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java.lang.Object | +--javax.microedition.lcdui.Displayable | +--javax.microedition.lcdui.Screen | +--javax.microedition.lcdui.TextBox
The TextBox class is a Screen that allows the user to enter and edit text.
A TextBox has a maximum size, which is the maximum number of characters that can be stored in the object at any time (its capacity). This limit is enforced when the TextBox instance is constructed, when the user is editing text within the TextBox, as well as when the application program calls methods on the TextBox that modify its contents. The maximum size is the maximum stored capacity and is unrelated to the number of characters that may be displayed at any given time. The number of characters displayed and their arrangement into rows and columns are determined by the device.
The implementation may place a boundary on the maximum size, and the
maximum size actually assigned may be smaller than the application had
requested. The value actually assigned will be reflected in the value
returned by getMaxSize()
. A defensively-written
application should compare this value to the maximum size requested and be
prepared to handle cases where they differ.
The text contained within a TextBox may be more than can be displayed at one time. If this is the case, the implementation will let the user scroll to view and edit any part of the text. This scrolling occurs transparently to the application.
TextBox has the concept of input constraints that is identical to
TextField. The constraints
parameters of methods within the
TextBox class use constants defined in the TextField
class. See the description of
input constraints
in the TextField class for the definition of these constants.
Constructor Summary | |
TextBox(String title,
String text,
int maxSize,
int constraints)
Creates a new TextBox object with the given title string, initial contents, maximum size in characters, and constraints. |
Method Summary | |
void |
delete(int offset,
int length)
Deletes characters from the TextBox. |
int |
getCaretPosition()
Gets the current input position. |
int |
getChars(char[] data)
Copies the contents of the TextBox into a character array starting at index zero. |
int |
getConstraints()
Get the current input constraints of the TextBox. |
int |
getMaxSize()
Returns the maximum size (number of characters) that can be stored in this TextBox. |
String |
getString()
Gets the contents of the TextBox as a string value. |
void |
insert(char[] data,
int offset,
int length,
int position)
Inserts a subrange of an array of characters into the contents of the TextBox. |
void |
insert(String src,
int position)
Inserts a string into the contents of the TextBox. |
void |
setChars(char[] data,
int offset,
int length)
Sets the contents of the TextBox from a character array, replacing the previous contents. |
void |
setConstraints(int constraints)
Sets the input constraints of the TextBox. |
int |
setMaxSize(int maxSize)
Sets the maximum size (number of characters) that can be contained in this TextBox. |
void |
setString(String text)
Sets the contents of the TextBox as a string value, replacing the previous contents. |
int |
size()
Gets the number of characters that are currently stored in this TextBox. |
Methods inherited from class javax.microedition.lcdui.Screen |
getTicker, getTitle, setTicker, setTitle |
Methods inherited from class javax.microedition.lcdui.Displayable |
addCommand, isShown, removeCommand, setCommandListener |
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public TextBox(String title, String text, int maxSize, int constraints)
title
- the title text to be shown with the displaytext
- the initial contents of the text editing area,
null may be used to indicate no initial content.maxSize
- the maximum capacity in characters. The implementation
may limit
boundary maximum capacity and the actually assigned capacity may
me smaller than requested. A defensive application will test the
actually given
capacity with getMaxSize()
.constraints
- see
input constraintsIllegalArgumentException
- if maxSize is zero or lessIllegalArgumentException
- if the constraints parameter
is invalidIllegalArgumentException
- if text is illegal
for the specified constraintsIllegalArgumentException
- if the length of the string exceeds
the requested maximum capacity
or the maximum capacity actually assignedMethod Detail |
public String getString()
setString(java.lang.String)
public void setString(String text)
text
- the new value of the TextBox, or null if the TextBox is to
be made emptyIllegalArgumentException
- if the text is illegal
for the current
input constraintsIllegalArgumentException
- if the text would exceed the current
maximum capacitygetString()
public int getChars(char[] data)
data
- the character array to receive the valueArrayIndexOutOfBoundsException
- if the array is too short for the
contentsNullPointerException
- if data
is null
setChars(char[], int, int)
public void setChars(char[] data, int offset, int length)
data
array
starting at array index offset
and running for
length
characters.
If the data array is null, the TextBox
is set to be empty and the other parameters are ignored.data
- the source of the character dataoffset
- the beginning of the region of characters to copylength
- the number of characters to copyArrayIndexOutOfBoundsException
- if offset and length do not
specify a valid range within the data arrayIllegalArgumentException
- if the text is illegal
for the current
input constraintsIllegalArgumentException
- if the text would exceed the current
maximum capacitygetChars(char[])
public void insert(String src, int position)
Inserts a string into the contents of the TextBox. The string is
inserted just prior to the character indicated by the
position
parameter, where zero specifies the first
character of the contents of the TextBox. If position
is
less than or equal to zero, the insertion occurs at the beginning of
the contents, thus effecting a prepend operation. If
position
is greater than or equal to the current size of
the contents, the insertion occurs immediately after the end of the
contents, thus effecting an append operation. For example,
text.insert(s, text.size())
always appends the string
s to the current contents.
The current size of the contents is increased by the number of inserted characters. The resulting string must fit within the current maximum capacity.
If the application needs to simulate typing of characters it can
determining the location of the current insertion point ("caret")
using the with getCaretPosition()
method.
For example,
text.insert(s, text.getCaretPosition())
inserts the string
s at the current caret position.
src
- the String to be insertedposition
- the position at which insertion is to occurIllegalArgumentException
- if the resulting contents are illegal
for the current
input constraintsIllegalArgumentException
- if the insertion would exceed the
current maximum capacityNullPointerException
- if src
is null
public void insert(char[] data, int offset, int length, int position)
Inserts a subrange of an array of characters into the contents of
the TextBox. The offset and length parameters indicate the subrange of
the data array to be used for insertion. Behavior is otherwise
identical to insert(String, int)
.
data
- the source of the character dataoffset
- the beginning of the region of characters to copylength
- the number of characters to copyposition
- the position at which insertion is to occurArrayIndexOutOfBoundsException
- if offset and length do not
specify a valid range within the data arrayIllegalArgumentException
- if the resulting contents are illegal
for the current
input constraintsIllegalArgumentException
- if the insertion would exceed the
current maximum capacityNullPointerException
- if data
is null
public void delete(int offset, int length)
Deletes characters from the TextBox.
offset
- the beginning of the region to be deletedlength
- the number of characters to be deletedStringIndexOutOfBoundsException
- if offset and length do not
specify a valid range within the contents of the TextBoxpublic int getMaxSize()
setMaxSize(int)
public int setMaxSize(int maxSize)
maxSize
- the new maximum sizeIllegalArgumentException
- if maxSize is zero or less.getMaxSize()
public int size()
public int getCaretPosition()
public void setConstraints(int constraints)
constraints
- see
input constraintsIllegalArgumentException
- if the value of the constraints
parameter is invalidgetConstraints()
public int getConstraints()
setConstraints(int)
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