Application ANR's. It will give you a popup anytime any applications freezes. (ANR stands for Application Not Responding).
This might help you to find out which all applications are freezing. This might bug you for a while though, as it will show ANR's for even background apps.