How to customize view to realize the effect of Ring Progress Bar in Android
这篇文章主要讲解了"Android中怎么自定义view实现圆环进度条效果"，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习"Android中怎么自定义view实现圆环进度条效果"吧!
核心代码
自定义view的属性
自定义view
package com.czhappy.ringprogressdemo.view;import android.content.Context;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.RectF;import android.graphics.Typeface;import android.util.AttributeSet;import android.util.Log;import android.view.View;import com.czhappy.ringprogressdemo.R;/** * Description: * User: chenzheng * Date: 2017/2/10 0010 * Time: 15:11 */public class RingProgressBar extends View { /** * 画笔对象的引用 */ private Paint ringPaint; private Paint ringProgressPaint; private Paint txtPaint; /** * 圆环的颜色 */ private int ringColor; /** * 圆环进度的颜色 */ private int ringProgressColor; /** * 中间进度百分比的字符串的颜色 */ private int textColor; /** * 中间进度百分比的字符串的字体 */ private float textSize; /** * 圆环的宽度 */ private float ringWidth; /** * 最大进度 */ private int max; /** * 当前进度 */ private int progress; /** * 是否显示中间的进度 */ private boolean textIsDisplayable; private Context mContext; /** * 进度的风格，实心或者空心 */ private int style; public static final int STROKE = 0; public static final int FILL = 1; public RingProgressBar(Context context) { this(context, null); } public RingProgressBar(Context context, AttributeSet attrs) { this(context, attrs, 0); } public RingProgressBar(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); this.mContext = context; // 获取自定义的属性 initAttrs(context, attrs); initPaint(); } private void initAttrs(Context context, AttributeSet attrs) { TypedArray mTypedArray = context.obtainStyledAttributes(attrs, R.styleable.RingProgressBar); //获取自定义属性和默认值 ringColor = mTypedArray.getColor(R.styleable.RingProgressBar_ringColor, Color.GRAY); ringProgressColor = mTypedArray.getColor(R.styleable.RingProgressBar_ringProgressColor, Color.GREEN); textColor = mTypedArray.getColor(R.styleable.RingProgressBar_textColor, Color.GREEN); textSize = mTypedArray.getDimension(R.styleable.RingProgressBar_textSize, 16); ringWidth = mTypedArray.getDimension(R.styleable.RingProgressBar_ringWidth, 5); max = mTypedArray.getInteger(R.styleable.RingProgressBar_max, 100); textIsDisplayable = mTypedArray.getBoolean(R.styleable.RingProgressBar_textIsDisplayable, true); style = mTypedArray.getInt(R.styleable.RingProgressBar_style, 0); //资源回收 mTypedArray.recycle(); } /** * 初始化画笔 */ private void initPaint() { //圆环画笔 ringPaint = new Paint(); ringPaint.setColor(ringColor); //设置圆环的颜色 ringPaint.setStyle(Paint.Style.STROKE); //设置空心 ringPaint.setStrokeWidth(ringWidth); //设置圆环的宽度 ringPaint.setAntiAlias(true); //消除锯齿 //圆环进度画笔 ringProgressPaint = new Paint(); ringProgressPaint.setColor(ringProgressColor); //设置圆环的颜色 ringProgressPaint.setStrokeWidth(ringWidth); //设置圆环的宽度 ringProgressPaint.setAntiAlias(true); //消除锯齿 switch (style) { case STROKE: ringProgressPaint.setStyle(Paint.Style.STROKE); break; case FILL: ringProgressPaint.setStyle(Paint.Style.FILL_AND_STROKE); break; } //百分比文字画笔 txtPaint = new Paint(); txtPaint.setColor(textColor); txtPaint.setTextSize(textSize); txtPaint.setTypeface(Typeface.DEFAULT_BOLD); //设置字体 } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //圆心坐标 int mXCenter = getWidth() / 2; int mYCenter = getHeight() / 2; int radius = (int) (mXCenter - ringWidth / 2); //圆环的半径 //绘制圆环 canvas.drawCircle(mXCenter, mYCenter, radius, ringPaint); //绘制圆环进度 RectF oval = new RectF(mXCenter - radius, mYCenter - radius, mXCenter + radius, mYCenter + radius); //用于定义的圆弧的形状和大小的界限 switch (style) { case STROKE: canvas.drawArc(oval, -90, 360 * progress / max, false, ringProgressPaint); //根据进度画圆弧 break; case FILL: if (progress != 0) canvas.drawArc(oval, -90, 360 * progress / max, true, ringProgressPaint); //根据进度画圆弧 break; } //绘制百分比数字 //文字绘制 String txt = progress + "%"; //文字的长度 float mTxtWidth = txtPaint.measureText(txt, 0, txt.length()); Log.e("tag", textIsDisplayable+","+progress+(style==STROKE)); if(textIsDisplayable && progress!=0 && style==STROKE){ canvas.drawText(txt, mXCenter - mTxtWidth / 2, mYCenter+textSize/2, txtPaint); } } public synchronized int getMax() { return max; } /** * 设置进度的最大值 * @param max */ public synchronized void setMax(int max) { if(max
< 0){ throw new IllegalArgumentException("max not less than 0"); } this.max = max; } /** * 获取进度.需要同步 * @return */ public synchronized int getProgress() { return progress; } /** * 设置进度，此为线程安全控件，由于考虑多线程的问题，需要同步 * 刷新界面调用postInvalidate()能在非UI线程刷新 * @param progress */ public synchronized void setProgress(int progress) { if(progress < 0){ throw new IllegalArgumentException("progress not less than 0"); } if(progress >max){ progress = max; } if(progress
