【文件属性】：
文件名称：txt文档阅读器
文件大小：2.32MB
文件格式：RAR
更新时间：2018-07-14 03:55:49
txt 阅读器
package cn.huang.my_txtreader;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.text.DecimalFormat;
import java.util.Vector;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Align;
public class BookPageFactory {
//把字体绘制到界面上
private File book_file = null;
private MappedByteBuffer m_mbBuf = null;//MappedByteBuffer 将文件直接映射到内存
private int m_mbBufLen = 0;
private int m_mbBufBegin = 0;
private int m_mbBufEnd = 0;
private String m_strCharsetName = "gbk";//文本格式
private Bitmap m_book_bg = null;//文本图像
private int mWidth;
private int mHeight;
private Vector m_lines = new Vector();
//用于一行一行显示
private int m_fontSize = 24;
private int m_textColor = Color.BLACK;//字体颜色
private int m_backColor = 0xffff9e85; // 背景颜色
private int marginWidth = 15; // 左右与边缘的距离
private int marginHeight = 20; // 上下与边缘的距离
private int mLineCount; // 每页可以显示的行数
private float mVisibleHeight; // 绘制内容的宽
private float mVisibleWidth; // 绘制内容的宽
private boolean m_isfirstPage,m_islastPage;
// private int m_nLineSpaceing = 5;
private Paint mPaint;
//设置阅读界面，包括字体，显示多少行
public BookPageFactory(int w, int h) {
// TODO Auto-generated constructor stub
mWidth = w;
mHeight = h;//获得宽和高
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setTextAlign(Align.LEFT);//设置文本对齐方式
mPaint.setTextSize(m_fontSize);//设置字体大小
mPaint.setColor(m_textColor);//设置颜色
mVisibleWidth = mWidth - marginWidth * 2;
mVisibleHeight = mHeight - marginHeight * 2;//绘制的内容宽和高
mLineCount = (int) (mVisibleHeight / m_fontSize); // 可显示的行数
}
//获得文件，并映射到内存
public void openbook(String strFilePath) throws IOException {
book_file = new File(strFilePath);
long lLen = book_file.length();//文本长度
m_mbBufLen = (int) lLen;//缓存的长度
m_mbBuf = new RandomAccessFile(book_file, "r").getChannel().map(
FileChannel.MapMode.READ_ONLY, 0, lLen);
//RandomAccessFile是用来访问那些保存数据记录的文件的
}
//读一段
protected byte[] readParagraphBack(int nFromPos) {
int nEnd = nFromPos;//字符缓存开始的位置
int i;
byte b0, b1;
if (m_strCharsetName.equals("UTF-16LE")) {
i = nEnd - 2;//？
while (i > 0) {
b0 = m_mbBuf.get(i);
b1 = m_mbBuf.get(i + 1);
if (b0 == 0x0a && b1 == 0x00 && i != nEnd - 2) {
i += 2;
break;
}
i--;
}
} else if (m_strCharsetName.equals("UTF-16BE")) {
i = nEnd - 2;
while (i > 0) {
b0 = m_mbBuf.get(i);//返回指定索引
b1 = m_mbBuf.get(i + 1);
if (b0 == 0x00 && b1 == 0x0a && i != nEnd - 2) {
i += 2;
break;
}//过段时
i--;
}
} else {
i = nEnd - 1;//？
while (i > 0) {
b0 = m_mbBuf.get(i);
if (b0 == 0x0a && i != nEnd - 1) {
i++;
break;
}//过段时
i--;
}
}
if (i < 0)
i = 0;
//i是过段的索引位置
int nParaSize = nEnd - i;
int j;
byte[] buf = new byte[nParaSize];
for (j = 0; j < nParaSize; j++) {
buf[j] = m_mbBuf.get(i + j);
}
return buf;
}
// 读取上一段落
protected byte[] readParagraphForward(int nFromPos) {
int nStart = nFromPos;//字符缓存开始的位置
int i = nStart;
byte b0, b1;
// 根据编码格式判断换行
if (m_strCharsetName.equals("UTF-16LE")) {
while (i < m_mbBufLen - 1) {
b0 = m_mbBuf.get(i++);
b1 = m_mbBuf.get(i++);
if (b0 == 0x0a && b1 == 0x00) {
break;
}
}
} else if (m_strCharsetName.equals("UTF-16BE")) {
while (i < m_mbBufLen - 1) {
b0 = m_mbBuf.get(i++);
b1 = m_mbBuf.get(i++);
if (b0 == 0x00 && b1 == 0x0a) {
break;
}
}
} else {
while (i < m_mbBufLen) {
b0 = m_mbBuf.get(i++);
if (b0 == 0x0a) {
break;
}
}
}
//这使i在换行的索引位置
int nParaSize = i - nStart;
byte[] buf = new byte[nParaSize];
for (i = 0; i < nParaSize; i++) {
buf[i] = m_mbBuf.get(nFromPos + i);
}//把读到的段输入字节流中
return buf;
}
protected Vector pageDown() {
String strParagraph = "";
Vector lines = new Vector();
while (lines.size() < mLineCount && m_mbBufEnd < m_mbBufLen) {
//不能大于给定的最多行数
byte[] paraBuf = readParagraphForward(m_mbBufEnd); // 读取一个段落
m_mbBufEnd += paraBuf.length;
//减去读到的长度，作为下一个结束的地步
try {
strParagraph = new String(paraBuf, m_strCharsetName);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String strReturn = "";
if (strParagraph.indexOf("\r\n") != -1) {
//"\r\n"在字符串中则，下同
strReturn = "\r\n";
strParagraph = strParagraph.replaceAll("\r\n", "");
} else if (strParagraph.indexOf("\n") != -1) {
strReturn = "\n";
strParagraph = strParagraph.replaceAll("\n", "");
}
if (strParagraph.length() == 0) {
lines.add(strParagraph);
}
while (strParagraph.length() > 0) {
int nSize = mPaint.breakText(strParagraph, true, mVisibleWidth,
null);
//返回刚好要超过规定长度mVisibleWidth的值
lines.add(strParagraph.substring(0, nSize));
strParagraph = strParagraph.substring(nSize);
if (lines.size() >= mLineCount) {//超过规定的行数
break;
}
}
if (strParagraph.length() != 0) {
try {
m_mbBufEnd -= (strParagraph + strReturn)
.getBytes(m_strCharsetName).length;
//即返回字符串在GBK、UTF-8和ISO8859-1编码下的byte数组表示
//目的在于把m_mbBufEnd改成指向下一行
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return lines;
}
//设置文本显示
//预防文本超过界面规定的范围
protected void pageUp() {
if (m_mbBufBegin < 0)
m_mbBufBegin = 0;
Vector lines = new Vector();
String strParagraph = "";
while (lines.size() < mLineCount && m_mbBufBegin > 0) {
//不能大于给定的最多行数
Vector paraLines = new Vector();
byte[] paraBuf = readParagraphBack(m_mbBufBegin);
//读到一段
//从头开始读
m_mbBufBegin -= paraBuf.length;
//减去读到的长度，作为下一个开始要读的标志
try {
strParagraph = new String(paraBuf, m_strCharsetName);
//第一个参数读到的字符串，第二个参数是文本格式
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
strParagraph = strParagraph.replaceAll("\r\n", "");
//用第二个参数的字符串替换第一个
strParagraph = strParagraph.replaceAll("\n", "");
//替换掉任何过行的记录
if (strParagraph.length() == 0) {//为空，没有字符串时
paraLines.add(strParagraph);
}
while (strParagraph.length() > 0) {
int nSize = mPaint.breakText(strParagraph, true, mVisibleWidth,
null);
//测量第一个字符串，与第三个参数即宽度相比
paraLines.add(strParagraph.substring(0, nSize));
//获得0到nSize的字符串
strParagraph = strParagraph.substring(nSize);
//字符串变成从nSize开始
}//在于把字符串变成不会超过规定长度mVisibleWidth的字符串
lines.addAll(0, paraLines);//加入所有Vector字符串列
}
while (lines.size() > mLineCount) {//超过规定行数时
try {
m_mbBufBegin += lines.get(0).getBytes(m_strCharsetName).length;
//.get()表示返回指定位置的元素
//String的getBytes()方法是得到一个操作系统默认的编码格式的字节数组
//即返回字符串在GBK、UTF-8和ISO8859-1编码下的byte数组表示
//目的在于把m_mbBufBegin改成指向下一行
lines.remove(0);
//删除指定位置的元素
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
m_mbBufEnd = m_mbBufBegin;
return;
}
protected void prePage() throws IOException {
if (m_mbBufBegin <= 0) {
m_mbBufBegin = 0;
m_isfirstPage=true;
return;
}else
m_isfirstPage=false;
m_lines.clear();
//删除所有元素
pageUp();
m_lines = pageDown();
//把收集到的文本放到m_lines中
}
public void nextPage() throws IOException {
if (m_mbBufEnd >= m_mbBufLen) {
m_islastPage=true;
return;
}else m_islastPage=false;
m_lines.clear();
m_mbBufBegin = m_mbBufEnd;
m_lines = pageDown();
}
public void onDraw(Canvas c) {
if (m_lines.size() == 0)
m_lines = pageDown();
//现在m_lines的格式是按照
//界面阅读规定的，即有多宽的，有多行
if (m_lines.size() > 0) {
if (m_book_bg == null)
c.drawColor(m_backColor);//设置背景颜色
else
c.drawBitmap(m_book_bg, 0, 0, null);
int y = marginHeight;
for (String strLine : m_lines) {
y += m_fontSize;
c.drawText(strLine, marginWidth, y, mPaint);
//给界面的每一行绘制
}
}
float fPercent = (float) (m_mbBufBegin * 1.0 / m_mbBufLen);
DecimalFormat df = new DecimalFormat("#0.0");//用于格式化十进制数字
//即按照参数的格式输出
String strPercent = df.format(fPercent * 100) + "%";
int nPercentWidth = (int) mPaint.measureText("999.9%") + 1;
//返回字符串的宽度
c.drawText(strPercent, mWidth - nPercentWidth, mHeight - 5, mPaint);
}
//绘制图像
public void setBgBitmap(Bitmap BG) {
m_book_bg = BG;
}
//返回第一页
public boolean isfirstPage() {
return m_isfirstPage;
}
//返回最后一页
public boolean islastPage() {
return m_islastPage;
}
}
