Android 清理缓存、优化内存空间

有时候项目中需要清理一些缓存数据（如：图片缓存、网络数据缓存等），当然也要对SharedPreferences存储的数据进行清理，当然App中有个这样的功能可能会提高逼格吧。

public class CacheDataManager {
    /**
     * 获取整体缓存大小
     * @param context
     * @return
     * @throws Exception
     */
    public static String getTotalCacheSize(Context context) throws Exception {
        long cacheSize = getFolderSize(context.getCacheDir());
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            cacheSize += getFolderSize(context.getExternalCacheDir());
        }
        return getFormatSize(cacheSize);
    }
    /**
     * 获取文件
     * 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
     * @param file
     * @return
     * @throws Exception
     */
    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;
    }
    /**
     * 格式化单位
     * @param size
     */
    public static String getFormatSize(long size) {
        long kb = size / 1024;
        int m = (int) (kb / 1024);
        int kbs = (int) (kb % 1024);
        return m + "." + kbs + "M";
//        double kiloByte = size / 1024;
//        if (kiloByte < 1) {
//            return size + "Byte";
//        }
//        double megaByte = kiloByte / 1024;
//        if (megaByte < 1) {
//            BigDecimal result1 = new BigDecimal(Double.toString(kiloByte));
//            return result1.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "KB";
//        }
//        double gigaByte = megaByte / 1024;
//        if (gigaByte < 1) {
//            BigDecimal result2 = new BigDecimal(Double.toString(megaByte));
//            return result2.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "MB";
//        }
//        double teraBytes = gigaByte / 1024;
//        if (teraBytes < 1) {
//            BigDecimal result3 = new BigDecimal(Double.toString(gigaByte));
//            return result3.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "GB";
//        }
//        BigDecimal result4 = new BigDecimal(teraBytes);
//        return result4.setScale(2, BigDecimal.ROUND_HALF_UP).toPlainString() + "TB";
    }

    /**
     * 清空方法
     * @param context
     */
    public static void clearAllCache(Context context) {
        deleteDir(context.getCacheDir());
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            deleteDir(context.getExternalCacheDir());
        }
    }

    private static boolean deleteDir(File dir) {
        if (dir != null && dir.isDirectory()) {
            String[] children = dir.list();
            for (int i = 0; i < children.length; i++) {
                boolean success = deleteDir(new File(dir, children[i]));
                if (!success) {
                    return false;
                }
            }
        }
        return dir.delete();
    }

}

直接调用：

 CacheDataManager.clearAllCache(SettingActivity.this);

 其实它的清理速度是非常快的，那么做一个延时效果会让用户有一点点体验的：

    @OnClick(R.id.setting_cleancache)
    void clean() {
        //设置默认的等待效果
        mDlg = new WaitingDlg(SettingActivity.this, "", "", true);
        PromptDialog dialog = new PromptDialog(SettingActivity.this, R.string.prompt, R.string.cleancache_title);
        dialog.showYesNo(new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                SPUtils.clear();
                mDlg.start();
                new Thread(new clearCache()).start();
                dialog.dismiss();
            }
        });
    }

    private Handler handler = new Handler() {
        public void handleMessage(android.os.Message msg) {
            switch (msg.what) {
                case 0:
                    mDlg.dismiss();
                    Toast.makeText(SettingActivity.this, "清理完成", Toast.LENGTH_SHORT).show();
                    try {
                        cachetext.setText(CacheDataManager.getTotalCacheSize(SettingActivity.this));
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
            }
        }

    };

    class clearCache implements Runnable {
        @Override
        public void run() {
            try {
                CacheDataManager.clearAllCache(SettingActivity.this);
                Thread.sleep(1000);
                if (CacheDataManager.getTotalCacheSize(SettingActivity.this).startsWith("0")) {
                    handler.sendEmptyMessage(0);
                }
            } catch (Exception e) {
                return;
            }
        }
    }