jfeinstein10/SlidingMenu · error · IllegalStateException

Cannot set both behindOffset and behindWidth for a…

Error message

Cannot set both behindOffset and behindWidth for a SlidingMenu

What it means

When inflating SlidingMenu from XML, the attributes behindOffset and behindWidth are mutually exclusive: the behind view's size is defined either as a fixed offset from the edge or an explicit width, never both. If both are set in the layout's styleable, the constructor throws IllegalStateException.

Solutions

1. Remove either app:behindOffset or app:behindWidth from the XML declaration
2. Keep behindOffset for margin-based layout or behindWidth for fixed-width menu
3. Set one of them programmatically via setBehindOffset()/setBehindWidth() instead of XML

Example fix

// before (XML)
app:behindOffset="100dp"
app:behindWidth="300dp"
// after (XML)
app:behindOffset="100dp"

// ensure only one of the two attributes is present in the style/attr set
if (hasBehindOffset && hasBehindWidth) throw new IllegalStateException("set only behindOffset OR behindWidth");

try { slidingMenu = new SlidingMenu(context, attrs); } catch (IllegalStateException e) { slidingMenu = new SlidingMenu(context); slidingMenu.setBehindOffset(offsetPx); }

When it happens

Trigger: Declaring both app:behindOffset and app:behindWidth on a <com.jeremyfeinstein.slidingmenu.lib.SlidingMenu> element in a layout XML, both resolving to values other than -1.

Common situations: Merging styles/themes that each set one of the two attributes; copy-pasting an example layout that already had behindOffset and then adding behindWidth; defaulting both in a style.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

• The BehindFadeDegree must be between 0.0f and 1.0f
• slideStyle must be either SLIDING_WINDOW or SLIDING_CONTENT
• This SlidingMenu appears to already be attached
• SlidingMenu mode must be LEFT, RIGHT, or LEFT_RIGHT
• ScrollScale must be between 0 and 1

AI-assisted analysis of jfeinstein10/SlidingMenu@4254feca3e (2026-09-09). Data as JSON: /api/errors/97b4b99847ca8c6a. Report an issue: GitHub.

Appendix: source

Thrown at library/src/com/jeremyfeinstein/slidingmenu/lib/SlidingMenu.java:258

			setContent(viewAbove);
		} else {
			setContent(new FrameLayout(context));
		}
		int viewBehind = ta.getResourceId(R.styleable.SlidingMenu_viewBehind, -1);
		if (viewBehind != -1) {
			setMenu(viewBehind); 
		} else {
			setMenu(new FrameLayout(context));
		}
		int touchModeAbove = ta.getInt(R.styleable.SlidingMenu_touchModeAbove, TOUCHMODE_MARGIN);
		setTouchModeAbove(touchModeAbove);
		int touchModeBehind = ta.getInt(R.styleable.SlidingMenu_touchModeBehind, TOUCHMODE_MARGIN);
		setTouchModeBehind(touchModeBehind);

		int offsetBehind = (int) ta.getDimension(R.styleable.SlidingMenu_behindOffset, -1);
		int widthBehind = (int) ta.getDimension(R.styleable.SlidingMenu_behindWidth, -1);
		if (offsetBehind != -1 && widthBehind != -1)
			throw new IllegalStateException("Cannot set both behindOffset and behindWidth for a SlidingMenu");
		else if (offsetBehind != -1)
			setBehindOffset(offsetBehind);
		else if (widthBehind != -1)
			setBehindWidth(widthBehind);
		else
			setBehindOffset(0);
		float scrollOffsetBehind = ta.getFloat(R.styleable.SlidingMenu_behindScrollScale, 0.33f);
		setBehindScrollScale(scrollOffsetBehind);
		int shadowRes = ta.getResourceId(R.styleable.SlidingMenu_shadowDrawable, -1);
		if (shadowRes != -1) {
			setShadowDrawable(shadowRes);
		}
		int shadowWidth = (int) ta.getDimension(R.styleable.SlidingMenu_shadowWidth, 0);
		setShadowWidth(shadowWidth);
		boolean fadeEnabled = ta.getBoolean(R.styleable.SlidingMenu_fadeEnabled, true);
		setFadeEnabled(fadeEnabled);
		float fadeDeg = ta.getFloat(R.styleable.SlidingMenu_fadeDegree, 0.33f);
		setFadeDegree(fadeDeg);

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