The ProgressBar is typically used to display the progress of a long running
operation. It provides a visual clue that processing is underway. The
ProgressBar can be used in two different modes: percentage mode and activity
mode.
When an application can determine how much work needs to take place (e.g.
read a fixed number of bytes from a file) and can monitor its progress, it
can use the ProgressBar in percentage mode and the user sees a growing bar
indicating the percentage of the work that has been completed. In this mode,
the application is required to call
setFraction(double)
periodically
to update the progress bar.
When an application has no accurate way of knowing the amount of work to do,
it can use the ProgressBar in activity mode, which shows activity by a block
moving back and forth within the progress area. In this mode, the application
is required to call
pulse()
periodically to update the progress bar.
There is quite a bit of flexibility provided to control the appearance of the
ProgressBar. Functions are provided to control the orientation of the bar,
optional text can be displayed along with the bar, and the step size used in
activity mode can be set.
getEllipsize
public EllipsizeMode getEllipsize()
Returns the ellipsizing position.
getFraction
public double getFraction()
Returns the current value of the display. This value will be returned as
a value between 0.0 and 1.0.
getProgressBar
public static ProgressBar getProgressBar(Handle handle)
Internal static factory method to be used by Java-Gnome only.
getType
public static Type getType()
Retrieve the runtime type used by the GLib library.
- getType in interface Widget
pulse
public void pulse()
Indicates that some progress is made, but you don't know how much. Causes
the progress bar to enter "activity mode," where a block bounces back and
forth. Each call to pulse() causes the block to move by a little bit (the
amount of movement per pulse is determined by
setPulseStep(double)
).
setEllipsize
public void setEllipsize(EllipsizeMode mode)
Sets the mode used to ellipsize (add an ellipsis: "...") the text if
there is not enough space to render the entire string.
setFraction
public void setFraction(double fraction)
Causes the progress bar to "fill in" the given fraction of the bar. The
fraction should be between 0.0 and 1.0, inclusive. Any value less than
0.0 will be considered as 0.0, and any value bigger than 1.0 will be
considered as 1.0. The reason why this is done is because Java has a
strict implementation of doubles and floats, and sometimes that can cause
unwanted rounding of numbers.
For example, you may think '0.9 + 0.1 = 1.0', but the fact is that could
actually result in 1.00001, or anything like that.
fraction
- The fraction of the progress bar which should be filled in
setOrientation
public void setOrientation(ProgressBarOrientation orientation)
Causes the progress bar to switch to a different orientation
(left-to-right, right-to-left, top-to-bottom, or bottom-to-top).
setPulseStep
public void setPulseStep(double fraction)
Sets the fraction of total progress bar length to move the bouncing block
for each call to
pulse()
.
fraction
- fraction between 0.0 and 1.0
setText
public void setText(String text)
Causes the given text to appear superimposed on the progress bar.
text
- The string to appear on the progress bar