CODEWITHSUNDEEP
android
pearmak
pearmak

Reputation: 5027

Android calculator: Backspace button

I have recently designing for an android calculator, and the display is named fakedisplay. i am now adding a backspace button for the calculator, and the code is as follows:

    backspace.setOnClickListener(new View.OnClickListener() {        
        @Override 
        public void onClick(View v) { 

            clearCalcDisplay = DONT_CLEAR; 
            String str=Fakedisplay.getText().toString();
            if (str.length() >=1 ) { 
                str = str.substring(0, str.length() - 1);
                Fakedisplay.setText(str);
                };
            if (str.length() <1 ) {
                Fakedisplay.setText("0");
            }
    });

My questions are that

  1. I have tried the above and it works for inputs longer than 1 characters, eg 145 it will give out 14, when it is 14 it gives out 1, but when further pressed, the program will be forced-close. Why?

  2. And how to consider for decimal input?

Would there be any better codes for this function?

Upvotes: 1

Views: 16058

Answers (5)

Akash Jaiswal
Akash Jaiswal

Reputation: 31

 String str=Fakedisplay.getText().toString();
    if (str.length() >1 ) { 
        str = str.substring(0, str.length() - 1);
        Fakedisplay.setText(str);
        }
   else if (str.length() <=1 ) {
        Fakedisplay.setText("0");
    }

**I used this code in the buttonBackspace public void section **

Upvotes: 0

user8704383
user8704383

Reputation:

I simply did this:

void delete(EditText expr) {
        String str = expr.getText().toString();
        if(str.length() == 0)
            return;
        str = str.substring(0, str.length() - 1);
        expr.setText(str);
}

And I used the xml onclick element. It worked.

Upvotes: 0

Raymond Thompson
Raymond Thompson

Reputation: 11

//Needed an extra closing bracket. If you don't include the 0 and just leave //"" instead you will have a blank space instead of a zero.

backspace.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                String str = Fakedisplay.getText().toString();
                if (str.length() > 1) {
                    str = str.substring(0, str.length() - 1);
                    Fakedisplay.setText(str);
                } else if (str.length() <= 1) {
                    Fakedisplay.setText("0");
                }
            }
        });

Upvotes: 0

Devam03
Devam03

Reputation: 141

I combined both codes and got the perfect code

backspace.setOnClickListener(new             View.OnClickListener() {        
    @Override 
    public void onClick(View v) { 


        String str=Fakedisplay.getText().toString();
        if (str.length() >=1 ) { 
            str = str.substring(0, str.length() - 1);
            Fakedisplay.setText(str);
            } else if (str.length() <=1 ) {
        Fakedisplay.setText("0");
    }
  });

Upvotes: 0

Athul Harikumar
Athul Harikumar

Reputation: 2491

change the code to

 backspace.setOnClickListener(new View.OnClickListener() {        
    @Override 
    public void onClick(View v) { 

        clearCalcDisplay = DONT_CLEAR; 
        String str=Fakedisplay.getText().toString();
        if (str.length() >1 ) { 
            str = str.substring(0, str.length() - 1);
            Fakedisplay.setText(str);
            }
       else if (str.length() <=1 ) {
            Fakedisplay.setText("0");
        }
});

Upvotes: 6

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