Android - 将文件从资产复制到 /data/data 文件夹
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Android - Copy files from assets to /data/data folder
提问by superuser
I need to use some files in my app. They are kept in asset folder. I saw discussions on SO, where the files are being copied from asset folder, to /data/data/ on the internal storage, and then being used. I get the code, but what I do not get is, what is the need to copy the assets to internal storage ? If anybody has experience with this, help !
我需要在我的应用程序中使用一些文件。它们保存在资产文件夹中。我看到了关于 SO 的讨论，文件被从资产文件夹复制到内部存储上的 /data/data/，然后被使用。我得到了代码，但我没有得到的是，将资产复制到内部存储有什么需要？如果有人有这方面的经验，请帮忙！
回答by Markus Toman
One reason that just popped up for me is when using existing C/C++ code with NDK that requires a path to a file and you don't want to modify that code.
我突然想到的一个原因是，将现有的 C/C++ 代码与 NDK 一起使用时，需要文件路径并且您不想修改该代码。
For example, I'm using an existing C library that needs some data files and the only existing interface is some "load( char* path )" function.
例如，我正在使用一个需要一些数据文件的现有 C 库，唯一现有的接口是一些“加载（字符*路径）”函数。
Perhaps there is actually some better method but I have not found any yet.
也许实际上有一些更好的方法，但我还没有找到。
回答by Lavekush Agrawal
Try this:(Use all three method its work for me and assign destination path in "toPath" string object)
试试这个:(使用所有三种方法对我有用，并在“toPath”字符串对象中分配目标路径）
String toPath = "/data/data/" + getPackageName(); // Your application path
private static boolean copyAssetFolder(AssetManager assetManager,
String fromAssetPath, String toPath) {
try {
String[] files = assetManager.list(fromAssetPath);
new File(toPath).mkdirs();
boolean res = true;
for (String file : files)
if (file.contains("."))
res &= copyAsset(assetManager,
fromAssetPath + "/" + file,
toPath + "/" + file);
else
res &= copyAssetFolder(assetManager,
fromAssetPath + "/" + file,
toPath + "/" + file);
return res;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
private static boolean copyAsset(AssetManager assetManager,
String fromAssetPath, String toPath) {
InputStream in = null;
OutputStream out = null;
try {
in = assetManager.open(fromAssetPath);
new File(toPath).createNewFile();
out = new FileOutputStream(toPath);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
return true;
} catch(Exception e) {
e.printStackTrace();
return false;
}
}
private static void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
}
回答by ali server
public final String path = "/data/data/com.aliserver.shop/databases/";
public final String Name = "store_db";
public void _copydatabase() throws IOException {
OutputStream myOutput = new FileOutputStream(path + Name);
byte[] buffer = new byte[1024];
int length;
InputStream myInput = MyContext.getAssets().open("store_db");
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myInput.close();
myOutput.flush();
myOutput.close();
}
回答by Rakki s
I think you can't edit/modify data in asset folder in run time or after application installed .So we move files into internal folder then start working on it.
我认为您无法在运行时或安装应用程序后编辑/修改资产文件夹中的数据。所以我们将文件移动到内部文件夹然后开始处理它。
