Path類可以預先在View上將N個點連成一條"路徑",然后調用Canvas的drawPath(path,paint)即可沿著路徑繪制圖形

Android還為路徑繪制提供了PathEffect來定義繪制效果,PathEffect包含如下子類

ComposePathEffect

CornerPathEffect

DashPathEffect

DiscretePathEffect

PathDashPathEffect

SumPathEffect

下面的示例將會逐一使用上面的繪制效果

[java]?view plaincopyprint?

package?WangLi.Graphics.PathTest;??

??

import?android.app.Activity;??

import?android.content.Context;??

import?android.graphics.Canvas;??

import?android.graphics.Color;??

import?android.graphics.ComposePathEffect;??

import?android.graphics.CornerPathEffect;??

import?android.graphics.DashPathEffect;??

import?android.graphics.DiscretePathEffect;??

import?android.graphics.Paint;??

import?android.graphics.Path;??

import?android.graphics.PathDashPathEffect;??

import?android.graphics.PathEffect;??

import?android.graphics.SumPathEffect;??

import?android.os.Bundle;??

import?android.view.View;??

??

public?class?PathTest?extends?Activity?{??

????/**?Called?when?the?activity?is?first?created.?*/??

????@Override??

????public?void?onCreate(Bundle?savedInstanceState)?{??

????????super.onCreate(savedInstanceState);??

????????setContentView(new?MyView(this));??

????}??

????class?MyView?extends?View??

????{??

????????float?phase;??

????????PathEffect[]?effects?=?new?PathEffect[7];??

????????int[]?colors;??

????????private?Paint?paint;??

????????Path?path;??

????????public?MyView(Context?context)?{??

????????????super(context);??

????????????paint?=?new?Paint();??

????????????paint.setStyle(Paint.Style.STROKE);??

????????????paint.setStrokeWidth(4);??

????????????//創建,并初始化Path??

????????????path?=?new?Path();??

????????????path.moveTo(0,?0);??

????????????for(int?i?=?1;?i<=?15;?i++)??

????????????{??

????????????????//生成15個點,隨機生成它們的坐標,并將它們連成一條Path??

????????????????path.lineTo(i*20,?(float)Math.random()*60);??

????????????}??

????????????//初始化七個顏色??

????????????colors?=?new?int[]?{??

????????????????????Color.BLACK,Color.BLUE,Color.CYAN,??

????????????????????Color.GREEN,Color.MAGENTA,Color.RED,Color.YELLOW??

????????????};??

????????}??

????????protected?void?onDraw(Canvas?canvas)??

????????{??

????????????//將背景填充成白色??

????????????canvas.drawColor(Color.WHITE);??

????????????//-------下面開始初始化7中路徑的效果??

????????????//使用路徑效果??

????????????effects[0]?=?null;??

????????????//使用CornerPathEffect路徑效果??

????????????effects[1]?=?new?CornerPathEffect(10);??

????????????//初始化DiscretePathEffect??

????????????effects[2]?=?new?DiscretePathEffect(3.0f,5.0f);??

????????????//初始化DashPathEffect??

????????????effects[3]?=?new?DashPathEffect(new?float[]{20,10,5,10},phase);??

????????????//初始化PathDashPathEffect??

????????????Path?p?=?new?Path();??

????????????p.addRect(0,?0,?8,?8,?Path.Direction.CCW);??

????????????effects[4]?=?new?PathDashPathEffect(p,12,phase,PathDashPathEffect.Style.ROTATE);??

????????????//初始化PathDashPathEffect??

????????????effects[5]?=?new?ComposePathEffect(effects[2],effects[4]);??

????????????effects[6]?=?new?SumPathEffect(effects[4],effects[3]);??

????????????//將畫布移到8,8處開始繪制??

????????????canvas.translate(8,?8);??

????????????//依次使用7中不同路徑效果,7種不同的顏色來繪制路徑??

????????????for(int?i?=?0;?i?<?effects.length;?i++)??

????????????{??

????????????????paint.setPathEffect(effects[i]);??

????????????????paint.setColor(colors[i]);??

????????????????canvas.drawPath(path,?paint);??

????????????????canvas.translate(0,?60);??

????????????}??

????????????//改變phase值,形成動畫效果??

????????????phase?+=?1;??

????????????invalidate();??

????????}??

????}??

}??

效果如下

總結

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