Checking empty fields in android application

Question

I Have a form with 3 activities in my application. The user shouldn't go into the 2nd activity if he didn't complete filling-in the fields in 1st activity, the NextButton is kept disabled until the fields are complete.

The form contains: picture, edit text and a spinner..

Questions:

1-I created a function that checks whether the spinner and edittext has a value or not... but I didn't know where I should call this function...

2- How can I check if the imageview has contains a picture or not? note: the user will take the picture from the Gallery ..

-----------My Code ------------

// For Disabling The Buttons
    void updateButtonState() {


        if(checkimg()&& CheckSpinner() && checkEditText2(CaseName) && checkEditText2(CaseAge) && CheckRButtons(RBMale, RBFemale) ) {
        Nextb.setEnabled(true);}
        else {Nextb.setEnabled(false);}

            }

// For Spinner
    private boolean CheckSpinner(){
        boolean checkspiner=false;
        if( strH == "0" && strM == "0")
            checkspiner=false;
        else checkspiner= true;
        return checkspiner;
    }



// For Buttons

     private boolean CheckRButtons(RadioButton rBMale2, RadioButton rBFemale2) {
    // TODO Auto-generated method stub
     boolean but = false;
        if ( RBMale.isChecked() || RBFemale.isChecked())
            but = true;
        return but;

}


// For EditText  
         private boolean checkEditText2(EditText edit) {
                return edit.getText().length() != 0;
            }

Answer 1

about the checking the ImageView , when you set the bitmap to your imageView , try to set a Tag to your ImageView like this :

imgView.setTag(myBitmap);

and when you will try to check if there is an image or not , you will just get the tag and test if it's not null :

Bitmap b = (Bitmap) imgView.getTag();
if(b == null ) { 
    //the imageView is empty
} 
else {
     // there is an image
}