What do I need to get my phone app to connect to a https database?

I want to build an app that talks to a database. Analogy would be the youtube app for example. It connects to a secure host (requires login and password), and then returns to user results based on their query.

What I need the app to do is:

Get user Login information (preferrably do it in a secure way and not store it unencrypted on the users phone - This is I think easily solved with GetPassword so not worried about this)
Once user clicks 'login' Authenticate the user on my site (no clue at all how to even research how to do this. I know where the source code for the login page from regular browser is but not sure what to do)
How do I do queries based on who the user is? (for example their email, and other related data).

I would love some specific examples as well as general, and if there is a tutorial for a way to get the phone app talking to a server I would love that as well. Or any other related tutorial for that matter.

Solution

You can use HttpPost and HttpGet requests to communicate with a server. HttpGet sends parameters in the url (ex: http://mysite.com/index.html?username=admin&password=cleartext). That is obviously not the preferred method for secure information. The HttpPost sends the data in a packet which is encrypted using https. Here's an example of sending user entered data to a web page.

    EditText usernameText = (EditText)findViewById(R.id.username);
    EditText passwordText = (EditText)findViewById(R.id.password);
    String postParameters = "u=" + usernameText.getText() + "&p=" + passwordText.getText();
    try {
        DefaultHttpClient kccClient = new DefaultHttpClient();

        HttpPost postRequest = new HttpPost("http://www.mywebsite.com/login.php");
        HttpEntity postEntity = new StringEntity(postParameters);
        postRequest.setHeader("Content-Type", "application/x-www-form-urlencoded");
        postRequest.setEntity(postEntity);

        HttpResponse postResponse = kccClient.execute(postRequest);
        HttpEntity postResponseEntity = postResponse.getEntity();

        responseText.setText(EntityUtils.toString(postResponseEntity));
    } catch(Exception e) {
        responseText.setText(e.getMessage());
    }

To use a secure connection, just change the web url to https://www.mywebsite.com/login.php.