Android 自定义滑动进度条

自定义进度条继承View。自定义View主要重写onMeasure()方法和onDraw()方法。onMeasure方法中主要计算控件的大小，onDraw方法绘制内容。

在计算控件大小的时候要注意测量模式。

先看下不同的测量模式下的打印结果

先设置match_parent 测量模式是EXACTLY

设置指定的大小测量模式还是EXACTLY

设置包裹内容测量模式变成了UNSPECIFIED

增加一个可滑动的父控件，测量模式变成了AT_MOST

不管是UNSPECIFIED还是AT_MOST最后MeasureSpec.getSize(widthMeasureSpec);获取的都是父控件的大小。

package com.test;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

import androidx.annotation.Nullable;

public class MyProgress extends View {

    
    private int mBackgroundColor; //背景颜色
    private RectF mBgRectF;  //背景矩形
    private Paint mBgPaint;  //bg画笔

    
    private int mProgress=0;  //当前进度
    private int mProgressColor;  //进度颜色
    private Paint mProgressPaint;  //进度画笔
    private RectF mProgressRectF;  //进度矩形

    
    private Paint mSliderPaint;  //滑块画笔
    private RectF mSliderRectF;  //滑块矩形

    
    private int mWidth;
    private int mHeight;
    private int  mRadius;

    
    private int mViewWidth;
    private int mViewHeight=0;

    
    private Bitmap circleBitmap;
    private int mBitmatWidth;
    private int mBitmatHeight;

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

    public MyProgress(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs,0);
    }

    public MyProgress(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context,attrs);
        initPaint();

    }

    private void init(Context context,AttributeSet attrs) {
        TypedArray ta=context.obtainStyledAttributes(attrs,R.styleable.MyProgress);
        mBackgroundColor=ta.getColor(R.styleable.MyProgress_myProgressBgColor,context.getResources().getColor(R.color.colorLine));
        mProgressColor=ta.getColor(R.styleable.MyProgress_myProgressColor,context.getResources().getColor(R.color.text));
        mProgress=ta.getColor(R.styleable.MyProgress_myProgress,0);
        mHeight=ta.getDimensionPixelSize(R.styleable.MyProgress_myProgressHeight,10);

        circleBitmap= BitmapFactory.decodeResource(getResources(),ta.getResourceId(R.styleable.MyProgress_myProgressImg,R.mipmap.img_test));
        mRadius=ta.getDimensionPixelSize(R.styleable.MyProgress_myProgressRadius,10);
        ta.recycle();

        mBitmatWidth = circleBitmap.getWidth();
        mBitmatHeight = circleBitmap.getHeight();
    }

    private void initPaint() {
        mBgPaint = new Paint();
        mBgPaint.setAntiAlias(true);
        mBgPaint.setColor(mBackgroundColor);
        mBgPaint.setStyle(Paint.Style.FILL);
        mBgPaint.setStrokeCap(Paint.Cap.ROUND);

        mSliderPaint = new Paint();
        mSliderPaint.setAntiAlias(true);
        mSliderPaint.setColor(mProgressColor);
        mSliderPaint.setStyle(Paint.Style.FILL);
        mSliderPaint.setStrokeCap(Paint.Cap.ROUND);

        mProgressPaint = new Paint();
        mProgressPaint.setAntiAlias(true);
        mProgressPaint.setFilterBitmap(true);//paint抗锯齿(true);
        mProgressPaint.setColor(mProgressColor);
        mProgressPaint.setStyle(Paint.Style.FILL);
        mProgressPaint.setStrokeCap(Paint.Cap.ROUND);

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //宽的测量模式
        int widthMode=MeasureSpec.getMode(widthMeasureSpec);
        //Extracts the size from the supplied measure specification.
        //翻译 从提供的度量规范中提取大小  获取指定大小没有就获取父控件的大小
        int width=MeasureSpec.getSize(widthMeasureSpec);

        int heightMode=MeasureSpec.getMode(heightMeasureSpec);
        int height=MeasureSpec.getSize(heightMeasureSpec);

        //EXACTLY == 1073741824
        //UNSPECIFIED == -2147483648
        //AT_MOST == 0
        Log.e("test","widthMode=="+widthMode);
        Log.e("test","width=="+width);

        int widthSize;
        int heightSize;
        if(widthMode==MeasureSpec.EXACTLY){ //已经确定具体大小 如设置match_parent或者设置具体值
            widthSize=width;
        }else{ //没有确定大小
            //为了方便随便定义一个大小
            widthSize=500;
        }

        if (heightMode == MeasureSpec.EXACTLY) {
            heightSize = height;
        } else {
            heightSize = mBitmatHeight; //没有定义高度就取滑块的高度
        }

        mViewWidth = widthSize;
        mViewHeight = heightSize;

        //进度条的宽度=控件宽-滑块宽
        mWidth = mViewWidth - mBitmatWidth;

        setMeasuredDimension(mViewWidth, mViewHeight);
    }

    private PaintFlagsDrawFilter mPaintFilter;

    private int left,top,right,bottom;

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mPaintFilter == null) {
            mPaintFilter = new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
            //初始化背景的起始位置
            left=mBitmatWidth / 2;
            top=(mBitmatHeight - mHeight) / 2;
            right=(left + mWidth);
            bottom=(mBitmatHeight + mHeight)/2;

        }
        canvas.setDrawFilter(mPaintFilter);//canvas抗锯齿
        //画背景
        if (mBgRectF == null) {
            mBgRectF = new RectF(left, top, right, bottom);
        }
        canvas.drawRoundRect(mBgRectF, mRadius, mRadius, mBgPaint);

        //step2:画进度
        //起始位置和背景的起始位置一样
        if (mProgress == 0) {
            mProgressRectF = new RectF(left, top, left, top);
        } else {
            mProgressRectF = new RectF(left, top, (mViewWidth-mBitmatWidth)* mProgress/ 100+left, bottom);
        }
        canvas.drawRoundRect(mProgressRectF, mRadius, mRadius, mProgressPaint);

        //step3:画滑块
//        canvas.translate(0, -(circleBitmap.getHeight() - mHeight) / 2);
        if (mProgress == 0) {
            mSliderRectF = new RectF(0, 0, mBitmatWidth, mBitmatHeight);
        } else {
            mSliderRectF = new RectF((mViewWidth-mBitmatWidth)*mProgress/100 , 0, (mViewWidth-mBitmatWidth)* mProgress/ 100 + mBitmatWidth, mBitmatHeight);
        }
        canvas.drawBitmap(circleBitmap, null, mSliderRectF, mSliderPaint);

    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {

        if (event.getAction() == MotionEvent.ACTION_DOWN) {
            //按下，获取点击的位置
            float x = event.getX();
            float y = event.getY();
            if (x-mBitmatWidth/2-mWidth >= 0) {
                mProgress = 100;
            } else if (x <= mBitmatWidth / 2) {
                mProgress = 0;
            } else {
                mProgress = (int) ((x-mBitmatHeight/2) * 100 / mWidth);
            }


        } else if (event.getAction() == MotionEvent.ACTION_MOVE) {
            //移动，获取移动后的位置
            float x = event.getX();
            float y = event.getY();
            //触摸在这个控件范围内
            if ((y > 0 && y < mBitmatHeight)  && ((x>= mBitmatWidth/2) || (x<=mWidth + mBitmatWidth/2))) {
                if (x-mBitmatWidth/2-mWidth >= 0) {
                    mProgress = 100;
                } else if (x <= mBitmatWidth / 2) {
                    mProgress = 0;
                } else {
                    mProgress = (int) ((x-mBitmatHeight/2) * 100 / mWidth);
                }

            }
        }
        invalidate();
        return true;
    }
}

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最后使用

 最后博客写的少，没写好。不喜勿喷。