How to use the new Android M feature of “Text Selection” to be offered from outside of your app?

Question

Background

Android M presents a new way to handle selected text (link here), even from outside of your app . Text selection can be handled as such:

I know it's possible to handle the selected text from outside the app, because if I go to the web browser (or any other place that allows text selection), I can see that I can use the "API demos" app to handle the selected text.

The problem

I can't see a lot of information about how to do it.

The question

1. What should be added in code (and manifest) to be able to handle the selected text from outside the app ?
2. Is it possible to limit the selection to certain types of texts ? For example, offer to show the app only if the text type is a valid phone number ?

Answer 1

First, to clarify the question: On an M emulator, if you highlight text, you will see the new floating action mode. If you click the overflow icon, you will see "API DEMOS" show up:

Clicking that brings up an activity from the API Demos app, showing the highlighted text:

Replacing the value in the field and clicking the button puts your replacement text in as a replacement for whatever you had highlighted.

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WARNING: The following explanation is from inspecting the API Demos code and the M Developer Preview documentation. It is very possible that this will change before M ships for realz. YMMV, unless you use the metric system, in which case YKMV.

The activity in question, that is receiving the text, supports ACTION_PROCESS_TEXT as the Intent action. EXTRA_PROCESS_TEXT will hold some text, or EXTRA_PROCESS_TEXT_READONLY will hold it if the text is read-only. The activity will be invoked via startActivityForResult(). The result Intent can have its own EXTRA_PROCESS_TEXT value, which will be the replacement text.

So, to the specific questions:

What should be added in code (and manifest) to be able to handle the selected text from outside the app ?

See above. Note that the API Demos activity (ProcessText) has this <intent-filter>:

        <intent-filter >
            <action android:name="android.intent.action.PROCESS_TEXT"/>
            <category android:name="android.intent.category.DEFAULT" />
            <data android:mimeType="text/plain" />
        </intent-filter>

The documentation does not discuss a MIME type. I have not run any experiments to determine if the MIME type is required, and what else we might get (text/html for stuff that has spans?).

Is it possible to limit the selection to certain types of texts ? For example, offer to show the app only if the text type is a valid phone number ?

That wouldn't seem to be possible given the documentation. That being said, it's certainly a reasonable idea (e.g., advertise a regex, or multiple regexes, via metadata in the manifest that the text must match).

Answer 2

This article on Android Developers Blog may be relevant, it describes how Google Translate option can be added to overflow text selection menu.

Android apps that use Android text selection behavior will already have this feature enabled, so no extra steps need to be taken. Developers who created custom text selection behavior for their apps can easily implement this feature by following the below steps:

Scan via the PackageManager through all packages that have the PROCESS_TEXT intent filter (for example: com.google.android.apps.translate - if it installed) and add them as MenuItems into TextView selections for your app

To query the package manager, first build an intent with the action Intent.ACTION_PROCESS_TEXT, then retrieve the supported activities and add an item for each retrieved activity and attach an intent to it to launch the action

public void onInitializeMenu(Menu menu) {
    // Start with a menu Item order value that is high enough
    // so that your "PROCESS_TEXT" menu items appear after the
    // standard selection menu items like Cut, Copy, Paste.
    int menuItemOrder = 100;
    for (ResolveInfo resolveInfo : getSupportedActivities()) {
        menu.add(Menu.NONE, Menu.NONE,
                menuItemOrder++,
                getLabel(resolveInfo))
            .setIntent(createProcessTextIntentForResolveInfo(resolveInfo))
            .setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
    }
}