从内部存储器下载并安装应用程序 (apk) - 无 SD 卡

Question

Greetings and a happy new year to all my fellow programmers.

My code downloads an apk file from a remote server. I need to initiate the installation procedure through code, without user having to explicitly install it. The catch is that i cannot use an SD card download the apk file.

I can navigate to the data/data/files folder and can see my file downloaded. The only problem is that i cannot get it installed. This is what i get

 '/data/data/org.obs.testinstall.main/files/app.apk': Permission denied 

I understand that Android does not give permission to access the data directory. My question is how can i download and install an application(apk) without using a SD card. This application is not intended to be published in the market. I have tried using both the Internal Storage using

FileOutputStream fos = openFileOutput("app.apk", Context.MODE_PRIVATE);

and the cache directory

File file = getCacheDir();
File outputFile = new File(file, "app.apk");

Both give the same result .. "Permission denied"

When i change the code to incorporate an SD card the application works perfectly, but using an SD card is not an option.

Surely there must be a way to do this. It is hard to believe that such a handicap exist in the Android O/S.

Has anybody done this? Any workarounds? Any pointers would be helpful.

Answer 1

It it caused by android application can not read from another application file if it is written using PRIVATE mode.

You can do this:

String fileName = "tmp.apk";
FileOutputStream fos = openFileOutput(fileName,
        MODE_WORLD_READABLE | MODE_WORLD_WRITEABLE);

// write the .apk content here ... flush() and close()

// Now start the standard instalation window
File fileLocation = new File(context.getFilesDir(), fileName);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(fileLocation),
                       "application/vnd.android.package-archive");
context.startActivity(intent);

Be careful though, because that file is now world-visible, and can be seen by any application in the same device, if they know the file location.

Answer 2

No need to root. You can just use linux command chmod to do it.

public static String exec(String[] args) {
    String result = "";
    ProcessBuilder processBuilder = new ProcessBuilder(args);
    Process process = null;
    InputStream errIs = null;
    InputStream inIs = null;
    try {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        int read = -1;
        process = processBuilder.start();
        errIs = process.getErrorStream();
        while ((read = errIs.read()) != -1) {
            baos.write(read);
        }
        baos.write('\n');
        inIs = process.getInputStream();
        while ((read = inIs.read()) != -1) {
            baos.write(read);
        }
        byte[] data = baos.toByteArray();
        result = new String(data);
    } catch (IOException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (errIs != null) {
                errIs.close();
            }
            if (inIs != null) {
                inIs.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        if (process != null) {
            process.destroy();
        }
    }
    return result;
}

in your program,it can be invoked like this:

    String[] args1 = { "chmod", "705", "/data/data/org.obs.testinstall.main/files/" };
    exec(args1);
    String[] args2 = { "chmod", "604", "/data/data/org.obs.testinstall.main/files/app.apk" };
    exec(args2);

Then you can install the app.apk as wished.

Answer 3

Also you can use

downloadedFile.setReadable(true, false);

with

fileOutputStream = openFileOutput(fileName, Context.MODE_PRIVATE);

There are two setReadable method. The first has one parameter and the second one has two parameters.

setReadable(boolean readable)
setReadable(boolean readable, boolean ownerOnly)

Answer 4

For me I deleted the apk file right after the startActivity , which is asynchronous.

Too bad there is no better description of the parsing error (file not found, access denied, corrupted file in package,...)

Answer 5

when you send intent to install apk, you can use this function to change mode for apk directory.

private static boolean changeMode(String filePath, String prefixPath) {
    if (TextUtils.isEmpty(prefixPath) || !filePath.startsWith(prefixPath)) {
        return true;
    }

    try {
        String[] args1 = { "chmod", "705", prefixPath};
        Runtime.getRuntime().exec(args1);
    } catch (IOException e) {
        e.printStackTrace();
        return false;
    }

    String subPath = filePath.split(prefixPath)[1];
    String[] subArr = subPath.split(File.separator);
    for (String path : subArr) {
        if (!TextUtils.isEmpty(path)) {
            prefixPath = prefixPath + File.separator + path;
            try {
                if (!prefixPath.endsWith(".apk")) {
                    String[] progArray1 = {"chmod", "705", prefixPath};
                    Runtime.getRuntime().exec(progArray1);
                } else {
                    String[] progArray2 = {"chmod", "604", prefixPath};
                    Runtime.getRuntime().exec(progArray2);
                }
            } catch (IOException e) {
                e.printStackTrace();
                return false;
            }
        }
    }
    return true;
}

And before you send intent, check chmod is it alreay success.

    boolean chmodRes = changeMode(filePath, context.getCacheDir().getAbsolutePath())
            && changeMode(filePath, context.getFilesDir().getAbsolutePath());
    if (!chmodRes) {
        return false;
    }

Answer 6

尝试生根您的设备，然后从设备运行程序，而不是使用模拟器。