Material Design Dialog Icons for Android — Examples & Assets

Optimizing Android Dialog Icons: Sizes, Formats, and Tips

1) Purpose & placement

• Dialog icons clarify intent (error, warning, info, success) and draw attention without overwhelming content.
• Place icons left of text or above title depending on dialog style; keep them visually secondary to the message.

2) Sizes and density guidance

• Use scalable vectors (preferred) or multiple raster sizes for density buckets.
• Common sizes (recommended as baseline visual sizes, adapt to design):
  • Small inline icon: 16–20 dp
  • Dialog title/leading icon: 24–32 dp
  • Large centered icon (illustrative): 48–64 dp
• Provide assets for Android density buckets (if using PNGs): mdpi, hdpi, xhdpi, xxhdpi, xxxhdpi with scale factors 1x, 1.5x, 2x, 3x, 4x.

3) Formats

• Preferred: Vector Drawable (XML / SVG converted to VectorDrawable) — scales crisply, smaller APK size, easy to tint.
• Acceptable raster formats: PNG (lossless) for legacy or complex bitmap art; provide density-specific versions.
• Avoid large JPGs; use PNG or webp for raster when supported (webp can reduce size).

4) Coloring and theming

• Use single-color (monochrome) or limited palette so icons are easily tintable.
• Follow Material color roles: use semantic colors (error, warning, primary, on-surface) rather than hard-coded hex.
• Support light and dark themes: use tints or provide separate assets if icon has multi-color details.

5) Accessibility & contrast

• Ensure icon contrast ratio against background meets accessibility guidelines (WCAG AA ideally >4.5:1 for small elements; use larger sizes or stronger contrast if needed).
• Provide contentDescription for screen readers; if icon is decorative and redundant with text, mark it as null (android:contentDescription=“@null”).

6) Performance and size

• Prefer VectorDrawable to reduce APK size and avoid multiple raster files.
• For animations, use AnimatedVectorDrawable or Lottie for richer motion with manageable size.
• Compress raster assets (lossless or webp) and remove unused assets.

7) Implementation tips

• Use AppCompat/Material components to automatically apply tints and theme colors.
• Inflate icons in XML via android:src or app:icon for Material dialogs; for VectorDrawables use android:drawableTint or tint attributes.
• Keep padding consistent: align icon baseline with title text or center it visually (use 8–16 dp spacing).
• Test on multiple screen sizes and densities; check dialogs stacked over different backgrounds.

8) Examples & checklist

• File types: VectorDrawable XML + optional PNGs for legacy.
• Sizes provided: 24dp, 32dp, 48dp (with density variants for PNGs).
• Theme support: tintable, dark/light-ready.
• Accessibility: contentDescription present or null if decorative; adequate contrast.
• Performance: optimized file sizes; animated icons only when meaningful.

If you want, I can generate a ready-to-use VectorDrawable template for a common dialog icon (info, warning, or error).