android - AlertDialog with positive button and validating custom EditText

Question

I have created simple AlertDialog with positive and negative buttons. Positive button has registered DialogInterface.OnClickListener, where I get EditText value. I have to validate it (for example if it has to be not null) and if value is not correct, disallow to close this dialog. How to prevent dismissing dialog after click and validate ?

Answer 1

Dialog creation:

AlertDialog.Builder builder = new AlertDialog.Builder(YourActivity.this);
builder.setCancelable(false)
.setMessage("Please Enter data")
.setView(edtLayout) //<-- layout containing EditText
.setPositiveButton("Enter", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int id) {
        //All of the fun happens inside the CustomListener now.
        //I had to move it to enable data validation.
    }
});
AlertDialog alertDialog = builder.create();
alertDialog.show();
Button theButton = alertDialog.getButton(DialogInterface.BUTTON_POSITIVE);
theButton.setOnClickListener(new CustomListener(alertDialog));

CustomListener:

class CustomListener implements View.OnClickListener {
    private final Dialog dialog;
    public CustomListener(Dialog dialog) {
        this.dialog = dialog;
    }
    @Override
    public void onClick(View v) {
        // put your code here
        String mValue = mEdtText.getText().toString();
        if(validate(mValue)){
            dialog.dismiss();
        }else{
            Toast.makeText(YourActivity.this, "Invalid data", Toast.LENGTH_SHORT).show();
        }
    }
}