Viewpager图片自动轮播，网络图片加载，图片自动刷新

package com.teffy.viewpager;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.Reader;

import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.os.Environment;
import android.util.Log;

public class FileCache {

private static FileCache fileCache; // 本类的引用
private String strImgPath; // 图片保存的路径
private String strJsonPath;// Json保存的路径

private FileCache() {
String strPathHead = null;
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
strPathHead = Environment.getExternalStorageDirectory().toString();
} else{
strPathHead = "/data/data/com.teffy.viewpager";
}
strImgPath = strPathHead + "/vp/images/";
strJsonPath = strPathHead + "/vp/json/";
}

public static FileCache getInstance() {
if (null == fileCache) {
fileCache = new FileCache();
}
return fileCache;
}

public boolean saveData(String strApiUrl, String dataJson,String imgurl, Bitmap bmp) {
String fileName = this.toHexString(strApiUrl);
String imgName = imgurl.substring(
imgurl.lastIndexOf('/') + 2,
imgurl.length());
File jsonFile = new File(strJsonPath);
File imgFile = new File(strImgPath);
if (!jsonFile.exists()) {
jsonFile.mkdirs();
}
if (!imgFile.exists()) {
imgFile.mkdirs();
}
File fTXT = new File(strJsonPath + fileName + ".txt");
File fImg = new File(strImgPath + imgName);
this.writeToFile(dataJson, fTXT);
this.writeToFile(bmp, fImg);
return true;
}

/**
* 保存json数据
* */
public boolean savaJsonData(String strApiUrl, String dataJson) {
String fileName = this.toHexString(strApiUrl);
File jsonFile = new File(strJsonPath);
if (!jsonFile.exists()) {
jsonFile.mkdirs();
}
File fTXT = new File(strJsonPath + fileName + ".txt");
if (fTXT.exists()) {
fTXT.delete();
}
this.writeToFile(dataJson, fTXT);
return true;
}

// 用图片的URL来命名图片，并保存图片
public boolean savaBmpData(String imgurl, Bitmap bmp) {
String imgName = imgurl.substring(
imgurl.lastIndexOf('/') + 2,
imgurl.length());
File imgFileDirs = new File(strImgPath);
if (!imgFileDirs.exists()) {
imgFileDirs.mkdirs();
}
File fImg = new File(strImgPath + imgName);
if (fImg.exists()) {
fImg.delete();
}
this.writeToFile(bmp, fImg);
return true;
}

// 自己给图片命名并保存图片
public boolean saveBmpDataByName(String bmpName, Bitmap bmp) {
File imgFileDirs = new File(strImgPath);
if (!imgFileDirs.exists()) {
imgFileDirs.mkdirs();
}
File fImg = new File(strImgPath + bmpName);
if (fImg.exists()) {
fImg.delete();
}
this.writeToFile(bmp, fImg);
return true;
}

/**
*
* 参数fileName需与 fileName和saveData()方法中的fileName参数一致时，才能读出与保存时一致的数据
*
* */
public String getJson(String strApiUrl) {
String fileName = this.toHexString(strApiUrl);
File file = new File(strJsonPath + fileName + ".txt");
StringBuffer sb = new StringBuffer();
if (file.exists()) {
Reader reader = null;
try {
reader = new java.io.FileReader(file);
BufferedReader br = new BufferedReader(reader);
String str;
while (null != (str = br.readLine())) {
sb.append(str);
}
return sb.toString();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}

/**
* 传入图片的URL地址，来获得Bitmap
* */
public Bitmap getBmp(String imgurl) {

String imgName = imgurl.substring(
imgurl.lastIndexOf('/') + 2,
imgurl.length());

File imgFile = new File(strImgPath + imgName);
if (imgFile.exists()) {
FileInputStream fis;
try {
fis = new FileInputStream(imgFile);
return BitmapFactory.decodeStream(fis);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} else
Log.v("提醒", "要请求的图片文件不存在");
return null;
}

// 通过图片名字来获得图片
public Bitmap getBmpByName(String bmpName) {
File imgFile = new File(strImgPath + bmpName);
if (imgFile.exists()) {
FileInputStream fis;
try {
fis = new FileInputStream(imgFile);
return BitmapFactory.decodeStream(fis);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} else {
Log.v("提醒", "要请求的图片文件不存在");
}
return null;
}

/**
* 传入图片的URL来获得图片文件
* */
public File getImgFile(String imgurl) {
String imgName = imgurl.substring(
imgurl.lastIndexOf('/') + 2,
imgurl.length());
File imgFile = new File(strImgPath + imgName);
return imgFile;
}

private boolean writeToFile(String strData, File file) {
if (file.exists()) {
file.delete();
}
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
BufferedOutputStream bos = new BufferedOutputStream(fos);
bos.write(strData.getBytes());
bos.flush();
bos.close();
return true;
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (null != fos) {
try {
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return false;
}

private boolean writeToFile(Bitmap bmp, File file) {
if (file.exists()) {
file.delete();
}
String name = file.getName();
String geShi = name.substring(name.lastIndexOf('.'), name.length());

FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
BufferedOutputStream bos = new BufferedOutputStream(fos);
if (null != bmp) {
if (".JPEG".equalsIgnoreCase(geShi)
|| ".JPG".equalsIgnoreCase(geShi)) {
bmp.compress(CompressFormat.JPEG, 100, bos);
bos.flush();
bos.close();
} else if (".PNG".equalsIgnoreCase(geShi)) {
bmp.compress(CompressFormat.PNG, 100, bos);
bos.flush();
bos.close();
}
return true;
} else
bos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (null != fos) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
Log.v("错误", "图片写入缓存文件错误");
}
}
}
return false;
}

public boolean clearImgByImgUrl(String imgurl) {
File imgFile = this.getImgFile(imgurl);
if (imgFile.exists()) {
imgFile.delete();
return true;
}
return false;
}

/**
* 删除SD卡上的全部缓存
* */
public int clearAllData() {
File imgDir = new File(strImgPath);
File txtDir = new File(strJsonPath);
File[] imgFiles = imgDir.listFiles();
File[] txtFiles = txtDir.listFiles();
int m = imgFiles.length;
int x = txtFiles.length;

int g = 0;
int t = 0;
for (int i = 0; i < m; i++) {
if (imgFiles[i].exists()) {
if (imgFiles[i].delete())
g++;
} else
g++;

}
for (int i = 0; i < x; i++) {
if (txtFiles[i].exists()) {
if (txtFiles[i].delete()) {
t++;
}
} else
t++;
}
if (g == m && t == x) {
return 1;
}
return 0;
}
private String toHexString(String s) {
String str = "";
for (int i = 0; i < s.length(); i++) {
int ch = (int) s.charAt(i);
String s4 = Integer.toHexString(ch);
str = str + s4;
}
return "0x" + str;// 0x表示十六进制
}

// 转换十六进制编码为字符串
private String toStringHex(String s) {
if ("0x".equals(s.substring(0, 2))) {
s = s.substring(2);
}
byte[] baKeyword = new byte[s.length() / 2];
for (int i = 0; i < baKeyword.length; i++) {
try {
baKeyword[i] = (byte) (0xff & Integer.parseInt(
s.substring(i * 2, i * 2 + 2), 16));
} catch (Exception e) {
e.printStackTrace();
}
}
try {
s = new String(baKeyword, "utf-8");// UTF-16le:Not
} catch (Exception e1) {
e1.printStackTrace();
}
return s;
}
}