本文为大家分享了Android图片加载的缓存类，供大家参考，具体内容如下
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.LinkedHashMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Build;
import android.os.Handler;
import android.text.TextUtils;
public class ImageLoaderEngine {
public static final int LOAD_IMG_SUCCESS = 2010;
private final int MAX_CAPACITY = Build.VERSION.SDK_INT > Build.VERSION_CODES.GINGERBREAD_MR1 ? 50 : 10;// 一级缓存缓存图片数
private static ImageLoaderEngine instance;
private static Handler mHandler;
private ExecutorService pool;// 后台线程池
// 这里用LinkedHashMap不用LruCache的原因是LruCache直接申请内存大小而不是图片个数。此App已经有一个全局的LruCache了，重复申请内存大小对应用不利
private LinkedHashMap<String, Bitmap> mFirstLevelCache;// <momentId>一级缓存，硬链接bitmap，只保留最近用的图片。
private ConcurrentHashMap<String, SoftReference<Bitmap>> mSecondLevelCache;// <momentId>
public static ImageLoaderEngine getInstance(Handler handler) {
if (instance == null) {
instance = new ImageLoaderEngine();
}
if(handler != null) {
mHandler = handler;
}
return instance;
}
private ImageLoaderEngine() {
pool = Executors.newFixedThreadPool(4);// 默认线程池大小为6
initCache();
}
private void initCache() {
mFirstLevelCache = new LinkedHashMap<String, Bitmap>(MAX_CAPACITY / 2,
0.75f, true) {
private static final long serialVersionUID = 1L;
protected boolean removeEldestEntry(Entry<String, Bitmap> eldest) {
if (size() > MAX_CAPACITY) {// 超过一级缓存大小后会挪到二级缓存中
mSecondLevelCache.put(eldest.getKey(),
new SoftReference<Bitmap>(eldest.getValue()));
return true;
}
return false;
};
};
mSecondLevelCache = new ConcurrentHashMap<String, SoftReference<Bitmap>>();// <momentId>
}
public void deleteCacheByKey(String key) {
String sdCacheingPath = IOHelper.getCachedPicturePath(
Global.packageName, key);
String sdCacheedPath = sdCacheingPath +".png";
File file = new File(sdCacheingPath);
if(file.exists()) {
file.delete();
}
file = new File(sdCacheedPath);
if(file.exists()) {
file.delete();
}
mFirstLevelCache.remove(key);
mSecondLevelCache.remove(key);
}
public void recycleImageLoader() {
new Thread(new Runnable() {
@Override
public void run() {
if (pool != null) {
pool.shutdownNow();
}
if (mFirstLevelCache != null) {
for (Bitmap bmp : mFirstLevelCache.values()) {
if (bmp != null) {
bmp.recycle();
bmp = null;
}
}
mFirstLevelCache.clear();
mFirstLevelCache = null;
}
if (mSecondLevelCache != null) {
mSecondLevelCache.clear();
}
mHandler = null;
}
}).start();
}
public void loadImageByMoment(final NMoment moment,String photoTag) {
if (moment.isPicture()
|| moment.isVideo()) {
String id = moment.id + photoTag;
loadImageByUrl(id+"", moment.getPicture(Global.widthPixels/3*2),moment.orientation);
}
}
public void loadImageByUrl(final String key,final String url,final int orientation) {
pool.submit(new Runnable() {
public void run() {
LogHelper.e("ImageLoaderEngine","从网络中下载");
// 如果内存中有就算了
if (mFirstLevelCache.get(key) != null
|| mSecondLevelCache.get(key) != null) {// 如果图片已经缓存了
LogHelper.e("ImageLoaderEngine","下载图片错误 1");
return;
}
// 如果SD卡缓存中有就算了
final String sdCacheingPath = IOHelper.getCachedPicturePath(
Global.packageName, key);
File cacheingFile = new File(sdCacheingPath);
if (cacheingFile.exists()) {// 如果正在缓存就算了
long currentTime = System.currentTimeMillis();
if((currentTime - cacheingFile.lastModified()) >2 * 60 * 1000) {
LogHelper.e("ImageLoaderEngine","2分钟都还没下载完，准备删除它.."+currentTime+"="+cacheingFile.lastModified());
cacheingFile.delete();
} else {
getBitmapFromNetworkAndAddToMemory(url, key, orientation);
LogHelper.e("ImageLoaderEngine","第二次进来应该走这里..");
return;
}
}
String sdCacheedPath = sdCacheingPath + ".png";// 缓存完成后会改名字，否则会导致缓存错误，图片变黑
File cacheedFile = new File(sdCacheedPath);
if (cacheedFile.exists()) {// 如果缓存了就算了
LogHelper.e("ImageLoaderEngine","下载图片错误 2");
return;
}
getBitmapFromNetworkAndAddToMemory(url, key, orientation);
}
});
}
private void getBitmapFromNetworkAndAddToMemory(String url,String key,int orientation) {
Bitmap bmp = getBitmapFromUrl(url);
if(bmp!= null) {
LogHelper.e("ImageLoaderEngine","下载网络图片成功");
if(key.endsWith("_DetailDaily")) {
bmp = scaledBitmap(bmp, Global.getThumbWidth());
}
if(orientation != 0) {
mFirstLevelCache.put(key, ViewHelper.rotateBitmap(orientation, bmp));// 从网络下载后直接显示
} else {
mFirstLevelCache.put(key, bmp);// 从网络下载后直接显示
}
if (mHandler != null) {
mHandler.removeMessages(LOAD_IMG_SUCCESS);
mHandler.sendEmptyMessageDelayed(
LOAD_IMG_SUCCESS, 600);// 延时提示没有数据了
}
final String sdCacheingPath = IOHelper.getCachedPicturePath(
Global.packageName, key);
saveBitmapToFile(sdCacheingPath, bmp);
} else {
LogHelper.e("ImageLoaderEngine","下载网络图片失败...");
}
}
public Bitmap getBitmapFromUrl(String url) {
URL myFileUrl = null;
Bitmap bitmap = null;
InputStream is = null;
try {
if (!UIUtils.isNetworkAvailable(MyApplication.getInstance())) {
return null;
}
myFileUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) myFileUrl
.openConnection();
conn.setDoInput(true);
conn.connect();
is = conn.getInputStream();
bitmap = BitmapFactory.decodeStream(is);
} catch (Exception e) {
try {
if(is != null) {
is.close();
}
} catch (IOException e1) {
e1.printStackTrace();
}
e.printStackTrace();
}
return bitmap;
}
public Bitmap getImageInMemory(NMoment moment) {
return getImageInMemory(moment, "");
}
public Bitmap getImageInMemory(NMoment moment, String photoTag) {
String id = moment.id + photoTag;
Bitmap bmp = null;
// 1. 从一级缓存中获取
bmp = getFromFirstLevelCache(id);
if (bmp != null && !bmp.isRecycled()) {
LogHelper.e("ImageLoaderEngine","一级缓存获取:"+id);
return bmp;
}
// 2. 从二级缓存中获取
bmp = getFromSecondLevelCache(id);
if (bmp != null && !bmp.isRecycled()) {
LogHelper.e("ImageLoaderEngine","二级缓存获取:"+id);
return bmp;
}
if(bmp != null && bmp.isRecycled()) {
return null;
} else {
return bmp;
}
}
public void setImage(String key,Bitmap picture) {
mFirstLevelCache.put(key, picture);
}
public Bitmap getImage(NMoment moment) {
return getImage(moment, "");
}
public Bitmap getImage(NMoment moment, String photoTag) {
String id = moment.id + photoTag;
Bitmap bmp = null;
// 1. 从一级缓存中获取
bmp = getFromFirstLevelCache(id);
if (bmp != null && !bmp.isRecycled()) {
LogHelper.e("ImageLoaderEngine","一级缓存获取:"+id);
return bmp;
}
// 2. 从二级缓存中获取
bmp = getFromSecondLevelCache(id);
if (bmp != null && !bmp.isRecycled()) {
LogHelper.e("ImageLoaderEngine","二级缓存获取:"+id);
return bmp;
}
// 3. 从SD卡缓存中获取
bmp = getFromSDCache(moment, photoTag);
if (bmp != null && !bmp.isRecycled()) {
LogHelper.e("ImageLoaderEngine","SD卡缓存获取:"+id);
return bmp;
}
// 4. 从网络中获取
loadImageByMoment(moment, photoTag);
// LogHelper.e("ImageLoaderEngine","本地获取图片失败:"+moment.id+"="+moment.getPicture());
if(bmp != null && bmp.isRecycled()) {
return null;
} else {
return bmp;
}
}
public Bitmap getImage(String key,String url) {
Bitmap bmp = null;
// 1. 从一级缓存中获取
bmp = getFromFirstLevelCache(key);
if (bmp != null && !bmp.isRecycled()) {
return bmp;
}
// 2. 从二级缓存中获取
bmp = getFromSecondLevelCache(key);
if (bmp != null && !bmp.isRecycled()) {
return bmp;
}
// 3. 从SD卡缓存中获取
bmp = getFromSDCacheByKey(key,0);
if (bmp != null && !bmp.isRecycled()) {
return bmp;
}
// 4. 从网络中获取
loadImageByUrl(key, url,0);
if(bmp != null && bmp.isRecycled()) {
return null;
} else {
return bmp;
}
}
private Bitmap getFromFirstLevelCache(String imgId) {
Bitmap bitmap = null;
synchronized (mFirstLevelCache) {
bitmap = mFirstLevelCache.get(imgId);
if (bitmap != null) {
mFirstLevelCache.remove(imgId);
mFirstLevelCache.put(imgId, bitmap);
}
}
return bitmap;
}
private Bitmap getFromSecondLevelCache(String imgId) {
Bitmap bitmap = null;
SoftReference<Bitmap> softReference = mSecondLevelCache.get(imgId);
if (softReference != null) {
bitmap = softReference.get();
if (bitmap == null) {
mSecondLevelCache.remove(imgId);
}
}
return bitmap;
}
private Bitmap getFromSDCache(final NMoment moment,final String photoTag) {
Bitmap drawable = null;
String id = moment.id + photoTag;
String sdCacheingPath = IOHelper.getCachedPicturePath(Global.packageName,
id);
String sdCacheedPath = sdCacheingPath + ".png";
if(moment.isLocal){
if(moment.isVideo()) {
//获取本地路径
sdCacheedPath = moment.getPicture(Global.widthPixels/3*2);
} else {
sdCacheedPath = moment.local_res_path;
}
}
File cacheFile = new File(sdCacheedPath);
if (!cacheFile.exists()) {// 如果没有缓存完成就退出
LogHelper.e("ImageLoaderEngine","找不到缓存文件:"+sdCacheedPath);
if(!TextUtils.isEmpty(moment.local_res_path)) {// 如果本地有图片，就先用本地图片代替
sdCacheedPath = moment.local_res_path;
cacheFile = new File(sdCacheedPath);
if (cacheFile.exists() && !GlobalData.PHONE_MANUFACTURER.equalsIgnoreCase("samsung")) {
LogHelper.e("ImageLoaderEngine","AK47...:"+GlobalData.PHONE_MANUFACTURER);// 先从本地找替代图片..
new Thread(new Runnable() {// 从网络下载
@Override
public void run() {
loadImageByMoment(moment, photoTag);
}
}).start();
return getFitPhoto(sdCacheedPath, moment, cacheFile);
} else {
return null;
}
} else {
return null;
}
}
drawable = getFitPhoto(sdCacheedPath, moment, cacheFile);
if (drawable != null) {
if (moment.orientation != 0) {
drawable = ViewHelper
.rotateBitmap(moment.orientation, drawable);
}
if(mFirstLevelCache != null) {
mFirstLevelCache.put(id, drawable);
}
} else {
cacheFile.delete();
}
return drawable;
}
private Bitmap getFitPhoto(String sdCacheedPath,NMoment moment,File cacheFile) {
FileInputStream fs = null;
Bitmap result;
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(sdCacheedPath, options);
int hRatio = (int) Math.ceil(options.outHeight
/ (float) moment.picture_height); // 算高度
int wRatio = (int) Math.ceil(options.outWidth
/ (float) Global.widthPixels); // 算宽度
if (hRatio > 1 || wRatio > 1) {
if (hRatio > wRatio) {
options.inSampleSize = hRatio;
} else
options.inSampleSize = wRatio;
}
options.inPurgeable = true;
options.inInputShareable = true;
options.inDither = false;
options.inJustDecodeBounds = false;
try {
fs = new FileInputStream(cacheFile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
result = BitmapFactory.decodeFileDescriptor(fs.getFD(), null,
options);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (fs != null) {
try {
fs.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
private Bitmap getFromSDCacheByKey(String key,int orientation) {
Bitmap drawable = null;
FileInputStream fs = null;
String sdCacheedPath = IOHelper.getCachedPicturePath(
Global.packageName, key) + ".png";
File cacheFile = new File(sdCacheedPath);
if (!cacheFile.exists()) {// 如果没有缓存完成就退出
return null;
}
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(sdCacheedPath, options);
int wRatio = (int) Math.ceil(options.outWidth
/ (float) Global.widthPixels); // 算宽度
options.inSampleSize = wRatio;
options.inPurgeable = true;
options.inInputShareable = true;
options.inDither = false;
options.inJustDecodeBounds = false;
try {
fs = new FileInputStream(cacheFile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
drawable = BitmapFactory.decodeFileDescriptor(fs.getFD(), null,
options);
if (drawable != null) {
if(orientation != 0) {
drawable = ViewHelper.rotateBitmap(orientation, drawable);
}
mFirstLevelCache.put(key, drawable);
} else {
cacheFile.delete();
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (fs != null) {
try {
fs.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return drawable;
}
public Bitmap getDefaultBitmap(NMoment moment) {
return ImageHelper.createBitmap(moment.picture_width, moment.picture_height,
R.color.image_bg_daily);
}
public void saveBitmapToFile(String filePath, Bitmap mBitmap) {
try {
File file = new File(filePath);
if (!file.getParentFile().exists()) {
file.getParentFile().mkdirs();
}
if (file.exists() && file.length() > 0) {
long currentTime = System.currentTimeMillis();
if ((currentTime - file.lastModified()) > 2 * 60 * 1000) {
LogHelper.e("ImageLoaderEngine",
"2分钟都还没下载完，准备删除它.." + currentTime + "="
+ file.lastModified());
file.delete();
} else {
return;
}
} else {
file.createNewFile();
}
FileOutputStream fOut = null;
fOut = new FileOutputStream(file);
mBitmap.compress(Bitmap.CompressFormat.JPEG, 80, fOut);
fOut.flush();
fOut.close();
file.renameTo(new File(filePath+".png"));
} catch (Exception e) {
e.printStackTrace();
LogHelper.e("ImageLoaderEngine","保存图片错误:"+e);
}
LogHelper.e("ImageLoaderEngine","保存网络图片成功"+filePath+".png");
}
public boolean saveUrlBitmapToFile(String url, String filePath) {
if (TextUtils.isEmpty(filePath)) {
return false;
}
File iconFile = new File(filePath);
if (iconFile.getParentFile() == null) {
return false;
}
if (!iconFile.getParentFile().exists()) {
iconFile.getParentFile().mkdirs();
}
if (iconFile.exists() && iconFile.length() > 0) {
long currentTime = System.currentTimeMillis();
if((currentTime - iconFile.lastModified()) >2 * 60 * 1000) {
LogHelper.e("ImageLoaderEngine","2分钟都还没下载完，准备删除它.."+currentTime+"="+iconFile.lastModified());
iconFile.delete();
} else {
return true;
}
}
FileOutputStream fos = null;
InputStream is = null;
try {
fos = new FileOutputStream(filePath);
is = new URL(url).openStream();
int data = is.read();
while (data != -1) {
fos.write(data);
data = is.read();
}
} catch (IOException e) {
LogHelper.e("ImageLoaderEngine", "ImageLoaderEngine 下载图片错误" + e);
iconFile.delete();
e.printStackTrace();
return false;
} finally {
try {
if (is != null) {
is.close();
}
if (fos != null) {
fos.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
iconFile.renameTo(new File(filePath+".png"));
return true;
}
public Bitmap scaledBitmap(Bitmap bmp,int scaledValue) {
int bmpWidth = bmp.getWidth();
int bmpHeight = bmp.getHeight();
if(bmpWidth >= bmpHeight) {// 横图
bmpWidth = (bmpWidth * scaledValue / bmpHeight);
bmpHeight = scaledValue;
} else {
bmpHeight = (bmpHeight * scaledValue / bmpWidth);
bmpWidth = scaledValue;
}
Bitmap scaledBmp = Bitmap.createScaledBitmap(bmp,bmpWidth,bmpHeight,true);
bmp.recycle();
bmp = null;
return scaledBmp;
}
}
以上就是一个完整的Android图片加载缓存类，希望对大家的学习有所帮助。
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