Android自定义控件实现圆形进度CircleProgressBar
近日有朋友问我有没有如下图效果的开源控件
相信大家无论是用ios还是android,都对这种效果不陌生,很多主流app都会有这样或类似的效果,之前也打算研究一下这类控件的代码,苦于一直不知道应该怎么搜索这种效果(就是关键词)或者所搜的结果不是自己想要的,所以就一直搁置了下来。
正好朋友需要这种效果,所以就忙里偷闲写了一个类似的、更加常见和适用范围更多的控件,效果如下图所示:
自定义上图所示效果的控件时,其实就是用canvas绘制不同效果,比如渐变圆弧背景、圆周白色分割线、中间文字等,这篇博客也根据绘制的顺序依次阐述。
1.自定义circleprogressbar,继承view,并实现响应的构造函数
代码如下:
/** * created by wangchunlei on 2016.1.16 * e-mail:wcl_android@163.com */ public class gradientprogressbar extends view { public gradientprogressbar(context context) { super(context); init(); } public gradientprogressbar(context context, attributeset attrs) { super(context, attrs); init(); } public gradientprogressbar(context context, attributeset attrs, int defstyleattr) { super(context, attrs, defstyleattr); init(); } }
其中init方法是对相关画笔进行初始化的方法,init方法代码如下:
private void init() { backcirclepaint = new paint(); backcirclepaint.setstyle(paint.style.stroke); backcirclepaint.setantialias(true); backcirclepaint.setcolor(color.ltgray); backcirclepaint.setstrokewidth(circleborderwidth); // backcirclepaint.setmaskfilter(new blurmaskfilter(20, blurmaskfilter.blur.outer)); gradientcirclepaint = new paint(); gradientcirclepaint.setstyle(paint.style.stroke); gradientcirclepaint.setantialias(true); gradientcirclepaint.setcolor(color.ltgray); gradientcirclepaint.setstrokewidth(circleborderwidth); linepaint = new paint(); linepaint.setcolor(color.white); linepaint.setstrokewidth(5); textpaint = new paint(); textpaint.setantialias(true); textpaint.settextsize(textsize); textpaint.setcolor(color.black); }
2.测量控件的宽高-onmeasure
onmeasure是自定义控件的第一步,目的就是测量得到该控件应该占有的宽高尺寸。其中onmeasure方法的代码如下:
@override protected void onmeasure(int widthmeasurespec, int heightmeasurespec) { int measurewidth = measurespec.getsize(widthmeasurespec); int measureheight = measurespec.getsize(heightmeasurespec); setmeasureddimension(math.min(measurewidth, measureheight), math.min(measurewidth, measureheight)); }
贴上onmeasure的代码后,大家估计是很少见过测量过程这么简单的onmeasure,不要介意,有兴趣的同僚们可以细化一下这个测量过程,对不同的测量模式分别进行处理和测量,让控件适配效果更好更完善!
onmeasure方法中,分别获取期望的宽度和高度,并取其中较小的尺寸作为该控件的宽和高。
3.依次绘制不同的控件组成部分。
因为控件是直接继承自view,所以不需要再处理onlayout方法,这也是自定义view的难度远小于自定义viewgroup的原因,但继承viewgroup也并不一定要重写onmeasure。
要实现如图所示的效果,需要分以下步骤依次实现
(1)绘制灰色空心圆环
(2)绘制颜色渐变的圆环
(3)绘制圆环上分割的白色线条
(4)绘制百分比文字等。
绘制过程过,后绘制的内容如果与之前绘制的内容存在交集,则后绘制的内容会覆盖掉之前绘制的内容。
按照上述步骤依次介绍
在绘制过程中,会产生以下成员变量,下文中会用到:
/*圆弧线宽*/ private float circleborderwidth = typedvalue.applydimension(typedvalue.complex_unit_dip, 20, getresources().getdisplaymetrics()); /*内边距*/ private float circlepadding = typedvalue.applydimension(typedvalue.complex_unit_dip, 20, getresources().getdisplaymetrics()); /*字体大小*/ private float textsize = typedvalue.applydimension(typedvalue.complex_unit_sp, 50, getresources().getdisplaymetrics()); /*绘制圆周的画笔*/ private paint backcirclepaint; /*绘制圆周白色分割线的画笔*/ private paint linepaint; /*绘制文字的画笔*/ private paint textpaint; /*百分比*/ private int percent = 0; /*渐变圆周颜色数组*/ private int[] gradientcolorarray = new int[]{color.green, color.parsecolor("#fe751a"), color.parsecolor("#13be23"), color.green}; private paint gradientcirclepaint;
3.1绘制灰色空心圆环
代码如下:
//1.绘制灰色背景圆环 canvas.drawarc( new rectf(circlepadding * 2, circlepadding * 2, getmeasuredwidth() - circlepadding * 2, getmeasuredheight() - circlepadding * 2), -90, 360, false, backcirclepaint);
其中,-90为绘制圆弧的起始角度,360是圆弧绘制的角度,即sweepangle.
3.2绘制颜色渐变的圆环
//2.绘制颜色渐变圆环 lineargradient lineargradient = new lineargradient(circlepadding, circlepadding, getmeasuredwidth() - circlepadding, getmeasuredheight() - circlepadding, gradientcolorarray, null, shader.tilemode.mirror); gradientcirclepaint.setshader(lineargradient); gradientcirclepaint.setshadowlayer(10, 10, 10, color.red); canvas.drawarc( new rectf(circlepadding * 2, circlepadding * 2, getmeasuredwidth() - circlepadding * 2, getmeasuredheight() - circlepadding * 2), -90, (float) (percent / 100.0) * 360, false, gradientcirclepaint);
其中,lineargradient是paint的shadow,是为了圆弧的颜色渐变效果的而需要设置的,日常开发中应用频率不高,但的确是可以实现非常理想的颜色渐变效果。
3.3绘制圆环上分割的白色线条
绘制圆弧上的白色线条时,需要进行一些简单的运算,比如线条的起始坐标startx,starty和线条的终止坐标stopx,stopy等,利用简单的三角函数还是很容易去计算出来的。
效果中,将圆弧使用白色线条平分成100分,每一个的阶级为1,可以满足int类型的百分比与效果图比例的一致。
//半径 float radius = (getmeasuredwidth() - circlepadding * 3) / 2; //x轴中点坐标 int centerx = getmeasuredwidth() / 2; //3.绘制100份线段,切分空心圆弧 for (float i = 0; i < 360; i += 3.6) { double rad = i * math.pi / 180; float startx = (float) (centerx + (radius - circleborderwidth) * math.sin(rad)); float starty = (float) (centerx + (radius - circleborderwidth) * math.cos(rad)); float stopx = (float) (centerx + radius * math.sin(rad) + 1); float stopy = (float) (centerx + radius * math.cos(rad) + 1); canvas.drawline(startx, starty, stopx, stopy, linepaint); }
3.4绘制百分比文字等
最后绘制百分比文字。
绘制文字时,为了保持文字的中心点和圆弧的原点一致,需要先测量得到要显示文字的宽度和高度,然后再进行一些简单的运算,原理不再赘述,相信大家数学一定都比我好。
//4.绘制文字 float textwidth = textpaint.measuretext(percent + "%"); int textheight = (int) (math.ceil(textpaint.getfontmetrics().descent - textpaint.getfontmetrics().ascent) + 2); canvas.drawtext(percent + "%", centerx - textwidth / 2, centerx + textheight / 4, textpaint);
最后,暴漏一个公共的方法供改变显示的百分比,代码如下:
/** * 设置百分比 * * @param percent */ public void setpercent(int percent) { if (percent < 0) { percent = 0; } else if (percent > 100) { percent = 100; } this.percent = percent; invalidate(); }
至此,所有绘制过程简述完毕,130行代码就能实现很炫酷的效果有木有?
最后,贴上项目完整代码,供懒得看实现过程的同僚们使用,o(∩_∩)o哈哈~
package com.example.myview; import android.content.context; import android.graphics.*; import android.util.attributeset; import android.util.typedvalue; import android.view.view; /** * created by wangchunlei on 2016.1.16 * e-mail:wcl_android@163.com */ public class gradientprogressbar extends view { /*圆弧线宽*/ private float circleborderwidth = typedvalue.applydimension(typedvalue.complex_unit_dip, 20, getresources().getdisplaymetrics()); /*内边距*/ private float circlepadding = typedvalue.applydimension(typedvalue.complex_unit_dip, 20, getresources().getdisplaymetrics()); /*字体大小*/ private float textsize = typedvalue.applydimension(typedvalue.complex_unit_sp, 50, getresources().getdisplaymetrics()); /*绘制圆周的画笔*/ private paint backcirclepaint; /*绘制圆周白色分割线的画笔*/ private paint linepaint; /*绘制文字的画笔*/ private paint textpaint; /*百分比*/ private int percent = 0; /*渐变圆周颜色数组*/ private int[] gradientcolorarray = new int[]{color.green, color.parsecolor("#fe751a"), color.parsecolor("#13be23"), color.green}; private paint gradientcirclepaint; public gradientprogressbar(context context) { super(context); init(); } public gradientprogressbar(context context, attributeset attrs) { super(context, attrs); init(); } public gradientprogressbar(context context, attributeset attrs, int defstyleattr) { super(context, attrs, defstyleattr); init(); } private void init() { backcirclepaint = new paint(); backcirclepaint.setstyle(paint.style.stroke); backcirclepaint.setantialias(true); backcirclepaint.setcolor(color.ltgray); backcirclepaint.setstrokewidth(circleborderwidth); // backcirclepaint.setmaskfilter(new blurmaskfilter(20, blurmaskfilter.blur.outer)); gradientcirclepaint = new paint(); gradientcirclepaint.setstyle(paint.style.stroke); gradientcirclepaint.setantialias(true); gradientcirclepaint.setcolor(color.ltgray); gradientcirclepaint.setstrokewidth(circleborderwidth); linepaint = new paint(); linepaint.setcolor(color.white); linepaint.setstrokewidth(5); textpaint = new paint(); textpaint.setantialias(true); textpaint.settextsize(textsize); textpaint.setcolor(color.black); } @override protected void onmeasure(int widthmeasurespec, int heightmeasurespec) { int measurewidth = measurespec.getsize(widthmeasurespec); int measureheight = measurespec.getsize(heightmeasurespec); setmeasureddimension(math.min(measurewidth, measureheight), math.min(measurewidth, measureheight)); } @override protected void ondraw(canvas canvas) { super.ondraw(canvas); //1.绘制灰色背景圆环 canvas.drawarc( new rectf(circlepadding * 2, circlepadding * 2, getmeasuredwidth() - circlepadding * 2, getmeasuredheight() - circlepadding * 2), -90, 360, false, backcirclepaint); //2.绘制颜色渐变圆环 lineargradient lineargradient = new lineargradient(circlepadding, circlepadding, getmeasuredwidth() - circlepadding, getmeasuredheight() - circlepadding, gradientcolorarray, null, shader.tilemode.mirror); gradientcirclepaint.setshader(lineargradient); gradientcirclepaint.setshadowlayer(10, 10, 10, color.red); canvas.drawarc( new rectf(circlepadding * 2, circlepadding * 2, getmeasuredwidth() - circlepadding * 2, getmeasuredheight() - circlepadding * 2), -90, (float) (percent / 100.0) * 360, false, gradientcirclepaint); //半径 float radius = (getmeasuredwidth() - circlepadding * 3) / 2; //x轴中点坐标 int centerx = getmeasuredwidth() / 2; //3.绘制100份线段,切分空心圆弧 for (float i = 0; i < 360; i += 3.6) { double rad = i * math.pi / 180; float startx = (float) (centerx + (radius - circleborderwidth) * math.sin(rad)); float starty = (float) (centerx + (radius - circleborderwidth) * math.cos(rad)); float stopx = (float) (centerx + radius * math.sin(rad) + 1); float stopy = (float) (centerx + radius * math.cos(rad) + 1); canvas.drawline(startx, starty, stopx, stopy, linepaint); } //4.绘制文字 float textwidth = textpaint.measuretext(percent + "%"); int textheight = (int) (math.ceil(textpaint.getfontmetrics().descent - textpaint.getfontmetrics().ascent) + 2); canvas.drawtext(percent + "%", centerx - textwidth / 2, centerx + textheight / 4, textpaint); } /** * 设置百分比 * * @param percent */ public void setpercent(int percent) { if (percent < 0) { percent = 0; } else if (percent > 100) { percent = 100; } this.percent = percent; invalidate(); } }
最后,贴上自定义控件代码(自定义控件、activity,布局文件)下载地址: android圆形进度circleprogressbar
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。
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