如何使用存储卷 (/StorageAccessFramework) 解压缩文件？

Question

我正在使用此代码 (Android 7.0/Nougat) 解压缩外部存储中的 zip 文件（包括内部的多个文件夹级别）：

try {
    ZipFile zip = new ZipFile(zippath);
    Enumeration enu = zip.entries();

    while(enu.hasMoreElements()) {
        ZipEntry zipEntry = (ZipEntry) enu.nextElement();
        BufferedInputStream bis = null;
        String fileName = null;

        try {
            fileName = zipEntry.getName();
            fileName = fileName.replace("\",File.separator).replace("/",File.separator);
            int p = fileName.lastIndexOf(File.separator);

            if(p>=0) {
                File fd=new File(folderpath+File.separator+fileName.substring(0,p));
                fd.mkdirs();
            }

            BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(folderpath+File.separator+fileName));
            bis = new BufferedInputStream(zip.getInputStream(zipEntry));
            byte[] buffer = new byte[10000];
            int len = 0;

            while ((len = bis.read(buffer, 0, 10000)) > 0) {
                bos.write(buffer, 0, len);
            }

            bis.close();
            bos.close();
        } catch (IOException e1) {
            e1.printStackTrace();
            return;
        }
    }
} catch (IOException e2) {
    e2.printStackTrace();
}

为了获得对 SD 卡的写入权限，我使用 createAccessIntent（存储卷），它使用 DocumentFiles 而不是正常的 File。

我已经这样做了 ZipInputStream:

InputStream inputStream = this.getContentResolver().openInputStream(myDocumentFileZip.getUri());
BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);
ZipInputStream zipInputStream = new ZipInputStream(bufferedInputStream);
ZipEntry zipEntry;

...我猜你会继续这样：

while ((zipEntry = zipInputStream.getNextEntry()) != null) {

但是你从那里做什么 - 如何将文件复制到 SD 卡上并仍然保持上面代码中的文件夹结构但使用存储卷（或存储访问框架）提供的内容？

Answer 1

使用存储卷解压：

小心：如果您多次解压同一个 .zip 文件，它会创建副本，而我在第一个 post 中的原始代码（不能用于 SD 卡）不会而是自动覆盖！

try {
    InputStream is = getContentResolver().openInputStream(myZip.getUri());
    BufferedInputStream bis = new BufferedInputStream(is);
    ZipInputStream zis = new ZipInputStream(bis);
    ZipEntry zipEntry;

    while ((zipEntry = zis.getNextEntry()) != null) {
        String fileName = null; 

        try {
            fileName = zipEntry.getName();        
            fileName = fileName.replace("\",File.separator).replace("/",File.separator);
            int p=fileName.lastIndexOf(File.separator);        
            DocumentFile destFolder = myDestFolder; //DocumentFile of the destination folder
            String destName = fileName;

            if (p>=0) {
                String[] split = fileName.split(File.separator);

                //If the .zip file contains multiple folder levels, this is where you  
                //have to check and then create them, e.g. for 3 levels:
                if(split.length==1) {
                    destFolder = myFolder;
                    destName = filename;
                } else if(split.length==2) {
                    if(mySubFolder==null) {
                        mySubFolder = myFolder.createDirectory(split[0]);
                    }

                    destFolder = mySubFolder;
                    destName = split[1];
                } else if(split.length==3) {
                    if(mySubFolder==null) {
                        mySubFolder = myFolder.createDirectory(split[0]);
                    }
                    if(mySubSubFolder==null) {
                        mySubSubFolder = mySubFolder.createDirectory(split[1]);
                    }

                    destFolder = mySubSubFolder;
                    destName = split[2];
                }
            }

            DocumentFile df = null;

            //Now you have to tell it what file extensions ("MIME" type) you want to use, e.g.:
            if(destName.endsWith(".txt")) {
                df = destFolder.createFile("text/plain",destName.substring(0,destName.length()-4));
            } else if(destName.endsWith(".jpg")) {
                df = destFolder.createFile("image/jpeg",destName.substring(0,destName.length()-4));
            }

            OutputStream out = getContentResolver().openOutputStream(df.getUri());
            BufferedOutputStream bos = new BufferedOutputStream(out);
            long zipfilesize = zipEntry.getSize();

            byte[] buffer = new byte[10000];
            int len = 0;
            int totlen = 0;

            while (((len = zis.read(buffer, 0, 10000)) > 0) && (totlen < zipfilesize)) {
                bos.write(buffer, 0, len);
                totlen += len;
            }

            bos.close();
        } catch (IOException e1) {
            e1.printStackTrace();
            return;
        }
    }

    is.close();
    bis.close();
    zis.close();
} catch (IOException e2) {
    e2.printStackTrace();
}

编辑：重要：java.util.zip 没有设置 size 或 compressedSize（将 return "-1 ")，这就是为什么此代码将仅创建大小为 0B 的文件以及由库创建的 zip 文件的原因 - 手动创建的 zip 文件（例如使用 WinRar）工作正常。要修复它，请替换

while (((len = zis.read(buffer, 0, 10000)) > 0) && (totlen < zipfilesize)) {

和

while (((len = zis.read(buffer, 0, 10000)) > 0)) {

可以这样做是因为：

the call to ZipInputStream.getNextEntry() positions the InputStream at the start of the entry and therefore supplying the ZipInputStream is the equivalent of supplying a ZipEntry's InputStream.

来源：

这样做的缺点（与我的非 StorageVolume 版本相比）是您 a) 无法获取 zip 中的文件总数和 b) 也无法获取（总）大小文件，这意味着您不能在 "Unzipping..." 对话框中设置进度条，除非您首先遍历所有 zip 条目以计算它们。

如何使用存储卷 (/StorageAccessFramework) 解压缩文件？

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