Android自定义水平或垂直虚线效果

package com.chen.demo;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.DashPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathEffect;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;

/**
 * 自定义垂直虚线view
 * chenjianqiang
 * 2017/6/14
 * 

 * 使用方法：
 * 在代码中findview之后，调用setLineAttribute方法，自定义虚线颜色及宽度
 */
public class ImaginaryLineView extends View {

 private Context ct;
 private Paint mPaint;
 private Path mPath;
 private PathEffect effects;
 private int width;
 private int height;

 private int defaultColor=0xffff0000;

 public ImaginaryLineView(Context context) {
 this(context, null);
 }

 public ImaginaryLineView(Context context, @Nullable AttributeSet attrs) {
 this(context, attrs, -1);
 }

 public ImaginaryLineView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);

 ct = context;
 init();
 }

 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
 super.onSizeChanged(w, h, oldw, oldh);
 width = w;
 height = h;

 }

 private void init() {

 //初始化，并打开抗锯齿
 mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mPaint.setStyle(Paint.Style.STROKE);
 mPaint.setColor(defaultColor);
 mPaint.setStrokeWidth(dip2px(ct, 1));

 mPath = new Path();
 //数组含义：里面最少要有2个值，值的个数必须是偶数个。偶数位（包含0），表示实线长度，奇数位表示断开的长度
 effects = new DashPathEffect(new float[]{4, 2}, 0);


 }

 /**
 * 设置线的必要属性
 *
 * @param color 十六进制颜色值
 * @param lineWidth 虚线宽度，单位是dp
 */
 public void setLineAttribute(int color, float lineWidth,float[] f) {

 if (color == 0) {
  color = defaultColor;
 }
 if (lineWidth == 0) {
  lineWidth = 1;
 }
 if(f==null){
  f=new float[]{4,2};
 }
 effects = new DashPathEffect(f, 0);

 mPaint.setStrokeWidth(dip2px(ct, lineWidth));
 mPaint.setColor(color);

 invalidate();
 }

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

 //定义起点
 mPath.moveTo(0, 0);
 //定义终点
 if(width>height){
  //宽度比高度大，是横线
  mPath.lineTo(width, 0);
 }else{
  //竖线。（根据实际情况，这里不考虑宽高相等情况）
  mPath.lineTo(0, height);
 }

 mPaint.setPathEffect(effects);

 canvas.drawPath(mPath, mPaint);
 }

 private static int dip2px(Context context, float dpValue) {
 final float scale = context.getResources().getDisplayMetrics().density;
 return (int) (dpValue * scale + 0.5f);
 }

}

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package com.chen.demo;

import android.app.Activity;
import android.os.Bundle;
import android.view.Window;

public class MainActivity extends Activity {

 private ImaginaryLineView horizontal_line;
 private ImaginaryLineView vertical_line;

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

 horizontal_line= (ImaginaryLineView) findViewById(R.id.horizontal_line);
 horizontal_line.setLineAttribute(0xff00ff00,5,null);


 vertical_line= (ImaginaryLineView) findViewById(R.id.vertical_line);
 vertical_line.setLineAttribute(0xff0000ff,5,new float[]{10,2,5,5});


 }

}