632
android 加载图片轻松避免OOM(out of memory) 支持设置缓存大小,不再强制catch OOM
https://blog.csdn.net/liaoxingliao/article/details/7168500
package l.test1.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapFactory.Options;
public class BitmapUtil {
private static final Size ZERO_SIZE = new Size(0,0);
private static final Options OPTIONS_GET_SIZE = new Options();
private static final Options OPTIONS_DECODE = new Options();
static{
OPTIONS_GET_SIZE.inJustDecodeBounds = true;
}
public static Size getBitMapSize(String path){
File file = new File(path);
if(file.exists()){
InputStream in = null;
try{
in = new FileInputStream(file);
BitmapFactory.decodeStream(in, null, OPTIONS_GET_SIZE);
return new Size(OPTIONS_GET_SIZE.outWidth,OPTIONS_GET_SIZE.outHeight);
} catch (FileNotFoundException e) {
return ZERO_SIZE;
}finally{
closeInputStream(in);
}
}
return ZERO_SIZE;
}
public static Bitmap createBitmap(String path,int width,int height){
File file = new File(path);
if(file.exists()){
InputStream in = null;
try {
in = new FileInputStream(file);
Size size = getBitMapSize(path);
if(size.equals(ZERO_SIZE)){
return null;
}
int scale = 1;
int a = size.getWidth() / width;
int b = size.getHeight() / height;
scale = Math.max(a, b);
synchronized (OPTIONS_DECODE) {
OPTIONS_DECODE.inSampleSize = scale;
Bitmap bitMap = BitmapFactory.decodeStream(in,null,OPTIONS_DECODE);
return bitMap;
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
finally{
closeInputStream(in);
}
}
return null;
}
public static void destory(Bitmap bitmap){
if(null != bitmap && !bitmap.isRecycled()){
bitmap.recycle();
bitmap = null;
}
}
private static void closeInputStream(InputStream in) {
if(null != in){
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
class Size{
private int width,height;
Size(int width,int height){
this.width = width;
this.height = height;
}
public int getWidth() {
return width;
}
public int getHeight() {
return height;
}
}
package l.test1.util;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;
import java.util.Stack;
import android.graphics.Bitmap;
/**
* Bitmap工具类,缓存用过的指定数量的图片,使用此工具类,不再需要手动管理Bitmap内存
* 原理:
* 用一个队列保存使用Bitmap的顺序,每次使用Bitmap将对象移动到队列头
* 当内存不够,或者达到制定的缓存数量的时候,回收队列尾部图片
* 保证当前使用最多的图片得到最长时间的缓存,提高速度
* @author liaoxingliao
*
*/
public final class BitMapLRU {
private static int CACHE_BYTE_SIZE = 10*1024*1024; //缓存10M图片
private static int CACHE_SIZE = 2000; //缓存图片数量
private static int byteSize = 0;
private static final byte[] LOCKED = new byte[0];
private static final LinkedList<String> CACHE_ENTRIES = //此对象用来保持Bitmap的回收顺序,保证最后使用的图片被回收
new LinkedList<String>(){
private static final long serialVersionUID = 1L;
@Override
public void addFirst(String object) {
while(remove(object));
super.addFirst(object);
}
};
private static final Stack<QueueEntry> TASK_QUEUE = new Stack<QueueEntry>(); //线程请求创建图片的队列
private static final Set<String> TASK_QUEUE_INDEX = new HashSet<String>(); //保存队列中正在处理的图片的key,有效防止重复添加到请求创建队列
private static final Map<String,Bitmap> IMG_CACHE_INDEX = new HashMap<String,Bitmap>(); //缓存Bitmap 通过图片路径,图片大小
static{
// 初始化创建图片线程,并等待处理
new Thread(){
{setDaemon(true);}
public void run() {
while(true) {
synchronized (TASK_QUEUE) {
if(TASK_QUEUE.isEmpty()) {
try {
TASK_QUEUE.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
QueueEntry entry = TASK_QUEUE.pop();
String key = createKey(entry.path,entry.width,entry.height);
TASK_QUEUE_INDEX.remove(key);
createBitmap(entry.path, entry.width, entry.height);
}
}
}.start();
}
/**
* 创建一张图片 如果缓存中已经存在,则返回缓存中的图,否则创建一个新的对象,并加入缓存
* 宽度,高度,为了缩放原图减少内存的,如果输入的宽,高,比原图大,返回原图
* @param path 图片物理路径 (必须是本地路径,不能是网络路径)
* @param width 需要的宽度
* @param height 需要的高度
* @return
*/
public static Bitmap createBitmap(String path, int width, int height) {
Bitmap bitMap = null;
try{
while(CACHE_ENTRIES.size() >= CACHE_SIZE || byteSize >= CACHE_BYTE_SIZE) {
destoryLast();
}
bitMap = useBitmap(path, width, height);
if( bitMap != null && !bitMap.isRecycled()){
return bitMap;//4294967296
}
bitMap = BitmapUtil.createBitmap(path, width, height);
if(bitMap == null) { //可能不是有效的图片..
return null;
}
byteSize += (bitMap.getRowBytes() * bitMap.getHeight());
String key = createKey(path,width,height);
synchronized (LOCKED) {
IMG_CACHE_INDEX.put(key, bitMap);
CACHE_ENTRIES.addFirst(key);
}
}catch(OutOfMemoryError err) {
System.out.println("OOM:" + byteSize);
destoryLast();
return createBitmap(path, width, height);
}
return bitMap;
}
/**
* 设置缓存图片数量 如果输入负数,会产生异常
* @param size
*/
public static void setCacheSize(int size) {
if(size <=0 ){
throw new RuntimeException("size :"+size);
}
while(size < CACHE_ENTRIES.size()){
destoryLast();
}
CACHE_SIZE = size;
}
/**
* 加入一个图片处理请求到图片创建队列
* @param path 图片路径(本地)
* @param width 图片宽度
* @param height 图片高度
*/
public static void addTask(String path, int width, int height) {
QueueEntry entry = new QueueEntry();
entry.path = path;
entry.width = width;
entry.height = height;
synchronized (TASK_QUEUE) {
while(TASK_QUEUE.size() > 20) {
QueueEntry e = TASK_QUEUE.lastElement();
TASK_QUEUE.remove(e);
TASK_QUEUE_INDEX.remove(createKey(e.path, e.width, e.height));
}
String key = createKey(path,width,height);
if(!TASK_QUEUE_INDEX.contains(key) && !IMG_CACHE_INDEX.containsKey(key)){
TASK_QUEUE.push(entry);
TASK_QUEUE_INDEX.add(key);
TASK_QUEUE.notify();
}
}
}
public static void cleanTask() {
synchronized (TASK_QUEUE) {
TASK_QUEUE_INDEX.clear();
TASK_QUEUE.clear();
}
}
// 将图片加入队列头
private static Bitmap useBitmap(String path,int width,int height) {
Bitmap bitMap = null;
String key = createKey(path,width,height);
synchronized (LOCKED) {
bitMap = IMG_CACHE_INDEX.get(key);
if(null != bitMap){
CACHE_ENTRIES.addFirst(key);
}
}
return bitMap;
}
// 回收最后一张图片
private static void destoryLast() {
synchronized (LOCKED) {
if(!CACHE_ENTRIES.isEmpty()) {
String key = CACHE_ENTRIES.removeLast();
if(key.length() > 0) {
Bitmap bitMap = IMG_CACHE_INDEX.remove(key);
if(bitMap != null) {
bitMap.recycle();
byteSize -= (bitMap.getRowBytes() * bitMap.getHeight());
bitMap = null;
}
}
}
}
}
// 创建键
private static String createKey(String path,int width,int height) {
if(null == path || path.length() == 0) {
return "";
}
return path+"_"+width+"_"+height;
}
// 队列缓存参数对象
static class QueueEntry{
public String path;
public int width;
public int height;
}
}
最后更新：2017-04-02 16:47:34
上一篇：
java.text.format 将字符串“060503”转化为06:05:03或者将"20081002102030“转化为2008-10-02 10:00:30
下一篇： Android 开发图片压缩/缩略图的方法
- C# 数据库存储过程的讲解应用
- 电子商务类站点终极资源大全
- 云上Docker的Spring Cloud微服务应用实践分享
- windows7用VMware workstation安装ubuntu server 16.04 虚拟机
- swing开发图形界面工具配置（可自由拖控件上去）
- 《Cucumber：行为驱动开发指南》——第6章 Cucumber常见问题及解决之道 6.1感受痛苦
- 【云栖你的美】pk十10交流6747·777群
- lucene join解决父子关系索引
- Hadoop 这样业界顶级的大规模数据处理平台，均发现满足不了类似双十一这样全世界的剁手党蜂拥而至的热情
- 满江红开放技术研究组织发布Seam 2.0中文文档RC版