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I'm writing a custom view to be able to use custom XML attributes to set a view's margin and size based on these attributes, everything worked fine until i got to the part where children of ConstraintLayout get's their margins and size determined by custom values. The margins doesn't make any difference and the view stays on the top left corner of its parent ConstraintLayout. What could be the problem? (The Image should be 500PXs away from the screen boundaries)
if (hasCustomWidth || hasCustomHeight || hasCustomTopMargin || hasCustomRightMargin || hasCustomBottomMargin || hasCustomLeftMargin) {
if(((ViewGroup)getParent()) instanceof LinearLayout) {
LinearLayout.LayoutParams newLayoutParams = new LinearLayout.LayoutParams((int) Math.round(customWidth), (int) Math.round(customHeight));
ViewGroup.MarginLayoutParams marginLayoutParams = (ViewGroup.MarginLayoutParams) newLayoutParams;
marginLayoutParams.setMargins((int) Math.round(customLeftMargin), (int) Math.round(customTopMargin), (int) Math.round(customRightMargin), (int) Math.round(customBottomMargin));
setLayoutParams(newLayoutParams);
} else if(((ViewGroup)getParent()) instanceof ConstraintLayout) {
ConstraintLayout parentConstraintLayout = (ConstraintLayout)CustomAppCompatImageView.this.getParent();
ConstraintLayout.LayoutParams newLayoutParams = new ConstraintLayout.LayoutParams((int) Math.round(customWidth), (int) Math.round(customHeight));
ConstraintSet constraintSet = new ConstraintSet();
constraintSet.clone(parentConstraintLayout);
constraintSet.connect(CustomAppCompatImageView.this.getId(), ConstraintSet.LEFT, ConstraintSet.PARENT_ID, ConstraintSet.LEFT, 500);
constraintSet.setMargin(CustomAppCompatImageView.this.getId(), ConstraintSet.LEFT, 500);
setLayoutParams(newLayoutParams);
constraintSet.applyTo(parentConstraintLayout);
parentConstraintLayout.invalidate();
} else {
throw new RuntimeException("no listed parent LayoutParams subclass!");
}
invalidate();
}
Result:
651
margin); int marginTopPx = (int) (marginTopDp * getResources(). getDisplayMetrics(). density + 0.5f); layoutParams. setMargins(0, marginTopPx, 0, 0); recyclerView.
Applying Constraints to a Layout Once the constraint set is configured, it must be applied to a ConstraintLayout instance before it will take effect. A constraint set is applied via a call to the applyTo () method, passing through a reference to the layout object to which the settings are to be applied:
The NSLayoutAnchor class provides a fluent interface for creating constraints. To use this API, access the anchor properties on the items you want to constrain. For example, the view controller’s top and bottom layout guides have topAnchor, bottomAnchor, and heightAnchor properties.
Barriers are one of my favourite features in ConstraintLayout. A barrier is an invisible view that contains reference to the views that you wish to use to form a “barrier” against. If one of the views grows, the barrier will adjust its size to the largest height or width of the referenced items.
Back in 2016, Google introduced a new container view class called ConstraintLayout which makes this task much easier. One nice feature of the ConstraintLayout class is its ability to chain views in a horizontal or vertical sequence and then configure how those views will be distributed across the screen.
I found the solution: apparently Android doesn't take ConstraintSet.LEFT and ConstraintSet.RIGHT as proper arguments, and must be replaced with ConstraintSet.START and ConstraintSet.END.
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