在安全卫生上，经常看到有圆形的进度条在转动，效果非常好看，于是就尝试去实现一下，具体实现过程不多说了，直接上效果图，先炫耀下。
效果图：
分析：比较常见于扫描结果、进度条等场景
利用canvas.drawarc(rectf oval, float startangle, float sweepangle, boolean usecenter, paint paint)绘制圆弧
paint的一些属性定义粗细、颜色、样式等
lineargradient实现颜色的线型渐变
同样的道理，可以画出长条进度条，扇图饼图等，感兴趣可以试下..
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package com.liujing.progressviewdemo;/*** * 自定义圆弧进度条 * * @author liujing */public class progressview extends view { //分段颜色 private static final int[] section_colors = { color.green, color.yellow, color.red }; private static final string[] alarm_level = { "安全", "低危", "中危", "高危" }; private float maxcount; private float currentcount; private int score; private string crrentlevel; private paint mpaint; private paint mtextpaint; private int mwidth, mheight; public progressview(context context, attributeset attrs, int defstyleattr) { super(context, attrs, defstyleattr); init(context); } public progressview(context context, attributeset attrs) { this(context, attrs, 0); } public progressview(context context) { this(context, null); } private void init(context context) { mpaint = new paint(); mtextpaint = new paint(); } @override protected void ondraw(canvas canvas) { super.ondraw(canvas); initpaint(); rectf rectblackbg = new rectf(20, 20, mwidth - 20, mheight - 20); canvas.drawarc(rectblackbg, 0, 360, false, mpaint); mpaint.setcolor(color.black); canvas.drawtext(score + "分", mwidth / 2, mheight / 2, mtextpaint); mtextpaint.settextsize(40); if (crrentlevel != null) { canvas.drawtext(crrentlevel, mwidth / 2, mheight / 2 + 50, mtextpaint); } float section = currentcount / maxcount; if (section <= 1.0f / 3.0f) { if (section != 0.0f) { mpaint.setcolor(section_colors[0]); } else { mpaint.setcolor(color.transparent); } } else { int count = (section <= 1.0f / 3.0f * 2) ? 2 : 3; int[] colors = new int[count]; system.arraycopy(section_colors, 0, colors, 0, count); float[] positions = new float[count]; if (count == 2) { positions[0] = 0.0f; positions[1] = 1.0f - positions[0]; } else { positions[0] = 0.0f; positions[1] = (maxcount / 3) / currentcount; positions[2] = 1.0f - positions[0] * 2; } positions[positions.length - 1] = 1.0f; lineargradient shader = new lineargradient(3, 3, (mwidth - 3) * section, mheight - 3, colors, null, shader.tilemode.mirror); mpaint.setshader(shader); } canvas.drawarc(rectblackbg, 180, section * 360, false, mpaint); } private void initpaint() { mpaint.setantialias(true); mpaint.setstrokewidth((float) 40.0); mpaint.setstyle(style.stroke); mpaint.setstrokecap(cap.round); mpaint.setcolor(color.transparent); mtextpaint.setantialias(true); mtextpaint.setstrokewidth((float) 3.0); mtextpaint.settextalign(paint.align.center); mtextpaint.settextsize(50); mtextpaint.setcolor(color.black); } private int diptopx(int dip) { float scale = getcontext().getresources().getdisplaymetrics().density; return (int) (dip * scale + 0.5f * (dip >= 0 ? 1 : -1)); } public int getscore() { return score; } public string getcrrentlevel() { return crrentlevel; } public void setcrrentlevel(string crrentlevel) { this.crrentlevel = crrentlevel; } public float getmaxcount() { return maxcount; } public float getcurrentcount() { return currentcount; } public void setscore(int score) { this.score = score; if (score == 100) { this.crrentlevel = alarm_level[0]; } else if (score >= 70 && score < 100) { this.crrentlevel = alarm_level[1]; } else if (score >= 30 && score < 70) { this.crrentlevel = alarm_level[2]; } else { this.crrentlevel = alarm_level[3]; } invalidate(); } /*** * 设置最大的进度值 * * @param maxcount */ public void setmaxcount(float maxcount) { this.maxcount = maxcount; } /*** * 设置当前的进度值 * * @param currentcount */ public void setcurrentcount(float currentcount) { this.currentcount = currentcount > maxcount ? maxcount : currentcount; invalidate(); } @override protected void onmeasure(int widthmeasurespec, int heightmeasurespec) { int widthspecmode = measurespec.getmode(widthmeasurespec); int widthspecsize = measurespec.getsize(widthmeasurespec); int heightspecmode = measurespec.getmode(heightmeasurespec); int heightspecsize = measurespec.getsize(heightmeasurespec); if (widthspecmode == measurespec.exactly || widthspecmode == measurespec.at_most) { mwidth = widthspecsize; } else { mwidth = 0; } if (heightspecmode == measurespec.at_most || heightspecmode == measurespec.unspecified) { mheight = diptopx(15); } else { mheight = heightspecsize; } setmeasureddimension(mwidth, mheight); }} |
demo：progressviewdemo.rar
以上内容就是实现android自定义进度条渐变圆形的代码，希望对大家有所帮助。
