Android中绘制虚线

2024-01-10 23:32

文章标签 android 绘制虚线

本文主要是介绍Android中绘制虚线，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！

概述

今天给大家介绍两种实现虚线的方式

方式一：利用shape绘制

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"android:shape="line"><stroke
        android:width="3px"android:color="#FF0000"android:dashWidth="10px"android:dashGap="10px" />
</shape>

下面对属性进行一下介绍：

width:线段的高度
color:线段的颜色
dashWidth:线段宽度
dashGap:线段之间间隔宽度

然后在布局文件中使用如下：

 <View
        android:layout_width="match_parent"android:layout_height="wrap_content"android:background="@drawable/dash_view"android:layerType="software"/>

在4.0的设备上，虚线会变成实线，我们需要加入 android:layerType=”software”属性

方式二：自定义View绘制虚线

这种方式更加灵活，可以实现水平和竖直方向的虚线，当然实现的难度也要高于第一种方式

先看效果图

水平虚线
这里写图片描述

竖直虚线
这里写图片描述

最后给出代码的实现

public class DashView extends View {private static final String TAG = "DashView";public static final int DEFAULT_DASH_WIDTH = 100;public static final int DEFAULT_LINE_WIDTH = 100;public static final int DEFAULT_LINE_HEIGHT = 10;public static final int DEFAULT_LINE_COLOR = 0x9E9E9E;/**虚线的方向*/public static final int ORIENTATION_HORIZONTAL = 0;public static final int ORIENTATION_VERTICAL = 1;/**默认为水平方向*/public static final int DEFAULT_DASH_ORIENTATION = ORIENTATION_HORIZONTAL;/**间距宽度*/private float dashWidth;/**线段高度*/private float lineHeight;/**线段宽度*/private float lineWidth;/**线段颜色*/private int lineColor;private int dashOrientation;private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);private int widthSize;private int heightSize;public DashView(Context context) {this(context,null);}public DashView(Context context, AttributeSet attrs) {super(context, attrs);TypedArray typedArray = context.obtainStyledAttributes(attrs,R.styleable.DashView);dashWidth = typedArray.getDimension(R.styleable.DashView_dashWidth,DEFAULT_DASH_WIDTH);lineHeight = typedArray.getDimension(R.styleable.DashView_lineHeight, DEFAULT_LINE_HEIGHT);lineWidth = typedArray.getDimension(R.styleable.DashView_lineWidth, DEFAULT_LINE_WIDTH);lineColor = typedArray.getColor(R.styleable.DashView_lineColor, DEFAULT_LINE_COLOR);dashOrientation = typedArray.getInteger(R.styleable.DashView_dashOrientation,DEFAULT_DASH_ORIENTATION);mPaint.setColor(lineColor);mPaint.setStrokeWidth(lineHeight);typedArray.recycle();}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);widthSize = MeasureSpec.getSize(widthMeasureSpec)-getPaddingLeft()-getPaddingRight();heightSize = MeasureSpec.getSize(heightMeasureSpec - getPaddingTop() - getPaddingBottom());Log.d(TAG, "onMeasure: "+widthSize+"----"+heightSize);Log.d(TAG, "dashOrientation: "+dashOrientation);if(dashOrientation == ORIENTATION_HORIZONTAL){//不管在布局文件中虚线高度设置为多少，虚线的高度统一设置为实体线段的高度setMeasuredDimension(widthSize, (int) lineHeight);}else{setMeasuredDimension((int) lineHeight, heightSize);}}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);switch (dashOrientation){case ORIENTATION_VERTICAL:drawVerticalLine(canvas);break;default:drawHorizontalLine(canvas);}}/*** 画水平方向虚线* @param canvas*/public void drawHorizontalLine(Canvas canvas){float totalWidth = 0;canvas.save();float[] pts = {0,0,lineWidth,0};//在画线之前需要先把画布向下平移办个线段高度的位置，目的就是为了防止线段只画出一半的高度//因为画线段的起点位置在线段左下角canvas.translate(0,lineHeight/2);while(totalWidth<=widthSize){canvas.drawLines(pts,mPaint);canvas.translate(lineWidth + dashWidth,0);totalWidth += lineWidth + dashWidth;}canvas.restore();}/*** 画竖直方向虚线* @param canvas*/public void drawVerticalLine(Canvas canvas){float totalWidth = 0;canvas.save();float[] pts = {0,0,0,lineWidth};//在画线之前需要先把画布向右平移半个线段高度的位置，目的就是为了防止线段只画出一半的高度//因为画线段的起点位置在线段左下角canvas.translate(lineHeight/2,0);while(totalWidth<=heightSize){canvas.drawLines(pts,mPaint);canvas.translate(0,lineWidth + dashWidth);totalWidth += lineWidth + dashWidth;}canvas.restore();}
}