github 下载地址 : github:https://github.com/zlz3371062/TestViewTurn；
1.开发原理：如图是由canvas 画成，主要用了canvas 的画弧 画字 画圆方法 ，同时还用了画布的转向 去定点写字和改变指针的直线，这里需要注意的是 在我们转变了坐标系的角度后必须要转回来，不然会影响到下次的画图方法
2.控件说明：这个view 向外暴露了3个方法
1. setvalue 设置控件初始化时的指针指向，如果不设置默认为0；
2.changevalue 在初始化之后想要改变指针指向需要调用这一方法
3.setspeed :设置指针转向的速度，越靠近用户的设置的指针指向值速度越快（不可超过指针值），假如超过100或者超过设置值，这此次设置无效;
源码如下 ，配置时请自行加上图片资源和color资源 或直接不使用资源 ：
package com.example.getpath;
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.RectF;
import android.os.Handler;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
/**
* @author : zlz
* @time : 2016/7/22
* @version : 1.2
* @Description : android 自定义仪表盘控件
*/
public class ViewForTurn extends View {
private Context context;
private Paint paint;// 画笔
private RectF oval; // RectF对象（圆环）
private int height;//
private int width;//
private int circleWidth;//
private int strokeWidth;// 画笔大小，可以控制圆环的宽度，可以看作小长方形的�?
private int padingwidth;// 圆环距离边缘的距离，距离越大圆环越小
private float fTurn = -120;
private Bitmap bit;
private int intZlzValue;
private float flZlzvalue;
private boolean turn = false;
private int intSpeed = 20;
public ViewForTurn(Context context) {
super(context);
this.context = context;
init();
}
public ViewForTurn(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
init();
}
public ViewForTurn(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.context = context;
init();
}
private void init() {
padingwidth = px2dip(context, 30f);// 圆环距离边缘的距离，距离越大圆环越小
strokeWidth = px2dip(context, 30f);// 画
paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(Color.RED);
oval = new RectF();
paint.setStrokeWidth(strokeWidth); // 线宽
paint.setStyle(Paint.Style.STROKE);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
height = View.MeasureSpec.getSize(heightMeasureSpec);
width = View.MeasureSpec.getSize(widthMeasureSpec);
if (width >= height) {
circleWidth = height;
} else {
circleWidth = width;
}
setMeasuredDimension(circleWidth, circleWidth);
oval.left = padingwidth; // 左边
oval.top = padingwidth; // 上边
oval.right = circleWidth - padingwidth; // 右边
oval.bottom = circleWidth - padingwidth; // 下边
// 自动旋转
handler.postDelayed(runnable, 100);
}
@Override
protected void onDraw(Canvas canvas) {
// 画弧
paint.setColor(Color.GREEN);
canvas.drawArc(oval, 148, 1f, false, paint);
for (int i = 0; i < 240; i++) {
if (i % 24 == 0) {
int _intPer = i / 24;
if (_intPer < 6) {
paint.setColor(Color.GREEN);
} else if (_intPer > 5 && _intPer < 8) {
paint.setColor(Color.MAGENTA);
} else {
paint.setColor(getResources().getColor(R.color.whatusee));
canvas.drawArc(oval, 30, 1f, false, paint);
}
canvas.drawArc(oval, 150 + i, 23f, false, paint);
}
}
// 画弧结束
// 画文字
Paint _txtPaint = new Paint();
_txtPaint.setAntiAlias(true);
_txtPaint.setColor(Color.BLACK);
_txtPaint.setTextSize(25);
_txtPaint.setStyle(Paint.Style.FILL);
canvas.drawText("50", circleWidth / 2 - px2dip(context, 10), padingwidth * 3 / 2 + px2dip(context, 20),
_txtPaint);
for (int i = 1; i < 6; i++) {
int _per = (5 - i) * 10;
String _strPer = _per + "";
canvas.rotate(-24, circleWidth / 2, circleWidth / 2);
canvas.drawText(_strPer, circleWidth / 2 - px2dip(context, 10), padingwidth * 3 / 2 + px2dip(context, 20),
_txtPaint);
}
canvas.rotate(120, circleWidth / 2, circleWidth / 2);
for (int j = 1; j < 6; j++) {
int _per = (5 + j) * 10;
String _strPer = _per + "";
canvas.rotate(24, circleWidth / 2, circleWidth / 2);
canvas.drawText(_strPer, circleWidth / 2 - px2dip(context, 10), padingwidth * 3 / 2 + px2dip(context, 20),
_txtPaint);
}
canvas.rotate(-120, circleWidth / 2, circleWidth / 2);
// 文字结束
// 画指针中心
bit = BitmapFactory.decodeResource(getResources(), R.drawable.bz);
canvas.drawCircle(circleWidth / 2, circleWidth / 2, px2dip(context, 25), _txtPaint);
canvas.rotate(fTurn, circleWidth / 2, circleWidth / 2);
canvas.drawBitmap(bit, circleWidth / 2 - px2dip(context, 7), circleWidth / 2 - px2dip(context, 90), _txtPaint);
canvas.rotate(-fTurn, circleWidth / 2, circleWidth / 2);
if (!turn) {
fTurn = -120;
}
// 画文字方框
_txtPaint.setColor(Color.GRAY);
canvas.drawRect(circleWidth / 2 - px2dip(context, 45), circleWidth / 2 + px2dip(context, 40),
circleWidth / 2 + px2dip(context, 45), circleWidth / 2 + px2dip(context, 60), _txtPaint);
String zlztxt = "当前值：" + intZlzValue;
_txtPaint.setColor(Color.BLACK);
_txtPaint.setTextSize(30);
canvas.drawText(zlztxt, circleWidth / 2 - px2dip(context, 40), circleWidth / 2 + px2dip(context, 55),
_txtPaint);
}
public static int px2dip(Context context, float pxValue) {
final float scale = context.getResources().getDisplayMetrics().density;
int zlz = (int) (pxValue / scale + 0.5f);
return (int) (pxValue * scale + 0.5f);
}
Handler handler = new Handler();
Runnable runnable = new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
turn = true;
invalidate();
handler.postDelayed(runnable, 1);
if (flZlzvalue - fTurn < intSpeed) {
fTurn = fTurn + 1;
if (fTurn > flZlzvalue) {
turn = false;
handler.removeCallbacks(runnable);
}
} else {
fTurn = fTurn + intSpeed;
}
}
};
/**
* @Description:设置指针初次指向的值
* @Parameters:整数类型0到100的闭区间
*/
public void setValue(int pzlz) {
intZlzValue = pzlz;
flZlzvalue = ((float) pzlz / 100f) * 240 - 120;
Log.e("zlz", flZlzvalue + "");
}
/**
* @Description:临时改变指针指向的值
* @Parameters:整数类型0到100的闭区间
*/
public void changeValue(int pzlz) {
intZlzValue = pzlz;
flZlzvalue = ((float) pzlz / 100f) * 240 - 120;
handler.postDelayed(runnable, 100);
invalidate();
}
/**
* @Description:设置指针转动的速度一般是越靠近指针指向的值(不大于指针指向的值) 指针转向越快
* @Parameters:是一个正整数只要设置的速度大于指针指向的值那个设置的速度就无效
*/
public void setTurnSpeed(int pspeed) {
intSpeed = pspeed;
}
}