千丝海阁

原文地址：http://www.deepgraysea.com/bbroundedrect.htm


import net.rim.device.api.ui.*;
import net.rim.device.api.ui.container.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.decor.*;
// Our application.
public class RoundedRectWithGradient extends UiApplication {
// Entry point.
public static void main(String[] args) {
RoundedRectWithGradient theApp = new RoundedRectWithGradient();
theApp.enterEventDispatcher();
}
// Display the rounded rect demo screen when the app starts.
public RoundedRectWithGradient() {
pushScreen(new DemoScreen());
}
// Simple demo screen with a title and a rounded rectangle with gradient.
class DemoScreen extends MainScreen {
public DemoScreen() {
super(DEFAULT_CLOSE | DEFAULT_MENU);
setTitle("Rounded Rectangle with Gradient");
VerticalFieldManager vfm = (VerticalFieldManager) getMainManager();
vfm.setBackground(BackgroundFactory.createSolidBackground(0xFFFFFF));
LabelField spacer = new LabelField("", USE_ALL_WIDTH);
vfm.add(spacer);
RoundedRectField rrField = new RoundedRectField();
vfm.add(rrField);
}
}
}
// Extending field to display a rounded rectangle with a gradient.
class RoundedRectField extends Field {
// Layout values
private static final int CURVE_X = 12; // X-axis inset of curve
private static final int CURVE_Y = 12; // Y-axis inset of curve
private static final int MARGIN = 2; // Space within component boundary
// Static colors
private static final int TEXT_COLOR = 0xFFFFFF; // White
private static final int BORDER_COLOR = 0x4A4A4A; // dark gray
private static final int BACKGROUND_COLOR = 0xFFFFFF; // White
// Point types array for rounded rectangle. Each point type
// corresponds to one of the colors in the colors array. The
// space marks the division between points on the top half of
// the rectangle and those on the bottom.
private static final byte[] PATH_POINT_TYPES = {
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_END_POINT,
Graphics.CURVEDPATH_QUADRATIC_BEZIER_CONTROL_POINT,
Graphics.CURVEDPATH_END_POINT,
};
// Colors array for rounded rectangle gradient. Each color corresponds
// to one of the points in the point types array. Top light, bottom black.
private static final int[] PATH_GRADIENT = {
0xAAAAAA, 0xAAAAAA, 0xAAAAAA, 0xAAAAAA, 0xAAAAAA, 0xAAAAAA,
0x000000, 0x000000, 0x000000, 0x000000, 0x000000, 0x000000
};
// Center our readonly field in the space we're given.
public RoundedRectField() {
super(FIELD_HCENTER | FIELD_VCENTER | READONLY);
}
// This field in this demo has a fixed height.
public int getPreferredHeight() { return 70; }
// This field in this demo has a fixed width.
public int getPreferredWidth() { return 240; }
// When layout is requested, return our height and width.
protected void layout (int width, int height) {
setExtent(getPreferredWidth(), getPreferredHeight());
}
// When painting is requested, do it ourselves.
protected void paint(Graphics g) {
// Clear this area to white background, fully opaque.
g.clear();
g.setGlobalAlpha(255);
g.setBackgroundColor(BACKGROUND_COLOR);
// Drawing within our margin.
int width = getPreferredWidth() - (MARGIN * 2);
int height = getPreferredHeight() - (MARGIN * 2);
// Compute paths for the rounded rectangle. The 1st point (0) is on the left
// side, right where the curve in the top left corner starts. So the top left
// corner is point 1. These points correspond to our static arrays.
int[] xPts = {
0, 0, CURVE_X, width - CURVE_X, width, width,
width, width, width - CURVE_X, CURVE_X, 0, 0
};
int[] yPts = {
CURVE_Y, 0, 0, 0, 0, CURVE_Y,
height - CURVE_Y, height, height, height, height, height - CURVE_Y
};
// Draw the gradient fill.
g.drawShadedFilledPath(xPts, yPts, PATH_POINT_TYPES, PATH_GRADIENT, null);
// Draw a rounded rectangle for the outline.
// I think that drawRoundRect looks better than drawPathOutline.
g.setColor(BORDER_COLOR);
g.drawRoundRect(0, 0, width, height, CURVE_X * 2, CURVE_Y * 2);
// Place some text in the center.
String someText = "Some Text";
Font font = Font.getDefault().derive(Font.PLAIN, 9, Ui.UNITS_pt);
int textWidth = font.getAdvance(someText);
int textHeight = font.getHeight();
g.setColor(TEXT_COLOR);
g.setFont(font);
g.drawText(someText, (width / 2) - (textWidth / 2) - MARGIN,(height / 2) - (textHeight / 2) - MARGIN);
}
}