Hello I have bellow Button ``` lt Button android id= +id pro

Question

Hello I have bellow Button ``` lt Button android id= +id profileButton android layout width= 28dp android layout height= 28dp android layout marginStart= 200dp android layout marginTop= 7dp android background= drawable round corners avatar android text= AL android textColor= FFFFFF android onClick= profileBtnClicked android textSize= 16sp gt ``` I would like to change the `android layout marginStart` parameter based on the information i receive from `resources displayMetrics density` However I do not know how to access marginStart parameter programatically Any clues would be much appreciated

Android Mahi · Answer

you can t do that in xml you can do in the java kotlin file

Nav · Answer

Thank you for replying Do you know the exact method that allows doing this Example `val btn = FindViewById R id profilebtn ` `btn setMarginStart `

Android Mahi · Answer

```LayoutParams params = new LayoutParams LayoutParams WRAP CONTENT LayoutParams WRAP CONTENT params setMargins left top right bottom ```

Android Mahi · Answer

```button setLayoutParams params ```

Nav · Answer

Thank you Did you ever come across the top and bottom parameter being unresolved error

Android Mahi · Answer

what was that error

Android Mahi · Answer

check the type for top amp bottom

Nav · Answer

It is `Unresolved reference top` error

Android Mahi · Answer

variables are unresolved check the scope or send the whole file

Nav · Answer

Which is weird because the variables are defined inside the file

Nav · Answer

Maybe i made the wrong imports I ll check

Nav · Answer

Solved it by adding imports ```import android R attr left import android R attr right import <http android R attr top|android R attr top> import android R attr bottom```

Android Mahi · Answer

Great

Nav · Answer

I am guessing the marginStart property is equal to the left parameter here

Android Mahi · Answer

you re right

Nav · Answer

So if i want to change `marginStart = 358dp` to `marginStart = 340dp` i change `left = 340`

Nav · Answer

Alright thanks I ll give it a shot

Nav · Answer

After running I am getting a casting error for ConstraintLayout `java lang ClassCastException androidx constraintlayout widget ConstraintLayout$LayoutParams cannot be cast to android widget FrameLayout$LayoutParams`

Nav · Answer

I wonder if `FrameLayout LayoutParams` would make it work

Android Mahi · Answer

importing based on the parent layout type would be better choice

Nav · Answer

Yes changing it to `FrameLayout LayoutParams` fixed it Thank you

Nav · Answer

< Android Mahi> Just one more question If i only change the `left` parameter and keep the rest of it the same then those would default to whatever the initial XML file defined them as right So for example `android layout marginTop= 7dp ` means that top ill default to `7dp`