Convert number in textview to int

Question

So, I am messing around with java/android programming and right now I am trying to make a really basic calculator. I am hung up on this issue though. This is the code I have r

Answer 1

TextView tv = (TextView)findviewbyID(R.id.textView);
String text = tv.getText().toString();
int n;
if(text.matches("\\d+")) //check if only digits. Could also be text.matches("[0-9]+")
{
   n = Integer.parseInt(text);
}
else
{
   System.out.println("not a valid number");
}

Answer 2

You can read on the usage of TextView.

How to declare it:

TextView tv;

Initialize it:

tv = (TextView) findViewById(R.id.textView);

or:

tv = new TextView(MyActivity.this);

or, if you are inflating a layout,

tv = (TextView) inflatedView.findViewById(R.id.textView);

To set a string to tv, use tv.setText(some_string) or tv.setText("this_string"). If you need to set an integer value, use tv.setText("" + 5) as setText() is an overloaded method that can handle string and int arguments.

To get a value from tv use tv.getText().

Always check if the parser can handle the possible values that textView.getText().toString() can supply. A NumberFormatException is thrown if you try to parse an empty string(""). Or, if you try to parse ..

String tvValue = tv.getText().toString();

if (!tvValue.equals("") && !tvValue.equals(......)) {
    int num1 = Integer.parseInt(tvValue);
}

Answer 3

TextView tv = (TextView)findviewbyID(R.id.textView);
int num = Integer.valueOf(tv.getText().toString());

Answer 4

this code actually works better:

//this code to increment the value in the text view by 1

TextView quantityTextView = (TextView)findViewById(R.id.quantity_text_view);
        CharSequence v1=quantityTextView.getText();
        int q=Integer.parseInt(v1.toString());
        q+=1;
        quantityTextView.setText(q +"");


//I hope u like this

Answer 5

Here is the kotlin version :

var value = textview.text.toString().toIntOrNull() ?: 0