如果存在，如何检查内部和外部存储答案

【问题标题】：how to check internal and external storage if exist如果存在，如何检查内部和外部存储
【发布时间】：2011-11-28 20:09:35
【问题描述】：

我怎么知道android中是否有内部和外部存储？有谁知道如何检查内部和外部存储

提前致谢

【问题讨论】：

stackoverflow.com/questions/3598445/…

标签： android storage

【解决方案1】：

android documentation已经解释过了。

取自文档的代码

boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
String state = Environment.getExternalStorageState();

if (Environment.MEDIA_MOUNTED.equals(state)) {
    // We can read and write the media
    mExternalStorageAvailable = mExternalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
    // We can only read the media
    mExternalStorageAvailable = true;
    mExternalStorageWriteable = false;
} else {
    // Something else is wrong. It may be one of many other states, but all we need
    //  to know is we can neither read nor write
    mExternalStorageAvailable = mExternalStorageWriteable = false;
}

【讨论】：

【解决方案2】：

如果有人在搜索这个，我会得到它的工作......它会有所帮助：D

try {
            File dir = new File("/mnt/");
            File[] dirs = dir.listFiles();
            for (File _tempDIR : dirs) {
                String sdCard = _tempDIR.getAbsolutePath().toString();

                File file = new File(sdCard + "/"
                        + Environment.DIRECTORY_DOWNLOADS);
                File[] files = file.listFiles();
                if (files != null) {
                    for (int i = 0; i < files.length; i++) {
                        String _temp = files[i].getAbsoluteFile().getName()
                                .toString();/*Your code, and what you want to find, from all the Sdcard, internal and external. Everything mounted will be found :D*/

【讨论】：

【解决方案3】：

我写了一个小类来检查存储状态。或许对你有用。

更新： 清理了代码，删除了 cmets 并将类设为静态。

import android.os.Environment;

public class StorageHelper {

    private static boolean externalStorageReadable, externalStorageWritable;

    public static boolean isExternalStorageReadable() {
        checkStorage();
        return externalStorageReadable;
    }

    public static boolean isExternalStorageWritable() {
        checkStorage();
        return externalStorageWritable;
    }

    public static boolean isExternalStorageReadableAndWritable() {
        checkStorage();
        return externalStorageReadable && externalStorageWritable;
    }

    private static void checkStorage() {
        String state = Environment.getExternalStorageState();
        if (state.equals(Environment.MEDIA_MOUNTED)) {
            externalStorageReadable = externalStorageWritable = true;
        } else if (state.equals(Environment.MEDIA_MOUNTED) || state.equals(Environment.MEDIA_MOUNTED_READ_ONLY)) {
            externalStorageReadable = true;
            externalStorageWritable = false;
        } else {
            externalStorageReadable = externalStorageWritable = false;
        }
    }

}

【讨论】：

有点离题，但我将如何使用这个类？没有构造函数！
@jesses.co.tt 就像这样：StorageHelper helper = new StorageHelper();
嗯......这就是我尝试过的，但它给了我错误......我最终只是编写了一个默认构造函数，这很好......也许在我的编译设置中？无论如何，谢谢！
对于代码片段 if (state.equals(Environment.MEDIA_MOUNTED)) {...} else if (state.equals(Environment.MEDIA_MOUNTED) || state.equals(Environment.MEDIA_MOUNTED_READ_ONLY)) { 。 ..else if (state.equals(Environment.MEDIA_MOUNTED) ||.. 有什么作用？
else if (state.equals(Environment.MEDIA_MOUNTED) || state.equals(Environment.MEDIA_MOUNTED_READ_ONLY) 应该是else if (state.equals(Environment.MEDIA_MOUNTED_READ_ONLY)

【解决方案4】：

File f = new File("/mnt/sdcard/ext_sd");
    if (f.exists()) {
        // Do Whatever you want sdcard exists
    }
    else{
        Toast.makeText(MainActivity.this, "Sdcard not Exists", Toast.LENGTH_SHORT).show();
    }

【讨论】：

你不应该硬编码任何外部 sd 卡路径，因为没有关于路径的标准。每个供应商都可以使用自己的路径标准。它有很多变体，比如三星galaxy家族使用的"/mnt/sdcard/external_sd"，LG使用的"/storage/external_SD"，HTC One Max使用的"/storage/ext_sd"等。请改用Environment.getExternalStorageDirectory().getPath()

【解决方案5】：

the documentation 中的代码自之前的答案以来已经简化了一点：

/* Checks if external storage is available for read and write */
public boolean isExternalStorageWritable() {
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
        return true;
    }
    return false;
}

/* Checks if external storage is available to at least read */
public boolean isExternalStorageReadable() {
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state) ||
        Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
        return true;
    }
    return false;
}

【讨论】：