How does density value calculate in android

Can anybody explain me what formula android use to cal开发者_如何学JAVAculate screen density?

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Density can be calculated by the following formula:

Density = sqrt((wp * wp) + (hp * hp)) / di

Where:

wp is width resolution in pixels,

hp is height resolution in pixels, and

di is diagonal size in inches.

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The formula is actual-dpi / 160. (Everything is scaled to 160 dpi.)

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int pixel = 120;
final float scale = getResources().getDisplayMetrics().density;
int dip = (int) (pixel* scale + 0.5f);

Refer this following links

• getDisplayMetrics(), for current display metrics
• density, This is a scaling factor for the Density Independent Pixel unit

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To calculate screen density, you can use this equation:

Screen density = Screen width (or height) in pixels / Screen width (or height) in inches