how to make hint disappear when edittext is touched?

You can also custom your XML code by using Selector. Here is an example code.

Create a selector. In file selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_focused="true" android:color="@android:color/transparent" />
    <item android:color="@color/gray" />
</selector>

In your view

android:textColorHint="@drawable/selector"

Hint only disappears when you type in any text, not on focus. I don't think that there is any automatic way to do it, may be I am wrong. However, as a workaround I use the following code to remove hint on focus in EditText

myEditText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
    public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus)
            myEditText.setHint("");
        else
            myEditText.setHint("Your hint");
    }
});

Here's my solution, where the hint disappear when user focus editText and appears again when focus changes to other place if the edittext is still empty:

editText.setOnTouchListener(new OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        editText.setHint("");
        return false;
    }
});

editText.setOnFocusChangeListener(new OnFocusChangeListener() {
    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (!hasFocus) {
            editText.setHint("Hint");
        }
    }
});

hope this helps someone