Hello I have bellow Button : ```<Button android:id="@+id/profileButton" android:layout_...

# android

[Nav]

Hello

I have bellow Button :

<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" />

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]

you can’t do that in xml .. you can do in the java/kotlin file

[Nav]

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]

LayoutParams params = new LayoutParams(
            LayoutParams.WRAP_CONTENT,      
            LayoutParams.WRAP_CONTENT
    );
params.setMargins(left, top, right, bottom);

[Android Mahi]

button.setLayoutParams(params);

[Nav]

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

[Android Mahi]

what was that error ?

[Android Mahi]

check the type for top & bottom

[Nav]

It is Unresolved reference : top error

[Android Mahi]

variables are unresolved check the scope or send the whole file

[Nav]

Which is weird because the variables are defined inside the file.

[Nav]

Maybe i made the wrong imports. I'll check.

[Nav]

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]

Great

[Nav]

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

[Android Mahi]

you’re right

[Nav]

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

[Nav]

Alright thanks. I'll give it a shot.

[Nav]

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]

I wonder if FrameLayout.LayoutParams would make it work?

[Android Mahi]

importing based on the parent layout type would be better choice

[Nav]

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

[Nav]

@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 ?