如何获取Android SD卡上的可用空间？

Question

我正在使用 Environment.getExternalStorageDirectory() 创建文件，在创建和存储文件之前我需要知道是否有足够的可用空间。

如果您可以引用 Android Ref 文档，那也会很有帮助。

Answer 1

您必须使用 StatFs 类。以下是如何使用它的示例，该示例取自手机上“设置”应用程序的源代码。

        if (status.equals(Environment.MEDIA_MOUNTED)) {
        try {
            File path = Environment.getExternalStorageDirectory();
            StatFs stat = new StatFs(path.getPath());
            long blockSize = stat.getBlockSize();
            long totalBlocks = stat.getBlockCount();
            long availableBlocks = stat.getAvailableBlocks();

            mSdSize.setSummary(formatSize(totalBlocks * blockSize));
            mSdAvail.setSummary(formatSize(availableBlocks * blockSize) + readOnly);

            mSdMountToggle.setEnabled(true);
            mSdMountToggle.setTitle(mRes.getString(R.string.sd_eject));
            mSdMountToggle.setSummary(mRes.getString(R.string.sd_eject_summary));

        } catch (IllegalArgumentException e) {
            // this can occur if the SD card is removed, but we haven't received the 
            // ACTION_MEDIA_REMOVED Intent yet.
            status = Environment.MEDIA_REMOVED;
        }

Answer 2

使用 StatFS。如果您将 Environment.getExternalStorageDirectory() 中的值传递给构造函数（当然，转换为 String），它应该可以工作。

Answer 3

您可能需要重新设置才能获得准确的结果：

StatFs stat = new StatFs(Environment.getExternalStorageDirectory().getAbsolutePath());
stat.restat(Environment.getExternalStorageDirectory().getAbsolutePath());
long available = ((long) stat.getAvailableBlocks() * (long) stat.getBlockSize());

Answer 4

自 API 级别 9 起可用：

Environment.getExternalStorageDirectory().getUsableSpace();

http://developer.android .com/reference/java/io/File.html#getUsableSpace()