自定义EditText编辑框

package com.example.administrator.app3;

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

/**
* Created by Administrator on 2016/6/17 0017.
* 继承编辑框控件
*/
public class MyNotePad extends EditText {
private Paint paint;

public MyNotePad(Context context) {
super(context);
init();
}

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

private void init() {
paint = new Paint();
paint.setAntiAlias(true);
paint.setStrokeWidth(2);
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.RED);

}

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

this.setGravity(Gravity.TOP);//从上面开始写
this.setBackgroundColor(Color.TRANSPARENT);//背景颜色

int height = getHeight();//高度
int width = getWidth();//宽度
int lineHeight=getLineHeight();//每一行的高度

int lines=height/lineHeight;//显示多少行

for(int i=0;i<lines;i++){
canvas.drawLine(0,(i+1)*lineHeight+lineHeight/2,width,(i+1)*lineHeight+lineHeight/2,paint);
}

int count=getLineCount();//获取总行数
if(count>lines){
//在原来的基础上增加
for(int i=0;i<count;i++){
canvas.drawLine(0,(i+1)*lineHeight+lineHeight/2,width,(i+1)*lineHeight+lineHeight/2,paint);
}

}

}
}

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.administrator.app3.MainActivity">

<com.example.administrator.app3.MyNotePad
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</ScrollView>