Android 2高级编程 源代码

package com.paad.compass; import android.content.Context; import android.graphics.*; import android.graphics.Paint.Align; import android.graphics.Path.Direction; import android.graphics.Shader.TileMode; import android.view.*; import android.util.AttributeSet; import android.content.res.Resources; public class CompassView extends View { private enum CompassDirection { N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW, NNW } int[] borderGradientColors; float[] borderGradientPositions; int[] glassGradientColors; float[] glassGradientPositions; int skyHorizonColorFrom; int skyHorizonColorTo; int groundHorizonColorFrom; int groundHorizonColorTo; private Paint markerPaint; private Paint textPaint; private Paint circlePaint; private int textHeight; private float bearing; float pitch = 0; float roll = 0; public void setBearing(float _bearing) { bearing = _bearing; } public float getBearing() { return bearing; } public float getPitch() { return pitch; } public void setPitch(float pitch) { this.pitch = pitch; } public float getRoll() { return roll; } public void setRoll(float roll) { this.roll = roll; } 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); // Get external resources Resources r = this.getResources(); circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG); circlePaint.setColor(R.color.background_color); circlePaint.setStrokeWidth(1); circlePaint.setStyle(Paint.Style.STROKE); textPaint = new Paint(Paint.ANTI_ALIAS_FLAG); textPaint.setColor(r.getColor(R.color.text_color)); textPaint.setFakeBoldText(true); textPaint.setSubpixelText(true); textPaint.setTextAlign(Align.LEFT); textHeight = (int)textPaint.measureText("yY"); markerPaint = new Paint(Paint.ANTI_ALIAS_FLAG); markerPaint.setColor(r.getColor(R.color.marker_color)); markerPaint.setAlpha(200); markerPaint.setStrokeWidth(1); markerPaint.setStyle(Paint.Style.STROKE); markerPaint.setShadowLayer(2, 1, 1, r.getColor(R.color.shadow_color)); borderGradientColors = new int[4]; borderGradientPositions = new float[4]; borderGradientColors[3] = r.getColor(R.color.outer_border); borderGradientColors[2] = r.getColor(R.color.inner_border_one); borderGradientColors[1] = r.getColor(R.color.inner_border_two); borderGradientColors[0] = r.getColor(R.color.inner_border); borderGradientPositions[3] = 0.0f; borderGradientPositions[2] = 1-0.03f; borderGradientPositions[1] = 1-0.06f; borderGradientPositions[0] = 1.0f; glassGradientColors = new int[5]; glassGradientPositions = new float[5]; int glassColor = 245; glassGradientColors[4] = Color.argb(65, glassColor, glassColor, glassColor); glassGradientColors[3] = Color.argb(100, glassColor, glassColor, glassColor); glassGradientColors[2] = Color.argb(50, glassColor, glassColor, glassColor); glassGradientColors[1] = Color.argb(0, glassColor, glassColor, glassColor); glassGradientColors[0] = Color.argb(0, glassColor, glassColor, glassColor); glassGradientPositions[4] = 1-0.0f; glassGradientPositions[3] = 1-0.06f; glassGradientPositions[2] = 1-0.10f; glassGradientPositions[1] = 1-0.20f; glassGradientPositions[0] = 1-1.0f; skyHorizonColorFrom = r.getColor(R.color.horizon_sky_from); skyHorizonColorTo = r.getColor(R.color.horizon_sky_to); groundHorizonColorFrom = r.getColor(R.color.horizon_ground_from); groundHorizonColorTo = r.getColor(R.color.horizon_ground_to); } @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) { float ringWidth = textHeight + 4; int height = getMeasuredHeight(); int width =getMeasuredWidth(); int px = width/2; int py = height/2; Point center = new Point(px, py); int radius = Math.min(px, py)-2; RectF boundingBox = new RectF(center.x - radius, center.y - radius, center.x + radius, center.y + radius); RectF innerBoundingBox = new RectF(center.x - radius + ringWidth, center.y - radius + ringWidth, center.x + radius - ringWidth, center.y + radius - ringWidth); float innerRadius = innerBoundingBox.height()/2; RadialGradient borderGradient = new RadialGradient(px, py, radius, borderGradientColors, borderGradientPositions, TileMode.CLAMP); Paint pgb = new Paint(); pgb.setShader(borderGradient); Path outerRingPath = new Path(); outerRingPath.addOval(boundingBox, Direction.CW); canvas.drawPath(outerRingPath, pgb); LinearGradient skyShader = new LinearGradient(center.x, innerBoundingBox.top, center.x, innerBoundingBox.bottom, skyHorizonColorFrom, skyHorizonColorTo, TileMode.CLAMP); Paint skyPaint = new Paint(); skyPaint.setShader(skyShader); LinearGradient groundShader = new LinearGradient(center.x, innerBoundingBox.top, center.x, innerBoundingBox.bottom, groundHorizonColorFrom, groundHorizonColorTo, TileMode.CLAMP); Paint groundPaint = new Paint(); groundPaint.setShader(groundShader); float tiltDegree = pitch; while (tiltDegree > 90 || tiltDegree < -90) { if (tiltDegree > 90) tiltDegree = -90 + (tiltDegree - 90); if (tiltDegree < -90) tiltDegree = 90 - (tiltDegree + 90); } float rollDegree = roll; while (rollDegree > 180 || rollDegree < -180) { if (rollDegree > 180) rollDegree = -180 + (rollDegree - 180); if (rollDegree < -180) rollDegree = 180 - (rollDegree + 180); } Path skyPath = new Path(); skyPath.addArc(innerBoundingBox, -tiltDegree, (180 + (2 * tiltDegree))); canvas.rotate(-rollDegree, px, py); canvas.drawOval(innerBoundingBox, groundPaint); canvas.drawPath(skyPath, skyPaint); canvas.drawPath(skyPath, markerPaint); int markWidth = radius / 3; int startX = center.x - markWidth; int endX = center.x + markWidth; double h = innerRadius*Math.cos(Math.toRadians(90