使用Canvas的drawTextOnPath方法实现沿着Path绘制文本

Android的Canvas提供了一个drawTextOnPath(String text,Path path,float hOffset,float vOffset,Paint paint)方法，该方法可以沿着Path路径绘制文本，其中text指文本内容，hOffset参数指定水平偏移、vOffset指定垂直偏移，下面用一个简单实例来演示，代码如下：

Activity：

package com.lovo.testcanvasactivity;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.View;

public class TestPathActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new MyView(this));
	}

	class MyView extends View {
		final String DRAW_STR = "天行健，君子以自强不息";
		// 画笔
		private Paint paint;
		// 声明路径对象数组
		Path[] paths = new Path[3];

		public MyView(Context context) {
			super(context);
			paths[0] = new Path();
			paths[0].moveTo(0, 0);
			for (int i = 0; i <= 7; i++) {
				// 生成7个点，随机生成Y坐标，并连成一条
				paths[0].lineTo(i * 30, (float) Math.random() * 30);
			}
			paths[1] = new Path();
			RectF rectF = new RectF(0, 0, 200, 120);
			paths[1].addOval(rectF, Path.Direction.CCW);
			paths[2] = new Path();
			paths[2].addArc(rectF, 60, 180);
			// 初始化画笔
			paint = new Paint();
			paint.setAntiAlias(true);
			paint.setColor(Color.CYAN);
			paint.setStrokeWidth(1);
		}

		@Override
		protected void onDraw(Canvas canvas) {
			// 将背景填充为白色
			canvas.drawColor(Color.WHITE);
			canvas.translate(40, 40);
			// 设置从右边开始绘制（右对齐）
			paint.setTextAlign(Paint.Align.RIGHT);
			paint.setTextSize(20);

			// 绘制路径
			paint.setStyle(Paint.Style.STROKE);
			canvas.drawPath(paths[0], paint);
			// 沿着路径绘制一段文本
			paint.setStyle(Paint.Style.FILL);
			canvas.drawTextOnPath(DRAW_STR, paths[0], -8, 20, paint);

			// 画布下移120
			canvas.translate(0, 120);

			// 绘制路径
			paint.setStyle(Paint.Style.STROKE);
			canvas.drawPath(paths[1], paint);
			// 沿着路径绘制一段文本
			paint.setStyle(Paint.Style.FILL);
			canvas.drawTextOnPath(DRAW_STR, paths[1], -20, 20, paint);

			// 画布下移120
			canvas.translate(0, 120);

			// 绘制路径
			paint.setStyle(Paint.Style.STROKE);
			canvas.drawPath(paths[2], paint);
			// 沿着路径绘制一段文本
			paint.setStyle(Paint.Style.FILL);
			canvas.drawTextOnPath(DRAW_STR, paths[2], -10, 20, paint);
		}
	}
}

附上图片效果：