任何人都可以告诉我如何使用背景颜色增加高度来创建多行文本框。
谢谢
答案 0 :(得分：1)
public class CustomTextBox extends Manager
{
/**
* Default margins
*/
private final static int DEFAULT_LEFT_MARGIN = 10;
private final static int DEFAULT_RIGHT_MARGIN = 10;
private final static int DEFAULT_TOP_MARGIN = 5;
private final static int DEFAULT_BOTTOM_MARGIN = 5;
/**
* Default paddings
*/
private final static int DEFAULT_LEFT_PADDING = 10;
private final static int DEFAULT_RIGHT_PADDING = 10;
private final static int DEFAULT_TOP_PADDING = 5;
private final static int DEFAULT_BOTTOM_PADDING = 5;
/**
* Margins around the text box
*/
private int topMargin = DEFAULT_TOP_MARGIN;
private int bottomMargin = DEFAULT_BOTTOM_MARGIN;
private int leftMargin = DEFAULT_LEFT_MARGIN;
private int rightMargin = DEFAULT_RIGHT_MARGIN;
/**
* Padding around the text box
*/
private int topPadding = DEFAULT_TOP_PADDING;
private int bottomPadding = DEFAULT_BOTTOM_PADDING;
private int leftPadding = DEFAULT_LEFT_PADDING;
private int rightPadding = DEFAULT_RIGHT_PADDING;
/**
* Amount of empty space horizontally around the text box
*/
private int totalHorizontalEmptySpace = leftMargin + leftPadding
+ rightPadding + rightMargin;
/**
* Amount of empty space vertically around the text box
*/
private int totalVerticalEmptySpace = topMargin + topPadding
+ bottomPadding + bottomMargin;
/**
* Minimum height of the text box required to display the text entered
*/
private int minHeight = getFont().getHeight() + totalVerticalEmptySpace;
/**
* Width of the text box
*/
private int width = Display.getWidth();
/**
* Height of the text box
*/
private int height = minHeight;
/**
* Background image for the text box
*/
private EncodedImage backgroundImage;
/**
* Bitmap version of the backgroundImage.
* Needed to reduce the calculation overhead incurred by
* scaling of the given image
* and derivation of Bitmap from the
* EncodedImage every time it is needed.
*/
private Bitmap bitmapBackgroundImage;
/**
* The core element of this text box
*/
private EditField editField;
//private BasicEditField editField;
//private String entireText;
public CustomTextBox()
{
// Let the super class initialize the core
super(0);
// An edit field is the sole field of this manager.
editField = new EditField();
//editField = new CustomEditField();
add(editField);
}
public CustomTextBox(EncodedImage backgroundImage)
{
this();
setBackgroundImage(backgroundImage);
}
public void setSize(int width, int height)
{
boolean isChanged = false;
if (width > 0 // Ignore invalid width
&& this.width != width)
{
this.width = width;
isChanged = true;
}
// Ignore the specified height if it is less
// than the minimum height required to display the text.
if (height > minHeight && height != this.height)
{
this.height = height;
isChanged = true;
}
// If width/height has been changed and background image
// is available, adapt it to the new dimension
if (isChanged == true && backgroundImage != null)
{
bitmapBackgroundImage = getScaledBitmapImage(backgroundImage,
this.width - (leftMargin+rightMargin),
this.height - (topMargin+bottomMargin));
}
}
public void setWidth(int width)
{
if (width > 0 && width != this.width)
{
this.width = width;
// If background image is available, adapt it to the new width
if (backgroundImage != null)
{
bitmapBackgroundImage = getScaledBitmapImage(backgroundImage,
this.width - (leftMargin+rightMargin),
this.height - (topMargin+bottomMargin));
}
}
}
public void setHeight(int height)
{
// Ignore the specified height if it is
// less than the minimum height required to display the text.
if (height > minHeight)
{
this.height = height;
// If background image is available, adapt it to the new width
if (backgroundImage != null)
{
bitmapBackgroundImage = getScaledBitmapImage(backgroundImage,
this.width - (leftMargin+rightMargin),
this.height - (topMargin+bottomMargin));
}
}
}
public void setBackgroundImage(EncodedImage backgroundImage)
{
this.backgroundImage = backgroundImage;
// Consider the height of background image in
// calculating the height of the text box.
// setHeight() does not ensure that specified
// height will be in effect, of course, for valid reasons.
// So derivation of Bitmap image in the setHeight() method is not sure.
setHeight(backgroundImage.getHeight() + topMargin + bottomMargin);
if (bitmapBackgroundImage == null)
{
bitmapBackgroundImage = getScaledBitmapImage(backgroundImage,
this.width - (leftMargin+rightMargin),
this.height - (topMargin+bottomMargin));
}
}
/**
* Generate and return a Bitmap Image scaled according
* to the specified width and height.
*
* @param image EncodedImage object
* @param width Intended width of the returned Bitmap object
* @param height Intended height of the returned Bitmap object
* @return Bitmap object
*/
private Bitmap getScaledBitmapImage(EncodedImage image, int width, int height)
{
// Handle null image
if (image == null)
{
return null;
}
int currentWidthFixed32 = Fixed32.toFP(image.getWidth());
int currentHeightFixed32 = Fixed32.toFP(image.getHeight());
int requiredWidthFixed32 = Fixed32.toFP(width);
int requiredHeightFixed32 = Fixed32.toFP(height);
int scaleXFixed32 = Fixed32.div(currentWidthFixed32, requiredWidthFixed32);
int scaleYFixed32 = Fixed32.div(currentHeightFixed32, requiredHeightFixed32);
image = image.scaleImage32(scaleXFixed32, scaleYFixed32);
return image.getBitmap();
}
protected void sublayout(int width, int height)
{
// We have one and only child - the edit field.
// Place it at the appropriate place.
Field field = getField(0);
layoutChild(field, this.width - totalHorizontalEmptySpace,
this.height - totalVerticalEmptySpace);
setPositionChild(field, leftMargin+leftPadding, topMargin+topPadding);
setExtent(this.width, this.height);
}
public void setTopMargin(int topMargin)
{
this.topMargin = topMargin;
}
public void setBottomMargin(int bottomMargin)
{
this.bottomMargin = bottomMargin;
}
protected void paint(Graphics graphics)
{
// Draw background image if available, otherwise draw a rectangle
if (bitmapBackgroundImage == null)
{
//graphics.drawRect(leftMargin, topMargin,
// width - (leftMargin+rightMargin),
//height - (topMargin+bottomMargin));
graphics.drawRoundRect(leftMargin, topMargin,
width - (leftMargin+rightMargin),
height - (topMargin+bottomMargin), 5, 5);
}
else
{
graphics.drawBitmap(leftMargin, topMargin,
width - (leftMargin+rightMargin),
height - (topMargin+bottomMargin),
bitmapBackgroundImage, 0, 0);
}
// Determine the rightward text that can fit into the visible edit field
EditField ef = (EditField)getField(0);
String entireText = ef.getText();
boolean longText = false;
String textToDraw = "";
Font font = getFont();
int availableWidth = width - totalHorizontalEmptySpace;
if (font.getAdvance(entireText) <= availableWidth)
{
textToDraw = entireText;
}
else
{
int endIndex = entireText.length();
for (int beginIndex = 1; beginIndex < endIndex; beginIndex++)
{
textToDraw = entireText.substring(beginIndex);
if (font.getAdvance(textToDraw) <= availableWidth)
{
longText = true;
break;
}
}
}
if (longText == true)
{
// Force the edit field display only the truncated text
ef.setText(textToDraw);
// Now let the components draw themselves
super.paint(graphics);
// Return the text field its original text
ef.setText(entireText);
}
else
{
super.paint(graphics);
}
}
public int getPreferredWidth()
{
return width;
}
public int getPreferredHeight()
{
return height;
}
protected boolean keyChar(char ch, int status, int time)
{
if (ch == Characters.ENTER)
{
return true;
}
else
{
return super.keyChar(ch, status, time);
}
}
public String getText()
{
return ((EditField)getField(0)).getText();
}
public void setText(final String text)
{
((EditField)getField(0)).setText(text);
}
}
答案 1 :(得分：0)
您可以在API中使用EditField并通过以下方式为其指定背景：
yourEditField.setBackground(yourBackground);