ACache【轻量级的开源缓存框架】

版权声明:本文为HaiyuKing原创文章,转载请注明出处!

前言

官方介绍

ASimpleCache 是一个为android制定的 轻量级的 开源缓存框架。轻量到只有一个java文件(由十几个类精简而来)。

1、它可以缓存什么东西?

普通的字符串、JsonObject、JsonArray、Bitmap、Drawable、序列化的java对象,和 byte数据。

2、它有什么特色?

特色主要是: 
1:轻,轻到只有一个JAVA文件。 
2:可配置,可以配置缓存路径,缓存大小,缓存数量等。 
3:可以设置缓存超时时间,缓存超时自动失效,并被删除。 
4:支持多进程。

3、它在android中可以用在哪些场景?

1、替换SharePreference当做配置文件 
2、可以缓存网络请求数据,比如oschina的android客户端可以缓存http请求的新闻内容,缓存时间假设为1个小时,超时后自动失效,让客户端重新请求新的数据,减少客户端流量,同时减少服务器并发量

4、如何使用 ASimpleCache? 以下有个小的demo,希望您能喜欢:

缓存数据

ACache.get(MainActivity.this).put("username_key", "admin"); 
ACache.get(MainActivity.this).put("password_key", "123456789", 10);//保存10秒,如果超过10秒去获取这个key,将为null
ACache.get(MainActivity.this).put("password_key", "123456789", 2 * ACache.TIME_DAY);//保存两天,如果超过两天去获取这个key,将为null

获取数据

ACache.get(MainActivity.this).getAsString("username_key");

效果图

 

代码分析

缓存文件放置在/data/data/app-package-name/cache/路径下,缓存的目录默认为ACache,缓存大小和数量均由ACache中的final变量控制。

存在的一个问题是,在部分机型(比如华为荣耀6)上当使用猎豹清理大师进行垃圾清理的时候会把acache中缓存的数据清理掉。

使用步骤

一、项目组织结构图

注意事项:

1、导入类文件后需要change包名以及重新import R文件路径

2、Values目录下的文件(strings.xml、dimens.xml、colors.xml等),如果项目中存在,则复制里面的内容,不要整个覆盖

二、导入步骤

将Acache复制到项目中

/**
 * Copyright (c) 2012-2013, Michael Yang 杨福海 (www.yangfuhai.com).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.why.project.acachedemo.utils;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.PixelFormat;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

import org.json.JSONArray;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

/**
 * https://github.com/yangfuhai/ASimpleCache
 * 缓存文件放置在/data/data/app-package-name/cache/路径下,缓存的目录默认为ACache,缓存大小和数量均由ACache中的final变量控制。
 */
public class ACache {
    /**设置的缓存的时间*/
    public static final int TIME_HOUR = 60 * 60;//1小时
    public static final int TIME_DAY = TIME_HOUR * 24;//1天
    /**设置的缓存的大小*/
    private static final int MAX_SIZE = 1000 * 1000 * 50; // 50 MB
    private static final int MAX_COUNT = Integer.MAX_VALUE; // 不限制存放数据的数量
    /**声明一个Map,用于存放ACache对象*/
    private static Map<String, ACache> mInstanceMap = new HashMap<String, ACache>();
    /**缓存管理器*/
    private ACacheManager mCacheManager;
    
    //ACache类的构造方法为private的,所以只能通过get方式获取实例。
    private ACache(File cacheDir, long max_size, int max_count) {
        //如果cacheDir文件不存在并且无法新建子目录,则报错
        if (!cacheDir.exists() && !cacheDir.mkdirs()) {
            throw new RuntimeException("can't make dirs in " + cacheDir.getAbsolutePath());
        }
        //实例化缓存管理器对象
        mCacheManager = new ACacheManager(cacheDir, max_size, max_count);
    }
    //默认情况下调用该方法
    public static ACache get(Context ctx) {
        return get(ctx, "ACache");
    }
    
    public static ACache get(Context ctx, long max_zise, int max_count) {
        File f = new File(ctx.getCacheDir(), "ACache");
        return get(f, max_zise, max_count);
    }

    public static ACache get(Context ctx, String cacheName) {
        File f = new File(ctx.getCacheDir(), cacheName);
        return get(f, MAX_SIZE, MAX_COUNT);
    }

    public static ACache get(File cacheDir) {
        return get(cacheDir, MAX_SIZE, MAX_COUNT);
    }
    //最终默认调用的实例方法
    public static ACache get(File cacheDir, long max_zise, int max_count) {
        //Map中的Key值为cacheDir.getAbsoluteFile() + myPid(),例如:/data/data/com.yangfuhai.asimplecachedemo/cache/ACache_16609
        ACache manager = mInstanceMap.get(cacheDir.getAbsoluteFile() + myPid());
        if (manager == null) {
            manager = new ACache(cacheDir, max_zise, max_count);
            //Log.v("ACache", cacheDir.getAbsolutePath() + myPid());
            mInstanceMap.put(cacheDir.getAbsolutePath() + myPid(), manager);
        }
        return manager;
    }
    
    private static String myPid() {
        return "_" + android.os.Process.myPid();
    }

    /**
     * Provides a means to save a cached file before the data are available.
     * Since writing about the file is complete, and its close method is called,
     * its contents will be registered in the cache. Example of use:
     * 
     * ACache cache = new ACache(this) try { OutputStream stream =
     * cache.put("myFileName") stream.write("some bytes".getBytes()); // now
     * update cache! stream.close(); } catch(FileNotFoundException e){
     * e.printStackTrace() }
     */
    class xFileOutputStream extends FileOutputStream {
        File file;

        public xFileOutputStream(File file) throws FileNotFoundException {
            super(file);
            this.file = file;
        }

        public void close() throws IOException {
            super.close();
            mCacheManager.put(file);
        }
    }

    // =======================================
    // ============ String数据 读写 ==============
    // =======================================
    /**
     * 保存 String数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的String数据
     */
    //在ACache目录下创建一个文件,文件名为:File(cacheDir, key.hashCode() + “”)。然后将数据存入文件
    public void put(String key, String value) {
        File file = mCacheManager.newFile(key);
        BufferedWriter out = null;
        try {
            out = new BufferedWriter(new FileWriter(file), 1024);
            out.write(value);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.flush();
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            mCacheManager.put(file);
        }
    }

    /**
     * 保存 String数据 到 缓存中一定时间
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的String数据
     * @param saveTime
     *            保存的时间,单位:秒
     */
    public void put(String key, String value, int saveTime) {
        put(key, Utils.newStringWithDateInfo(saveTime, value));
    }

    /**
     * 读取 String数据
     * 
     * @param key
     * @return String 数据
     */
    public String getAsString(String key) {
        File file = mCacheManager.get(key);
        if (!file.exists())
            return null;
        boolean removeFile = false;
        BufferedReader in = null;
        try {
            in = new BufferedReader(new FileReader(file));
            String readString = "";
            String currentLine;
            while ((currentLine = in.readLine()) != null) {
                readString += currentLine;
            }
            if (!Utils.isDue(readString)) {
                return Utils.clearDateInfo(readString);
            } else {
                removeFile = true;
                return null;
            }
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (removeFile)
                remove(key);
        }
    }

    // =======================================
    // ============= JSONObject 数据 读写 ==============
    // =======================================
    /**
     * 保存 JSONObject数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的JSON数据
     */
    public void put(String key, JSONObject value) {
        put(key, value.toString());
    }

    /**
     * 保存 JSONObject数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的JSONObject数据
     * @param saveTime
     *            保存的时间,单位:秒
     */
    public void put(String key, JSONObject value, int saveTime) {
        put(key, value.toString(), saveTime);
    }

    /**
     * 读取JSONObject数据
     * 
     * @param key
     * @return JSONObject数据
     */
    public JSONObject getAsJSONObject(String key) {
        String JSONString = getAsString(key);
        if(JSONString != null){
            try {
                JSONObject obj = new JSONObject(JSONString);
                return obj;
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        }else{
            return null;
        }
        
    }

    // =======================================
    // ============ JSONArray 数据 读写 =============
    // =======================================
    /**
     * 保存 JSONArray数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的JSONArray数据
     */
    public void put(String key, JSONArray value) {
        put(key, value.toString());
    }

    /**
     * 保存 JSONArray数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的JSONArray数据
     * @param saveTime
     *            保存的时间,单位:秒
     */
    public void put(String key, JSONArray value, int saveTime) {
        put(key, value.toString(), saveTime);
    }

    /**
     * 读取JSONArray数据
     * 
     * @param key
     * @return JSONArray数据
     */
    public JSONArray getAsJSONArray(String key) {
        String JSONString = getAsString(key);
        try {
            JSONArray obj = new JSONArray(JSONString);
            return obj;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    // =======================================
    // ============== byte 数据 读写 =============
    // =======================================
    /**
     * 保存 byte数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的数据
     */
    public void put(String key, byte[] value) {
        File file = mCacheManager.newFile(key);
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(file);
            out.write(value);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.flush();
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            mCacheManager.put(file);
        }
    }

    /**
     * Cache for a stream
     * 
     * @param key
     *            the file name.
     * @return OutputStream stream for writing data.
     * @throws FileNotFoundException
     *             if the file can not be created.
     */
    public OutputStream put(String key) throws FileNotFoundException {
        return new xFileOutputStream(mCacheManager.newFile(key));
    }

    /**
     * 
     * @param key
     *            the file name.
     * @return (InputStream or null) stream previously saved in cache.
     * @throws FileNotFoundException
     *             if the file can not be opened
     */
    public InputStream get(String key) throws FileNotFoundException {
        File file = mCacheManager.get(key);
        if (!file.exists())
            return null;
        return new FileInputStream(file);
    }

    /**
     * 保存 byte数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的数据
     * @param saveTime
     *            保存的时间,单位:秒
     */
    public void put(String key, byte[] value, int saveTime) {
        put(key, Utils.newByteArrayWithDateInfo(saveTime, value));
    }

    /**
     * 获取 byte 数据
     * 
     * @param key
     * @return byte 数据
     */
    public byte[] getAsBinary(String key) {
        RandomAccessFile RAFile = null;
        boolean removeFile = false;
        try {
            File file = mCacheManager.get(key);
            if (!file.exists())
                return null;
            RAFile = new RandomAccessFile(file, "r");
            byte[] byteArray = new byte[(int) RAFile.length()];
            RAFile.read(byteArray);
            if (!Utils.isDue(byteArray)) {
                return Utils.clearDateInfo(byteArray);
            } else {
                removeFile = true;
                return null;
            }
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        } finally {
            if (RAFile != null) {
                try {
                    RAFile.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (removeFile)
                remove(key);
        }
    }

    // =======================================
    // ============= 序列化 数据 读写 ===============
    // =======================================
    /**
     * 保存 Serializable数据 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的value
     */
    public void put(String key, Serializable value) {
        put(key, value, -1);
    }

    /**
     * 保存 Serializable数据到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的value
     * @param saveTime
     *            保存的时间,单位:秒
     */
    public void put(String key, Serializable value, int saveTime) {
        ByteArrayOutputStream baos = null;
        ObjectOutputStream oos = null;
        try {
            baos = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(baos);
            oos.writeObject(value);
            byte[] data = baos.toByteArray();
            if (saveTime != -1) {
                put(key, data, saveTime);
            } else {
                put(key, data);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                oos.close();
            } catch (IOException e) {
            }
        }
    }

    /**
     * 读取 Serializable数据
     * 
     * @param key
     * @return Serializable 数据
     */
    public Object getAsObject(String key) {
        byte[] data = getAsBinary(key);
        if (data != null) {
            ByteArrayInputStream bais = null;
            ObjectInputStream ois = null;
            try {
                bais = new ByteArrayInputStream(data);
                ois = new ObjectInputStream(bais);
                Object reObject = ois.readObject();
                return reObject;
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            } finally {
                try {
                    if (bais != null)
                        bais.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                try {
                    if (ois != null)
                        ois.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;

    }

    // =======================================
    // ============== bitmap 数据 读写 =============
    // =======================================
    /**
     * 保存 bitmap 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的bitmap数据
     */
    public void put(String key, Bitmap value) {
        put(key, Utils.Bitmap2Bytes(value));
    }

    /**
     * 保存 bitmap 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的 bitmap 数据
     * @param saveTime
     *            保存的时间,单位:秒
     */
    public void put(String key, Bitmap value, int saveTime) {
        put(key, Utils.Bitmap2Bytes(value), saveTime);
    }

    /**
     * 读取 bitmap 数据
     * 
     * @param key
     * @return bitmap 数据
     */
    public Bitmap getAsBitmap(String key) {
        if (getAsBinary(key) == null) {
            return null;
        }
        return Utils.Bytes2Bimap(getAsBinary(key));
    }

    // =======================================
    // ============= drawable 数据 读写 =============
    // =======================================
    /**
     * 保存 drawable 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的drawable数据
     */
    public void put(String key, Drawable value) {
        put(key, Utils.drawable2Bitmap(value));
    }

    /**
     * 保存 drawable 到 缓存中
     * 
     * @param key
     *            保存的key
     * @param value
     *            保存的 drawable 数据
     * @param saveTime
     *            保存的时间,单位:秒
     */
    public void put(String key, Drawable value, int saveTime) {
        put(key, Utils.drawable2Bitmap(value), saveTime);
    }

    /**
     * 读取 Drawable 数据
     * 
     * @param key
     * @return Drawable 数据
     */
    public Drawable getAsDrawable(String key) {
        if (getAsBinary(key) == null) {
            return null;
        }
        return Utils.bitmap2Drawable(Utils.Bytes2Bimap(getAsBinary(key)));
    }

    /**
     * 获取缓存文件
     * 
     * @param key
     * @return value 缓存的文件
     */
    public File file(String key) {
        File f = mCacheManager.newFile(key);
        if (f.exists())
            return f;
        return null;
    }

    /**
     * 移除某个key
     * 
     * @param key
     * @return 是否移除成功
     */
    public boolean remove(String key) {
        return mCacheManager.remove(key);
    }

    /**
     * 清除所有数据
     */
    public void clear() {
        mCacheManager.clear();
    }

    /**
     * @title 缓存管理器
     * @author 杨福海(michael) www.yangfuhai.com
     * @version 1.0
     */
    public class ACacheManager {
        private final AtomicLong cacheSize;
        private final AtomicInteger cacheCount;
        
        private final long sizeLimit;
        private final int countLimit;
        
        private final Map<File, Long> lastUsageDates = Collections.synchronizedMap(new HashMap<File, Long>());
        protected File cacheDir;

        private ACacheManager(File cacheDir, long sizeLimit, int countLimit) {
            this.cacheDir = cacheDir;
            this.sizeLimit = sizeLimit;
            this.countLimit = countLimit;
            
            cacheSize = new AtomicLong();
            cacheCount = new AtomicInteger();
            calculateCacheSizeAndCacheCount();
        }

        /**
         * 计算 cacheSize和cacheCount
         */
        private void calculateCacheSizeAndCacheCount() {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    int size = 0;
                    int count = 0;
                    File[] cachedFiles = cacheDir.listFiles();
                    if (cachedFiles != null) {
                        for (File cachedFile : cachedFiles) {
                            size += calculateSize(cachedFile);
                            count += 1;
                            lastUsageDates.put(cachedFile, cachedFile.lastModified());
                        }
                        cacheSize.set(size);
                        cacheCount.set(count);
                    }
                }
            }).start();
        }

        private void put(File file) {
            int curCacheCount = cacheCount.get();
            while (curCacheCount + 1 > countLimit) {
                long freedSize = removeNext();
                cacheSize.addAndGet(-freedSize);

                curCacheCount = cacheCount.addAndGet(-1);
            }
            cacheCount.addAndGet(1);

            long valueSize = calculateSize(file);
            long curCacheSize = cacheSize.get();
            while (curCacheSize + valueSize > sizeLimit) {
                long freedSize = removeNext();
                curCacheSize = cacheSize.addAndGet(-freedSize);
            }
            cacheSize.addAndGet(valueSize);

            Long currentTime = System.currentTimeMillis();
            file.setLastModified(currentTime);
            lastUsageDates.put(file, currentTime);
        }

        private File get(String key) {
            File file = newFile(key);
            Long currentTime = System.currentTimeMillis();
            file.setLastModified(currentTime);
            lastUsageDates.put(file, currentTime);

            return file;
        }

        private File newFile(String key) {
            return new File(cacheDir, key.hashCode() + "");
        }

        private boolean remove(String key) {
            File image = get(key);
            return image.delete();
        }

        private void clear() {
            lastUsageDates.clear();
            cacheSize.set(0);
            File[] files = cacheDir.listFiles();
            if (files != null) {
                for (File f : files) {
                    f.delete();
                }
            }
        }

        /**
         * 移除旧的文件
         * 
         * @return
         */
        private long removeNext() {
            if (lastUsageDates.isEmpty()) {
                return 0;
            }

            Long oldestUsage = null;
            File mostLongUsedFile = null;
            Set<Entry<File, Long>> entries = lastUsageDates.entrySet();
            synchronized (lastUsageDates) {
                for (Entry<File, Long> entry : entries) {
                    if (mostLongUsedFile == null) {
                        mostLongUsedFile = entry.getKey();
                        oldestUsage = entry.getValue();
                    } else {
                        Long lastValueUsage = entry.getValue();
                        if (lastValueUsage < oldestUsage) {
                            oldestUsage = lastValueUsage;
                            mostLongUsedFile = entry.getKey();
                        }
                    }
                }
            }

            long fileSize = calculateSize(mostLongUsedFile);
            if (mostLongUsedFile.delete()) {
                lastUsageDates.remove(mostLongUsedFile);
            }
            return fileSize;
        }

        private long calculateSize(File file) {
            return file.length();
        }
    }

    /**
     * @title 时间计算工具类
     * @author 杨福海(michael) www.yangfuhai.com
     * @version 1.0
     */
    private static class Utils {

        /**
         * 判断缓存的String数据是否到期
         * 
         * @param str
         * @return true:到期了 false:还没有到期
         */
        private static boolean isDue(String str) {
            return isDue(str.getBytes());
        }

        /**
         * 判断缓存的byte数据是否到期
         * 
         * @param data
         * @return true:到期了 false:还没有到期
         */
        private static boolean isDue(byte[] data) {
            String[] strs = getDateInfoFromDate(data);
            if (strs != null && strs.length == 2) {
                String saveTimeStr = strs[0];
                while (saveTimeStr.startsWith("0")) {
                    saveTimeStr = saveTimeStr.substring(1, saveTimeStr.length());
                }
                long saveTime = Long.valueOf(saveTimeStr);
                long deleteAfter = Long.valueOf(strs[1]);
                if (System.currentTimeMillis() > saveTime + deleteAfter * 1000) {
                    return true;
                }
            }
            return false;
        }

        private static String newStringWithDateInfo(int second, String strInfo) {
            return createDateInfo(second) + strInfo;
        }

        private static byte[] newByteArrayWithDateInfo(int second, byte[] data2) {
            byte[] data1 = createDateInfo(second).getBytes();
            byte[] retdata = new byte[data1.length + data2.length];
            System.arraycopy(data1, 0, retdata, 0, data1.length);
            System.arraycopy(data2, 0, retdata, data1.length, data2.length);
            return retdata;
        }

        private static String clearDateInfo(String strInfo) {
            if (strInfo != null && hasDateInfo(strInfo.getBytes())) {
                strInfo = strInfo.substring(strInfo.indexOf(mSeparator) + 1, strInfo.length());
            }
            return strInfo;
        }

        private static byte[] clearDateInfo(byte[] data) {
            if (hasDateInfo(data)) {
                return copyOfRange(data, indexOf(data, mSeparator) + 1, data.length);
            }
            return data;
        }

        private static boolean hasDateInfo(byte[] data) {
            return data != null && data.length > 15 && data[13] == '-' && indexOf(data, mSeparator) > 14;
        }

        private static String[] getDateInfoFromDate(byte[] data) {
            if (hasDateInfo(data)) {
                String saveDate = new String(copyOfRange(data, 0, 13));
                String deleteAfter = new String(copyOfRange(data, 14, indexOf(data, mSeparator)));
                return new String[] { saveDate, deleteAfter };
            }
            return null;
        }

        private static int indexOf(byte[] data, char c) {
            for (int i = 0; i < data.length; i++) {
                if (data[i] == c) {
                    return i;
                }
            }
            return -1;
        }

        private static byte[] copyOfRange(byte[] original, int from, int to) {
            int newLength = to - from;
            if (newLength < 0)
                throw new IllegalArgumentException(from + " > " + to);
            byte[] copy = new byte[newLength];
            System.arraycopy(original, from, copy, 0, Math.min(original.length - from, newLength));
            return copy;
        }

        private static final char mSeparator = ' ';

        private static String createDateInfo(int second) {
            String currentTime = System.currentTimeMillis() + "";
            while (currentTime.length() < 13) {
                currentTime = "0" + currentTime;
            }
            return currentTime + "-" + second + mSeparator;
        }

        /*
         * Bitmap → byte[]
         */
        private static byte[] Bitmap2Bytes(Bitmap bm) {
            if (bm == null) {
                return null;
            }
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
            return baos.toByteArray();
        }

        /*
         * byte[] → Bitmap
         */
        private static Bitmap Bytes2Bimap(byte[] b) {
            if (b.length == 0) {
                return null;
            }
            return BitmapFactory.decodeByteArray(b, 0, b.length);
        }

        /*
         * Drawable → Bitmap
         */
        private static Bitmap drawable2Bitmap(Drawable drawable) {
            if (drawable == null) {
                return null;
            }
            // 取 drawable 的长宽
            int w = drawable.getIntrinsicWidth();
            int h = drawable.getIntrinsicHeight();
            // 取 drawable 的颜色格式
            Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
            // 建立对应 bitmap
            Bitmap bitmap = Bitmap.createBitmap(w, h, config);
            // 建立对应 bitmap 的画布
            Canvas canvas = new Canvas(bitmap);
            drawable.setBounds(0, 0, w, h);
            // 把 drawable 内容画到画布中
            drawable.draw(canvas);
            return bitmap;
        }

        /*
         * Bitmap → Drawable
         */
        @SuppressWarnings("deprecation")
        private static Drawable bitmap2Drawable(Bitmap bm) {
            if (bm == null) {
                return null;
            }
            BitmapDrawable bd=new BitmapDrawable(bm);
            bd.setTargetDensity(bm.getDensity());
            return new BitmapDrawable(bm);
        }
    }

}
ACache.java

将Globals复制到项目中(或者在类似文件(用于存放全局变量和公共方法)中添加以下代码)

package com.why.project.acachedemo.utils;

/**
 * Created HaiyuKing
 * Used  全局变量和公共方法
 */
public class Globals {
    
    /**==================缓存的key值===============================*/
    /**用户名*/
    public static final String USERNAME_KEY = "username";
    
}

三、使用方法

package com.why.project.acachedemo;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.why.project.acachedemo.utils.ACache;
import com.why.project.acachedemo.utils.Globals;

public class MainActivity extends AppCompatActivity {

    private EditText mUsernameEdt;
    private Button mLoginBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initViews();
        initDatas();
        initEvents();
    }

    //初始化控件
    private void initViews(){
        mUsernameEdt = (EditText) findViewById(R.id.edt_username);
        mLoginBtn = (Button) findViewById(R.id.btn_login);
    }

    //初始化数据
    private void initDatas(){
        //判断是否缓存了用户名,如果是的话,读取缓存的用户名并填充到输入框中
        initNamePwdFromCache();
    }

    //初始化事件
    private void initEvents(){
        mLoginBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String userName = mUsernameEdt.getText().toString();
                //缓存用户名
                ACache.get(MainActivity.this).put(Globals.USERNAME_KEY,userName);
                Toast.makeText(MainActivity.this,"已缓存用户名:"+userName,Toast.LENGTH_SHORT).show();
            }
        });
    }

    /**
     * 从缓存中查询用户名是否保存,并加载用户名
     * */
    private void initNamePwdFromCache() {
        //有缓存文件
        String userNameCache = ACache.get(this).getAsString(Globals.USERNAME_KEY);
        if (userNameCache != null) {
            mUsernameEdt.setText(userNameCache);
            Toast.makeText(MainActivity.this,"已加载缓存的用户名:"+userNameCache,Toast.LENGTH_SHORT).show();
        }
    }
}

混淆配置

参考资料

【Android开源项目分析】android轻量级开源缓存框架——ASimpleCache(ACache)源码分析

http://blog.csdn.net/zhoubin1992/article/details/46379055

ASimpleCache框架源码链接

https://github.com/yangfuhai/ASimpleCache

ASimpleCache开源库使用分析

http://blog.csdn.net/yanbober/article/details/45306851

项目demo下载地址

https://github.com/haiyuKing/AcacheDemo

posted @ 2017-05-21 16:11  HaiyuKing  阅读(7691)  评论(0编辑  收藏  举报