/**
* 指针移到上一页页首
*/
private void pageUp()
{
Java.Lang.String strParagraph = new Java.Lang.String();
Vector lines = new Vector(); // 页面行
int paraSpace = 0;
mPageLineCount = mVisibleHeight / (mFontSize + mLineSpace);
while ((lines.Size() < mPageLineCount) && (curBeginPos > 0))
{
Vector paraLines = new Vector(); // 段落行
byte[] parabuffer = readParagraphBack(curBeginPos); // 1.读取上一个段落
curBeginPos -= parabuffer.Length; // 2.变换起始位置指针
try
{
strParagraph = new Java.Lang.String(parabuffer, charset);
}
catch (UnsupportedEncodingException e)
{
e.PrintStackTrace();
}
strParagraph = new Java.Lang.String(strParagraph.ReplaceAll("\r\n", " "));
strParagraph = new Java.Lang.String(strParagraph.ReplaceAll("\n", " "));
while (strParagraph.Length() > 0)
{ // 3.逐行添加到lines
int paintSize = mPaint.BreakText(strParagraph.ToString(), true, mVisibleWidth, null);
paraLines.Add(strParagraph.Substring(0, paintSize));
strParagraph = new Java.Lang.String(strParagraph.Substring(paintSize));
}
lines.AddAll(0, paraLines.ToArray());
while (lines.Size() > mPageLineCount)
{ // 4.如果段落添加完，但是超出一页，则超出部分需删减
try
{
curBeginPos += (new Java.Lang.String(lines.Get(0).ToString())).GetBytes(charset).Length; // 5.删减行数同时起始位置指针也要跟着偏移
lines.Remove(0);
}
catch (UnsupportedEncodingException e)
{
e.PrintStackTrace();
}
}
curEndPos = curBeginPos; // 6.最后结束指针指向下一段的开始处
paraSpace += mLineSpace;
mPageLineCount = (mVisibleHeight - paraSpace) / (mFontSize + mLineSpace); // 添加段落间距，实时更新容纳行数
}
}
