Question

I am still a beginner but trying to learn so probably doing something extremely silly. My question is about a simple Android calculator I am trying to make but I think the question concerns basic Java which I thought I understood. I get the value from the button that’s pressed then pass it to a method to display the input then set a global variable for the input. The value in the method header is “1” if I press “1” but then gets lost in that method. Maybe I don’t understand how to handle the Java types as I thought I did–don’t know. I had the logic working at one time but had to change how it was displayed and that, of course, screwed up my logic somewhere. Anyway, I will post the passing statements and the receiving method for now. Thanks in advance.

  public void initButtons()
{
    //register buttons as listeners
    final Button button1 = (Button) findViewById(R.id.button1);
    final Button button2 = (Button) findViewById(R.id.button2);
    final Button button3 = (Button) findViewById(R.id.button3);
    final Button button4 = (Button) findViewById(R.id.button4);
    final Button button5 = (Button) findViewById(R.id.button5);
    final Button button6 = (Button) findViewById(R.id.button6);
    final Button button7 = (Button) findViewById(R.id.button7);
    final Button button8 = (Button) findViewById(R.id.button8);
    final Button button9 = (Button) findViewById(R.id.button9);
    final Button button10 = (Button) findViewById(R.id.button10);
    final Button addButton = (Button) findViewById(R.id.addButton);
    final Button subButton = (Button) findViewById(R.id.subButton);
    final Button multButton = (Button) findViewById(R.id.multButton);
    final Button divButton = (Button) findViewById(R.id.divButton);
    final Button calcButton = (Button) findViewById(R.id.calcButton);
    final Button clearButton = (Button) findViewById(R.id.clearButton);

    //when button is pressed, send num to calc function
    button1.setOnClickListener
    (new Button.OnClickListener()
        {
            public void onClick(View v)
            {
                inputString = button1.getText().toString();
                displayCalc(inputString);
                //displayCalc(1.0);
            }
        }
    );

    private void displayCalc(String curValue)
{
    if (hasChanged = false)
    {
        //display number if reset
        String display = curValue;
        number1 = Double.parseDouble(display);
    }
    else                                                    
    {
    //  display = display + operator + curValue;
        //number2 = Double.parseDouble(curValue);
    }
    //showDisplay(display);
}

Answer 1

Comparisons in Java are made with double equal signs “==”.

It is considered better form to test for booleans simply by putting them between the parentheses like this :

if(myBool){
    //do something
}
else if(!myOtherBool){
    //do something else
}