Set margins in a LinearLayout programmatically

Question

I m trying to use Java  not XML  to create a LinearLayout with buttons that fill the screen  and have margins  Here is code that works without margins   LinearLayout buttonsView   new LinearLayout this   buttonsView setOrientation LinearLayout VERTICAL   for  int r   0  r  lt  6    r        Button btn   new Button this       btn setText  A         LinearLayout LayoutParams lp   new LinearLayout LayoutParams LinearLayout LayoutParams FILL PARENT  LinearLayout LayoutParams FILL PARENT      Verbose      lp weight   1 0f     This is critical  Doesn t work without it      buttonsView addView btn  lp      ViewGroup LayoutParams lp   new ViewGroup LayoutParams ViewGroup LayoutParams FILL PARENT  ViewGroup LayoutParams FILL PARENT   setContentView buttonsView  lp     So that works fine  but how on earth do you give the buttons margins so there is space between them  I tried using LinearLayout MarginLayoutParams  but that has no weight member so it s no good  And it doesn t work if you pass it lp in its constructor either   Is this impossible  Because it sure looks it  and it wouldn t be the first Android layout task you can only do in XML

User · Answer

Due to variation in device screen pixel densities its good to always use DIP unit to set margin programmatically. Like below_

//get resources
Resources r = getResources();
float pxLeftMargin = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 10, r.getDisplayMetrics());
float pxTopMargin = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 10, r.getDisplayMetrics());
float pxRightMargin = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 10, r.getDisplayMetrics());
float pxBottomMargin = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 20, r.getDisplayMetrics());

//get layout params...
LayoutParams params=new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
params.setMargins(Math.round(pxLeftMargin), Math.round(pxTopMargin), Math.round(pxRightMargin), Math.round(pxBottomMargin));

//set margin...
yourLayoutTOsetMargin.setLayoutParams(params);

Hope this will help.

User · Answer

Try this   MarginLayoutParams params    MarginLayoutParams  view getLayoutParams    params width   250  params leftMargin   50  params topMargin   50

User · Answer

To add margins directly to items  some items allow direct editing of margins   you can do   LayoutParams lp     ViewGroup  something  getLayoutParams    if  lp instanceof MarginLayoutParams           MarginLayoutParams  lp  topMargin              MarginLayoutParams  lp  leftMargin                  etc   else     Log e  MyApp    Attempted to set the margins on a class that doesn t support margins    something getClass   getName           this works without needing to know about   edit the surrounding layout  Note the  instanceof  check in case you try and run this against something that doesn t support margins

User · Answer

Here a single line Solution     LinearLayout LayoutParams  yourLinearLayout getLayoutParams    marginToAdd     int  Resources getSystem   getDisplayMetrics   density   yourDPValue

User · Answer

So that works fine  but how on earth   do you give the buttons margins so   there is space between them    You call setMargins   on the LinearLayout LayoutParams object      I tried using   LinearLayout MarginLayoutParams  but   that has no weight member so it s no   good    LinearLayout LayoutParams is a subclass of LinearLayout MarginLayoutParams  as indicated in the documentation      Is this impossible    No      it wouldn t be the first Android   layout task you can only do in XML   You are welcome to supply proof of this claim   Personally  I am unaware of anything that can only be accomplished via XML and not through Java methods in the SDK  In fact  by definition  everything has to be doable via Java  though not necessarily via SDK-reachable methods   since XML is not executable code  But  if you re aware of something  point it out  because that s a bug in the SDK that should get fixed someday

User · Answer

I have set up margins directly using below code  LinearLayout layout    LinearLayout findViewById R id yourrelative layout   LayoutParams params   new LayoutParams LayoutParams MATCH PARENT LayoutParams WRAP CONTENT               params setMargins 3  300  3  3    layout setLayoutParams params     Only thing here is to notice that LayoutParams should be imported for following package android widget RelativeLayout LayoutParams  or else there will be an error

User · Answer

Here is a little code to accomplish it   LinearLayout ll   new LinearLayout this   ll setOrientation LinearLayout VERTICAL    LinearLayout LayoutParams layoutParams   new LinearLayout LayoutParams       LinearLayout LayoutParams MATCH PARENT  LinearLayout LayoutParams WRAP CONTENT    layoutParams setMargins 30  20  30  0    Button okButton new Button this   okButton setText  some text    ll addView okButton  layoutParams

User · Answer

invalid margin     private void invalidMarginBottom         RelativeLayout LayoutParams lp    RelativeLayout LayoutParams  frameLayoutContent getLayoutParams        lp setMargins 0  0  0  0       frameLayoutContent setLayoutParams lp       you should be ware of the type of the view s viewGroup In the code above  for example I want to change the frameLayout s margin and the frameLayout s view group is a RelativeLayout so you need to covert to  RelativeLayout LayoutParams

User · Answer

MarginLayoutParams layoutParams    MarginLayoutParams  getLayoutParams     layoutParams setMargins leftMargin  topMargin  rightMargin  bottomMargin

User · Answer

Try this   LayoutParams params   new LayoutParams              LayoutParams WRAP CONTENT                    LayoutParams WRAP CONTENT            params setMargins left  top  right  bottom       yourbutton setLayoutParams params

[java] Set margins in a LinearLayout programmatically

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