Hi all,
According to the book I am learning from the following code should
create a sad looking, but working, compass. All I have managed to get
is the sad lookout of it. The compass draws correctly but doesn't
rotate. I am testing it on a real device with a accelerometer. The
rest of the files in the project have nothing to do with the rotation.
Everything happens in this class. Could anyone point me to my mistake?
Any help would be appreciated.
package com.raghavsood.compass;
import android.content.Context;
import android.graphics.*;
import android.view.*;
import android.util.AttributeSet;
import android.content.res.Resources;
public class CompassView extends View {
private Paint markerPaint;
private Paint textPaint;
private Paint circlePaint;
private String northString;
private String eastString;
private String southString;
private String westString;
private int textHeight;
private float bearing;
public void setBearing(float _bearing) {
bearing = _bearing;
}
public float getBearing() {
return bearing;
}
public CompassView(Context context) {
super(context);
initCompassView();
}
public CompassView(Context context, AttributeSet attrs) {
super(context, attrs);
initCompassView();
}
public CompassView(Context context,
AttributeSet ats,
int defaultStyle) {
super(context, ats, defaultStyle);
initCompassView();
}
protected void initCompassView() {
setFocusable(true);
Resources r = this.getResources();
circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
circlePaint.setColor(r.getColor(R.color.background_color));
circlePaint.setStrokeWidth(1);
circlePaint.setStyle(Paint.Style.FILL_AND_STROKE);
northString = r.getString(R.string.cardinal_north);
eastString = r.getString(R.string.cardinal_east);
southString = r.getString(R.string.cardinal_south);
westString = r.getString(R.string.cardinal_west);
textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
textPaint.setColor(r.getColor(R.color.text_color));
textHeight = (int)textPaint.measureText("yY");
markerPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
markerPaint.setColor(r.getColor(R.color.marker_color));
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// The compass is a circle that fills as much space as possible.
// Set the measured dimensions by figuring out the shortest boundary,
// height or width.
int measuredWidth = measure(widthMeasureSpec);
int measuredHeight = measure(heightMeasureSpec);
int d = Math.min(measuredWidth, measuredHeight);
setMeasuredDimension(d, d);
}
private int measure(int measureSpec) {
int result = 0;
// Decode the measurement specifications.
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.UNSPECIFIED) {
// Return a default size of 200 if no bounds are specified.
result = 200;
} else {
// As you want to fill the available space
// always return the full available bounds.
result = specSize;
}
return result;
}
@Override
protected void onDraw(Canvas canvas) {
int px = getMeasuredWidth() / 2;
int py = getMeasuredHeight() /2 ;
int radius = Math.min(px, py);
// Draw the background
canvas.drawCircle(px, py, radius, circlePaint);
// Rotate our perspective so that the ‘top’ is
// facing the current bearing.
canvas.save();
canvas.rotate(-bearing, px, py);
int textWidth = (int)textPaint.measureText("W");
int cardinalX = px-textWidth/2;
int cardinalY = py-radius+textHeight;
// Draw the marker every 15 degrees and text every 45.
for (int i = 0; i < 24; i++) {
// Draw a marker.
canvas.drawLine(px, py-radius, px, py-radius+10, markerPaint);
canvas.save();
canvas.translate(0, textHeight);
// Draw the cardinal points
if (i % 6 == 0) {
String dirString = "";
switch (i) {
case(0) : {
dirString = northString;
int arrowY = 2*textHeight;
canvas.drawLine(px, arrowY, px-5, 3*textHeight,
markerPaint);
canvas.drawLine(px, arrowY, px+5, 3*textHeight,
markerPaint);
break;
}
case(6) : dirString = eastString; break;
case(12) : dirString = southString; break;
case(18) : dirString = westString; break;
}
canvas.drawText(dirString, cardinalX, cardinalY, textPaint);
}
else if (i % 3 == 0) {
// Draw the text every alternate 45deg
String angle = String.valueOf(i*15);
float angleTextWidth = textPaint.measureText(angle);
int angleTextX = (int)(px-angleTextWidth/2);
int angleTextY = py-radius+textHeight;
canvas.drawText(angle, angleTextX, angleTextY, textPaint);
}
canvas.restore();
canvas.rotate(15, px, py);
}
canvas.restore();
}
}
Thanks
--
Raghav Sood
http://www.raghavsood.com/
http://www.androidappcheck.com/
http://www.telstop.tel/
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