Margins of a LinearLayout, programmatically with dp

Is it possib开发者_如何学Gole to set the Margins of a LinearLayout, programmatically but not with pixels, but dp?

You can use DisplayMetrics and determine the screen density. Something like this:

int dpValue = 5; // margin in dips
float d = context.getResources().getDisplayMetrics().density;
int margin = (int)(dpValue * d); // margin in pixels

As I remember it's better to use flooring for offsets and rounding for widths.

I had the same issue and used this technique to solve it:

First, I added an xml file to my res/values folder called dimensions.xml. It looks like this:

<?xml version="1.0" encoding="utf-8" ?>
<resources>
  <dimen name="my_margin">5dip</dimen>
</resources>

Second, in my code, I got the pixel equivalent of that margin as follows (note I'm using Xamarin so this is C# code, but the pure Java version should be very similar):

int myMarginPx = Resources.GetDimensionPixelSize(Resource.Dimension.my_margin);

Finally, I create my layout params:

LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FillParent, LinearLayout.LayoutParams.WrapContent);
layoutParams.SetMargins(myMarginPx, myMarginPx, myMarginPx, myMarginPx);

You can convert dp to px, for example convert 5dp to px:

Resources r = mContext.getResources();
int px = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 5, r.getDisplayMetrics());

The following method works for me for converting pixels to dp:

int pixelToDP(int pixel) {
    final float scale = RaditazApplication.getInstance().getResources().getDisplayMetrics().density;
    return (int) ((pixel * scale) + 0.5f);
}

convert DP to Pixel value

int Whatever_valueInDP=10;//value in dp
int Value_In_Pixel= (int) TypedValue.applyDimension(
            TypedValue.COMPLEX_UNIT_DIP, Whatever_valueInDP, getResources()
                    .getDisplayMetrics());

Well for the kotlin guys i have got handy helper fun which works perfectly :)

fun setMarginsInDp(v: View, l: Int, t: Int, r: Int, b: Int) {
    if (v.layoutParams is ViewGroup.MarginLayoutParams){
        val screenDensity: Float = v.context.resources.displayMetrics.density
        val params: ViewGroup.MarginLayoutParams = v.layoutParams as ViewGroup.MarginLayoutParams
        params.setMargins(l*screenDensity.toInt(), t*screenDensity.toInt(), r*screenDensity.toInt(), b*screenDensity.toInt())
        v.requestLayout()
    }
}

Just pass in a valid view and all set up!