ZoomBar 设计

 package com.example.canvasdemo;

 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.EmbossMaskFilter;
 import android.graphics.Paint;
 import android.graphics.SweepGradient;
 import android.util.AttributeSet;
 import android.view.View;
 /**
  *
  * @author liemng  QQ:859686819
  *
  */
 public class ZoomPinch extends View{

     private Paint mLinePaint;
     private Paint mPointPaint;
     private int mLineWitdh = 18;
     private int mPointPaintWitdh = 12;

     private String mForeground = "#FFFFFF";
     private String mBackground = "#ff0000";

     // 梯度渐变的填充颜色
     private int[] arcColors = new int[] { 0xFF48cbdc, 0xFF4c9fda, 0xFFeac83d,
             0xFFc7427e, 0xFF48cbdc, 0xFF48cbdc };

     public ZoomPinch(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
         initData();
     }

     public ZoomPinch(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
     }

     public ZoomPinch(Context context) {
         this(context, null);
     }

     public void initData(){
         //--绘制线段画笔
         mLinePaint = new Paint();
         //--抗锯齿
         mLinePaint.setAntiAlias(true);
         //--防抖
         mLinePaint.setDither(true);
         //--线段两端的形状
         mLinePaint.setStrokeCap(Paint.Cap.ROUND);
         // 线段的宽度
         mLinePaint.setStrokeWidth(mLineWitdh);
         //--画笔颜色
         mLinePaint.setColor(Color.parseColor("#000000"));

         //--设置光源的方向
         float[] direction = new float[]{ 1, 1, 1 };
         //--设置环境光亮度
         float light = 0.4f;
         //--选择要应用的反射等级
         float specular = 6;
         //--向mask应用一定级别的模糊
         float blur = 3.5f;
         EmbossMaskFilter emboss=new EmbossMaskFilter(direction,light,specular,blur);
         mLinePaint.setMaskFilter(emboss);

         //--绘制圆环的画笔
         mPointPaint = new Paint();
         //--抗锯齿
         mPointPaint.setAntiAlias(true);
         //--防抖
         mPointPaint.setDither(true);
         //--线段两端的形状
         mPointPaint.setStrokeCap(Paint.Cap.ROUND);
         //--线段的宽度
         mPointPaint.setStrokeWidth(mPointPaintWitdh);
         //--画笔颜色
         SweepGradient  mSweepGradient = new SweepGradient(mH/2, mW/2, arcColors, null);
         mPointPaint.setShader(mSweepGradient);
     }

     private int mH ;
     private int mW ;
     private int mMaxHight = 500;
     private int topsurplus = mLineWitdh/2 + 10;

     private int mProgres = 0;
     private float mTotalProgress = mMaxHight;

     private int inCircleR = 6;
     private int outCircleR = 14;

     private int currentLineProgress = 0;

     @Override
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         // TODO Auto-generated method stub
         super.onSizeChanged(w, h, oldw, oldh);

         mH = w;
         mW = h;
     }

     @Override
     protected void onDraw(Canvas canvas) {
         // TODO Auto-generated method stub
         super.onDraw(canvas);
         //--平移画布
         canvas.translate(0, topsurplus);
         //--绘制背景色
         mLinePaint.setColor(Color.parseColor(mBackground));
         canvas.drawLine(mW/2, mMaxHight, mW/2, 0, mLinePaint);

         //--绘制前景色
         mLinePaint.setColor(Color.parseColor(mForeground));
         canvas.drawLine(mW/2, mMaxHight, mW/2, mMaxHight - currentLineProgress, mLinePaint);

         //--绘制圆环
         mPointPaint.setStyle(Paint.Style.STROKE);
         canvas.drawCircle(mW/2, mMaxHight - currentLineProgress , outCircleR, mPointPaint);
         mPointPaint.setStyle(Paint.Style.FILL);
         canvas.drawCircle(mW/2, mMaxHight - currentLineProgress , inCircleR, mPointPaint);
     }

     public void setBackgroup(String mBackgroup){
         this.mBackground = mBackgroup;
     }

     public void setForeground(String mForeground){
         this.mForeground = mForeground;
     }

     public void setProgress(float mProgress){
         if(this.mProgres >= mTotalProgress && mProgress > 0)
             return;
         this.mProgres += mProgress;

         float percent = mProgres/mTotalProgress;

         if(percent <0){
             this.mProgres = 0;
             return;
         }
         this.currentLineProgress = (int) (percent*mMaxHight);
         invalidate();
     }

     public void setMax(float mTotalProgress){
         if(mTotalProgress < 0)
             new IllegalArgumentException("invalid args && doubi");
         this.mTotalProgress = mTotalProgress;
     }
 }

效果图如下：

左侧增加文字属性：

package com.example.canvasdemo;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.EmbossMaskFilter;
import android.graphics.Paint;
import android.graphics.Paint.FontMetrics;
import android.graphics.SweepGradient;
import android.util.AttributeSet;
import android.view.View;
/**
 *
 * @author liemng  QQ:859686819
 *
 */
public class ZoomPinch extends View{

	private Paint mLinePaint;
	private Paint mPointPaint;
	private int mLineWitdh = 18;
	private int mPointPaintWitdh = 12;

	private String mForeground = "#FFFFFF";
	private String mBackground = "#ff0000";

	private String[] mTips = new String[]{"1.0X", "2.0X", "3.0X", "4.0X"};

	// 梯度渐变的填充颜色
	private int[] arcColors = new int[] { 0xFF48cbdc, 0xFF4c9fda, 0xFFeac83d,
			0xFFc7427e, 0xFF48cbdc, 0xFF48cbdc };

	public ZoomPinch(Context context, AttributeSet attrs, int defStyleAttr) {
		super(context, attrs, defStyleAttr);
		initData();
	}

	public ZoomPinch(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public ZoomPinch(Context context) {
		this(context, null);
	}

	public void initData(){
		//--绘制线段画笔
		mLinePaint = new Paint();
		//--抗锯齿
		mLinePaint.setAntiAlias(true);
		//--防抖
		mLinePaint.setDither(true);
		//--线段两端的形状
		mLinePaint.setStrokeCap(Paint.Cap.ROUND);
		// 线段的宽度
		mLinePaint.setStrokeWidth(mLineWitdh);
		//--画笔颜色
		mLinePaint.setColor(Color.parseColor("#000000"));

		//--设置光源的方向
		float[] direction = new float[]{ 1, 1, 1 };
		//--设置环境光亮度
		float light = 0.4f;
		//--选择要应用的反射等级
		float specular = 6;
		//--向mask应用一定级别的模糊
		float blur = 3.5f;
		EmbossMaskFilter emboss=new EmbossMaskFilter(direction,light,specular,blur);
		mLinePaint.setMaskFilter(emboss);

		//--绘制圆环的画笔
		mPointPaint = new Paint();
		//--抗锯齿
		mPointPaint.setAntiAlias(true);
		//--防抖
		mPointPaint.setDither(true);
		//--线段两端的形状
		mPointPaint.setStrokeCap(Paint.Cap.ROUND);
		//--线段的宽度
		mPointPaint.setStrokeWidth(mPointPaintWitdh);
		//--画笔颜色
		SweepGradient  mSweepGradient = new SweepGradient(mH/2, mW/2, arcColors, null);
		mPointPaint.setShader(mSweepGradient);

		mTextPaint = new Paint();
		mTextPaint.setTextSize(32);
		mTextPaint.setColor(Color.parseColor("#FFFFFF"));
	}

	private int averH;

	private int mH ;
	private int mW ;
	private int mMaxHight = 500;
	private int topsurplus = mLineWitdh/2 + 10;

	private int mProgres = 0;
	private float mTotalProgress = mMaxHight;

	private int inCircleR = 6;
	private int outCircleR = 14;

	private int currentLineProgress = 0;
	private Paint mTextPaint;

	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
		super.onSizeChanged(w, h, oldw, oldh);

		mH = w;
		mW = h;
	}

	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		//--平移画布
		canvas.translate(0, topsurplus);
		//--绘制背景色
		mLinePaint.setColor(Color.parseColor(mBackground));
		canvas.drawLine(mW/2, mMaxHight, mW/2, 0, mLinePaint);

		//--绘制前景色
		mLinePaint.setColor(Color.parseColor(mForeground));
		canvas.drawLine(mW/2, mMaxHight, mW/2, mMaxHight - currentLineProgress, mLinePaint);

		//--绘制圆环
		mPointPaint.setStyle(Paint.Style.STROKE);
		canvas.drawCircle(mW/2, mMaxHight - currentLineProgress , outCircleR, mPointPaint);
		mPointPaint.setStyle(Paint.Style.FILL);
		canvas.drawCircle(mW/2, mMaxHight - currentLineProgress , inCircleR, mPointPaint);
		//--绘制左侧文字
		for (int i = 0; i < mTips.length; i++) {
			float textW = mTextPaint.measureText(mTips[i]);
			FontMetrics fontMetrics = mTextPaint.getFontMetrics();
			int textH = (int) (fontMetrics.descent - fontMetrics.ascent);
			if(i == 0){
				canvas.drawText(mTips[i], mW/2 - textW*3/2, mMaxHight, mTextPaint);
				continue;
			}
			if(i == (mTips.length -1)){
				canvas.drawText(mTips[i], mW/2 - textW*3/2, topsurplus, mTextPaint);
				continue;
			}
			averH = mMaxHight/(mTips.length -1); 

			canvas.drawText(mTips[i], mW/2 - textW*3/2, mMaxHight - topsurplus - (averH*i - textH/2) , mTextPaint);
		}

	}

	public void setBackgroup(String mBackgroup){
		this.mBackground = mBackgroup;
	}

	public void setForeground(String mForeground){
		this.mForeground = mForeground;
	}

	public void setProgress(float mProgress){
		if(this.mProgres >= mTotalProgress && mProgress > 0)
			return;
		this.mProgres += mProgress;

		float percent = mProgres/mTotalProgress;

		if(percent <0){
			this.mProgres = 0;
			return;
		}
		this.currentLineProgress = (int) (percent*mMaxHight);
		invalidate();
	}

	public void setMax(float mTotalProgress){
		if(mTotalProgress < 0)
			new IllegalArgumentException("invalid args && doubi");
		this.mTotalProgress = mTotalProgress;
	}
}

效果图如下：