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In this section, we'll look at creating progress meters.
A progress meter is a bar that indicates how much of a task has been completed. You typically see it when downloading files or when performing a lengthy operation. XUL has a progress meter element which can be used to create these. There are two types of progress meters: determinate and undeterminate.
Determinate progress meters are used when you know the length of time that an operation will take. The progress meter will fill up and, once full, the operation should be finished. This can be used for the download file dialog as the size of the file is known.
Undeterminate progress meters are used when you do not know the length of time of an operation. In Mozilla, the progress meter will look like a spinning barber pole, and will animate like one.
Determinate progress meter:
Undeterminate progress meter:
The progress meter has the following syntax:
<progressmeter id="identifier" mode="determined" value="0%"/>
The attributes are as follows:
Let's add a progress meter to our find file dialog. We would normally put an undeterministic progress meter as we don't know how many files we'll be searching or how long the search will take. However, we'll add a normal one for now as an animating one can be distracting during development. The progress meter would normally only appear while the search is taking place. We'll add a script later to turn it on and off.
<hbox> <progressmeter value="50%" style="margin: 4px;"/> <spacer flex="1"/>
The value has been set to 50% so that we can see the meter on the window. A margin has been set to 4 pixels so that it is separated from the edge of the window. As was stated earlier, we only want the progress bar to be displayed while the search was occuring. A script will show and hide it as necessary.
(Next) Next, we'll look at how to create a scroll bar.
Find files example so far: Source View