如何将db.zip从资产复制到android中的SD卡 [英] How to copy db.zip from asset to SD card in android

问题描述

我有一个40MB大小的SQLite数据库。我使用SQLite Asset Helper库复制数据库并使用它。由于APK大小问题，我应该压缩我的数据库。该lib可以很好地运行，但是它将数据库复制到内部存储器中，并且40MB的数据库大小会导致将来出现问题。
i想要将我的数据库复制到SD。

i have a SQLite DB with 40MB size. i use SQLite Asset Helper library to copy DB and use it. because of APK size issue i should to zip my DB. the lib works great, but it copy DB into internal memory and 40MB size of DB causes future problems. i want to copy my DB into SD.

解决方案1：将带有SQLite Asset Helper lib的压缩数据库复制到内部存储器中，然后将数据库移至SD。

solution 1: copy zipped DB with SQLite Asset Helper lib into internal memory and then move DB to SD.

解决方案2：直接将压缩的DB复制到SD卡中。

Solution 2: copy zipped DB into SD card directly.

所以请帮助我，哪一个更好，以及我如何可以做到。

So please help me which one is better and how i can do it.

推荐答案

我的数据库很小，所以我不压缩它，但是我压缩了一些图像（主要是（将它们捆在一起），然后直接将其打开包装。您应该能够为数据库zip文件改编以下代码。

我创建了一个AsyncTask，该脚本在初始屏幕中触发，并保持初始屏幕打开直到复制完成。

I created an AsyncTask that is triggered in my splash screen and will keep the splash screen open until the copy was finished.

复制过程非常简单：

protected Void doInBackground(String... params) {
    final File dataBaseFile = new File(mDestinationFile);

    if (!dataBaseFile.exists()) {
        try {
            copyFromAssetsToSdcard();
            FileUtils.unzip(mContext.getAssets().open("images.zip"), Constants.IMAGE_CACHE_PATH + "/");
        } catch (IOException ioe) {
            Log.e(LOG_TAG, "Database can not be copied", ioe);
        }
    } else {
        Log.w(LOG_TAG, "Destination database already exists");
    }

    return null;
}

private void copyFromAssetsToSdcard() throws IOException {
    final BufferedInputStream inputStream = new BufferedInputStream(mContext.getAssets().open(mSourceFile));
    final OutputStream outputStream = new FileOutputStream(mTmpDestinationFile);
    copyStream(inputStream, outputStream);
    outputStream.flush();
    outputStream.close();
    inputStream.close();
    File tmpFile = new File(mTmpDestinationFile);
    if (tmpFile.renameTo(new File(mDestinationFile))) {
        Log.w(LOG_TAG, "Database file successfully copied!");
    } else {
        Log.w(LOG_TAG, "Database file couldn't be renamed!");
    }
}

我的FileUtils.unzip方法只是解压缩到指定的文件中位置：

And my FileUtils.unzip method just unpacks into the specified location:

public static void unzip(InputStream zipInput, String location) throws IOException {
    try {
        File f = new File(location);
        if (!f.isDirectory()) {
            f.mkdirs();
        }
        ZipInputStream zin = new ZipInputStream(zipInput);
        try {
            ZipEntry ze = null;
            final byte[] buffer = new byte[BUFFER_SIZE];
            while ((ze = zin.getNextEntry()) != null) {
                String path = location + ze.getName();

                if (ze.isDirectory()) {
                    File unzipFile = new File(path);
                    if (!unzipFile.isDirectory()) {
                        unzipFile.mkdirs();
                    }
                } else {
                    FileOutputStream fout = new FileOutputStream(path, false);
                    try {
                        int length = zin.read(buffer);
                        while (length > 0) {
                            fout.write(buffer, 0, length);
                            length = zin.read(buffer);
                        }
                        zin.closeEntry();
                    } finally {
                        fout.close();
                    }
                }
            }
        } finally {
            zin.close();
        }
    } catch (Exception e) {
        Log.e(LOG_TAG, "Unzip exception", e);
    }
}

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