自定义颜色、大小渐变的圆点指示器

2024-08-31 23:18

本文主要是介绍自定义颜色、大小渐变的圆点指示器,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!


源码 点击打开链接

首先看布局文件activity_main.xml

布局很简单只有装图片的ViewPager--以及自定义的圆点指示器

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context="com.example.pageindicator.MainActivity" ><android.support.v4.view.ViewPagerandroid:id="@+id/mViewpager"android:layout_width="match_parent"android:layout_height="300dp" ></android.support.v4.view.ViewPager><com.example.pageindicator.CustomPageIndicatorandroid:id="@+id/mPagerIndicator"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_gravity="center_horizontal"android:layout_marginTop="50dp" ></com.example.pageindicator.CustomPageIndicator></LinearLayout>

首先看主界面把MainActivity

package com.example.pageindicator;  import java.util.ArrayList;import android.app.Activity;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;public class MainActivity extends Activity {  private ViewPager mViewPager;  CustomPageIndicator mPagerIndicator;MyAdapter mAdapter;  private ArrayList<ImageView> imageViewList;  private boolean isScrolling = false;@SuppressWarnings("deprecation")  @Override  protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  imageViewList = new ArrayList<ImageView>();  int[] imagesInt = {R.drawable.p1,R.drawable.p2,R.drawable.p3};  for (int i = 0; i < imagesInt.length; i++) {  ImageView imageView = new ImageView(MainActivity.this);  imageView.setBackgroundResource(imagesInt[i]);  imageViewList.add(imageView);  }  mPagerIndicator = (CustomPageIndicator) findViewById(R.id.mPagerIndicator);mViewPager = (ViewPager) findViewById(R.id.mViewpager);  mAdapter = new MyAdapter();  mViewPager.setAdapter(mAdapter);  mViewPager.setOnPageChangeListener(new OnPageChangeListener() {  @Override  public void onPageSelected(int position) {  mPagerIndicator.setActivityCircle(position);}  @Override  public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {float percent = positionOffset;if(isScrolling && percent > 0.0f && percent < 1.0f){mPagerIndicator.setScrollProgress(position,percent);}}  @Override  public void onPageScrollStateChanged(int arg0) {if(arg0 != 0){isScrolling = true;}else{isScrolling = false;}//下面判断不严谨
//            	if(arg0 == 1){
//        			isScrolling = true;
//        		}else{
//        			isScrolling = false;
//        		}}  });  }  class MyAdapter extends PagerAdapter{  @Override  public int getCount() {  return imageViewList.size();  }  @Override  public boolean isViewFromObject(View arg0, Object arg1) {  return arg0 == arg1;  }  @Override  public void destroyItem(ViewGroup container, int position, Object object) {  container.removeView(imageViewList.get(position));  }  @Override  public Object instantiateItem(ViewGroup container, int position) {  container.addView(imageViewList.get(position));  return imageViewList.get(position);  }  }  
}  

主界面是最简单的ViewPager页面切换效果--主要是看    mPagerIndicator.setScrollProgress(position,percent);、mPagerIndicator.setActivityCircle(position);的代码

接下来就看圆点指示器自定义类把CustomPageIndicator 先贴出代码来,然后在稍微讲解下

package com.example.pageindicator;import java.util.ArrayList;import android.R.color;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.provider.CalendarContract.Colors;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;public class CustomPageIndicator extends View {int[] imagesInt = { R.drawable.p1, R.drawable.p2, R.drawable.p3 };private int circleCount = imagesInt.length;private int activeCircleIndex = 0;private int circleRadius;// 半径4private int activeCircleRadius;// 当前小球半径6private int circleDivider;// 间距6private ArrayList<Circle> circles = null;Paint mPaint;private int normalCircleColor;private int acitiveCircleColor;public CustomPageIndicator(Context context, AttributeSet attrs) {this(context, attrs, 0);}public CustomPageIndicator(Context context) {this(context, null);}public CustomPageIndicator(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);initCircle();}private void initCircle() {normalCircleColor = Color.parseColor("#000000");acitiveCircleColor = Color.parseColor("#EE3B3B");// 填充、抗锯齿--颜色、大小mPaint = new Paint();mPaint.setStyle(Paint.Style.FILL);mPaint.setAntiAlias(true);circleRadius = PhoneUtils.dp2px(getContext(), 4);activeCircleRadius = PhoneUtils.dp2px(getContext(), 6);circleDivider = PhoneUtils.dp2px(getContext(), 6);circles = new ArrayList<CustomPageIndicator.Circle>();// 创建3个原点集合for (int i = 0; i < circleCount; i++) {Circle circle = new Circle();if (activeCircleIndex == i) {// 当前的点位circle.color = acitiveCircleColor;circle.radius = activeCircleRadius;circle.centerX = activeCircleRadius;circle.centerY = activeCircleRadius;} else {// 其他点位circle.color = normalCircleColor;circle.radius = circleRadius;circle.centerX = activeCircleRadius + i* PhoneUtils.dp2px(getContext(), 14);circle.centerY = activeCircleRadius;}circles.add(circle);}}/*** 设置目前活动的小球* 第一部分根据startValue求出其中A,R,G,B中各个色彩的初始值;第二部分根据endValue求出其中A,R,G,B中各个色彩的结束值* ,最后是根据当前动画的百分比进度求出对应的数值*/public void setActivityCircle(int index) {lastCircle = circles.get(activeCircleIndex);lastCircle.color = ColorHelper.evaluate(0.1f, normalCircleColor,acitiveCircleColor);lastCircle.radius = circleRadius;activeCircleIndex = index;currentActivedCircele = circles.get(activeCircleIndex);currentActivedCircele.color = ColorHelper.evaluate(0.1f,acitiveCircleColor, normalCircleColor);currentActivedCircele.radius = activeCircleRadius;invalidate();}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {int resultWidth = 0;int resultHeight = 0;resultWidth = circleCount * circleRadius * 2 + (circleCount - 1)* circleDivider + 2 * (activeCircleRadius - circleRadius);resultHeight = 2 * activeCircleRadius;setMeasuredDimension(resultWidth, resultHeight);}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);for (int i = 0; i < circleCount; i++) {Circle circle = circles.get(i);mPaint.setColor(circle.color);canvas.drawCircle(circle.centerX, circle.centerY, circle.radius,mPaint);}}/*** 圆心xy坐标,半径,颜色*/private class Circle {float centerX;float centerY;float radius;int color;}private float lastPercent = -1;private Circle lastCircle;private Circle currentActivedCircele;private Circle right;private Circle left;public void setScrollProgress(int leftPosition, float percent) {right = circles.get(leftPosition + 1);left = circles.get(leftPosition);// 手指右滑-递减if (lastPercent > percent) {left.radius = circleRadius + (1 - percent)* PhoneUtils.dp2px(getContext(), 2);right.radius = circleRadius + percent* PhoneUtils.dp2px(getContext(), 2);if (left.color == normalCircleColor) {left.color = ColorHelper.evaluate(percent, normalCircleColor,acitiveCircleColor);} else {left.color = ColorHelper.evaluate(percent, acitiveCircleColor,normalCircleColor);}if (right.color == normalCircleColor) {right.color = ColorHelper.evaluate(1 - percent,normalCircleColor, acitiveCircleColor);} else {right.color = ColorHelper.evaluate(1 - percent,acitiveCircleColor, normalCircleColor);}}// 手指左滑-递增if (lastPercent < percent) {left.radius = circleRadius + (1 - percent)* PhoneUtils.dp2px(getContext(), 2);right.radius = circleRadius + percent* PhoneUtils.dp2px(getContext(), 2);if (right.color == normalCircleColor) {right.color = ColorHelper.evaluate(1 - percent,normalCircleColor, acitiveCircleColor);} else {right.color = ColorHelper.evaluate(1 - percent,acitiveCircleColor, normalCircleColor);}if (left.color == normalCircleColor) {left.color = ColorHelper.evaluate(percent, normalCircleColor,acitiveCircleColor);} else {left.color = ColorHelper.evaluate(percent, acitiveCircleColor,normalCircleColor);}}invalidate();lastPercent = percent;}}


上面的initCircle方法中是进行原点初始化操作,定义了圆点的默认色normalCircleColor,选中色acitiveCircleColor,以及圆点之间的距离circleDivider,

默认圆点的半径circleRadius,选中原点的半径activeCircleRadius,然后根据ViewPager的图片数量进行分装圆点对象集合

然后看onMeasure去测量View的整体大小--不解释了

最后看onDraw就是去绘制圆点,这些方法比较简单


    mPagerIndicator.setActivityCircle(position);这个就是滚动到某一页面进行的逻辑处理

/*** 设置目前活动的小球* 第一部分根据startValue求出其中A,R,G,B中各个色彩的初始值;第二部分根据endValue求出其中A,R,G,B中各个色彩的结束值* ,最后是根据当前动画的百分比进度求出对应的数值*/public void setActivityCircle(int index) {lastCircle = circles.get(activeCircleIndex);lastCircle.color = ColorHelper.evaluate(0.1f, normalCircleColor,acitiveCircleColor);lastCircle.radius = circleRadius;activeCircleIndex = index;currentActivedCircele = circles.get(activeCircleIndex);currentActivedCircele.color = ColorHelper.evaluate(0.1f,acitiveCircleColor, normalCircleColor);currentActivedCircele.radius = activeCircleRadius;invalidate();}

逻辑比较简单,就是判断上一个原点,和目前选中的圆点,然后进行颜色和半径的设置修改,在进行重绘操作

最后看比较复杂的mPagerIndicator.setScrollProgress(position,percent);逻辑处理

public void setScrollProgress(int leftPosition, float percent) {right = circles.get(leftPosition + 1);left = circles.get(leftPosition);// 手指右滑-递减if (lastPercent > percent) {left.radius = circleRadius + (1 - percent)* PhoneUtils.dp2px(getContext(), 2);right.radius = circleRadius + percent* PhoneUtils.dp2px(getContext(), 2);if (left.color == normalCircleColor) {left.color = ColorHelper.evaluate(percent, normalCircleColor,acitiveCircleColor);} else {left.color = ColorHelper.evaluate(percent, acitiveCircleColor,normalCircleColor);}if (right.color == normalCircleColor) {right.color = ColorHelper.evaluate(1 - percent,normalCircleColor, acitiveCircleColor);} else {right.color = ColorHelper.evaluate(1 - percent,acitiveCircleColor, normalCircleColor);}}// 手指左滑-递增if (lastPercent < percent) {left.radius = circleRadius + (1 - percent)* PhoneUtils.dp2px(getContext(), 2);right.radius = circleRadius + percent* PhoneUtils.dp2px(getContext(), 2);if (right.color == normalCircleColor) {right.color = ColorHelper.evaluate(1 - percent,normalCircleColor, acitiveCircleColor);} else {right.color = ColorHelper.evaluate(1 - percent,acitiveCircleColor, normalCircleColor);}if (left.color == normalCircleColor) {left.color = ColorHelper.evaluate(percent, normalCircleColor,acitiveCircleColor);} else {left.color = ColorHelper.evaluate(percent, acitiveCircleColor,normalCircleColor);}}invalidate();lastPercent = percent;}

以上的代码,我感觉还有bug,不过效果基本上出来了,就是判断左右滑动的方向,进行颜色的变化修改


另外还有一下工具类

MeasureUtil

package com.example.pageindicator;  import android.app.Activity;  
import android.util.DisplayMetrics;  /** * 测绘工具�? */  
public final class MeasureUtil {  /** * 获取屏幕尺寸 *  * @param activity *            Activity * @return 屏幕尺寸像素值,下标�?的�?为宽,下标为1的�?为高 */  public static float[] getScreenSize(Activity activity) {  DisplayMetrics metrics = new DisplayMetrics();  activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);  return new float[] { metrics.widthPixels, metrics.heightPixels };  }  
}  


PhoneUtils

package com.example.pageindicator;  import android.content.Context;  public class PhoneUtils {  public static int dp2px(Context context,float dpValue){  float scale = context.getResources().getDisplayMetrics().density;  return (int)(dpValue * scale +0.5f);  }  
}  

ColorHelper

package com.example.pageindicator;import android.animation.ArgbEvaluator;
import android.graphics.Color;public class ColorHelper {private static final String TAG = "ColorHelper";private static ArgbEvaluator colorEvaluator = new ArgbEvaluator();public static Integer evaluate(float fraction,int start,int end ){return (Integer) colorEvaluator.evaluate(fraction, start, end);}}


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