自定义view（使用EditTetx实现记事本特效）

package com.wjt.day43_01_mynoteedittext;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.Gravity;
import android.widget.EditText;

public class MyNoteEditText extends EditText{
   private int lineColor = Color.RED  ;
   private int lineStrokWidth = 1 ;
   private int padding = 10 ;
	public MyNoteEditText(Context context, AttributeSet attrs) {
		super(context, attrs);
		//这句话是让每一行的输入的数据都位于他的左上部分
		setGravity(Gravity.TOP);
		
		TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.MyNoteEditText);
		lineColor = array.getColor(R.styleable.MyNoteEditText_lineColor, lineColor);
		lineStrokWidth = (int) array.getDimension(R.styleable.MyNoteEditText_lineStrokWidth, lineStrokWidth);
		padding = (int) array.getDimension(R.styleable.MyNoteEditText_padding, padding);
		
		array.recycle();
		
		
		//实现内容和划线部分的一一对应
		setPadding(padding, 0, padding, 0);
		
	}

	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		//1,创建一个画笔
		Paint paint = new Paint();
		paint.setAntiAlias(true);
		paint.setColor(lineColor);
		paint.setStrokeWidth(lineStrokWidth);
		
		//2,获取当前整个控件的宽高
	    int viewHeight = getHeight();
		int viewWidth = getWidth() ;
		
		//3，获取EditText中每一行的宽度
		int lineHeight = getLineHeight();
		
		//4，通过计算屏幕中一共能放多少行
		int pageLineCounts = viewHeight/lineHeight ;
		
		//5,使用画布划线
		for (int i = 0; i < pageLineCounts; i++) {
			canvas.drawLine(padding, (i+1)*lineHeight, viewHeight - padding, (i+1)*lineHeight, paint);
		}
		
		//6,实现当文字写到下一页的时候继续划线
		int textLineCount =getLineCount() ; 
		
		if (textLineCount > pageLineCounts) {
			for (int i = pageLineCounts; i < textLineCount; i++) {
				canvas.drawLine(padding, (i+1)*lineHeight, viewHeight - padding, (i+1)*lineHeight, paint);
				
			}
		}
		
		
	}
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name = "NoteEditText">
        <attr name = "lineColor" format="color|reference"/>
        <attr name = "lineStrokeWidth" format="dimension|reference"/>
        <attr name = "padding" format="dimension|reference"/>
    </declare-styleable>
</resources>