想整个双向的进度条，就是可以选取播放范围的。
像这样：
20170905165905.png
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
