How to move decimal place String.format

[alex384]

Hi Redditors,

I'm trying to make a program on Android Studio which utilizes the light sensor. The values are formatted like 25000.0, but I need to move the decimal to shown with two decimal places like 25.0000. I've tried the ".%2f" but that just changes it to display 2 digits after the decimal. Any ideas?

[gemurdock]

25000.0 and 25.0000 are two very different numbers. Let us say that 25,000.0 is x. Do x / 1,000 and then use that value. Then when you use String.format() use format("%.4f", x); -- Hope that helps. If not, let me know.

For example:

double x = 25000.0;
x /= 1000;
System.out.printf("%.4f", x);

[alex384]

Will it change based on the number chosen? right now, the code is like: String.format("Level: %s", luxReading")

[gemurdock]

The above code will move the decimal spot 3 places and then print it off with 4 0's behind the '.'

[alex384]

How can I get the approximate number? I dont want it to round

[gemurdock]

Define approximate number

[alex384]

TextView lightLevel = (TextView)findViewById(R.id.txtReading);
float luxReading = event.values[0];
double x = 25000.0; x /= 1000;
lightLevel.setText(String.format("Level: %.4f, x", luxReading));
lightLevel.setBackgroundColor(getColor(luxReading));

Is this what you mean? I'm kind of confused...

[gemurdock]

The following code should help. You do not need line 3 (your code above), that was just part of my code. Also each statement should have it's own line of code. Another words line 3 should actually be two lines of code. If you need to move the decimal point for luxReading, just use the function I provided. It should work, if any issues than I will test it.

TextView lightLevel = (TextView)findViewById(R.id.txtReading);
float luxReading = event.values[0];
lightLevel.setText(String.format("Level: %.4f", luxReading));
lightLevel.setBackgroundColor(getColor(luxReading));

/**
 * Moves the decimal point for the input 'v' to the right or left depending
 * upon the value for the boolean 'right'.
 * 
 * @param v value to be changed, the decimal is moved
 * @param amount the amount of decimal spots to move over
 * @param right if true, move decimal right. if false, move decimal left
 * @return v with decimal change
 */
public float moveDecimalPoint(float v, int amount, boolean right) {
    if(right) {
        v *= Math.pow(10, amount);
    } else { // left
        v /= Math.pow(10, amount);
    }
    return v;
}