开始重新学习一下自定义View的相关知识，借鉴了一些网上的文章，目前在跟这位博主学习，大家可以关注一下

作者：红橙Darren
链接：https://www.jianshu.com/p/0a32e81c3c89
來源：简书

ArcView

实现效果

QQ截图20180323075921.png

package com.example.mylibrary.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.Rect;
import android.graphics.RectF;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;import com.example.mylibrary.R;/*** Created by renzhenming on 2018/3/22.* 圆弧形的进度条*/public class ArcView extends View{private final Paint mBackgroundPaint;private final Paint mForegroundPaint;private final Paint mTextPaint;//中间字体颜色private int mCenterTextColor = Color.RED;//中间字体大小private int mCenterTextSize = 40;//进度条宽度private float mBorderWidth = 20;//进度条已完成部分颜色private int mForegroundColor = Color.RED;//进度条进行中部分颜色private int mBackgroundColor = Color.BLUE;//总量和当前量private float mTotalPercent = 0f;private float mCurrentPercent = 0f;public ArcView(Context context) {this(context,null);}public ArcView(Context context, @Nullable AttributeSet attrs) {this(context, attrs,-1);}public ArcView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ArcView);mBackgroundColor = typedArray.getColor(R.styleable.ArcView_backgroundColor, mBackgroundColor);mForegroundColor = typedArray.getColor(R.styleable.ArcView_foregroundColor, mForegroundColor);mBorderWidth = typedArray.getDimension(R.styleable.ArcView_borderWidth,mBorderWidth);mCenterTextSize = typedArray.getDimensionPixelSize(R.styleable.ArcView_centerTextSize,mCenterTextSize);mCenterTextColor = typedArray.getColor(R.styleable.ArcView_centerTextColor,mCenterTextColor);typedArray.recycle();mBackgroundPaint = new Paint();mBackgroundPaint.setAntiAlias(true);mBackgroundPaint.setStrokeWidth(mBorderWidth);mBackgroundPaint.setColor(mBackgroundColor);//STROKE 画出来的圆弧不是封闭的，FILL是封闭的mBackgroundPaint.setStyle(Paint.Style.STROKE);mBackgroundPaint.setDither(true);//Paint.Cap.ROUND设置圆弧首尾位置是ROUND的，不是直角//Paint.Cap.SQUARE默认的是直角mBackgroundPaint.setStrokeCap(Paint.Cap.ROUND);mForegroundPaint = new Paint();mForegroundPaint.setAntiAlias(true);mForegroundPaint.setStrokeWidth(mBorderWidth);mForegroundPaint.setDither(true);mForegroundPaint.setColor(mForegroundColor);//STROKE 画出来的圆弧不是封闭的，FILL是封闭的mForegroundPaint.setStyle(Paint.Style.STROKE);//Paint.Cap.ROUND设置圆弧首尾位置是ROUND的，不是直角//Paint.Cap.SQUARE默认的是直角mForegroundPaint.setStrokeCap(Paint.Cap.ROUND);mTextPaint = new Paint();mTextPaint.setAntiAlias(true);mTextPaint.setDither(true);mTextPaint.setColor(mCenterTextColor);mTextPaint.setTextSize(mCenterTextSize);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);//如果宽度和高度不一样，取最小值，确保是个正方形int width = MeasureSpec.getSize(widthMeasureSpec);int height = MeasureSpec.getSize(heightMeasureSpec);setMeasuredDimension(width>height?height:width,width>height?height:width);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);//画背景,RectF rectF = new RectF(mBorderWidth / 2, mBorderWidth / 2, getWidth() - mBorderWidth / 2, getHeight() - mBorderWidth / 2);//false表示圆弧不闭合,绘制的宽度也要占空间，所以RectF的设置上下左右要考虑去掉宽度的一般，猜测，//绘制的时候是从边缘宽度的中心开始计算的canvas.drawArc(rectF, 135, 270, false, mBackgroundPaint);//画进行中的进度if (mTotalPercent ==0 )return;if ( mCurrentPercent > mTotalPercent){mCurrentPercent = mTotalPercent;}float sweepAngle = mCurrentPercent/mTotalPercent;canvas.drawArc(rectF,135,sweepAngle*270,false,mForegroundPaint);//画文字String s = ((int)mCurrentPercent) + "";Rect bounds = new Rect();mTextPaint.getTextBounds(s,0,s.length(),bounds);//获取文字的起始位置，文字位于控件中间，所以起始位置等于控件宽度的//一半减去文字宽度的一半int start = getWidth()/2-bounds.width()/2;Paint.FontMetrics metrics = mTextPaint.getFontMetrics();//文字高度//文字中心点距离底部的距离int dy = (int) ((metrics.bottom-metrics.top)/2-metrics.bottom);//获取基线baselineint baseLine = getHeight()/2+dy;canvas.drawText(s,start,baseLine,mTextPaint);}/*** 设置总量* @param totalProgress*/public synchronized void setTotalProgress(int totalProgress){this.mTotalPercent = totalProgress;}/*** 设置当前量* @param currentProgress*/public synchronized void setCurrentProgress(int currentProgress){this.mCurrentPercent = currentProgress;invalidate();}
}

attrs

<!--半圆弧进度条--><declare-styleable name="ArcView"><attr name="backgroundColor" format="color"/><attr name="foregroundColor" format="color"/><attr name="borderWidth" format="dimension"/><attr name="centerTextSize" format="dimension"/><attr name="centerTextColor" format="color"/></declare-styleable>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context="com.app.rzm.test.TextCustomeViewActivity"><com.example.mylibrary.view.ArcViewandroid:id="@+id/arcView"android:layout_width="match_parent"android:layout_height="match_parent" />
</LinearLayout>

测试

public class TextCustomeViewActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_text_custormer_view);final ArcView mArcView = (ArcView) findViewById(R.id.arcView);mArcView.setTotalProgress(1000);ValueAnimator animator = ValueAnimator.ofFloat(0,2000);animator.setDuration(2000);animator.start();animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {@Overridepublic void onAnimationUpdate(ValueAnimator animation) {float currentProgress = (float) animation.getAnimatedValue();mArcView.setCurrentProgress((int) currentProgress);}});}
}