Android How to create Intent Filter for custom fil

问题:

I have seen numerous answers on here about creating an intent filter for a custom file extension, but none of them seem to be answering my question:

I have an intent filter that works right now... when I browse for my file or when I open it from an email attachment, my app will appear in the list. The file itself has a custom extension of "tgtp", but it is basically just an xml file.

The problem I am having is that although this intent filter works, it also appears to add my app to every chooser for every type of file on my phone. An example would be if I clear my contacts app defaults and click on one of my contacts, it says my app can open it.

I've tried dozens of different combinations of intent filters with different schemes, mime types, etc... and some still let me open the file if i browse with a file browser, but I specifically need to be able to open email attachments and open as file browser. I am yet to find an intent filter(s) that allow me to do that without making my app available for every other intent chooser.

Here is my current intent-filter that uses my app to open everything:

<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="*/*" />
<data android:pathPattern=".*\\.tgtp" />   
</intent-filter>

Thank you in advance

回答1:

The only way to solve this problem is add scheme and host attributes to your intent filter:

<intent-filter>
  <action android:name="android.intent.action.VIEW" />
  <category android:name="android.intent.category.DEFAULT" />
  <data android:scheme="file" />
  <data android:mimeType="*/*" />
  <data android:pathPattern=".*\\.tgtp" />   
  <data android:host="*" />
</intent-filter>

That is because in documentation says that android:pathPattern only works if has an scheme and host defined. http://developer.android.com/guide/topics/manifest/data-element.html

Hope it helps.

回答2:

I've been struggling with this quite a bit for a custom file extension, myself. After a lot of searching, I found this web page where the poster discovered that Android's patternMatcher class (which is used for the pathPattern matching in Intent-Filters) has unexpected behavior when your path contains the first character of your match pattern elsewhere in the path (like if you're trying to match "*.xyz", the patternMatcher class stops if there's an "x" earlier in your path). Here's what he found for a workaround, and worked for me, although it is a bit of a hack:

PatternMatcher is used for pathPattern at IntentFilter But, PatternMatcher's algorithm is quite strange to me. Here is algorithm of Android PatternMatcher.

If there is 'next character' of '.*' pattern in the middle of string, PatternMatcher stops loop at that point. (See PatternMatcher.java of Android framework.)

Ex. string : "this is a my attachment" pattern : ".att.". Android PatternMatcher enter loop to match '.' pattern until meet the next character of pattern (at this example, 'a') So, '.' matching loop stops at index 8 - 'a' between 'is' and 'my'. Therefore result of this match returns 'false'.

Quite strange, isn't it. To workaround this - actually reduce possibility - developer should use annoying stupid pathPattern.

Ex. Goal : Matching uri path which includes 'message'.

<intent-filter>
...
<data android:pathPattern=".*message.*" />
<data android:pathPattern=".*m.*message.*" />
<data android:pathPattern=".*m.*m.*message.*" />
<data android:pathPattern=".*m.*m.*m.*message.*" />
<data android:pathPattern=".*m.*m.*m.*m.*message.*" />
...
</intent-filter>

This is especially issued when matching with custom file extention.

回答3:

I have the exact same problem, and in my case, both other answers don't work. The closest I came is when I combine both benjamin and sabadow's answers, -and- leave out the dot in the extension, so like this: (i'm using my custom ".trk" extension)

        <!-- For opening/viewing only trk-files: (works in google drive and "File Manager", not  gmail) -->
        <intent-filter>
            <action android:name="android.intent.action.VIEW" />
            <action android:name="android.intent.action.SEND" />
            <action android:name="android.intent.action.SEND_MULTIPLE" />
            <action android:name="android.intent.action.SENDTO" />

            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.BROWSABLE" />

            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*trk" android:host="*" />
            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*t.*trk" android:host="*" />
            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*t.*t.*trk" android:host="*" />
            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*t.*t.*t.*trk" android:host="*" />
            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*t.*t.*t.*t.*trk" android:host="*" />
            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*t.*t.*t.*t.*t.*trk" android:host="*" />
            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*t.*t.*t.*t.*t.*t.*trk" android:host="*" />
            <data android:scheme="file" android:mimeType="*/*" android:pathPattern=".*t.*t.*t.*t.*t.*t.*t.*trk" android:host="*" />
        </intent-filter>          
        <!-- For catching attachments in Gmail: (also triggers non-trk-files that aren't associated with some other app, but not non-trk-files that already have one of more associations, strangely) -->
        <intent-filter>
            <action android:name="android.intent.action.VIEW" />
            <action android:name="android.intent.action.SEND" />
            <action android:name="android.intent.action.SEND_MULTIPLE" />
            <action android:name="android.intent.action.SENDTO" />

            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.BROWSABLE" />
            <data android:mimeType="*/*" android:scheme="content" />
        </intent-filter>
        <!-- For catching share actions from apps: (also triggered by sharing actions for all other file types) -->
        <intent-filter>
            <action android:name="android.intent.action.SEND" />
            <category android:name="android.intent.category.DEFAULT" />

            <data android:mimeType="application/*" />
        </intent-filter>

It's a bit long, but you might not need all lines, like the SENDTO and SEND_MULTIPLE actions. I just need it to work in all cases where it could work. Sadly it also triggers in some, but not all, other cases.