自定义开源控件的绘制实例-——价格区间图

效果如图，废话不多说，直接上代码。

import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.graphics.Rect;import android.graphics.Typeface;import android.support.annotation.NonNull;import android.text.Layout;import android.text.Spannable;import android.text.SpannableString;import android.text.StaticLayout;import android.text.TextPaint;import android.text.style.AbsoluteSizeSpan;import android.text.style.ForegroundColorSpan;import android.text.style.StyleSpan;import android.util.AttributeSet;import android.view.View;import com.zhugefang.agent.R;/** * Created by Administrator on 2016/6/20. * 价格区间view */public class PriceIntervalView extends View {    private int lowX, lowY, heightX, heightY, curX, curY;    private Paint paint, pathPaint;    private TextPaint textPaint;    private float angle;    private int radius = 10, bigRadius = 18;    private int offset = 50;    private String unit = "m²";    private int topPrice = 10, floorPrice = 0, presentPrice;    public PriceIntervalView(Context context, AttributeSet attrs) {        super(context, attrs);        paint = new Paint();        pathPaint = new Paint();        textPaint = new TextPaint();        textPaint.setTextSize(context.getResources().getDimensionPixelSize(R.dimen.micro_micro));        textPaint.setStrokeWidth(3);        paint.setAntiAlias(true);        pathPaint.setAntiAlias(true);        textPaint.setAntiAlias(true);        textPaint.setColor(getResources().getColor(R.color.color_FF878787));        paint.setColor(getResources().getColor(R.color.color_FFFA891B));        pathPaint.setColor(Color.parseColor("#FFECD5"));    }    /**     * 设置价格区间参数     *     * @param topPrice     最高价格     * @param floorPrice   最低价格     * @param presentPrice 当前价格     */    public void setIntervalParams(int topPrice, int floorPrice, int presentPrice) {        this.setIntervalParams(topPrice, floorPrice, presentPrice, "m²");    }    public void setIntervalParams(int topPrice, int floorPrice, int presentPrice, String unit) {        this.topPrice = topPrice;        this.floorPrice = floorPrice;        this.presentPrice = presentPrice;        this.unit = unit;        invalidate();    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        angle = (getHeight() - offset) / (float) getWidth();        canvas.drawLine(0, getHeight(), getWidth(), offset, paint);        lowX = getWidth() / 4;        lowY = (int) (getHeight() - lowX * angle);        heightX = getWidth() * 3 / 4;        heightY = (int) (getHeight() - heightX * angle);        Path path = new Path();        path.moveTo(lowX, lowY);        path.lineTo(lowX, offset);        path.lineTo(heightX, offset);        path.lineTo(heightX, heightY);        canvas.drawPath(path, pathPaint);        canvas.drawCircle(lowX, lowY, radius, paint);        canvas.drawCircle(heightX, heightY, radius, paint);        String floorStr = floorPrice + "元/" + unit + "\r\n最低参考价";        String topStr = topPrice + "元/" + unit + "\r\n最高参考价";        SpannableString spannableString = getSpannableString(floorStr, (floorPrice + "").length(), (floorPrice + "元/" + unit).length(),                getResources().getColor(R.color.color_FF333333), (int) textPaint.getTextSize());        StaticLayout layout = new StaticLayout(spannableString, textPaint, 300,                Layout.Alignment.ALIGN_NORMAL, 1.0F, 0.0F, true);        SpannableString spannableString1 = getSpannableString(topStr, (topPrice + "").length(), (topPrice + "元/" + unit).length(),                getResources().getColor(R.color.color_FF333333), (int) textPaint.getTextSize());        StaticLayout layout1 = new StaticLayout(spannableString1, textPaint, 300,                Layout.Alignment.ALIGN_NORMAL, 1.0F, 0.0F, true);        canvas.save();        canvas.translate(lowX, lowY + 5);        layout.draw(canvas);        canvas.translate(heightX - lowX, heightY - lowY);        layout1.draw(canvas);        canvas.restore();        calculationCurLocation(canvas);    }    @NonNull    private SpannableString getSpannableString(String floorStr, int first, int second, int color, int size) {        SpannableString spannableString = new SpannableString(floorStr);        spannableString.setSpan(new StyleSpan(Typeface.BOLD), 0, first, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);        spannableString.setSpan(new AbsoluteSizeSpan((int) (size * 1.3)), 0, first, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);        spannableString.setSpan(new ForegroundColorSpan(color), 0, second, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);        return spannableString;    }    private void calculationCurLocation(Canvas canvas) {        if (presentPrice == 0) return;        if (presentPrice < floorPrice) {            curX = (int) (lowX - (heightX - lowX) * 0.1);            curY = (int) (getHeight() - angle * curX);        } else if (presentPrice <= topPrice) {            int interval = topPrice - floorPrice;            int curInterval = presentPrice - floorPrice;            float proportion = curInterval / (float) interval;            curX = (int) (lowX + (heightX - lowX) * proportion);            curY = (int) (getHeight() - angle * curX);        } else {            curX = (int) (heightX + (heightX - lowX) * 0.1);            curY = (int) (getHeight() - angle * curX);        }        paint.setColor(Color.parseColor("#99FA891B"));        canvas.drawCircle(curX, curY, bigRadius, paint);        paint.setColor(getResources().getColor(R.color.color_FFFA891B));        canvas.drawCircle(curX, curY, radius, paint);        String text = presentPrice + "元/" + unit + "\r\n当前单价";        Rect bounds = new Rect();        String text1 = presentPrice + "元/" + unit;        textPaint.getTextBounds(text1, 0, text1.length(), bounds);        SpannableString spannableString = getSpannableString(text, (presentPrice + "").length(), (presentPrice + "元/" + unit).length(),                getResources().getColor(R.color.color_FFFA891B), (int) textPaint.getTextSize());        StaticLayout layout = new StaticLayout(spannableString, textPaint, 300,                Layout.Alignment.ALIGN_NORMAL, 1.0F, 0.0F, true);        int layoutHeight = layout.getHeight();        float measureText = textPaint.measureText(spannableString, 0, (presentPrice + "元/" + unit).length());        BitmapFactory.Options options = new BitmapFactory.Options();        options.outWidth = (int) (measureText + offset);        options.outHeight = layoutHeight + offset;        Bitmap tv_Bg = BitmapFactory.decodeResource(getResources(), R.drawable.interval_textview_bg, options).copy(Bitmap.Config.ARGB_8888, true);        float bgX = curX - tv_Bg.getWidth() / 2;        float bgY = curY - tv_Bg.getHeight() - bigRadius;        canvas.drawBitmap(tv_Bg, bgX, bgY, paint);        canvas.save();        canvas.translate(curX - measureText / 2 - 10, curY - bigRadius - layoutHeight - 10);        layout.draw(canvas);        canvas.restore();    }}