layout textview viewgroup - In Android, how do I set margins in dp programmatically?



5 Answers

LayoutParams - NOT WORKING ! ! !

Need use type of: MarginLayoutParams

MarginLayoutParams params = (MarginLayoutParams) vector8.getLayoutParams();
params.width = 200; params.leftMargin = 100; params.topMargin = 200;

Code Example for MarginLayoutParams:

http://www.codota.com/android/classes/android.view.ViewGroup.MarginLayoutParams

kotlin to relativelayout

In this, this and this thread I tried to find an answer on how to set the margins on a single view. However, I was wondering if there isn't an easier way. I'll explain why I rather wouldn't want to use this approach:

I have a custom Button which extends Button. If the background is set to something else than the default background (by calling either setBackgroundResource(int id) or setBackgroundDrawable(Drawable d)), I want the margins to be 0. If I call this:

public void setBackgroundToDefault() {
    backgroundIsDefault = true;
    super.setBackgroundResource(android.R.drawable.btn_default);
    // Set margins somehow
}

I want the margins to reset to -3dp (I already read here how to convert from pixels to dp, so once I know how to set margins in px, I can manage the conversion myself). But since this is called in the CustomButton class, the parent can vary from LinearLayout to TableLayout, and I'd rather not have him get his parent and check the instanceof that parent. That'll also be quite inperformant, I imagine.

Also, when calling (using LayoutParams) parentLayout.addView(myCustomButton, newParams), I don't know if this adds it to the correct position (haven't tried however), say the middle button of a row of five.

Question: Is there any easier way to set the margin of a single Button programmatically besides using LayoutParams?

EDIT: I know of the LayoutParams way, but I'd like a solution that avoids handling each different container type:

ViewGroup.LayoutParams p = this.getLayoutParams();
    if (p instanceof LinearLayout.LayoutParams) {
        LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)p;
        if (_default) lp.setMargins(mc.oml, mc.omt, mc.omr, mc.omb);
        else lp.setMargins(mc.ml, mc.mt, mc.mr, mc.mb);
        this.setLayoutParams(lp);
    }
    else if (p instanceof RelativeLayout.LayoutParams) {
        RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams)p;
        if (_default) lp.setMargins(mc.oml, mc.omt, mc.omr, mc.omb);
        else lp.setMargins(mc.ml, mc.mt, mc.mr, mc.mb);
        this.setLayoutParams(lp);
    }
    else if (p instanceof TableRow.LayoutParams) {
        TableRow.LayoutParams lp = (TableRow.LayoutParams)p;
        if (_default) lp.setMargins(mc.oml, mc.omt, mc.omr, mc.omb);
        else lp.setMargins(mc.ml, mc.mt, mc.mr, mc.mb);
        this.setLayoutParams(lp);
    }
}

Because this.getLayoutParams();returns a ViewGroup.LayoutParams, which do not have the attributes topMargin, bottomMargin, leftMargin, rightMargin. The mc instance you see is just a MarginContainer which contains offset (-3dp) margins and (oml, omr, omt, omb) and the original margins (ml, mr, mt, mb).




int sizeInDP = 16;

int marginInDp = (int) TypedValue.applyDimension(
            TypedValue.COMPLEX_UNIT_DIP, sizeInDP, getResources()
                    .getDisplayMetrics());

Then

layoutParams = myView.getLayoutParams()
layoutParams.setMargins(marginInDp, marginInDp, marginInDp, marginInDp);
myView.setLayoutParams(layoutParams);

Or

LayoutParams layoutParams = new LayoutParams...
layoutParams.setMargins(marginInDp, marginInDp, marginInDp, marginInDp);
myView.setLayoutParams(layoutParams);



This method will let you set the Margin in DP

public void setMargin(Context con,ViewGroup.LayoutParams params,int dp) {

        final float scale = con.getResources().getDisplayMetrics().density;
        // convert the DP into pixel
        int pixel =  (int)(dp * scale + 0.5f); 

        ViewGroup.MarginLayoutParams s =(ViewGroup.MarginLayoutParams)params;
        s.setMargins(pixel,pixel,pixel,pixel);

        yourView.setLayoutParams(params);
}

UPDATE

You can change the parameter that suits your need.




As today, the best is probably to use Paris, a library provided by AirBnB.

Styles can then be applied like this:

Paris.style(myView).apply(R.style.MyStyle);

it also support custom view (if you extend a view) using annotations:

@Styleable and @Style



For a quick one-line setup use

((LayoutParams) cvHolder.getLayoutParams()).setMargins(0, 0, 0, 0);

but be carfull for any wrong use to LayoutParams, as this will have no if statment instance chech






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