How to set an alert box in Android and is there any API to send data from an app to a URL

I am a new developer. I am facing some problems in my new app.

1. I have placed three edit boxes. When the user hits the button next to those edit boxes, I want to set up an alert box if any of the edit boxes is not yet filled up.

2. When the user hits the button next to those edit boxes after filling up all the d开发者_运维技巧ata correctly, it must intents to the new page and at the same time I want to send the data to a particular URL. Is there any API for this?

I am familiar with normally moving over from one page to the other. I have already asked about sending data to an URL in SO but I didn't get a clear answer.

Please help me in clearing these problems. I am a fresher to this Android and I don't have any colleague in the same field. Please help me.

This is the answer of First Question . Show Alert Dialog

This is the Answer of Second Question . Send Data To Server .

In second answer it only send data to the server and you have to implemented script at the sever side to fetch the data.