BStatusBar

Derived from: public BView

Declared in: be/interface/StatusBar.h

Library: libbe.so

Summary

A BStatusBar is a cosmetic object that graphically indicates the progress of an operation. It displays a horizontal bar that's filled with color from left to right as operation is progresses.

The label and text are abutted and aligned at the left of the bar; the trailing text and trailing label are abutted and aligned at the right of the bar.

The texts can change each time the bar is updated. The label and trailing label are set by the constructor and remain constant throughout the display, or until the object is reset for another operation.

To set the amount that the status bar is filled, you can call Update(), which lets you add a delta to the current value. The "filling" itself reflects the ratio (current_value)/(max_value), where max_value is 100.0 by default, but can be reset through SetMaxValue(). The minimum value of the bar is always 0.0.

You can call Update() directly, or invoke it indirectly (and asynchronously) by sending a B_UPDATE_STATUS_BAR message to the BStatusBar.

The Reset() function, which empties the bar can also be invoked through a message (B_RESET_STATUS_BAR).

Constructor and Destructor

BStatusBar()

	BStatusBar(BRect frame, const char *name,       const char *label = NULL, const char *trailingLabel = NULL) BStatusBar(BMessage *archive)

Initializes the BStatusBar with a label and a trailingLabel, which can both be NULL. The frame rectangle is used for its origin and width only; when the BStatusBar is attached to a window, it will be resized to a height that precisely accommodates its parts. The name argument is passed on to the BView constructor.

The object is given a B_WILL_DRAW flag and a resizing mode that keeps it glued to the left and top sides of its parent.

The default font of the BStatusBar is the system plain font, and the default color of the bar is blue (50, 150, 255). It's initial value is 0.0, the minimum, and its default maximum value is 100.0.

See also: SetMaxValue(), SetBarColor()

~BStatusBar()

	virtual ~BStatusBar()

Frees the labels and the text.

Static Functions

Instantiate()

	static BArchivable *Instantiate(BMessage *archive)

Returns a new BStatusBar object, allocated by new and created with the version of the constructor that takes a BMessage archive. However, if the archive doesn't contain data for an BStatusBar object, this function returns NULL.

See also: BArchivable::Instantiate(), instantiate_object(), Archive()

Member Functions

Archive()

	virtual status_t Archive(BMessage *archive, bool deep = true) const

Calls the inherited version of Archive(), then adds the bar color, bar height, current value, and maximum value to the BMessage archive, along with the current text, trailing text, label, and trailing label.

AttachedToWindow()

	virtual void AttachedToWindow(void)

Resizes the frame rectangle to accommodate the object's graphical parts. The width isn't altered.

This function also sets the view and low colors of the BStatusBar to match the background view color of its new parent.

BarColor() see SetBarColor()

BarHeight() see SetBarHeight()

CurrentValue() see SetMaxValue()

Draw()

	virtual void Draw(BRect updateRect)

Draws the bar, labels, and text.

Label() , TrailingLabel()

	const char *Label(void) const const char *TrailingLabel(void) const

These functions return pointers to the object's label and trailing label. The returned strings belong to the BStatusBar object and should not be altered. They can be set only on construction or when all values are reset.

See also: Reset()

MaxValue() see SetMaxValue()

MessageReceived()

	virtual void MessageReceived(BMessage *message)

Responds to B_UPDATE_STATUS_BAR and B_RESET_STATUS_BAR messages by calling the Update() and Reset() functions. Each message contains data that can be passed as arguments to the functions.

See also: BView::MessageReceived(), Update(), Reset(), "BStatusBar Messages" in the Message Protocols appendix

Reset()

	virtual void Reset(const char *label = NULL, const char *trailingLabel = NULL)

Empties the status bar, sets its current value to 0.0 and its maximum value to 100.0, deletes and erases the text and trailing text, and replaces the label and trailing label with copies of the strings passed as arguments. If either argument is NULL, the label or trailing label will also be deleted and erased.

This gets the BStatusBar ready to be reused for another operation. For example, if several large files are being downloaded, the BStatusBar could be reset for each one.

You can call this function indirectly (and asynchronously) through a B_RESET_STATUS_BAR message. If the message has an entry named "label" containing a string (B_STRING_TYPE), the string will be passed to the function as the first argument. If there's a string in an entry named "trailing_label", it will be passed as the second argument. If either entry is absent, the value for the corresponding argument will be NULL.

See also: SetText(), Update()

SetBarColor() , BarColor()

	virtual void SetBarColor(rgb_color color) rgb_color BarColor(void) const

These functions set and return the color that fills the bar to show how much of an operation has been completed. The default bar color is blue (50, 150, 255).

SetBarHeight() , BarHeight()

	virtual void SetBarHeight(float height) float BarHeight(void) const

These functions set and return the height of the bar itself, minus the text and labels. The default height is 16.0 coordinate units. The frame rectangle is adjusted to accommodate the new height, and the object is redrawn.

SetMaxValue() , MaxValue() , CurrentValue()

	virtual void SetMaxValue(float max) float MaxValue(void) const float CurrentValue(void) const

SetMaxValue() sets the maximum value of the BStatusBar, which by default is 100.0. MaxValue() returns the current maximum. The minimum value is 0.0 and cannot be changed.

CurrentValue() returns the current value of the BStatusBar. The current value is set by Update() and reset to 0.0 by Reset().

The amount of "filling" in the status bar reflects the ratio CurrentValue()/MaxValue().

See also: Update(), Reset()

SetText() , SetTrailingText() , Text() , TrailingText()

	virtual void SetText(const char *string) virtual void SetTrailingText(const char *string) const char *Text(void) const const char *TrailingText(void) const

These SetText() and SetTrailingText() functions erase the previous text or trailing text and replace them with copies of the string argument. string can be NULL. The view is automatically redrawn.

Text() and TrailingText() return pointers to the current text strings.

SetText())

TrailingLabel() see SetLabel()

TrailingText() see SetText()

Update()

	virtual void Update(float delta, const char *text = NULL, const char *trailingText = NULL)

Update() updates the BStatusBar by adding delta to its current value and resetting its text and trailing text. Passing NULL for the text or trailingText argument retains the existing string(s). The status bar is automatically redrawn.

You can call Update() indirectly through a B_UPDATE_STATUS_BAR message that contains the following fields, which correspond to the function's arguments:

Field	Type
"delta"	B_FLOAT_TYPE
"text"	B_STRING_TYPE
"trailing text"	B_STRING_TYPE

To pass a NULL string through this message, simply don't add the "text" or "trailing text" field.

Archived Fields

The Archive() function adds the following fields to its BMessage argument:

Field	Type code	Meaning
"_high"	B_FLOAT_TYPE	Status bar height.
"_bcolor"	B_INT32_TYPE	Status bar color.
"_val"	B_FLOAT_TYPE	Current value.
"_max"	B_FLOAT_TYPE	Maximum value.
"_text"	B_STRING_TYPE	Status bar text.
"_ttext"	B_STRING_TYPE	Trailing text.
"_label"	B_STRING_TYPE	Status bar label.
"_tlabel"	B_STRING_TYPE	Trailing text label.

Some of these fields may not be present if the setting they represent isn't used, or is the default value. For example, if there is no trailing text, the "_ttext" field won't be found in the archive.