Progress Bar

Progress Bar shows the completion status of a task or process. The progress can be determinate or indeterminate. Use Progress Bar to show an ongoing process that takes a noticeable time to finish.

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<vaadin-progress-bar value="0.5"></vaadin-progress-bar>
Note
Global loading indicator
A global loading indicator shows at the top of the viewport while processing a server request, after a configurable delay. You do not need to provide an explicit Progress Bar for these situations.

Modes

Determinate

Use a determinate Progress Bar when progress can be computed.

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<div style="font-family: var(--lumo-font-family); color: var(--lumo-secondary-text-color);">
  <div>Processing Financials.xlsx (50%)</div>
  <vaadin-progress-bar value="0.5"></vaadin-progress-bar>
</div>

Indeterminate

Use an indeterminate Progress Bar to show that progress is ongoing but cannot be computed.

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<div style="font-family: var(--lumo-font-family); color: var(--lumo-secondary-text-color);">
  <div>Generating report...</div>
  <vaadin-progress-bar indeterminate></vaadin-progress-bar>
</div>

Bounds and Initial Value

The progress value defaults to a range from 0 to 1, with an initial value of 0. These can be changed to any numeric values:

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<div style="font-family: var(--lumo-font-family); color: var(--lumo-secondary-text-color);">
  <div>Processing files (50/100)</div>
  <vaadin-progress-bar min="0" max="100" value="50"></vaadin-progress-bar>
</div>

Theme Variants

Progress Bar comes with three theme variants: contrast, success and error.

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<div style="width: 100%;">
  <div>Transferring files... (60/120)</div>
  <vaadin-progress-bar value="0.5" theme="contrast"></vaadin-progress-bar>
</div>

<div style="width: 100%;">
  <div>Tasks (15/20)</div>
  <vaadin-progress-bar value="0.75" theme="success"></vaadin-progress-bar>
</div>

<div style="width: 100%;">
  <div>Tasks (4/20)</div>
  <vaadin-progress-bar value="0.2" theme="error"></vaadin-progress-bar>
</div>
VariantTheme nameUsage recommendations

Success

success

* When progress is satisfactory and/or nearing completion

* Visual preference

Error

error

* When progress is unsatisfactory

* Draw the user’s attention to a stalled or failed process

Contrast

contrast

* Visual preference

Best Practices

Provide a Label

Use labels to give context to a Progress Bar. Labels can also show the progress of a determinate progress bar in text in addition to graphical representation, for example, completion percentage or number of items processed.

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<div style="font-family: var(--lumo-font-family); color: var(--lumo-secondary-text-color);">
  <div style="display: flex; justify-content: space-between;">
    <div>Processing Financials.xlsx</div>
    <div>50%</div>
  </div>

  <vaadin-progress-bar value="0.5"></vaadin-progress-bar>
</div>

State Switching

Switch from indeterminate to determinate if the progress becomes computable, and vice versa.

Estimate Completion Time

Provide estimates when possible. If a process takes approximately 20 minutes communicate that to the user.

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<div style="font-family: var(--lumo-font-family); color: var(--lumo-secondary-text-color);">
  <div>Generating report, please wait...</div>
  <vaadin-progress-bar indeterminate></vaadin-progress-bar>
  <div style="font-size: var(--lumo-font-size-xs)">
    Process can take upwards of 10 minutes
  </div>
</div>

Asynchronous Processes

If the user is waiting for a process to finish use, consider using a Notification to notify them upon its completion and/or failure. This is useful if the processing takes place “off-screen” or the user is doing other work while waiting.

Note
Avoid blocking processes
Use asynchronous processes whenever possible so as not to block the user from completing other tasks while waiting for the process to finish.

When to Use

If a back-end process takes longer than 1 second, use a Progress Bar to show to the user that something is happening, especially if it blocks the user’s workflow.

Placement

A Progress Bar’s location in the UI indicates to the user its scope and whether the surrounding UI is operable during its progression.

For example, a Vaadin application’s built-in loading indicator is placed at the top of the viewport to show that it affects the entire application. The UI is generally not operable during pending server requests.

Placing a Progress Bar in a dialog, details panel or an otherwise defined section, indicates that the process displayed is specific to that section. Depending on the user case, the user may or may not be able to interact with the UI.

ComponentUsage recommendations

Upload

Component for uploading files.