Android清除缓存功能实现

Android清除缓存功能包含两个部分，一是计算缓存大小，二是清除缓存，并且由于计算缓存大小、清除缓存会比较耗时，要放在子线程执行。计算缓存大小、清除缓存，通过下面的工具类实现：

package com.xi.liuliu.topnews.utils;import android.content.Context;import android.os.Environment;import android.text.TextUtils;import java.io.File;import java.math.BigDecimal;import java.text.DecimalFormat;/** * 清除缓存工具类，清除内/外缓存，清除数据库，清除sharedPreference，清除files和清除自定义目录 * Created by zhangxb171 on 2017/9/30. */public class FileCacheUtil {    private static DecimalFormat df;    /**     * * 清除本应用内部缓存(/data/data/com.xxx.xxx/cache)     *     * @param context     */    public static void cleanInternalCache(Context context) {        deleteFilesByDirectory(context.getCacheDir());    }    /**     * * 清除本应用所有数据库(/data/data/com.xxx.xxx/databases)     *     * @param context     */    public static void cleanDatabases(Context context) {        deleteFilesByDirectory(new File("/data/data/"                + context.getPackageName() + "/databases"));    }    /**     * * 清除本应用SharedPreference(/data/data/com.xxx.xxx/shared_prefs)     *     * @param context     */    public static void cleanSharedPreference(Context context) {        deleteFilesByDirectory(new File("/data/data/"                + context.getPackageName() + "/shared_prefs"));    }    /**     * * 按名字清除本应用数据库     *     * @param context     * @param dbName     */    public static void cleanDatabaseByName(Context context, String dbName) {        context.deleteDatabase(dbName);    }    /**     * * 清除/data/data/com.xxx.xxx/files下的内容     *     * @param context     */    public static void cleanFiles(Context context) {        deleteFilesByDirectory(context.getFilesDir());    }    /**     * * 清除外部cache下的内容(/mnt/sdcard/android/data/com.xxx.xxx/cache)     *     * @param context     */    public static void cleanExternalCache(Context context) {        if (Environment.getExternalStorageState().equals(                Environment.MEDIA_MOUNTED)) {            deleteFilesByDirectory(context.getExternalCacheDir());        }    }    /**     * * 清除自定义路径下的文件     *     * @param filePath     */    public static void cleanCustomCache(String filePath) {        deleteFilesByDirectory(new File(filePath));    }    /**     * * 清除本应用所有的数据     *     * @param context     * @param filepath     */    public static void cleanApplicationData(Context context, String... filepath) {        cleanInternalCache(context);        cleanExternalCache(context);        cleanDatabases(context);        cleanSharedPreference(context);        cleanFiles(context);        if (filepath == null) {            return;        }        for (String filePath : filepath) {            cleanCustomCache(filePath);        }    }    /**     * * 删除方法 这里只会删除某个文件夹下的文件，如果传入的directory是个文件，将不做处理     *     * @param directory     */    private static void deleteFilesByDirectory(File directory) {        if (directory != null && directory.exists() && directory.isDirectory()) {            for (File item : directory.listFiles()) {                item.delete();            }        }    }    // 获取文件大小    //Context.getExternalFilesDir() --> SDCard/Android/data/你的应用的包名/files/ 目录，一般放一些长时间保存的数据    //Context.getExternalCacheDir() --> SDCard/Android/data/你的应用包名/cache/目录，一般存放临时缓存数据    public static long getFolderSize(File file) throws Exception {        long size = 0;        try {            File[] fileList = file.listFiles();            for (int i = 0; i < fileList.length; i++) {                // 如果下面还有文件                if (fileList[i].isDirectory()) {                    size = size + getFolderSize(fileList[i]);                } else {                    size = size + fileList[i].length();                }            }        } catch (Exception e) {            e.printStackTrace();        }        return size;    }    /**     * 删除指定目录下文件及目录     *     * @param filePath     * @param deleteThisPath     */    public static void deleteFolderFile(String filePath, boolean deleteThisPath) {        if (!TextUtils.isEmpty(filePath)) {            try {                File file = new File(filePath);                if (file.isDirectory()) {// 如果下面还有文件                    File files[] = file.listFiles();                    for (int i = 0; i < files.length; i++) {                        deleteFolderFile(files[i].getAbsolutePath(), true);                    }                }                if (deleteThisPath) {                    if (!file.isDirectory()) {// 如果是文件，删除                        file.delete();                    } else {// 目录                        if (file.listFiles().length == 0) {// 目录下没有文件或者目录，删除                            file.delete();                        }                    }                }            } catch (Exception e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }    /**     * 格式化单位     *     * @param size     * @return     */    public static String getFormatSize(double size) {        //保留两位小数        df = new DecimalFormat("0.00");        double kiloByte = size / 1024;        String format = df.format(size);        if (kiloByte < 1) {            return format + "B";        }        double megaByte = kiloByte / 1024;        if (megaByte < 1) {            BigDecimal result1 = new BigDecimal(Double.toString(kiloByte));            return result1.setScale(2, BigDecimal.ROUND_HALF_UP)                    .toPlainString() + "K";        }        double gigaByte = megaByte / 1024;        if (gigaByte < 1) {            BigDecimal result2 = new BigDecimal(Double.toString(megaByte));            return result2.setScale(2, BigDecimal.ROUND_HALF_UP)                    .toPlainString() + "M";        }        double teraBytes = gigaByte / 1024;        if (teraBytes < 1) {            BigDecimal result3 = new BigDecimal(Double.toString(gigaByte));            return result3.setScale(2, BigDecimal.ROUND_HALF_UP)                    .toPlainString() + "G";        }        BigDecimal result4 = new BigDecimal(teraBytes);        return result4.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString()                + "T";    }    /***     * 获取应用缓存大小     * @param file     * @return     * @throws Exception     */    public static String getCacheSize(File file) throws Exception {        return getFormatSize(getFolderSize(file));    }}

上面的工具类可清除内部(data/data/com.xxx.xxx/xxx)、外部(mnt/sdcard/android/data/com.xxx.xxx/xx)、自定义的缓存文件。

计算缓存在子线程中执行，缓存计算完成后，通过监听的接口回调，更新UI：

public void calculateCacheSize() {        CacheSizeCalculateListener listener = new CacheSizeCalculateListener() {            @Override            public void onCalculateFinished(long cacheSize) {                String size = FileUtils.formatFileSize(cacheSize, FileUtils.SIZETYPE_MB) + "MB";                mCacheSize.setText(size);            }        };        CaculateCacheSizeRunnable runnable = new CaculateCacheSizeRunnable(listener);        Thread thread = new Thread(runnable);        thread.start();    }    static class CaculateCacheSizeRunnable implements Runnable {        CacheSizeCalculateListener listener;        public CaculateCacheSizeRunnable(CacheSizeCalculateListener listener) {            this.listener = listener;        }        @Override        public void run() {            long cacheSize = 0;            try {                cacheSize = FileUtils.getCacheSize();            } catch (Exception e) {                e.printStackTrace();            }            listener.onCalculateFinished(cacheSize);        }    }    interface CacheSizeCalculateListener {        void onCalculateFinished(long cacheSize);    }

同样，清除缓存也在子线程中执行，清除完成后通过回调监听的接口，弹出Toast：

 private void clearCache() {        SettingsActivity.ClearCacheRunnable runnable = new SettingsActivity.ClearCacheRunnable(mClearCacheListener);        Thread thread = new Thread(runnable);        thread.start();    }    public void setClearCacheListener(SettingsActivity.ClearCacheListener listener) {        this.mClearCacheListener = listener;    }public static class ClearCacheRunnable implements Runnable {        ClearCacheListener listener;        public ClearCacheRunnable(ClearCacheListener listener) {            this.listener = listener;        }        @Override        public void run() {            FileUtils.clearCache();            listener.onClearCacheFinished();        }    }    public interface ClearCacheListener {        void onClearCacheFinished();    }

注：我的项目中主要是清除外部存储的图片，并未清除cache、files、sharePref、database等目录。地址： https://github.com/xiyy/TopNews

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