CODEWITHSUNDEEP
javaandroidstring-formatting
Ian
Ian

Reputation: 3520

display floats with precision of 3

I've been struggling with this problem for a while. I have numbers that are shown in a TextView. In this textview, I would only like the float to be shown with a precision of 3 as there is only room for 3 numbers. Here are some input - output examples of what I am trying to achieve:

1       -> 1.00
0.34   -> 0.34
-12.34  -> -12.3
123.45  -> 123

The input will always be rounded to the nearest hundredth. I've tried using String.format and even making a custom format. Currently I have logic to figure out the formatting, but there must be a one liner:

    float abs_d = Math.abs(my_float);

    String dist = "";
    if (abs_d < 10) {
        dist = String.format("%1.2f", d);
    }
    else if (abs_d < 100) {
        dist = String.format("%2.1f", d);
    }
    else {
        dist = String.format("%3.f",d);
    }
    my_text_view.setText(dist);

Perhaps there is a sneaky way to do it using the TextView? You can specify the pixel width, but how about the character width (but even then, would i accept a negative sign)? I imagine there should be some Java library to do this.

Upvotes: 0

Views: 946

Answers (3)

Ian
Ian

Reputation: 3520

@ikegami @Jack thanks for the conversation and suggestions. This seems to get the functionality for which I'm searching: 

    String str = "999";
    DecimalFormat f = null;
    if (abs_d < 1000) {
        if (abs_d < 1) {
            f = new DecimalFormat("@@");
            str = f.format(d);
        }
        else {
            f = new DecimalFormat("@@@");
            str = f.format(d);
        }
    }

    my_text_view.setText(str);

Upvotes: 0

ikegami
ikegami

Reputation: 385600

Of course there's a one liner. Put the logic in a function called format_float and use

my_text_view.setText(format_float(my_float));

Upvotes: 0

Jack
Jack

Reputation: 1240

I take it you've tried things like using DecimalFormat?

Upvotes: 2

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