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Android自定义双向进度条的实现代码

想整个双向的进度条，就是可以选取播放范围的。

像这样：


然而官方控件里只有单向的。不要慌，我们自己画一个。

绘制一个进度条主要是三方面。1.样式，2.尺寸，3.操作监听。

完整代码来一遍:

注释基本上就把原理说明了一下。

package util;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.support.v4.content.ContextCompat;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

import com.example.qzd.utildemo.R;

import java.math.BigDecimal;

/**
 * 双向滑块的进度条（区域选择）
 */
public class SeekRangeBar extends View {
  private Context _context;
  private static final int CLICK_ON_LOW = 1;    //手指在前滑块上滑动
  private static final int CLICK_ON_HIGH = 2;    //手指在后滑块上滑动
  private static final int CLICK_IN_LOW_AREA = 3;  //手指点击离前滑块近
  private static final int CLICK_IN_HIGH_AREA = 4; //手指点击离后滑块近
  private static final int CLICK_OUT_AREA = 5;   //手指点击在view外
  private static final int CLICK_INVAILD = 0;
  private static final int[] STATE_NORMAL = {};
  private static final int[] STATE_PRESSED =
 {android.R.attr.state_pressed,android.R.attr.state_window_focused,};
  private static int mThumbMarginTop = 0;  //滑动块顶部离view顶部的距离
  private static int mTextViewMarginTop = 0;  //当前滑块文字距离view顶部距离
  private Drawable hasScrollBarBg;    //滑动条滑动后背景图
  private Drawable notScrollBarBg;    //滑动条未滑动背景图
  private Drawable mThumbLow;     //前滑块
  private Drawable mThumbHigh;    //后滑块
  private int mScollBarWidth;   //控件宽度 = 滑动条宽度 + 滑动块宽度
  private int mScollBarHeight;  //控件高度
  private int mThumbWidth;    //滑动块直径
  private double mOffsetLow = 0;   //前滑块中心坐标
  private double mOffsetHigh = 0;  //后滑块中心坐标
  private int mDistance=0;   //总刻度是固定距离 两边各去掉半个滑块距离
  private int mFlag = CLICK_INVAILD;  //手指按下的类型
  private double defaultScreenLow = 0;  //默认前滑块位置百分比
  private double defaultScreenHigh = 100; //默认后滑块位置百分比
  private OnSeekBarChangeListener mBarChangeListener;
  private boolean editable=false;//是否处于可编辑状态
  private int miniGap=5;//AB的最小间隔
  private double progressLow;//起点(百分比)
  private double progressHigh;//终点

  public SeekRangeBar(Context context) {
    this(context, null);
  }
  public SeekRangeBar(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }
  public SeekRangeBar(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    _context=context;
    //这里设置背景图及滑块图，自定义过进度条的同学应该很熟悉了
    notScrollBarBg = ContextCompat.getDrawable(_context,R.mipmap.hp_wbf);
    hasScrollBarBg = ContextCompat.getDrawable(_context, R.mipmap.hp_ybf);
    mThumbLow = ContextCompat.getDrawable(_context,R.mipmap.hp_a);
    mThumbHigh = ContextCompat.getDrawable(_context,R.mipmap.hp_b);
    mThumbLow.setState(STATE_NORMAL);
    mThumbHigh.setState(STATE_NORMAL);
    //设置滑动条高度
    mScollBarHeight = notScrollBarBg.getIntrinsicHeight();
    //设置滑动块直径
    mThumbWidth = mThumbLow.getIntrinsicWidth();
  }

  /**
   * 测量view尺寸（在onDraw()之前）
   * @param widthMeasureSpec
   * @param heightMeasureSpec
   */
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int width = MeasureSpec.getSize(widthMeasureSpec);
    mScollBarWidth = width;
    if(mDistance==0) {//这里滑块中心坐标初始化的时候测量一下（根据mDistance是否赋值判断），并不需要不停地去测量。后面会根据进度计算滑块位置。
      mOffsetLow = mThumbWidth / 2;
      mOffsetHigh = width - mThumbWidth / 2;
    }
    mDistance = width - mThumbWidth;
    if(defaultScreenLow != 0) {
      mOffsetLow = formatInt(defaultScreenLow / 100 * (mDistance)) + mThumbWidth / 2;
    }
    if(defaultScreenHigh != 100) {
      mOffsetHigh = formatInt(defaultScreenHigh / 100 * (mDistance)) + mThumbWidth / 2;
    }
    setMeasuredDimension(width, mThumbWidth + mThumbMarginTop + 2);
  }

  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    super.onLayout(changed, l, t, r, b);
  }

  /**
   * 绘制进度条
   */
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    //设置绘制样式
    Paint text_Paint = new Paint();
    text_Paint.setTextAlign(Paint.Align.CENTER);
    text_Paint.setColor(Color.RED);
    text_Paint.setTextSize(20);

    int top = mThumbMarginTop + mThumbWidth / 2 - mScollBarHeight / 2;
    int bottom = top + mScollBarHeight;

    //绘制是否可操作状态的下的不同样式，仅可编辑状态下显示进度条
    if(editable) {
      //白色滑动条，两个滑块各两边部分
      notScrollBarBg.setBounds(mThumbWidth / 2, top, mScollBarWidth - mThumbWidth / 2, bottom);
      notScrollBarBg.draw(canvas);

      //红色滑动条，两个滑块中间部分
      hasScrollBarBg.setBounds((int) mOffsetLow, top, (int) mOffsetHigh, bottom);
      hasScrollBarBg.draw(canvas);
    }

    //前滑块
    mThumbLow.setBounds((int) (mOffsetLow - mThumbWidth / 2), mThumbMarginTop, (int) (mOffsetLow + mThumbWidth / 2), mThumbWidth + mThumbMarginTop);
    mThumbLow.draw(canvas);

    //后滑块
    mThumbHigh.setBounds((int) (mOffsetHigh - mThumbWidth / 2), mThumbMarginTop, (int) (mOffsetHigh + mThumbWidth / 2), mThumbWidth + mThumbMarginTop);
    mThumbHigh.draw(canvas);

    //当前滑块刻度
    progressLow = formatInt((mOffsetLow - mThumbWidth / 2) * 100 / mDistance);
    progressHigh = formatInt((mOffsetHigh - mThumbWidth / 2) * 100 / mDistance);
    canvas.drawText((int) progressLow + "", (int) mOffsetLow - 2 - 2, mTextViewMarginTop, text_Paint);
    canvas.drawText((int) progressHigh + "", (int) mOffsetHigh - 2, mTextViewMarginTop, text_Paint);

    if (mBarChangeListener != null) {
      mBarChangeListener.onProgressChanged(this, progressLow, progressHigh);
    }
  }

  //手势监听
  @Override
  public boolean onTouchEvent(MotionEvent e) {
    if(!editable) {
      return false;
    }
    if (e.getAction() == MotionEvent.ACTION_DOWN) {
      mFlag = getAreaFlag(e);
      if (mFlag == CLICK_ON_LOW) {
        mThumbLow.setState(STATE_PRESSED);
      } else if (mFlag == CLICK_ON_HIGH) {
        mThumbHigh.setState(STATE_PRESSED);
      } else if (mFlag == CLICK_IN_LOW_AREA) {
        mThumbLow.setState(STATE_PRESSED);
        mThumbHigh.setState(STATE_NORMAL);
        //如果点击0-mThumbWidth/2坐标
        if (e.getX() < 0 || e.getX() <= mThumbWidth / 2) {
          mOffsetLow = mThumbWidth / 2;
        } else if (e.getX() > mScollBarWidth - mThumbWidth / 2) {
          mOffsetLow = mThumbWidth / 2 + mDistance;
        } else {
          mOffsetLow = formatInt(e.getX());

        }
      } else if (mFlag == CLICK_IN_HIGH_AREA) {
        mThumbHigh.setState(STATE_PRESSED);
        mThumbLow.setState(STATE_NORMAL);
        if (e.getX() >= mScollBarWidth - mThumbWidth / 2) {
          mOffsetHigh = mDistance + mThumbWidth / 2;
        } else {
          mOffsetHigh = formatInt(e.getX());
        }
      }
      //更新滑块
      invalidate();
    } else if (e.getAction() == MotionEvent.ACTION_MOVE) {
      if (mFlag == CLICK_ON_LOW) {
        if (e.getX() < 0 || e.getX() <= mThumbWidth / 2) {
          mOffsetLow = mThumbWidth / 2;
        } else if (e.getX() >= mScollBarWidth - mThumbWidth / 2) {
          mOffsetLow = mThumbWidth / 2 + mDistance;
          mOffsetHigh = mOffsetLow;
        } else {
          mOffsetLow = formatInt(e.getX());
          if (mOffsetHigh - mOffsetLow <= 0) {
            mOffsetHigh = (mOffsetLow <= mDistance + mThumbWidth / 2) ? (mOffsetLow) : (mDistance + mThumbWidth / 2);
          }
        }
      } else if (mFlag == CLICK_ON_HIGH) {
        if (e.getX() < mThumbWidth / 2) {
          mOffsetHigh = mThumbWidth / 2;
          mOffsetLow = mThumbWidth / 2;
        } else if (e.getX() > mScollBarWidth - mThumbWidth / 2) {
          mOffsetHigh = mThumbWidth / 2 + mDistance;
        } else {
          mOffsetHigh = formatInt(e.getX());
          if (mOffsetHigh - mOffsetLow <= 0) {
            mOffsetLow = (mOffsetHigh >= mThumbWidth / 2) ? (mOffsetHigh) : mThumbWidth / 2;
          }
        }
      }
      //更新滑块，每次滑块有动作都要执行此函数触发onDraw方法绘制新图片
      invalidate();
    } else if (e.getAction() == MotionEvent.ACTION_UP) {
      Log.d("LOGCAT","ACTION UP:"+progressHigh+"-"+progressLow);
      mThumbLow.setState(STATE_NORMAL);
      mThumbHigh.setState(STATE_NORMAL);
      if(miniGap>0 && progressHigh<progressLow+miniGap){
        progressHigh=progressLow+miniGap;
        this.defaultScreenHigh = progressHigh;
        mOffsetHigh = formatInt(progressHigh / 100 * (mDistance)) + mThumbWidth / 2;
        invalidate();
      }
    }
    return true;
  }

  /**
   * 设置是否可编辑状态，非可编辑状态将不能对AB点进行操作
   * @param _b
   */
  public void setEditable(boolean _b){
    editable=_b;
    invalidate();
  }

  /**
   * 获取当前手指位置
   */
  public int getAreaFlag(MotionEvent e) {
    int top = mThumbMarginTop;
    int bottom = mThumbWidth + mThumbMarginTop;
    if (e.getY() >= top && e.getY() <= bottom && e.getX() >= (mOffsetLow - mThumbWidth / 2) && e.getX() <= mOffsetLow + mThumbWidth / 2) {
      return CLICK_ON_LOW;
    } else if (e.getY() >= top && e.getY() <= bottom && e.getX() >= (mOffsetHigh - mThumbWidth / 2) && e.getX() <= (mOffsetHigh + mThumbWidth / 2)) {
      return CLICK_ON_HIGH;
    } else if (e.getY() >= top
      && e.getY() <= bottom
      && ((e.getX() >= 0 && e.getX() < (mOffsetLow - mThumbWidth / 2)) || ((e.getX() > (mOffsetLow + mThumbWidth / 2))
      && e.getX() <= ((double) mOffsetHigh + mOffsetLow) / 2))) {
      return CLICK_IN_LOW_AREA;
    } else if (e.getY() >= top && e.getY() <= bottom && (((e.getX() > ((double) mOffsetHigh + mOffsetLow) / 2) && e.getX() < (mOffsetHigh - mThumbWidth / 2)) || (e.getX() > (mOffsetHigh + mThumbWidth / 2) && e.getX() <= mScollBarWidth))) {
      return CLICK_IN_HIGH_AREA;
    } else if (!(e.getX() >= 0 && e.getX() <= mScollBarWidth && e.getY() >= top && e.getY() <= bottom)) {
      return CLICK_OUT_AREA;
    } else {
      return CLICK_INVAILD;
    }
  }

  /**
   * 设置前滑块位置
   * @param progressLow
   */
  public void setProgressLow(double progressLow) {
    this.defaultScreenLow = progressLow;
    mOffsetLow = formatInt(progressLow / 100 * (mDistance)) + mThumbWidth / 2;
    invalidate();
  }

  /**
   * 设置后滑块位置
   * @param progressHigh
   */
  public void setProgressHigh(double progressHigh) {
    this.defaultScreenHigh = progressHigh;
    mOffsetHigh = formatInt(progressHigh / 100 * (mDistance)) + mThumbWidth / 2;
    invalidate();
  }

  /**
   * 设置滑动监听
   * @param mListener
   */
  public void setOnSeekBarChangeListener(OnSeekBarChangeListener mListener) {
    this.mBarChangeListener = mListener;
  }

  /**
   * 滑动监听，改变输入框的值
   */
  public interface OnSeekBarChangeListener {
    //滑动时
    public void onProgressChanged(SeekRangeBar seekBar, double progressLow, double progressHigh);
  }

  /**
   * 设置滑动结果为整数
   */
  private int formatInt(double value) {
    BigDecimal bd = new BigDecimal(value);
    BigDecimal bd1 = bd.setScale(0, BigDecimal.ROUND_HALF_UP);
    return bd1.intValue();
  }
}

然后就可以在程序中使用了。

布局中

<util.SeekRangeBar
  android:id="@+id/doubleSeekbar"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_centerVertical="true"/>

调用

private SeekRangeBar doubleSeekbar;//双向进度条
doubleSeekbar = (SeekRangeBar) findViewById(R.id.doubleSeekbar);
//监听进度范围变化
doubleSeekbar.setOnSeekBarChangeListener(new SeekRangeBar.OnSeekBarChangeListener() {
  @Override
  public void onProgressChanged(SeekRangeBar seekBar, double progressLow, double progressHigh) {
    Log.d("LOGCAT","低：" + progressLow + "高：" + progressHigh);
  }
});

相关GitHub项目地址：https://github.com/codeqian/android-class-lib

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持呐喊教程。

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