Android 自定义SeekBar 实现分段显示不同背景颜色的示例代码

在最近的开发工作中，要实现一个调色板的进度条，SeekBar要分成10段显示不同颜色，功夫不负有心人，终于实现了这个功能，下面分享给大家
示例图：

1.自定义SeekBar

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Build;
import android.util.AttributeSet;
import android.widget.SeekBar;

/**
 *
 * @time 2020/6/4 18:32
 * <p>
 * 类描述：自定义多颜色的SeekBar
 */
public class MulticolourSeekBar extends SeekBar {

 /**
 * 画笔
 */
 private Paint mMulticlourPaint;

 /**
 * 刻度线的个数,等分数等于刻度线的个数加1
 */
 private int mMulticlourCount = 9;

 /**
 * 每条刻度线的宽度
 */
 private int mMulticlourWidth = 2;

 /**
 * 刻度线的颜色
 */
 private int mMulticlourColor = Color.WHITE;

 /**
 * 滑块上面是否要显示刻度线
 */
 private boolean isShowTopOfThumb = false;

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

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

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

 /**
 * 初始化
 */
 private void init() {
 //创建绘制刻度线的画笔
 mMulticlourPaint = new Paint();
 mMulticlourPaint.setColor(mMulticlourColor);
 mMulticlourPaint.setAntiAlias(true);

 //Api21及以上调用，去掉滑块后面的背景
 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
  setSplitTrack(false);
 }
 }

 /**
 * 重写onDraw方法绘制刻度线
 *
 * @param canvas
 */
 @Override
 protected synchronized void onDraw(Canvas canvas) {
 super.onDraw(canvas);

 //极限条件校验
 if (getWidth() <= 0 || mMulticlourCount <= 0) {
  return;
 }

 //获取每一份的长度
// int length = (getWidth() - getPaddingLeft() - getPaddingRight() - mMulticlourCount * mMulticlourWidth) / (mMulticlourCount + 1);
 int length = (getWidth() - getPaddingLeft() - getPaddingRight()) / (mMulticlourCount + 1);
 //计算刻度线的顶部坐标和底部坐标
 int rulerTop = getHeight() / 2 - getMinimumHeight() / 2;
 int rulerBottom = rulerTop + getMinimumHeight();

 //获取滑块的位置信息
 Rect thumbRect = null;
 if (getThumb() != null) {
  thumbRect = getThumb().getBounds();
 }
 //绘制刻度线
// for (int i = 1; i <= mMulticlourCount; i++) {
//  //计算刻度线的左边坐标和右边坐标
//  int rulerLeft = i * length + getPaddingLeft();
//  int rulerRight = rulerLeft + mMulticlourWidth;
//
//  //判断是否需要绘制刻度线
//  if (!isShowTopOfThumb && thumbRect != null && rulerLeft - getPaddingLeft() > thumbRect.left && rulerRight - getPaddingLeft() < thumbRect.right) {
//  continue;
//  }
//
//  //进行绘制
//  canvas.drawRect(rulerLeft, rulerTop, rulerRight, rulerBottom, mMulticlourPaint);
// }
 for (int i = 0; i <= mMulticlourCount; i++) {
  int left = getPaddingLeft() + i * length;
  int right = left + length;
  if (i % 3 == 0) {
  mMulticlourPaint.setColor(Color.RED);
  } else if (i % 3 == 1) {
  mMulticlourPaint.setColor(Color.YELLOW);
  } else {
  mMulticlourPaint.setColor(Color.BLUE);
  }
  if (i == 0) {
  canvas.drawCircle(getPaddingLeft() + 10, 20, 10, mMulticlourPaint);
  left += 10;
  canvas.drawRect(left, 10, right, 30, mMulticlourPaint);
  } else if (i == mMulticlourCount) {
  right -= 10;
  canvas.drawRect(left, 10, right, 30, mMulticlourPaint);
  canvas.drawCircle(right, 20, 10, mMulticlourPaint);
  } else {
  canvas.drawRect(left, 10, right, 30, mMulticlourPaint);
  }
 }
 }

 /**
 * 设置刻度线的个数
 *
 * @param mRulerCount
 */
 public void setRulerCount(int mRulerCount) {
 this.mMulticlourCount = mRulerCount;
 requestLayout();
 }

 /**
 * 设置刻度线的宽度，单位(px)
 *
 * @param mRulerWidth
 */
 public void setRulerWidth(int mRulerWidth) {
 this.mMulticlourWidth = mRulerWidth;
 requestLayout();
 }

 /**
 * 设置刻度线的颜色
 *
 * @param mRulerColor
 */
 public void setRulerColor(int mRulerColor) {
 this.mMulticlourColor = mRulerColor;
 if (mMulticlourPaint != null) {
  mMulticlourPaint.setColor(mRulerColor);
  requestLayout();
 }
 }

 /**
 * 滑块上面是否需要显示刻度线
 *
 * @param isShowTopOfThumb
 */
 public void setShowTopOfThumb(boolean isShowTopOfThumb) {
 this.isShowTopOfThumb = isShowTopOfThumb;
 requestLayout();
 }
}

2.activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context=".MainActivity">

 <com.xinrui.view.MulticolourSeekBar
 android:id="@+id/seek_bar"
 android:layout_width="350px"
 android:layout_height="wrap_content"
 android:background="@null"
 android:maxHeight="20px"
 android:minHeight="20px"
 android:max="100"
 android:progress="5"
 android:progressDrawable="@drawable/shape_progress_drawable"
 android:thumb="@drawable/shape_thumb_icon"
 android:thumbOffset="-2px"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintEnd_toEndOf="parent"
 app:layout_constraintStart_toStartOf="parent"
 app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

3.shape_progress_drawable.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
 <item android:id="@android:id/background">
 <shape>
  <solid android:color="#e1e8f0" />
  <size android:height="8px" />
  <corners android:radius="8px" />
 </shape>
 </item>

 <item android:id="@android:id/progress">
 <clip>
  <shape>
  <gradient
   android:endColor="@android:color/transparent"
   android:startColor="@android:color/transparent" />
  <size android:height="8px" />
  <corners android:radius="8px" />
  </shape>
 </clip>
 </item>
</layer-list>

4.shape_thumb_icon.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
 android:shape="rectangle">

 <size
 android:width="5px"
 android:height="40px" />

 <solid android:color="@android:color/widget_edittext_dark" />
</shape>

总结

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