小米开源文件管理器MiCodeFileExplorer-源码研究(3)-使用最多的工具类Util-白红宇

小米开源文件管理器MiCodeFileExplorer-源码研究(3)-使用最多的工具类Util

阅读量：5278 次

发布时间：2019-06-14

本文共 13577 字，大约阅读时间需要 45 分钟。

Util.java,使用最广泛~

代码中很多地方，都写了注释说明~基本不需要怎么解释了~

package net.micode.fileexplorer.util;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FilenameFilter;import java.io.IOException;import java.text.DateFormat;import java.util.ArrayList;import java.util.Date;import java.util.HashSet;import net.micode.fileexplorer.FileViewActivity;import net.micode.fileexplorer.GlobalConsts;import net.micode.fileexplorer.R;import net.micode.fileexplorer.model.FavoriteItem;import net.micode.fileexplorer.model.FileInfo;import android.app.Notification;import android.app.NotificationManager;import android.app.PendingIntent;import android.content.Context;import android.content.Intent;import android.content.pm.ApplicationInfo;import android.content.pm.PackageInfo;import android.content.pm.PackageManager;import android.graphics.drawable.Drawable;import android.os.Environment;import android.util.Log;import android.view.ActionMode;import android.view.View;import android.widget.TextView;/**工具类，包含了很多通用的工具方法，被项目中的很多类调用。*/public class Util {	//这个文件夹里面存储的内容是app2sd产生的文件夹，也就是是你手机上所有安装到SD卡的应用程序的缓存文件夹。	//androidsecure文件夹可以删除吗？    //如果删除之后，软件不能正常使用，和系统没有关系。	//删的话除了会可能导致移动至sd卡的程序损坏，数据丢失，并不会造成什么严重后果。只要把移动到sd卡的损坏程序卸载，重装，手机就完全没有损伤，文件夹也会在再次app2sd时自动重建的。	private static String ANDROID_SECURE = "/mnt/sdcard/.android_secure";    //android.util.Log.log第1个参数，用到“tag”，和log4j中Logger.getLogger(getClass())用法不太一样	private static final String LOG_TAG = "Util";	//获得SD卡的存储状态，“mounted”表示已经就绪	public static boolean isSDCardReady() {		return Environment.getExternalStorageState().equals(				Environment.MEDIA_MOUNTED);	}	// if path1 contains path2	public static boolean containsPath(String path1, String path2) {		String path = path2;		while (path != null) {			if (path.equalsIgnoreCase(path1))				return true;			if (path.equals(GlobalConsts.ROOT_PATH))				break;			path = new File(path).getParent();		}		return false;	}	//2个路径相加的时候，是否需要加上文件分隔符	public static String makePath(String path1, String path2) {		if (path1.endsWith(File.separator))			return path1 + path2;		return path1 + File.separator + path2;	}	//获得SD卡的存储目录	public static String getSdDirectory() {		return Environment.getExternalStorageDirectory().getPath();	}	//判断1个文件是否为“普通文件”，ANDROID_SECURE下的文件都不是普通的	public static boolean isNormalFile(String fullName) {		return !fullName.equals(ANDROID_SECURE);	}	//根据文件路径，获得Java文件File，再包装成FileInfo	public static FileInfo GetFileInfo(String filePath) {		File lFile = new File(filePath);		if (!lFile.exists())			return null;		FileInfo lFileInfo = new FileInfo();		lFileInfo.canRead = lFile.canRead();		lFileInfo.canWrite = lFile.canWrite();		lFileInfo.isHidden = lFile.isHidden();		lFileInfo.fileName = Util.getNameFromFilepath(filePath);		lFileInfo.ModifiedDate = lFile.lastModified();		lFileInfo.IsDir = lFile.isDirectory();		lFileInfo.filePath = filePath;		lFileInfo.fileSize = lFile.length();		return lFileInfo;	}	//根据File对象，和FilenameFilter等选项，获得包装的FileInfo	//需要注意多少，如果File是个目录，Count就是当前目录下的文件的个数。如果是普通文件，就计算文件大小。	//这个时候，我们知道Count字段的含义了	public static FileInfo GetFileInfo(File f, FilenameFilter filter,			boolean showHidden) {		FileInfo lFileInfo = new FileInfo();		String filePath = f.getPath();		File lFile = new File(filePath);		lFileInfo.canRead = lFile.canRead();		lFileInfo.canWrite = lFile.canWrite();		lFileInfo.isHidden = lFile.isHidden();		lFileInfo.fileName = f.getName();		lFileInfo.ModifiedDate = lFile.lastModified();		lFileInfo.IsDir = lFile.isDirectory();		lFileInfo.filePath = filePath;		if (lFileInfo.IsDir) {			int lCount = 0;			File[] files = lFile.listFiles(filter);			// null means we cannot access this dir			if (files == null) {				return null;			}			for (File child : files) {				if ((!child.isHidden() || showHidden)						&& Util.isNormalFile(child.getAbsolutePath())) {					lCount++;				}			}			lFileInfo.Count = lCount;		} else {			lFileInfo.fileSize = lFile.length();		}		return lFileInfo;	}	/*	 * 采用了新的办法获取APK图标，之前的失败是因为android中存在的一个BUG,通过 appInfo.publicSourceDir =	 * apkPath;来修正这个问题，详情参见:	 * http://code.google.com/p/android/issues/detail?id=9151	 */	public static Drawable getApkIcon(Context context, String apkPath) {		//Android系统为我们提供了很多服务管理类，包括ActivityManager、PowerManager(电源管理)、AudioManager(音频管理)。		//PackageManager主要是管理应用程序包，通过它就可以获取应用程序信息		PackageManager pm = context.getPackageManager();		PackageInfo info = pm.getPackageArchiveInfo(apkPath,				PackageManager.GET_ACTIVITIES);		if (info != null) {			ApplicationInfo appInfo = info.applicationInfo;			appInfo.sourceDir = apkPath;			appInfo.publicSourceDir = apkPath;			try {				return appInfo.loadIcon(pm);			} catch (OutOfMemoryError e) {				Log.e(LOG_TAG, e.toString());			}		}		return null;	}	//获得文件的扩展名	public static String getExtFromFilename(String filename) {		int dotPosition = filename.lastIndexOf('.');		if (dotPosition != -1) {			return filename.substring(dotPosition + 1, filename.length());		}		return "";	}	//获得去掉“文件后缀”的文件名字，比如“C:/a/b/c.png”，输出“C:/a/b/c”	public static String getNameFromFilename(String filename) {		int dotPosition = filename.lastIndexOf('.');		if (dotPosition != -1) {			return filename.substring(0, dotPosition);		}		return "";	}	    //从文件路径中，获得路径	public static String getPathFromFilepath(String filepath) {		int pos = filepath.lastIndexOf('/');		if (pos != -1) {			return filepath.substring(0, pos);		}		return "";	}	//从文件路径中，获得文件名（带后缀，如果有）	public static String getNameFromFilepath(String filepath) {		int pos = filepath.lastIndexOf('/');		if (pos != -1) {			return filepath.substring(pos + 1);		}		return "";	}	// return new file path if successful, or return null	public static String copyFile(String src, String dest) {		File file = new File(src);		if (!file.exists() || file.isDirectory()) {			Log.v(LOG_TAG, "copyFile: file not exist or is directory, " + src);			return null;		}		FileInputStream fi = null;		FileOutputStream fo = null;		try {			fi = new FileInputStream(file);			File destPlace = new File(dest);			if (!destPlace.exists()) {				if (!destPlace.mkdirs())					return null;			}			String destPath = Util.makePath(dest, file.getName());			File destFile = new File(destPath);			int i = 1;			while (destFile.exists()) {				String destName = Util.getNameFromFilename(file.getName())						+ " " + i++ + "."						+ Util.getExtFromFilename(file.getName());				destPath = Util.makePath(dest, destName);				destFile = new File(destPath);			}			if (!destFile.createNewFile())				return null;			fo = new FileOutputStream(destFile);			int count = 102400;			byte[] buffer = new byte[count];			int read = 0;			while ((read = fi.read(buffer, 0, count)) != -1) {				fo.write(buffer, 0, read);			}			// TODO: set access privilege			return destPath;		} catch (FileNotFoundException e) {			Log.e(LOG_TAG, "copyFile: file not found, " + src);			e.printStackTrace();		} catch (IOException e) {			Log.e(LOG_TAG, "copyFile: " + e.toString());		} finally {			try {				if (fi != null)					fi.close();				if (fo != null)					fo.close();			} catch (IOException e) {				e.printStackTrace();			}		}		return null;	}	// does not include sd card folder	private static String[] SysFileDirs = new String[] { "miren_browser/imagecaches" };	//判断一个文件是否需要显示，根据Setting中的设置。特别说明：某个系统文件目录，不显示。	public static boolean shouldShowFile(String path) {		return shouldShowFile(new File(path));	}	//判断一个文件是否需要显示，根据Setting中的设置。特别说明：某个系统文件目录，不显示。	public static boolean shouldShowFile(File file) {		boolean show = Settings.instance().getShowDotAndHiddenFiles();		if (show)			return true;		if (file.isHidden())			return false;		if (file.getName().startsWith("."))			return false;		String sdFolder = getSdDirectory();		for (String s : SysFileDirs) {			if (file.getPath().startsWith(makePath(sdFolder, s)))				return false;		}		return true;	}	//根据上下文对象Context，获得默认的收藏集合	public static ArrayList
    
      getDefaultFavorites(Context context) {		ArrayList
     
       list = new ArrayList
      
       ();		list.add(new FavoriteItem(context.getString(R.string.favorite_photo),				makePath(getSdDirectory(), "DCIM/Camera")));		list.add(new FavoriteItem(context.getString(R.string.favorite_sdcard),				getSdDirectory()));		// list.add(new FavoriteItem(context.getString(R.string.favorite_root),		// getSdDirectory()));		list.add(new FavoriteItem(context				.getString(R.string.favorite_screen_cap), makePath(				getSdDirectory(), "MIUI/screen_cap")));		list.add(new FavoriteItem(				context.getString(R.string.favorite_ringtone), makePath(						getSdDirectory(), "MIUI/ringtone")));		return list;	}	//向View中的某个TextView设置文本	public static boolean setText(View view, int id, String text) {		TextView textView = (TextView) view.findViewById(id);		if (textView == null)			return false;		textView.setText(text);		return true;	}	//向View中的某个TextView设置文本	public static boolean setText(View view, int id, int text) {		TextView textView = (TextView) view.findViewById(id);		if (textView == null)			return false;		textView.setText(text);		return true;	}	// comma separated number	public static String convertNumber(long number) {		return String.format("%,d", number);	}	// storage, G M K B	public static String convertStorage(long size) {		long kb = 1024;		long mb = kb * 1024;		long gb = mb * 1024;		if (size >= gb) {			return String.format("%.1f GB", (float) size / gb);		} else if (size >= mb) {			float f = (float) size / mb;			return String.format(f > 100 ? "%.0f MB" : "%.1f MB", f);		} else if (size >= kb) {			float f = (float) size / kb;			return String.format(f > 100 ? "%.0f KB" : "%.1f KB", f);		} else			return String.format("%d B", size);	}	public static class SDCardInfo {		public long total;		public long free;	}	//获得SD卡的各种信息，总容量大小和剩余容量大小等	public static SDCardInfo getSDCardInfo() {		String sDcString = android.os.Environment.getExternalStorageState();		if (sDcString.equals(android.os.Environment.MEDIA_MOUNTED)) {			File pathFile = android.os.Environment					.getExternalStorageDirectory();			try {				android.os.StatFs statfs = new android.os.StatFs(						pathFile.getPath());				// 获取SDCard上BLOCK总数				long nTotalBlocks = statfs.getBlockCount();				// 获取SDCard上每个block的SIZE				long nBlocSize = statfs.getBlockSize();				// 获取可供程序使用的Block的数量				long nAvailaBlock = statfs.getAvailableBlocks();				// 获取剩下的所有Block的数量(包括预留的一般程序无法使用的块)				long nFreeBlock = statfs.getFreeBlocks();				SDCardInfo info = new SDCardInfo();				// 计算SDCard 总容量大小MB				info.total = nTotalBlocks * nBlocSize;				// 计算 SDCard 剩余大小MB				info.free = nAvailaBlock * nBlocSize;				return info;			} catch (IllegalArgumentException e) {				Log.e(LOG_TAG, e.toString());			}		}		return null;	}	//显示一条系统通知	public static void showNotification(Context context, Intent intent,			String title, String body, int drawableId) {		NotificationManager manager = (NotificationManager) context				.getSystemService(Context.NOTIFICATION_SERVICE);		Notification notification = new Notification(drawableId, body,				System.currentTimeMillis());		notification.flags = Notification.FLAG_AUTO_CANCEL;		notification.defaults = Notification.DEFAULT_SOUND;		if (intent == null) {			// FIXEME: category tab is disabled			intent = new Intent(context, FileViewActivity.class);		}		PendingIntent contentIntent = PendingIntent.getActivity(context, 0,				intent, PendingIntent.FLAG_ONE_SHOT);		notification.setLatestEventInfo(context, title, body, contentIntent);		manager.notify(drawableId, notification);	}	//格式化毫秒格式的时间	public static String formatDateString(Context context, long time) {		DateFormat dateFormat = android.text.format.DateFormat				.getDateFormat(context);		DateFormat timeFormat = android.text.format.DateFormat				.getTimeFormat(context);		Date date = new Date(time);		return dateFormat.format(date) + " " + timeFormat.format(date);	}	public static void updateActionModeTitle(ActionMode mode, Context context,			int selectedNum) {		if (mode != null) {			mode.setTitle(context.getString(R.string.multi_select_title,					selectedNum));			if (selectedNum == 0) {				mode.finish();			}		}	}	//MimeType	public static HashSet
       
         sDocMimeTypesSet = new HashSet
        
         () {		{			add("text/plain");			add("text/plain");			add("application/pdf");			add("application/msword");			add("application/vnd.ms-excel");			add("application/vnd.ms-excel");		}	};	public static String sZipFileMimeType = "application/zip";	public static int CATEGORY_TAB_INDEX = 0;	public static int SDCARD_TAB_INDEX = 1;}

遇到一个奇怪的问题，为了验证某个函数，写了个main函数执行，结果发生了奇葩事项~

在Java环境下的工程中执行以下代码，正常输出。

public class Test {	public static void main(String[] args) {			System.out.println(getNameFromFilename("C:/a/b/c.png"));		}	public static String getNameFromFilename(String filename) {		int dotPosition = filename.lastIndexOf('.');		if (dotPosition != -1) {			return filename.substring(0, dotPosition);		}		return "";	}}

打印“C:/a/b/c”

在Android环境下的工程中，竟然直接把JVM搞崩溃了，不明所以啊~

Invalid layout of java.lang.String at value

# A fatal error has been detected by the Java Runtime Environment:

# Internal Error (javaClasses.cpp:129), pid=8236, tid=3188

# fatal error: Invalid layout of preloaded class

# JRE version: 7.0_17-b02

# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.7-b01 mixed mode windows-amd64 compressed oops)

# Failed to write core dump. Minidumps are not enabled by default on client versions of Windows

# An error report file with more information is saved as:

# J:\AndroidCenter\MiCodeFileExplorer\hs_err_pid8236.log

# If you would like to submit a bug report, please visit: