Android-如何通过Intent在另一个应用程序中打开文件? [英] Android - How do I open a file in another app via Intent?

问题描述

我正在尝试使用其他应用打开文件，即使用Gallery打开.jpg，使用Acrobat打开.pdf等.

I'm trying to open a file using another app, i.e. opening a .jpg with Gallery, .pdf with Acrobat, etc.

我遇到的问题是，当我尝试在应用程序中打开文件时，它只会打开所选的应用程序，而不是在应用程序中打开文件.我尝试按照通过Intent进行Android打开pdf文件的操作，但我一定会丢失一些东西.

The problem I'm having with this is when I try to open the file in the app, it only opens the chosen app instead of opening the file within the app. I tried following Android open pdf file via Intent but I must be missing something.

public String get_mime_type(String url) {
    String ext = MimeTypeMap.getFileExtensionFromUrl(url);
    String mime = null;
    if (ext != null) {
        mime = MimeTypeMap.getSingleton().getMimeTypeFromExtension(ext);
    }
    return mime;
}

public void open_file(String filename) {
    File file = new File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_DOWNLOADS), filename);

    // Get URI and MIME type of file
    Uri uri = Uri.fromFile(file).normalizeScheme();
    String mime = get_mime_type(uri.toString());

    // Open file with user selected app
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_VIEW);
    intent.setData(uri);
    intent.setType(mime);
    context.startActivity(Intent.createChooser(intent, "Open file with"));
}

据我所知，它返回正确的URI和MIME类型:

As far as I can tell, it returns the right URI and MIME type:

URI: file:///storage/emulated/0/Download/Katamari-ringtone-985279.mp3
MIME: audio/mpeg

推荐答案

在此处发布我的更改，以防它可以帮助其他人.我最终将下载位置更改为一个内部文件夹，并添加了内容提供程序.

Posting my changes here in case it can help someone else. I ended up changing the download location to an internal folder and adding a content provider.

public void open_file(String filename) {
    File path = new File(getFilesDir(), "dl");
    File file = new File(path, filename);

    // Get URI and MIME type of file
    Uri uri = FileProvider.getUriForFile(this, App.PACKAGE_NAME + ".fileprovider", file);
    String mime = getContentResolver().getType(uri);

    // Open file with user selected app
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_VIEW);
    intent.setDataAndType(uri, mime);
    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    startActivity(intent);
}

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