blocks|key|315163|text|那是胡说。即使未挂载SD卡，/mnt/sdcard/external_sd也可以存在。在未挂载的情况下，当您尝试写入/mnt/sdcard/external_sd时，您的应用程序将崩溃。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|315164|您需要先使用以下方法检查SD卡是否已挂载：|315165|boolean+isSDPresent+=+Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);|code-block|syntax|javascript|315166|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

that's not true. /mnt/sdcard/external_sd can exist even if the SD card is not mounted. your application will crash when you try to write to /mnt/sdcard/external_sd when it's not mounted.

you need to check if the SD card is mounted first using:

<pre><code>boolean isSDPresent = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);
</code></pre>

blocks|key|532160|text|参考我的代码，希望能对你有所帮助：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532161|++++Runtime+runtime+=+Runtime.getRuntime();
++++Process+proc+=+runtime.exec("mount");
++++InputStream+is+=+proc.getInputStream();
++++InputStreamReader+isr+=+new+InputStreamReader(is);
++++String+line;
++++String+mount+=+new+String();
++++BufferedReader+br+=+new+BufferedReader(isr);
++++while+((line+=+br.readLine())+!=+null)+{
++++++++if+(line.contains("secure"))+continue;
++++++++if+(line.contains("asec"))+continue;

++++++++if+(line.contains("fat"))+{//TF+card
++++++++++++String+columns[]+=+line.split("+");
++++++++++++if+(columns+!=+null+&&+columns.length+>+1)+{
++++++++++++++++mount+=+mount.concat("*"+%2B+columns[1]+%2B+"\n");
++++++++++++}
++++++++}+else+if+(line.contains("fuse"))+{//internal+storage
++++++++++++String+columns[]+=+line.split("+");
++++++++++++if+(columns+!=+null+&&+columns.length+>+1)+{
++++++++++++++++mount+=+mount.concat(columns[1]+%2B+"\n");
++++++++++++}
++++++++}
++++}
++++txtView.setText(mount);|code-block|syntax|javascript|532162|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

refer to my code, hope helpful for you:

<pre><code> Runtime runtime = Runtime.getRuntime();
 Process proc = runtime.exec("mount");
 InputStream is = proc.getInputStream();
 InputStreamReader isr = new InputStreamReader(is);
 String line;
 String mount = new String();
 BufferedReader br = new BufferedReader(isr);
 while ((line = br.readLine()) != null) {
 if (line.contains("secure")) continue;
 if (line.contains("asec")) continue;

 if (line.contains("fat")) {//TF card
 String columns[] = line.split(" ");
 if (columns != null &amp;&amp; columns.length &gt; 1) {
 mount = mount.concat("*" + columns[1] + "\n");
 }
 } else if (line.contains("fuse")) {//internal storage
 String columns[] = line.split(" ");
 if (columns != null &amp;&amp; columns.length &gt; 1) {
 mount = mount.concat(columns[1] + "\n");
 }
 }
 }
 txtView.setText(mount);
</code></pre>

blocks|key|532194|text|感谢你们提供的线索，特别是@SmartLemon，我得到了解决方案。如果其他人需要它，我将我的最终解决方案放在这里(找到列出的第一个外部SD卡)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532195|public+File+getExternalSDCardDirectory()
{
++++File+innerDir+=+Environment.getExternalStorageDirectory();
++++File+rootDir+=+innerDir.getParentFile();
++++File+firstExtSdCard+=+innerDir+;
++++File[]+files+=+rootDir.listFiles();
++++for+(File+file+:+files)+{
++++++++if+(file.compareTo(innerDir)+!=+0)+{
++++++++++++firstExtSdCard+=+file;
++++++++++++break;
++++++++}
++++}
++++//Log.i("2",+firstExtSdCard.getAbsolutePath().toString());
++++return+firstExtSdCard;
}|code-block|syntax|javascript|532196|如果那里没有外部SD卡，则返回板载存储。如果SD卡不存在，我将使用它，您可能需要更换它。|532197|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Thanks for the clues provided by you guys, especially @SmartLemon, I got the solution. In case someone else need it, I put my final solution here( to find the first listed external SD card ):

<pre><code>public File getExternalSDCardDirectory()
{
 File innerDir = Environment.getExternalStorageDirectory();
 File rootDir = innerDir.getParentFile();
 File firstExtSdCard = innerDir ;
 File[] files = rootDir.listFiles();
 for (File file : files) {
 if (file.compareTo(innerDir) != 0) {
 firstExtSdCard = file;
 break;
 }
 }
 //Log.i("2", firstExtSdCard.getAbsolutePath().toString());
 return firstExtSdCard;
}
</code></pre>

If no external SD card there, then it returns the on board storage. I will use it if the sdcard is not exist, you may need to change it.

blocks|key|315259|text|我找到了更可靠的方法来获取系统中所有SD卡的路径。这在所有Android版本上都有效，并返回到所有存储的路径(包括模拟)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|315260|在我的所有设备上都能正常工作。|315261|附注:基于Environment类的源代码。|315262|private+static+final+Pattern+DIR_SEPORATOR+=+Pattern.compile("/");

/**
+*+Raturns+all+available+SD-Cards+in+the+system+(include+emulated)
+*
+*+Warning:+Hack!+Based+on+Android+source+code+of+version+4.3+(API+18)
+*+Because+there+is+no+standart+way+to+get+it.
+*+TODO:+Test+on+future+Android+versions+4.4%2B
+*
+*+@return+paths+to+all+available+SD-Cards+in+the+system+(include+emulated)
+*/
public+static+String[]+getStorageDirectories()
{
++++//+Final+set+of+paths
++++final+Set<String>+rv+=+new+HashSet<String>();
++++//+Primary+physical+SD-CARD+(not+emulated)
++++final+String+rawExternalStorage+=+System.getenv("EXTERNAL_STORAGE");
++++//+All+Secondary+SD-CARDs+(all+exclude+primary)+separated+by+":"
++++final+String+rawSecondaryStoragesStr+=+System.getenv("SECONDARY_STORAGE");
++++//+Primary+emulated+SD-CARD
++++final+String+rawEmulatedStorageTarget+=+System.getenv("EMULATED_STORAGE_TARGET");
++++if(TextUtils.isEmpty(rawEmulatedStorageTarget))
++++{
++++++++//+Device+has+physical+external+storage;+use+plain+paths.
++++++++if(TextUtils.isEmpty(rawExternalStorage))
++++++++{
++++++++++++//+EXTERNAL_STORAGE+undefined;+falling+back+to+default.
++++++++++++rv.add("/storage/sdcard0");
++++++++}
++++++++else
++++++++{
++++++++++++rv.add(rawExternalStorage);
++++++++}
++++}
++++else
++++{
++++++++//+Device+has+emulated+storage;+external+storage+paths+should+have
++++++++//+userId+burned+into+them.
++++++++final+String+rawUserId;
++++++++if(Build.VERSION.SDK_INT+<+Build.VERSION_CODES.JELLY_BEAN_MR1)
++++++++{
++++++++++++rawUserId+=+"";
++++++++}
++++++++else
++++++++{
++++++++++++final+String+path+=+Environment.getExternalStorageDirectory().getAbsolutePath();
++++++++++++final+String[]+folders+=+DIR_SEPORATOR.split(path);
++++++++++++final+String+lastFolder+=+folders[folders.length+-+1];
++++++++++++boolean+isDigit+=+false;
++++++++++++try
++++++++++++{
++++++++++++++++Integer.valueOf(lastFolder);
++++++++++++++++isDigit+=+true;
++++++++++++}
++++++++++++catch(NumberFormatException+ignored)
++++++++++++{
++++++++++++}
++++++++++++rawUserId+=+isDigit+?+lastFolder+:+"";
++++++++}
++++++++//+/storage/emulated/0[1,2,...]
++++++++if(TextUtils.isEmpty(rawUserId))
++++++++{
++++++++++++rv.add(rawEmulatedStorageTarget);
++++++++}
++++++++else
++++++++{
++++++++++++rv.add(rawEmulatedStorageTarget+%2B+File.separator+%2B+rawUserId);
++++++++}
++++}
++++//+Add+all+secondary+storages
++++if(!TextUtils.isEmpty(rawSecondaryStoragesStr))
++++{
++++++++//+All+Secondary+SD-CARDs+splited+into+array
++++++++final+String[]+rawSecondaryStorages+=+rawSecondaryStoragesStr.split(File.pathSeparator);
++++++++Collections.addAll(rv,+rawSecondaryStorages);
++++}
++++return+rv.toArray(new+String[rv.size()]);
}|code-block|syntax|javascript|315263|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I found more reliable way to get paths to all SD-CARDs in system.
This works on all Android versions and return paths to all storages (include emulated).

Works correctly on all my devices.

P.S.: Based on source code of Environment class.

<pre><code>private static final Pattern DIR_SEPORATOR = Pattern.compile("/");

/**
 * Raturns all available SD-Cards in the system (include emulated)
 *
 * Warning: Hack! Based on Android source code of version 4.3 (API 18)
 * Because there is no standart way to get it.
 * TODO: Test on future Android versions 4.4+
 *
 * @return paths to all available SD-Cards in the system (include emulated)
 */
public static String[] getStorageDirectories()
{
 // Final set of paths
 final Set&lt;String&gt; rv = new HashSet&lt;String&gt;();
 // Primary physical SD-CARD (not emulated)
 final String rawExternalStorage = System.getenv("EXTERNAL_STORAGE");
 // All Secondary SD-CARDs (all exclude primary) separated by ":"
 final String rawSecondaryStoragesStr = System.getenv("SECONDARY_STORAGE");
 // Primary emulated SD-CARD
 final String rawEmulatedStorageTarget = System.getenv("EMULATED_STORAGE_TARGET");
 if(TextUtils.isEmpty(rawEmulatedStorageTarget))
 {
 // Device has physical external storage; use plain paths.
 if(TextUtils.isEmpty(rawExternalStorage))
 {
 // EXTERNAL_STORAGE undefined; falling back to default.
 rv.add("/storage/sdcard0");
 }
 else
 {
 rv.add(rawExternalStorage);
 }
 }
 else
 {
 // Device has emulated storage; external storage paths should have
 // userId burned into them.
 final String rawUserId;
 if(Build.VERSION.SDK_INT &lt; Build.VERSION_CODES.JELLY_BEAN_MR1)
 {
 rawUserId = "";
 }
 else
 {
 final String path = Environment.getExternalStorageDirectory().getAbsolutePath();
 final String[] folders = DIR_SEPORATOR.split(path);
 final String lastFolder = folders[folders.length - 1];
 boolean isDigit = false;
 try
 {
 Integer.valueOf(lastFolder);
 isDigit = true;
 }
 catch(NumberFormatException ignored)
 {
 }
 rawUserId = isDigit ? lastFolder : "";
 }
 // /storage/emulated/0[1,2,...]
 if(TextUtils.isEmpty(rawUserId))
 {
 rv.add(rawEmulatedStorageTarget);
 }
 else
 {
 rv.add(rawEmulatedStorageTarget + File.separator + rawUserId);
 }
 }
 // Add all secondary storages
 if(!TextUtils.isEmpty(rawSecondaryStoragesStr))
 {
 // All Secondary SD-CARDs splited into array
 final String[] rawSecondaryStorages = rawSecondaryStoragesStr.split(File.pathSeparator);
 Collections.addAll(rv, rawSecondaryStorages);
 }
 return rv.toArray(new String[rv.size()]);
}
</code></pre>

blocks|key|532258|text|我做了以下操作来访问所有的外部SD卡。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532259|通过以下方式：|532260|File+primaryExtSd=Environment.getExternalStorageDirectory();|code-block|syntax|javascript|532261|您将获得主要外部SD的路径，然后使用以下命令：|532262|File+parentDir=new+File(primaryExtSd.getParent());|532263|您将获得主外部存储的父目录，它也是所有外部sd的父目录。现在，您可以列出所有存储并选择所需的存储。|532264|希望它是有用的。|532265|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

I did the following to get acces to all the external sd cards.

With:

<pre><code>File primaryExtSd=Environment.getExternalStorageDirectory();
</code></pre>

you get the path to the primary external SD
Then with:

<pre><code>File parentDir=new File(primaryExtSd.getParent());
</code></pre>

you get the parent dir of the primary external storage, and it is also the parent of all the external sd. 
Now, you can list all the storage and select the one that you want.

Hope it is usefull.

blocks|key|532319|text|在某些设备上(例如三星galaxy+sII+)，内部存储卡可能是vfat。在这种情况下，使用refer+last代码，我们获得path内部存储卡(/mnt/sdcad)，但没有外部卡。下面的代码参考解决了这个问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532320|static+String+getExternalStorage(){
+++++++++String+exts+=++Environment.getExternalStorageDirectory().getPath();
+++++++++try+{
++++++++++++FileReader+fr+=+new+FileReader(new+File("/proc/mounts"));+++++++
++++++++++++BufferedReader+br+=+new+BufferedReader(fr);
++++++++++++String+sdCard=null;
++++++++++++String+line;
++++++++++++while((line+=+br.readLine())!=null){
++++++++++++++++if(line.contains("secure")+%7C%7C+line.contains("asec"))+continue;
++++++++++++if(line.contains("fat")){
++++++++++++++++String[]+pars+=+line.split("\\s");
++++++++++++++++if(pars.length<2)+continue;
++++++++++++++++if(pars[1].equals(exts))+continue;
++++++++++++++++sdCard+=pars[1];+
++++++++++++++++break;
++++++++++++}
++++++++}
++++++++fr.close();
++++++++br.close();
++++++++return+sdCard;++

+++++}+catch+(Exception+e)+{
++++++++//+TODO+Auto-generated+catch+block
++++++++e.printStackTrace();
++++}
++++return+null;
}|code-block|syntax|javascript|532321|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

On some devices (for example samsung galaxy sII )internal memory card mabe be in vfat. In this case use refer last code, we obtain path internal memory card (/mnt/sdcad) but no external card. Code refer below solve this problem.

<pre><code>static String getExternalStorage(){
 String exts = Environment.getExternalStorageDirectory().getPath();
 try {
 FileReader fr = new FileReader(new File("/proc/mounts")); 
 BufferedReader br = new BufferedReader(fr);
 String sdCard=null;
 String line;
 while((line = br.readLine())!=null){
 if(line.contains("secure") || line.contains("asec")) continue;
 if(line.contains("fat")){
 String[] pars = line.split("\\s");
 if(pars.length&lt;2) continue;
 if(pars[1].equals(exts)) continue;
 sdCard =pars[1]; 
 break;
 }
 }
 fr.close();
 br.close();
 return sdCard; 

 } catch (Exception e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 return null;
}
</code></pre>

blocks|key|315347|text|+++++++File[]+files+=+null;
++++File+file+=+new+File("/storage");//+/storage/emulated
if+(file.exists())+{
++++++++files+=+file.listFiles();
++++++++++++}
++++++++++++if+(null+!=+files)
++++++++++++++++for+(int+j+=+0;+j+<+files.length;+j%2B%2B)+{
++++++++++++++++++++Log.e(TAG,+""+%2B+files[j]);
++++++++++++++++++++Log.e(TAG,+"//--//--//+"+%2B+++++++++++++files[j].exists());

++++++++++++++++++++if+(files[j].toString().replaceAll("_",+"")
++++++++++++++++++++++++++++.toLowerCase().contains("extsdcard"))+{
++++++++++++++++++++++++external_path+=+files[j].toString();
++++++++++++++++++++++++break;
++++++++++++++++++++}+else+if+(files[j].toString().replaceAll("_",+"")
++++++++++++++++++++++++++++.toLowerCase()
++++++++++++++++++++++++++++.contains("sdcard".concat(Integer.toString(j))))+{
++++++++++++++++++++++++//+external_path+=+files[j].toString();
++++++++++++++++++++}
++++++++++++++++++++Log.e(TAG,+"--///--///--++"+%2B+external_path);
++++++++++++++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|315348|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> File[] files = null;
 File file = new File("/storage");// /storage/emulated
if (file.exists()) {
 files = file.listFiles();
 }
 if (null != files)
 for (int j = 0; j &lt; files.length; j++) {
 Log.e(TAG, "" + files[j]);
 Log.e(TAG, "//--//--// " + files[j].exists());

 if (files[j].toString().replaceAll("_", "")
 .toLowerCase().contains("extsdcard")) {
 external_path = files[j].toString();
 break;
 } else if (files[j].toString().replaceAll("_", "")
 .toLowerCase()
 .contains("sdcard".concat(Integer.toString(j)))) {
 // external_path = files[j].toString();
 }
 Log.e(TAG, "--///--///-- " + external_path);
 }
</code></pre>

blocks|key|532377|text|好消息！在KitKat中，现在有一个公共应用程序接口，用于与这些辅助共享存储设备进行交互。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532378|新的Context.getExternalFilesDirs()和Context.getExternalCacheDirs()方法可以返回多个路径，包括主设备和辅助设备。然后，您可以遍历它们并检查Environment.getStorageState()和File.getFreeSpace()，以确定存储文件的最佳位置。这些方法也可以在ContextCompat上的support-v4库中找到。|offset|length|style|CODE|532379|还要注意，如果您只对使用Context返回的目录感兴趣，则不再需要READ_或WRITE_EXTERNAL_STORAGE权限。接下来，您将始终拥有对这些目录的读/写访问权限，而不需要额外的权限。|532380|应用程序也可以通过终止其权限请求来继续在旧设备上工作，如下所示：|532381|<uses-permission
++++android:name="android.permission.WRITE_EXTERNAL_STORAGE"
++++android:maxSdkVersion="18"+/>|code-block|syntax|javascript|532382|entityMap^0|0|2|U|X|U|2Q|T|3K|J|4P|D|0|C|7|X|5|13|M|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]|$D|W|E|X|F|G]|$D|Y|E|Z|F|G]|$D|10|E|11|F|G]|$D|12|E|13|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|14|8|@$D|15|E|16|F|G]|$D|17|E|18|F|G]|$D|19|E|1A|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|1B|8|@]|9|@]|A|$]]|$1|L|3|M|5|N|7|1C|8|@]|9|@]|A|$O|P]]|$1|Q|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|R|$]]

Good news! In KitKat there's now a public API for interacting with these secondary shared storage devices.

The new <code>Context.getExternalFilesDirs()</code> and <code>Context.getExternalCacheDirs()</code> methods can return multiple paths, including both primary and secondary devices. You can then iterate over them and check <code>Environment.getStorageState()</code> and <code>File.getFreeSpace()</code> to determine the best place to store your files. These methods are also available on <code>ContextCompat</code> in the support-v4 library.

Also note that if you're only interested in using the directories returned by <code>Context</code>, you no longer need the <code>READ_</code> or <code>WRITE_EXTERNAL_STORAGE</code> permissions. Going forward, you'll always have read/write access to these directories with no additional permissions required.

Apps can also continue working on older devices by end-of-lifing their permission request like this:

<pre><code>&lt;uses-permission
 android:name="android.permission.WRITE_EXTERNAL_STORAGE"
 android:maxSdkVersion="18" /&gt;
</code></pre>

blocks|key|532452|text|实际上，在某些设备中，外部SD卡的默认名称显示为extSdCard，而对于其他设备，则显示为sdcard1。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|532453|此代码片段有助于找到确切的路径，并帮助您检索外部设备的路径。|532454|String+sdpath,sd1path,usbdiskpath,sd0path;++++
++++++++if(new+File("/storage/extSdCard/").exists())
++++++++++++{
+++++++++++++++sdpath="/storage/extSdCard/";
+++++++++++++++Log.i("Sd+Cardext+Path",sdpath);
++++++++++++}
++++++++if(new+File("/storage/sdcard1/").exists())
+++++++++{
++++++++++++++sd1path="/storage/sdcard1/";
++++++++++++++Log.i("Sd+Card1+Path",sd1path);
+++++++++}
++++++++if(new+File("/storage/usbcard1/").exists())
+++++++++{
++++++++++++++usbdiskpath="/storage/usbcard1/";
++++++++++++++Log.i("USB+Path",usbdiskpath);
+++++++++}
++++++++if(new+File("/storage/sdcard0/").exists())
+++++++++{
++++++++++++++sd0path="/storage/sdcard0/";
++++++++++++++Log.i("Sd+Card0+Path",sd0path);
+++++++++}|code-block|syntax|javascript|532455|entityMap^0|O|9|1A|7|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

Actually in some devices the external sdcard default name is showing as <code>extSdCard</code> and for other it is <code>sdcard1</code>.

This code snippet helps to find out that exact path and helps to retrieve you the path of external device.

<pre><code>String sdpath,sd1path,usbdiskpath,sd0path; 
 if(new File("/storage/extSdCard/").exists())
 {
 sdpath="/storage/extSdCard/";
 Log.i("Sd Cardext Path",sdpath);
 }
 if(new File("/storage/sdcard1/").exists())
 {
 sd1path="/storage/sdcard1/";
 Log.i("Sd Card1 Path",sd1path);
 }
 if(new File("/storage/usbcard1/").exists())
 {
 usbdiskpath="/storage/usbcard1/";
 Log.i("USB Path",usbdiskpath);
 }
 if(new File("/storage/sdcard0/").exists())
 {
 sd0path="/storage/sdcard0/";
 Log.i("Sd Card0 Path",sd0path);
 }
</code></pre>

blocks|key|532493|text|我确信这段代码一定会解决你的issues...This对我来说工作得很好...\|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532494|try+{
++++++++++++File+mountFile+=+new+File("/proc/mounts");
++++++++++++usbFoundCount=0;
++++++++++++sdcardFoundCount=0;
++++++++++++if(mountFile.exists())
+++++++++++++{
++++++++++++++++Scanner+usbscanner+=+new+Scanner(mountFile);
++++++++++++++++while+(usbscanner.hasNext())+{
++++++++++++++++++++String+line+=+usbscanner.nextLine();
++++++++++++++++++++if+(line.startsWith("/dev/fuse+/storage/usbcard1"))+{
++++++++++++++++++++++++usbFoundCount=1;
++++++++++++++++++++++++Log.i("-----USB--------","USB+Connected+and+properly+mounted---/dev/fuse+/storage/usbcard1"+);
++++++++++++++++++++}
++++++++++++}
+++++++++}
++++++++++++if(mountFile.exists()){
++++++++++++++++Scanner+sdcardscanner+=+new+Scanner(mountFile);
++++++++++++++++while+(sdcardscanner.hasNext())+{
++++++++++++++++++++String+line+=+sdcardscanner.nextLine();
++++++++++++++++++++if+(line.startsWith("/dev/fuse+/storage/sdcard1"))+{
++++++++++++++++++++++++sdcardFoundCount=1;
++++++++++++++++++++++++Log.i("-----USB--------","USB+Connected+and+properly+mounted---/dev/fuse+/storage/sdcard1"+);
++++++++++++++++++++}
++++++++++++}
+++++++++}
++++++++++++if(usbFoundCount==1)
++++++++++++{
++++++++++++++++Toast.makeText(context,"USB+Connected+and+properly+mounted",+7000).show();
++++++++++++++++Log.i("-----USB--------","USB+Connected+and+properly+mounted"+);
++++++++++++}
++++++++++++else
++++++++++++{
++++++++++++++++Toast.makeText(context,"USB+not+found!!!!",+7000).show();
++++++++++++++++Log.i("-----USB--------","USB+not+found!!!!"+);

++++++++++++}
++++++++++++if(sdcardFoundCount==1)
++++++++++++{
++++++++++++++++Toast.makeText(context,"SDCard+Connected+and+properly+mounted",+7000).show();
++++++++++++++++Log.i("-----SDCard--------","SDCard+Connected+and+properly+mounted"+);
++++++++++++}
++++++++++++else
++++++++++++{
++++++++++++++++Toast.makeText(context,"SDCard+not+found!!!!",+7000).show();
++++++++++++++++Log.i("-----SDCard--------","SDCard+not+found!!!!"+);

++++++++++++}
++++++++}catch+(Exception+e)+{
++++++++++++e.printStackTrace();
++++++++}+|code-block|syntax|javascript|532495|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I am sure this code will surely resolve your issues...This is working fine for me...\

<pre><code>try {
 File mountFile = new File("/proc/mounts");
 usbFoundCount=0;
 sdcardFoundCount=0;
 if(mountFile.exists())
 {
 Scanner usbscanner = new Scanner(mountFile);
 while (usbscanner.hasNext()) {
 String line = usbscanner.nextLine();
 if (line.startsWith("/dev/fuse /storage/usbcard1")) {
 usbFoundCount=1;
 Log.i("-----USB--------","USB Connected and properly mounted---/dev/fuse /storage/usbcard1" );
 }
 }
 }
 if(mountFile.exists()){
 Scanner sdcardscanner = new Scanner(mountFile);
 while (sdcardscanner.hasNext()) {
 String line = sdcardscanner.nextLine();
 if (line.startsWith("/dev/fuse /storage/sdcard1")) {
 sdcardFoundCount=1;
 Log.i("-----USB--------","USB Connected and properly mounted---/dev/fuse /storage/sdcard1" );
 }
 }
 }
 if(usbFoundCount==1)
 {
 Toast.makeText(context,"USB Connected and properly mounted", 7000).show();
 Log.i("-----USB--------","USB Connected and properly mounted" );
 }
 else
 {
 Toast.makeText(context,"USB not found!!!!", 7000).show();
 Log.i("-----USB--------","USB not found!!!!" );

 }
 if(sdcardFoundCount==1)
 {
 Toast.makeText(context,"SDCard Connected and properly mounted", 7000).show();
 Log.i("-----SDCard--------","SDCard Connected and properly mounted" );
 }
 else
 {
 Toast.makeText(context,"SDCard not found!!!!", 7000).show();
 Log.i("-----SDCard--------","SDCard not found!!!!" );

 }
 }catch (Exception e) {
 e.printStackTrace();
 } 
</code></pre>

blocks|key|315485|text|是。不同制造商使用不同的SDcard名称，如三星Tab+3的extsd，而其他三星设备使用的是SD卡，不同的制造商使用不同的名称。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|315486|我和你有同样的要求。因此，我已经从我的项目中为您创建了一个示例，转到这个使用androi-dirchooser库的链接Android+Directory+chooser示例。此示例检测SDcard并列出所有子文件夹，还检测设备是否有多个SDcard。|offset|length|315487|对于完整的示例，代码的一部分如下所示:转到链接Android+Directory+Chooser|315488|/**
*+Returns+the+path+to+internal+storage+ex:-+/storage/emulated/0
+*
*+@return
+*/
private+String+getInternalDirectoryPath()+{
return+Environment.getExternalStorageDirectory().getAbsolutePath();
+}

/**
+*+Returns+the+SDcard+storage+path+for+samsung+ex:-+/storage/extSdCard
+*
+*+@return
+*/
++++private+String+getSDcardDirectoryPath()+{
++++return+System.getenv("SECONDARY_STORAGE");
}


+mSdcardLayout.setOnClickListener(new+OnClickListener()+{
++++@Override
++++public+void+onClick(View+view)+{
++++++++String+sdCardPath;
++++++++/***
+++++++++*+Null+check+because+user+may+click+on+already+selected+buton+before+selecting+the+folder
+++++++++*+And+mSelectedDir+may+contain+some+wrong+path+like+when+user+confirm+dialog+and+swith+back+again
+++++++++*/

++++++++if+(mSelectedDir+!=+null+&&+!mSelectedDir.getAbsolutePath().contains(System.getenv("SECONDARY_STORAGE")))+{
++++++++++++mCurrentInternalPath+=+mSelectedDir.getAbsolutePath();
++++++++}+else+{
++++++++++++mCurrentInternalPath+=+getInternalDirectoryPath();
++++++++}
++++++++if+(mCurrentSDcardPath+!=+null)+{
++++++++++++sdCardPath+=+mCurrentSDcardPath;
++++++++}+else+{
++++++++++++sdCardPath+=+getSDcardDirectoryPath();
++++++++}
++++++++//When+there+is+only+one+SDcard
++++++++if+(sdCardPath+!=+null)+{
++++++++++++if+(!sdCardPath.contains(":"))+{
++++++++++++++++updateButtonColor(STORAGE_EXTERNAL);
++++++++++++++++File+dir+=+new+File(sdCardPath);
++++++++++++++++changeDirectory(dir);
++++++++++++}+else+if+(sdCardPath.contains(":"))+{
++++++++++++++++//Multiple+Sdcards+show+root+folder+and+remove+the+Internal+storage+from+that.
++++++++++++++++updateButtonColor(STORAGE_EXTERNAL);
++++++++++++++++File+dir+=+new+File("/storage");
++++++++++++++++changeDirectory(dir);
++++++++++++}
++++++++}+else+{
++++++++++++//In+some+unknown+scenario+at+least+we+can+list+the+root+folder
++++++++++++updateButtonColor(STORAGE_EXTERNAL);
++++++++++++File+dir+=+new+File("/storage");
++++++++++++changeDirectory(dir);
++++++++}


++++}
});|code-block|syntax|javascript|315489|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/shivarajp/AndroidDirectoryChooserExample|1^0|0|1N|P|0|0|N|P|1|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|W|8|@]|9|@$D|X|E|Y|1|Z]]|A|$]]|$1|F|3|G|5|6|7|10|8|@]|9|@$D|11|E|12|1|13]]|A|$]]|$1|H|3|I|5|J|7|14|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]|U|$5|P|Q|R|A|$S|T]]]]

Yes. Different manufacturer use different SDcard name like in Samsung Tab 3 its extsd, and other samsung devices use sdcard like this different manufacturer use different names.

I had the same requirement as you. so i have created a sample example for you from my project goto this link <a href="https://github.com/shivarajp/AndroidDirectoryChooserExample" rel="nofollow">Android Directory chooser</a> example which uses the androi-dirchooser library. This example detect the SDcard and list all the subfolders and it also detects if the device has morethan one SDcard.

Part of the code looks like this For full example goto the link <a href="https://github.com/shivarajp/AndroidDirectoryChooserExample" rel="nofollow">Android Directory Chooser</a>

<pre><code>/**
* Returns the path to internal storage ex:- /storage/emulated/0
 *
* @return
 */
private String getInternalDirectoryPath() {
return Environment.getExternalStorageDirectory().getAbsolutePath();
 }

/**
 * Returns the SDcard storage path for samsung ex:- /storage/extSdCard
 *
 * @return
 */
 private String getSDcardDirectoryPath() {
 return System.getenv("SECONDARY_STORAGE");
}


 mSdcardLayout.setOnClickListener(new OnClickListener() {
 @Override
 public void onClick(View view) {
 String sdCardPath;
 /***
 * Null check because user may click on already selected buton before selecting the folder
 * And mSelectedDir may contain some wrong path like when user confirm dialog and swith back again
 */

 if (mSelectedDir != null &amp;&amp; !mSelectedDir.getAbsolutePath().contains(System.getenv("SECONDARY_STORAGE"))) {
 mCurrentInternalPath = mSelectedDir.getAbsolutePath();
 } else {
 mCurrentInternalPath = getInternalDirectoryPath();
 }
 if (mCurrentSDcardPath != null) {
 sdCardPath = mCurrentSDcardPath;
 } else {
 sdCardPath = getSDcardDirectoryPath();
 }
 //When there is only one SDcard
 if (sdCardPath != null) {
 if (!sdCardPath.contains(":")) {
 updateButtonColor(STORAGE_EXTERNAL);
 File dir = new File(sdCardPath);
 changeDirectory(dir);
 } else if (sdCardPath.contains(":")) {
 //Multiple Sdcards show root folder and remove the Internal storage from that.
 updateButtonColor(STORAGE_EXTERNAL);
 File dir = new File("/storage");
 changeDirectory(dir);
 }
 } else {
 //In some unknown scenario at least we can list the root folder
 updateButtonColor(STORAGE_EXTERNAL);
 File dir = new File("/storage");
 changeDirectory(dir);
 }


 }
});
</code></pre>

blocks|key|532522|text|+String+path+=+Environment.getExternalStorageDirectory()
++++++++++++++++++++++++%2B+File.separator+%2B+Environment.DIRECTORY_PICTURES;
++++++++++++++++File+dir+=+new+File(path);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|532523|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> String path = Environment.getExternalStorageDirectory()
 + File.separator + Environment.DIRECTORY_PICTURES;
 File dir = new File(path);
</code></pre>

blocks|key|532599|text|您可以使用-+Context.getExternalCacheDirs()或Context.getExternalFilesDirs()或Context.getObbDirs()。它们在所有外部存储设备中提供应用程序特定的目录，应用程序可以在这些目录中存储其文件。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532600|所以像这样-+Context.getExternalCacheDirs()i.getParentFile().getParentFile().getParentFile().getParent()可以得到外部存储设备的根路径。|532601|我知道这些命令有不同的用途，但其他答案对我不起作用。|532602|这个链接给了我很好的指针--+https://possiblemobile.com/2014/03/android-external-storage/|offset|length|532603|entityMap|0|LINK|mutability|MUTABLE|url|https://possiblemobile.com/2014/03/android-external-storage/^0|0|0|0|F|1O|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@$H|V|I|W|1|X]]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

You can use something like - Context.getExternalCacheDirs() or Context.getExternalFilesDirs() or Context.getObbDirs(). They give application specific directories in all external storage devices where the application can store its files.

So something like this - Context.getExternalCacheDirs()[i].getParentFile().getParentFile().getParentFile().getParent() can get you the root path of external storage devices.

I know these commands are for a different purpose but other answers didn't work for me.

This link gave me good pointers - <a href="https://possiblemobile.com/2014/03/android-external-storage/" rel="nofollow">https://possiblemobile.com/2014/03/android-external-storage/</a>

blocks|key|315649|text|System.getenv("SECONDARY_STORAGE")为棉花糖返回null。这是另一种查找所有外部目录的方法。您可以检查它是否是可移除的，这决定了内部/外部|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|315650|if+(Build.VERSION.SDK_INT+>=+Build.VERSION_CODES.M)+{
++++File[]+externalCacheDirs+=+context.getExternalCacheDirs();
++++for+(File+file+:+externalCacheDirs)+{
++++++++if+(Environment.isExternalStorageRemovable(file))+{
++++++++++++//+It's+a+removable+storage
++++++++}
++++}
}|code-block|syntax|javascript|315651|entityMap^0|0|Y|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

<code>System.getenv("SECONDARY_STORAGE")</code> returns null for Marshmallow. This is another way of finding all the externals dirs. You can check if it's removable which determines if internal/external

<pre><code>if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.M) {
 File[] externalCacheDirs = context.getExternalCacheDirs();
 for (File file : externalCacheDirs) {
 if (Environment.isExternalStorageRemovable(file)) {
 // It's a removable storage
 }
 }
}
</code></pre>

blocks|key|315710|text|String+secStore+=+System.getenv("SECONDARY_STORAGE");

File+externalsdpath+=+new+File(secStore);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|315711|这将获得外部sd二级存储的路径。|unstyled|315712|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>String secStore = System.getenv("SECONDARY_STORAGE");

File externalsdpath = new File(secStore);
</code></pre>

This will get the path of external sd secondary storage.

blocks|key|315739|text|//manifest+file+outside+the+application+tag
//please+give+permission+write+this+
//<uses-permission+android:name="android.permission.READ_EXTERNAL_STORAGE"/>
++++++++File+file+=+new+File("/mnt");
++++++++String[]+fileNameList+=+file.list();+//file+names+list+inside+the+mnr+folder
++++++++String+all_names+=+"";+//for+the+log+information
++++++++String+foundedFullNameOfExtCard+=+"";+//+full+name+of+ext+card+will+come+here
++++++++boolean+isExtCardFounded+=+false;
++++++++for+(String+name+:+fileNameList)+{
++++++++++++if+(!isExtCardFounded)+{
++++++++++++++++isExtCardFounded+=+name.contains("ext");
++++++++++++++++foundedFullNameOfExtCard+=+name;
++++++++++++}
++++++++++++all_names+%2B=+name+%2B+"\n";+//+for+log
++++++++}
++++++++Log.d("dialog",+all_names+%2B+foundedFullNameOfExtCard);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|315740|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>//manifest file outside the application tag
//please give permission write this 
//&lt;uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/&gt;
 File file = new File("/mnt");
 String[] fileNameList = file.list(); //file names list inside the mnr folder
 String all_names = ""; //for the log information
 String foundedFullNameOfExtCard = ""; // full name of ext card will come here
 boolean isExtCardFounded = false;
 for (String name : fileNameList) {
 if (!isExtCardFounded) {
 isExtCardFounded = name.contains("ext");
 foundedFullNameOfExtCard = name;
 }
 all_names += name + "\n"; // for log
 }
 Log.d("dialog", all_names + foundedFullNameOfExtCard);
</code></pre>

<a href="http://en.wikipedia.org/wiki/Samsung_Galaxy_S_III" rel="nofollow noreferrer">Samsung Galaxy S3</a> has an external SD card slot, which is mounted to <code>/mnt/extSdCard</code>.

How can I get this path by something like <code>Environment.getExternalStorageDirectory()</code>?

This will return <code>mnt/sdcard</code>, and I can't find the API for the external SD card. (Or removable USB storage on some tablets.)

How can I get the external SD card path for Android 4.0+?

Android

有一个安装在/mnt/extSdCard上的外部SD卡插槽。如何通过类似于Environment.getExternalStorageDirectory()的命令获得此路径这将返回mnt/sdcard，并且我找不到外部SD卡的接口。(或某些平板电脑上的可移动USB存储器。)

问如何获取Android 4.0+的外部SD卡路径？
EN

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问如何获取Android 4.0+的外部SD卡路径？
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