Data Visualization & Status (Android)

Components for displaying data and status information on Android widgets.

LinearProgressIndicator

A horizontal progress bar.

Parameters:

• progress (number, optional): Current progress value (0.0 to 1.0). If omitted, the indicator will be indeterminate.
• color (string, optional): Color for the progress indicator.
• backgroundColor (string, optional): Color for the background track.

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CircularProgressIndicator

A circular progress indicator.

Parameters:

• color (string, optional): Color for the progress indicator.

Indeterminate Only

Due to Jetpack Compose Glance limitations, the CircularProgressIndicator on Android renders in indeterminate mode.

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ArcProgressIndicator

A determinate arc gauge: a partial ring whose stroke fills clockwise, with rounded ends and a gap at the bottom by default. Children are centered on top of the arc, so a label, an icon, or nothing goes in the middle.

Parameters:

• progress (number, optional): Fill fraction, clamped to 0.0–1.0. Defaults to 0.
• color (string, optional): Stroke color of the filled arc. Defaults to the widget theme’s progress color.
• trackColor (string, optional): Stroke color of the unfilled arc. Defaults to the widget theme’s track color; use transparent to hide the track.
• strokeWidth (number, optional): Stroke width in dp of both arcs. Defaults to 8.
• startAngle (number, optional): Angle in degrees where the arc begins. 0 is 3 o’clock and positive is clockwise. Defaults to 135.
• sweepAngle (number, optional): Total angular length of the track in degrees. 360 makes a closed ring. Defaults to 270.
• lineCap ('round' | 'butt', optional): End shape of both arcs. Defaults to 'round'.
• gradientColors (string[], optional): Sweep gradient spread across the track, starting at startAngle. Overrides color. Needs at least two colors; a single color is drawn as a solid stroke, and the gradient is ignored if any color fails to parse.

<VoltraAndroid.ArcProgressIndicator
  progress={0.75}
  color="#22C55E"
  trackColor="#1F2937"
  strokeWidth={14}
  style={{ width: 140, height: 140 }}
>
  <VoltraAndroid.Text style={{ fontSize: 28, fontWeight: 'bold' }}>75%</VoltraAndroid.Text>
</VoltraAndroid.ArcProgressIndicator>

Unlike the other two indicators, this one works on every supported Android version, because it is drawn as a bitmap rather than composed from a Glance progress primitive.

Give the component a width and a height. When you leave an axis unsized it falls back to 64 dp, which is rarely what you want, and when you give it a flex weight the parent controls both axes, so size the arc through the parent instead. Because the arc occupies one of the ten child slots a Glance Box allows, you can nest at most nine elements inside it.

Bitmap Memory

The arc is a bitmap, so it costs memory that grows with the square of its pixel size. Voltra sizes it from the smaller of the component’s width and height, multiplies by the display density clamped to 1–3.5, and caps each edge at 512 px, so one gauge costs at most 1 MiB and a typical one around a quarter of that. Identical gauges share a single bitmap, so a fixed-size gauge costs its bytes once per widget no matter how many responsive size variants it appears in; a gauge sized with '100%' resolves to a different bitmap per variant. The system caps the bitmaps of one widget instance at roughly 1.5 screens’ worth of pixels, so very large or very many arcs in a single widget remain your responsibility.

The indicator does not animate. Changing progress redraws it.