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about typecasting in android source

Discussion in 'Android Lounge' started by proandceo, Jul 5, 2010.

  1. proandceo

    proandceo New Member
    Thread Starter

    Jul 5, 2010
    Dear Sir,

    as you know, we can see "CalculatorDisplay.java" in git.

    if you open the file, you can see line 59, 60(calc.adjustFontSize((TextView)getChildAt(0));)

    in here, I have a question.

    I searched for getChildAt, which it is in ViewGroup class.
    both android.widget.ViewGroup and android.view.TextView are sibling
    and two class received inheritance from android.view.View
    in addition, until now, I know that it is possible that typecasting is inheritance relative.

    so I can not understand why (TextView)getChildAt(0) is Ok??

    if someone know this reason, can you explain for me?


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