Android绘图基础之: Canvas 和 Paint

package com.test.canvasdemo;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.view.View;

/**
* Created by Administrator on 2016/6/24.
*/
public class MyView extends View {

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

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

//把整张画布设置成白色
canvas.drawColor(Color.WHITE);

Paint paint = new Paint(); //设置画笔

paint.setAntiAlias(true); //设置 抗锯齿
paint.setColor(Color.BLUE);  //设置 画笔颜色
paint.setStyle(Paint.Style.STROKE);  //设置画笔的填充风格
paint.setStrokeWidth(3); //设置画笔的触屏宽度

//绘制圆形
canvas.drawCircle(40, 40, 30, paint);

//绘制正方形
canvas.drawRect(10, 80, 70, 140, paint);

//绘制矩形
canvas.drawRect(10, 150, 70, 190, paint);

//绘制圆角矩形
RectF rel = new RectF(10, 200, 70, 230);
canvas.drawRoundRect(rel, 15, 15, paint);

//绘制椭圆
RectF rell = new RectF(10, 240, 70, 270);
canvas.drawOval(rell, paint);

//定义一个 path对象,封闭成一个三角形
Path path1 = new Path();

path1.moveTo(10, 340);
path1.lineTo(70, 340);
path1.lineTo(40, 290);
path1.close();

//根据Path进行绘制,绘制三角形
canvas.drawPath(path1, paint);

//定义一个path 对象封闭成一个五角星
Path path2 = new Path();

path2.moveTo(26, 360);
path2.lineTo(54, 360);
path2.lineTo(70, 392);
path2.lineTo(40, 420);
path2.lineTo(10, 392);
path2.close();
canvas.drawPath(path2, paint);

//*************设置填充风格后的绘制______________-------
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.RED);

canvas.drawCircle(120, 40, 30, paint);

//绘制正方形
canvas.drawRect(90, 80, 150, 140, paint);

//绘制矩形
canvas.drawRect(90, 150, 150, 190, paint);
RectF re2 = new RectF(90, 200, 150, 230);
//绘制圆角矩形
canvas.drawRoundRect(re2,15,15,paint);

//绘制椭圆
RectF re21 = new RectF(90,240,150,270);
canvas.drawOval(re21,paint);

Path path3 = new Path();
path3.moveTo(90,340);
path3.lineTo(150, 340);
path3.lineTo(120,290);
path3.close();

//绘制三角形
canvas.drawPath(path3,paint);

//绘制5角形
Path path4 = new Path();
path4.moveTo(106,360);
path4.lineTo(134, 360);
path4.lineTo(150, 392);
path4.lineTo(120, 420);
path4.lineTo(90,392);

path4.close();
canvas.drawPath(path4, paint);

//************设置渐变器后绘制************

Shader shader = new LinearGradient(0,0,40,60,
new int[]{Color.RED,Color.GREEN,Color.BLUE,Color.YELLOW,},null,Shader.TileMode.REPEAT);

paint.setShader(shader);

//设置阴影
paint.setShadowLayer(45, 10, 10, Color.GRAY);

//绘制圆形
canvas.drawCircle(200, 40, 30, paint);

//绘制正方形
canvas.drawRect(170, 80, 230, 140, paint);

//绘制矩形
canvas.drawRect(170, 150, 230, 190, paint);

//绘制圆角矩形
RectF ref3 = new RectF(170,200,230,230);
canvas.drawRoundRect(ref3, 15, 15, paint);

//绘制椭圆
RectF ref31 = new RectF(170,240,230,240);

canvas.drawOval(ref31, paint);

Path path5 = new Path();
path5.moveTo(170, 340);
path5.lineTo(230, 340);
path5.lineTo(200,290);
path5.close();

canvas.drawPath(path5, paint);

//绘制五角形
Path path6 = new Path();
path6.moveTo(186, 360);
path6.lineTo(214, 360);
path6.lineTo(230, 392);
path6.lineTo(200,420);
path6.lineTo(170, 392);
path6.close();
canvas.drawPath(path6, paint);

//------------设置字符大小后的绘制-----

paint.setTextSize(24);
paint.setShader(null);

//绘制7个字符串

canvas.drawText(getResources().getString(R.string.circle),240,50,paint);
canvas.drawText(getResources().getString(R.string.square),240,120,paint);
canvas.drawText(getResources().getString(R.string.rect),240,175,paint);
canvas.drawText(getResources().getString(R.string.round_rect),230,220,paint);
canvas.drawText(getResources().getString(R.string.oval),240,260,paint);
canvas.drawText(getResources().getString(R.string.triangle),240,325,paint);
canvas.drawText(getResources().getString(R.string.pentagon),240,390,paint);
}
}

布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<com.test.canvasdemo.MyView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>

主界面　很简单

package com.test.canvasdemo;
import android.app.Activity;
import android.os.Bundle;

/**
* Canvas("画布") 和 Paint("画笔")
*/
public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}