[android] How to resize a custom view programmatically?

I am coding a custom view, extended from RelativeLayout, and I want to resize it programmatically, How can I do?

the custom view Class is something like:

public ActiveSlideView(Context context, AttributeSet attr){
        super(context, attr);
        LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        if(inflater != null){       
            inflater.inflate(R.layout.active_slide, this);
        }

Android throws an exception if you fail to pass the height or width of a view. Instead of creating a new LayoutParams object, use the original one, so that all other set parameters are kept. Note that the type of LayoutParams returned by getLayoutParams is that of the parent layout, not the view you are resizing.

RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) someLayout.getLayoutParams();
params.height = 130;
someLayout.setLayoutParams(params);

try a this one:

...
View view = inflater.inflate(R.layout.active_slide, this);
view.setMinimumWidth(200);

if you are overriding onMeasure, don't forget to update the new sizes

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    setMeasuredDimension(newWidth, newHeight);
}

This works for me:

ViewGroup.LayoutParams params = layout.getLayoutParams();
params.height = customHeight;
layout.requestLayout();

I solved it this way.. I have basically a simple view inside xml file.

 View viewname = findViewById(R.id.prod_extra);
             prodExtra.getLayoutParams().height=64;

Here's a more generic version of the solution above from @herbertD :

private void resizeView(View view, int newWidth, int newHeight) { 
    try { 
        Constructor<? extends LayoutParams> ctor = view.getLayoutParams().getClass().getDeclaredConstructor(int.class, int.class); 
        view.setLayoutParams(ctor.newInstance(newWidth, newHeight));   
    } catch (Exception e) { 
        e.printStackTrace(); 
    }
}

For what it's worth, let's say you wanted to resize the view in device independent pixels (dp): -

You need to use a method called applyDimension, that's a member of the class TypedValue to convert from dp to pixels. So if I want to set the height to 150dp (say) - then I could do this:

float pixels = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 150, getResources().getDisplayMetrics());
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) someLayout.getLayoutParams();
params.height = (int) pixels;
someLayout.setLayoutParams(params);

where the expression: getResources().getDisplayMetrics() gets the screen density/resolution

In Kotlin, you can use the ktx extensions:

yourView.updateLayoutParams {
   height = <YOUR_HEIGHT>
}

If you have only two or three condition(sizes) then you can use @Overide onMeasure like

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) 
{
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

And change your size for these conditions in CustomView class easily.

This is what I did:

View myView;  
myView.getLayoutParams().height = 32;  
myView.getLayoutParams().width = 32;

If there is a view group that this view belongs to, you may also need to call yourViewGroup.requestLayout() for it to take effect.

With Kotlin and using dp unit:

myView.updateLayoutParams {
    val pixels = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 200f, context.resources.displayMetrics)
    height = pixels.toInt()
}

I used this way to increase width of custom view

customDrawingView.post(new Runnable() {
                            @Override
                            public void run() {
                                View view_instance = customDrawingView;
                                android.view.ViewGroup.LayoutParams params = view_instance
                                        .getLayoutParams();
                                int newLayoutWidth = customDrawingView
                                        .getWidth()
                                        + customDrawingView.getWidth();
                                params.width = newLayoutWidth;
                                view_instance.setLayoutParams(params);
                                screenWidthBackup = params.width;
                            }
                        });

This is how I achieved this. In Sileria answer he/she did the following:

ViewGroup.LayoutParams params = layout.getLayoutParams();
params.height = customHeight;
layout.requestLayout();

This is correct, but it expects us to give the height in pixels, but I wanted to give the dp I want the height to be so I added:

public int convertDpToPixelInt(float dp, Context context) {
    return (int) (dp * (((float) context.getResources().getDisplayMetrics().densityDpi) / 160.0f));
}

So it will look like this:

ViewGroup.LayoutParams params = layout.getLayoutParams();
params.height = convertDpToPixelInt(50, getContext());
layout.requestLayout();