我们走肾不走心好吗
本文实例为大家分享了android绘制仪表盘指针刻度的具体代码，供大家参考，具体内容如下
不废话,先看效果图:
表盘的绘制重点有两点:
1.表盘刻度的绘制
2.表盘指针旋转到指定刻度的实现
表盘刻度的绘制
刻度的绘制可以采用画线.然后循环旋转画布的方式实现,我这里通过绘制弧线,第一个刻度占1度,与第二个刻度的间距是2度,那么第二个刻度的起始角度为第一个刻度的起始角度+1度+间距2度,以此类推,循环绘制,完成刻度的绘制.实现代码如下:
//绘制刻度线,通过两次不同大小圆的遮罩,达到刻度的长短粗细效果
rectf oval3 = new rectf(20, 20, sidelength-20, sidelength-20);//sidelength表盘控件的边长
float i1 = (270.0f-110) / 99;//第一次绘制细刻度线没有绘制粗刻度线,一共空缺10度所以-110
float startangle = 135;
arraylist<float> floats = new arraylist<>();
for (int i = 0; i < 100; i++) {
if (string.valueof(i+1).contains("0")||i==0){
floats.add(startangle);
startangle = startangle+i1+2;
}else{
canvas.drawarc(oval3, startangle, 1, true, paint2);
startangle = startangle+i1+1;
}
}
canvas.drawcircle(sidelength/2, sidelength/2, sidelength/2-40, paint1);
for (int i = 0; i < floats.size(); i++) {//循环绘制粗刻度线
canvas.drawarc(oval3, floats.get(i), 2, true, quenlinepaint);
}
canvas.drawcircle(sidelength/2, sidelength/2, sidelength/2-50, paint1);
表盘指针旋转到指定刻度的实现
1、方式一:绘制一条直线,通过旋转画布的方式实现指针的旋转效果
canvas.save();//先保存之前的 canvas.rotate(row,200, 200);//延中心点旋转角度 canvas.drawline(200,200,200,390,paint);//画线 canvas.restore();//恢复
2、方式二:通过圆函数,计算旋转任意角度后的圆上一点的坐标,然后绘制圆心到圆上一点的半径,就是指针的位置
x1 = x0 + r * cos(ao * 3.14 /180 ) y1 = y0 + r * sin(ao * 3.14 /180 ) float linex = (float)(200+170*math.cos(row*3.14f/180)); float liney = (float)(200+170*math.sin(row*3.14f/180)); canvas.drawline(200,200,linex,liney,paint);
这里我采用的原理与方式一类似,只不过绘制的不是简单的直线而是多边形位图
canvas.save(); canvas.rotate(row,sidelength/2, sidelength/2); canvas.drawbitmap(bmp,sidelength/2-10,sidelength/2-60,paintwendu); canvas.restore();
提供公开方法,调用使指针旋转起来:
/**
*
* @param minnumb 表盘最小值
* @param maxnumb 最大值
* @param temp 实际温度
*/
public void setdata(float minnumb,float maxnumb,float temp){
this.minnumb = minnumb;//
this.maxnumb = maxnumb;//
span = maxnumb-minnumb;//跨度
this.temp = temp;
float v = 100.0f / span;
row = 2.7f*(temp-minnumb)*v+45; //计算出的旋转角度,由于前面绘制指针控件的角度是垂直向下的,表盘的起始角度是135度,所有加45度
postinvalidate();//子线程模拟调用此方法重绘
}
在activity中开启一个线程,模拟温度数据实时变化,调用上面的方法,最终效果如开头展示:
new thread(new runnable() {
@override
public void run() {
for (int i = 0; i < 1000; i++) {
random random = new random();
int i1 = random.nextint(3);
test.setdata(30,60,i1+ 40f);//温度区间30-60,实时温度i1+40
test2.setdata(30,60,i1 + 38f);
test3.setdata(30,60,i1 + 44f);
test4.setdata(30,60,i1 + 55f);
try {
thread.sleep(1000);
} catch (interruptedexception e) {
e.printstacktrace();
}
}
}
}).start();
完整代码如下,复制可用:
public class meterview extends view {
private int prewidth;
private int preheight;
private paint quenlinepaint;
private paint paint1;
private paint paint2;
private float row;
private float temp;
private bitmap bmp;
private paint paintpoint;
private paint paintdu;
private paint paintwendu;
private path pathdu;
private int sidelength;
private shader mshader;
private float minnumb;
private float maxnumb;
private float span;
public meterview(context context) {
this(context, null);
}
public meterview(context context, @nullable attributeset attrs) {
this(context, attrs, -1);
}
public meterview(context context, @nullable attributeset attrs, int defstyleattr) {
super(context, attrs, defstyleattr);
quenlinepaint = new paint();
quenlinepaint.setantialias(true);
paint1 = new paint();
paint1.setcolor(color.white);
paint1.setantialias(true);
paint2 = new paint();
paint2.setantialias(true);
paintpoint = new paint();
paintpoint.setcolor(color.white);
paintpoint.setstrokewidth(10);
paintpoint.setantialias(true);
paintpoint.setstyle(paint.style.fill);
paintdu = new paint();
paintdu.settextalign(paint.align.right);
paintdu.settextsize(24);
paintdu.setantialias(true);
paintdu.setcolor(color.black);
paintwendu = new paint();
paintwendu.setantialias(true);
paintwendu.settextsize(40);
pathdu = new path();
}
@override
protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
super.onmeasure(widthmeasurespec, heightmeasurespec);
prewidth = measurespec.getsize(widthmeasurespec);
preheight = measurespec.getsize(heightmeasurespec);
int max = math.max(prewidth, preheight);
if (max<240){
sidelength = 240;//保证刻度清晰可见,设置边长下限
}else{
sidelength =max;
}
//颜色过渡,这里采用线性过渡
mshader = new lineargradient(20, sidelength, sidelength-20, sidelength,
new int[] { getresources().getcolor(r.color.green),getresources().getcolor(r.color.orang),getresources().getcolor(r.color.red)
}, null, shader.tilemode.clamp);
quenlinepaint.setshader(mshader);
paint2.setshader(mshader);
//通过path绘制棱形表盘指针
bmp = bitmap.createbitmap(20, sidelength/2+50, bitmap.config.argb_8888);
canvas canvas = new canvas(bmp);
paint paint6 = new paint();
paint6.setantialias(true);
paint6.setcolor(getresources().getcolor(r.color.blue));
path path = new path();
path.moveto(10,0);
path.lineto(20,50);
path.lineto(10,sidelength/2+50);
path.lineto(0,50);
path.lineto(10,0);
canvas.drawpath(path,paint6);
canvas.drawbitmap(bmp, 170,10, paint6);
canvas.save(canvas.all_save_flag);
canvas.restore();
}
@override
protected void ondraw(canvas canvas) {
super.ondraw(canvas);
rectf oval2 = new rectf(0, 0, sidelength, sidelength);//绘制区域
canvas.drawarc(oval2, 135, 270, true, quenlinepaint);//绘制圆弧从135度开始绘制270度
canvas.drawcircle(sidelength/2, sidelength/2, sidelength/2-20, paint1);//绘制圆,重叠达到环形边框的效果
//绘制刻度线,通过两次不同大小圆的遮罩,达到刻度的长短粗细效果
rectf oval3 = new rectf(20, 20, sidelength-20, sidelength-20);//
float i1 = (270.0f-110) / 99;
float startangle = 135;
arraylist<float> floats = new arraylist<>();
for (int i = 0; i < 100; i++) {
if (string.valueof(i+1).contains("0")||i==0){
floats.add(startangle);
startangle = startangle+i1+2;
}else{
canvas.drawarc(oval3, startangle, 1, true, paint2);
startangle = startangle+i1+1;
}
}
canvas.drawcircle(sidelength/2, sidelength/2, sidelength/2-40, paint1);
for (int i = 0; i < floats.size(); i++) {
canvas.drawarc(oval3, floats.get(i), 2, true, quenlinepaint);
}
canvas.drawcircle(sidelength/2, sidelength/2, sidelength/2-50, paint1);
//刻度数绘制,通过path确定位置,然后通过drawtextonpath绘制text
rectf oval4 = new rectf(30, 30, sidelength-30, sidelength-30);//
float pathstart = 135-20;
for (int i = 0; i < 11; i++) {
pathdu.reset();
pathdu.addarc(oval4,pathstart,25);
canvas.drawtextonpath(""+(i*(int)span/10+(int)span),pathdu,0,50,paintdu);
pathstart+=27;
}
// 绘制表盘指针,以及旋转效果的实现
// 方式一:绘制一条直线,通过旋转画布的方式实现指针的旋转效果
// canvas.save();//先保存之前的
// canvas.rotate(row,200, 200);//延中心点旋转角度
// canvas.drawline(200,200,200,390,paint);//画线
// canvas.restore();//恢复
// 方式二:通过圆函数,计算旋转任意角度后的圆上一点的坐标,然后绘制圆心到圆上一点的半径,就是指针的位置,
// x1 = x0 + r * cos(ao * 3.14 /180 )
// y1 = y0 + r * sin(ao * 3.14 /180 )
// float linex = (float)(200+170*math.cos(row*3.14f/180));
// float liney = (float)(200+170*math.sin(row*3.14f/180));
// canvas.drawline(200,200,linex,liney,paint);
// 这里我采用的原理与方式一类似,只不过绘制的不是简单的直线而是多边形位图(bitmap)
canvas.drawtext(temp+"℃",sidelength/2-50,sidelength-50,paintwendu);
canvas.save();
canvas.rotate(row,sidelength/2, sidelength/2);
canvas.drawbitmap(bmp,sidelength/2-10,sidelength/2-60,paintwendu);
canvas.drawcircle(sidelength/2,sidelength/2,6,paintpoint);
canvas.restore();
}
/**
*
* @param minnumb 表盘最小值
* @param maxnumb 最大值
* @param temp 实际温度
*/
public void setdata(float minnumb,float maxnumb,float temp){
this.minnumb = minnumb;//
this.maxnumb = maxnumb;//
span = maxnumb-minnumb;//跨度
this.temp = temp;
float v = 100.0f / span;
row = 2.7f*(temp-minnumb)*v+45; //计算出的旋转角度,由于前面绘制指针控件的角度是垂直向下的,表盘的起始角度是135度,所有加45度
postinvalidate();//子线程模拟调用此方法重绘
}
}
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。
