Android: How do I respond to the "Hot Code Replace Failed" dialog in Eclipse?

Question

When my Android application is already running and I change the code, I get the "Hot Code Replace Failed" dialog box.

• I am wondering what the correct answer is (stop or disable) if I want Eclipse to update my code on the device when I meet it.

• What is the difference between shutdown and shutdown?

• Also, I am wondering if I click the "Do not show error if hot-code replacement is not supported" button, what will Eclipse do in the future when this scenario occurs?

Answer 1

Depending on the virtual machine used (Dalvik in this case), some code changes may be made during debugging, which will be a hot deployment or a hot swap. This means that code changes will take effect immediately for the emulator, and you can test them without having to redeploy your application. This hot redeployment is more often used when working with enterprise applications, which can take 10 minutes to create and deploy, and therefore spends a lot of time developing.

The HotSpot virtual machine (a virtual machine commonly used on a PC) allows you to simply replace the code and crash if you are trying to add / rename an element or field method. I’m not sure what support Dalvik VM offers, but if you make changes, it will not help, you will get this dialog box.

Now for the buttons:

• Proceed. Accept that your changes will not immediately take effect in the emulator and continue to debug
• Completion: kill the application
• Disconnect: do not kill the application, but end the debugging session (i.e. disable the debugger)

If you check the box, it will always continue.

Answer 2

I am wondering what the correct answer is (stop or disable) if I want Eclipse to update my code on the device when I meet it.

There is no direct way for Eclipse to update your current emulator code when you encounter this dialog, because VM Dalvik does not support hot swapping, i.e. updating running code. You will have to manually reconfigure the application to your emulator.

What is the difference between shutdown and shutdown?

• Terminate finishes debugging the application on the emulator / device.

• Disabling will simply disable the debugger and leave the application running on the emulator / device.

Also, I am wondering if I click the "Do not show error if hot-code replacement is not supported" button, what will Eclipse do in the future when this scenario occurs?

It "will not show an error if replacing the" hot "code is not supported" obviously;) - that is, it will not warn you, and any changes you make will not be subjected to hot-swapping in the running application (since Dalvik VM does not support hot swap, e.g. Oracle JVM).

Answer 3

I usually end and then re-publish the application with the modified code.