Does setWidth(int pixels) use dip or px?

问题

Does setWidth(int pixels) use device independent pixel or physical pixel as unit? For example, does setWidth(100) set the a view's width to 100 dips or 100 pxs?

Thanks.

回答1:

It uses pixels, but I'm sure you're wondering how to use dips instead. The answer is in TypedValue.applyDimension(). Here's an example of how to convert dips to px in code:

// Converts 14 dip into its equivalent px
Resources r = getResources();
int px = Math.round(TypedValue.applyDimension(
    TypedValue.COMPLEX_UNIT_DIP, 14,r.getDisplayMetrics()));

回答2:

The correct way to obtain a constant number of DIPs in code is to create a resources XML file containing dp values a bit like:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="image_width">100dp</dimen>
    <dimen name="image_height">75dp</dimen>
</resources>

Then refer to the resource in your code like so:

float width = getResources().getDimension(R.dimen.image_width));
float height = getResources().getDimension(R.dimen.image_height));

The float you have returned will be scaled accordingly for the pixel density of the device and so you don't need to keep replicating a conversion method throughout your application.

回答3:

Method setWidth(100), set 100 px as width(not in dp).So you may face width varying problems on different android phones.So use measurement in dp instead of pixels.Use the below code to get measurement in dp of sample width=300px and height=400px.

int width = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 300, getResources().getDisplayMetrics());

int Height = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 400, getResources().getDisplayMetrics());

回答4:

float dps = 100;
float pxs = dps * getResources().getDisplayMetrics().density;

Source (@Romain Guy)

回答5:

Pixels of course, the method is asking for pixels as parameter.

回答6:

Based on above answers which works fine to me, i generate some helper methods, just add them in your utils to use them in whole project.

   // value in DP
   public static int getValueInDP(Context context, int value){
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, value, context.getResources().getDisplayMetrics());
    }

    public static float getValueInDP(Context context, float value){
        return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, value, context.getResources().getDisplayMetrics());
    }

    // value in PX
    public static int getValueInPixel(Context context, int value){
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, value, context.getResources().getDisplayMetrics());
    }

    public static float getValueInPixel(Context context, float value){
        return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, value, context.getResources().getDisplayMetrics());
    }

来源：https://stackoverflow.com/questions/2406449/does-setwidthint-pixels-use-dip-or-px