Android 自定义可选择范围的控件

package com.elink.tianyu.cardslistview.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import com.elink.tianyu.cardslistview.R;

/**
* 选择范围控件
* Created by zty on 2016/5/12.
*/
public class RangeSelectionView extends View {

private Paint paintBackground;//背景线的画笔
private Paint paintCircle;//起始点圆环的画笔
private Paint paintWhileCircle;//起始点内圈白色区域的画笔
private Paint paintText;//起始点数值的画笔
private Paint paintConnectLine;//起始点连接线的画笔

private int height = 0;//控件的高度
private int width = 0;//控件的宽度

private float centerVertical = 0;//y轴的中间位置

private float backlineWidth = 5;//底线的宽度

private float marginhorizontal = 35;//横向边距

private float marginTop = 50;//文字距顶部的距离

private float pointStart = 0;//起点的X轴位置

private float pointEnd = 0;//始点的Y轴位置

private float circleRadius = 30;//起始点圆环的半径

private float numStart = 0;//数值的开始值

private float numEnd = 0;//数值的结束值

private int textSize = 30;//文字的大小

private String strUnit = "¥";//刻度的单位

private boolean isRunning = false;//是否可以滑动

private boolean isStart = true;//起点还是终点 true：起点；false：终点。

public RangeSelectionView(Context context) {
super(context);
init();
}

public RangeSelectionView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}

public RangeSelectionView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);

//获取控件的宽高、中线位置、起始点、起始数值
height = MeasureSpec.getSize(heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
centerVertical = height / 2;

pointStart = marginhorizontal;
pointEnd = width - marginhorizontal;

numStart = getProgressNum(pointStart);

numEnd = getProgressNum(pointEnd);

}

@Override
public boolean onTouchEvent(MotionEvent event) {
super.onTouchEvent(event);
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//如果点击的点在第一个圆内就是起点,并且可以滑动
if (event.getX() >= (pointStart - circleRadius) && event.getX() <= (pointStart + circleRadius)) {
isRunning = true;
isStart = true;

pointStart = event.getX();
//如果点击的点在第二个圆内就是终点,并且可以滑动
} else if (event.getX() <= (pointEnd + circleRadius) && event.getX() >= (pointEnd - circleRadius)) {
isRunning = true;
isStart = false;

pointEnd = event.getX();
} else {
//如果触控点不在圆环内，则不能滑动
isRunning = false;
}

break;
case MotionEvent.ACTION_MOVE:
if (isRunning) {
if (isStart) {
//起点滑动时，重置起点的位置和进度值
pointStart = event.getX();
numStart = getProgressNum(pointStart);
} else {
//始点滑动时，重置始点的位置和进度值
pointEnd = event.getX();
numEnd = getProgressNum(pointEnd);
}

flushState();//刷新状态
}

break;
case MotionEvent.ACTION_UP:

flushState();
break;
}

return true;
}

/**
* 刷新状态和屏蔽非法值
*/
private void flushState() {

//起点非法值
if (pointStart < marginhorizontal) {
pointStart = marginhorizontal;
}
//终点非法值
if (pointEnd > width - marginhorizontal) {
pointEnd = width - marginhorizontal;
}

//防止起点位置大于终点位置（规定：如果起点位置大于终点位置，则将起点位置放在终点位置前面,即：终点可以推着起点走，而起点不能推着终点走）
if (pointStart + circleRadius > pointEnd - circleRadius) {

pointStart = pointEnd - 2 * circleRadius;

}

//防止终点把起点推到线性范围之外
if (pointEnd < marginhorizontal + 2 * circleRadius) {
pointEnd = marginhorizontal + 2 * circleRadius;
pointStart = marginhorizontal;
}

invalidate();//这个方法会导致onDraw方法重新绘制

}

//进度范围
float beginNum = 0;
float endNum = 1000;

//计算进度数值
private float getProgressNum(float progress) {

return (int) progress / (width - 2 * marginhorizontal) * (endNum - beginNum);

}

//初始化画笔
private void init() {

paintBackground = new Paint();
paintBackground.setColor(getResources().getColor(R.color.colorBackline));
paintBackground.setStrokeWidth(backlineWidth);
paintBackground.setAntiAlias(true);

paintCircle = new Paint();
paintCircle.setColor(getResources().getColor(R.color.colorTipCircle));
paintCircle.setStrokeWidth(backlineWidth);
paintCircle.setStyle(Paint.Style.STROKE);
paintCircle.setAntiAlias(true);

paintWhileCircle = new Paint();
paintWhileCircle.setColor(getResources().getColor(R.color.white));
paintCircle.setStyle(Paint.Style.FILL);
paintWhileCircle.setAntiAlias(true);

paintText = new Paint();
paintText.setColor(getResources().getColor(R.color.colorTipText));
paintText.setTextSize(textSize);
paintText.setAntiAlias(true);

paintConnectLine = new Paint();
paintConnectLine.setColor(getResources().getColor(R.color.colorTipCircle));
paintConnectLine.setStrokeWidth(backlineWidth + 5);
paintConnectLine.setAntiAlias(true);

}

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

//背景线
canvas.drawLine(marginhorizontal, centerVertical, width - marginhorizontal, centerVertical, paintBackground);
//起点位置的外圈圆
canvas.drawCircle(pointStart, centerVertical, circleRadius, paintCircle);
//起点位置的内圈圆
canvas.drawCircle(pointStart, centerVertical, circleRadius - backlineWidth, paintWhileCircle);
//终点位置的外圈圆
canvas.drawCircle(pointEnd, centerVertical, circleRadius, paintCircle);
//终点位置的内圈圆
canvas.drawCircle(pointEnd, centerVertical, circleRadius - backlineWidth, paintWhileCircle);
//起始点连接线
canvas.drawLine(pointStart + circleRadius, centerVertical, pointEnd - circleRadius, centerVertical, paintConnectLine);
//起点数值
canvas.drawText(numStart + strUnit, pointStart, marginTop, paintText);
//终点数值
canvas.drawText(numEnd + strUnit, pointEnd, marginTop, paintText);

}
}

<com.elink.tianyu.cardslistview.view.RangeSelectionView
android:layout_width="match_parent"
android:background="@android:color/white"
android:layout_height="100dp" />