Streaming text

FlowStreamingText animates the reveal of text that is still arriving. Drive it with the full text received so far — as the string grows, the widget reveals characters at an adaptive speed, catching up whenever the stream runs ahead, and fast-forwards the remainder the moment streaming completes. It is the same reveal FlowMessage uses for a streaming assistant turn, available on its own for custom layouts.

Streaming

Reveal as chunks arrive

FlowStreamingText(
  // The full text received so far — grows as chunks arrive.
  text: streamedText,
  // Animates the reveal while more text may arrive;
  // flip to false to fast-forward the remainder.
  isStreaming: true,
)

There is no stream to wire: append each chunk to your string, rebuild, and the widget does the rest. When the model finishes, set isStreaming: false and the tail fast-forwards instead of crawling.

Static

With isStreaming: false from the start, the text renders statically — history messages pay no animation cost:

History renders statically

// History messages render statically, with no animation cost.
FlowStreamingText(
  text: fullText,
  isStreaming: false,
)

Key API

• text — the accumulated text; grow it as chunks arrive. A new value that doesn’t extend the old one — a regenerate, a branch switch — restarts the reveal.
• isStreaming — true animates the reveal, flipping to false fast-forwards whatever hasn’t been shown yet.
• charactersPerSecond — the baseline speed (300); the widget adapts above it whenever the stream runs ahead.
• style, textAlign — merged over the default bodyLarge in onSurface.
• In a thread you rarely reach for this directly: give FlowMessageData a status of FlowMessageStatus.streaming and FlowMessage applies the same treatment.