本节引言：
1.相关方法详解
1)Paint(画笔):
2)Canvas(画布):
3)Path(路径)
2.动手试试：
/**
* Created by Jay on 2015/10/15 0015.
*/
public class MyView extends View{
private Paint mPaint;
public MyView(Context context) {
super(context);
init();
}
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init(){
mPaint = new Paint();
mPaint.setAntiAlias(true); //抗锯齿
mPaint.setColor(getResources().getColor(R.color.puple));//画笔颜色
mPaint.setStyle(Paint.Style.FILL); //画笔风格
mPaint.setTextSize(36); //绘制文字大小，单位px
mPaint.setStrokeWidth(5); //画笔粗细
}
//重写该方法，在这里绘图
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
}
}
然后布局那里设置下这个View就好，下述代码都写在onDrawable中~
1）设置画布颜色：
canvas.drawColor(getResources().getColor(R.color.yellow)); //设置画布背景颜色
2）绘制圆形：
canvas.drawCircle(200, 200, 100, mPaint); //画实心圆
3）绘制矩形：
canvas.drawRect(0, 0, 200, 100, mPaint); //画矩形
4）绘制Bitmap：
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher), 0, 0, mPaint);
5）绘制弧形区域：
canvas.drawArc(new RectF(0, 0, 100, 100),0,90,true,mPaint); //绘制弧形区域
假如true改为false：
6）绘制圆角矩形
canvas.drawRoundRect(new RectF(10,10,210,110),15,15,mPaint); //画圆角矩形
7）绘制椭圆
canvas.drawOval(new RectF(0,0,200,300),mPaint); //画椭圆
8)绘制多边形：
Path path = new Path(); path.moveTo(10, 10); //移动到 坐标10,10 path.lineTo(100, 50); path.lineTo(200,40); path.lineTo(300, 20); path.lineTo(200, 10); path.lineTo(100, 70); path.lineTo(50, 40); path.close(); canvas.drawPath(path,mPaint);
9)绘制文字：
canvas.drawText("最喜欢看曹神日狗了~",50,50,mPaint); //绘制文字
你也可以沿着某条Path来绘制这些文字：
Path path = new Path();
path.moveTo(50,50);
path.lineTo(100, 100);
path.lineTo(200, 200);
path.lineTo(300, 300);
path.close();
canvas.drawTextOnPath("最喜欢看曹神日狗了~", path, 50, 50, mPaint); //绘制文字
10)绘制自定义的图形：
代码来源于网上：
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.translate(canvas.getWidth()/2, 200); //将位置移动画纸的坐标点:150,150
canvas.drawCircle(0, 0, 100, mPaint); //画圆圈
//使用path绘制路径文字
canvas.save();
canvas.translate(-75, -75);
Path path = new Path();
path.addArc(new RectF(0,0,150,150), -180, 180);
Paint citePaint = new Paint(mPaint);
citePaint.setTextSize(14);
citePaint.setStrokeWidth(1);
canvas.drawTextOnPath("绘制表盘~", path, 28, 0, citePaint);
canvas.restore();
Paint tmpPaint = new Paint(mPaint); //小刻度画笔对象
tmpPaint.setStrokeWidth(1);
float y=100;
int count = 60; //总刻度数
for(int i=0 ; i <count ; i++){
if(i%5 == 0){
canvas.drawLine(0f, y, 0, y+12f, mPaint);
canvas.drawText(String.valueOf(i/5+1), -4f, y+25f, tmpPaint);
}else{
canvas.drawLine(0f, y, 0f, y +5f, tmpPaint);
}
canvas.rotate(360/count,0f,0f); //旋转画纸
}
//绘制指针
tmpPaint.setColor(Color.GRAY);
tmpPaint.setStrokeWidth(4);
canvas.drawCircle(0, 0, 7, tmpPaint);
tmpPaint.setStyle(Paint.Style.FILL);
tmpPaint.setColor(Color.YELLOW);
canvas.drawCircle(0, 0, 5, tmpPaint);
canvas.drawLine(0, 10, 0, -65, mPaint);
}
