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Mobile/IME: Difference between revisions
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= Introduction = | |||
Here we will be collecting information about keyboard/IME handling and issues in Fennec. | |||
= IME architecture = | |||
== Components == | |||
Android IME-handling code consists of 4 parts: Java, widget, content, and IPC. | |||
Java part is mostly in GeckoInputConnection.java, which deals with Android API, and translates Java interface calls made by Android system to the corresponding Gecko events. | |||
The IME events are the objects of GeckoEvent class with one of the IME_XXX types. They get sent using GeckoAppShell.sendEventToGecko() across JNI to nsWindow.cpp in widget, wrapped in AndroidGeckoEvent C++ class. | |||
nsWindow does minimum packaging and dispatches the events further to content, where they go all over the place. | |||
Many of those events are handled in [http://mxr.mozilla.org/mozilla-central/source/content/events/src/nsContentEventHandler.cpp content/events/src/nsContentEventHandler.cpp], for example NS_QUERY_SELECTED_TEXT is dispatched to nsContentEventHandler::OnQuerySelectedText. | |||
The IME events go only in one direction: from front-end to back-end, the reverse communication is done using notifications going from back-end to front-end. They pass through nsWindow::OnIMExxx in widget, across JNI to GeckoAppShell.NotifyIMEChange, and handled in GeckoInputConnection.notifyXXXChange. | |||
== Ranges == | |||
Some IMEs are marking a part of the text that you're working on. For example, here a part of the text being entered is underlined: | |||
[[Image:Fennec-IME-ranges.png|IME Ranges]] | |||
Information about those parts is passed to Gecko as an array of ranges. Each range has several properties, including a type, which defines the nature of the range, styles like underlining, and text colors. The most noticeable and important range types are the composing text, and the text selection. | |||
== Composition == | |||
A composing text is a range of text that you are currently working on. While it is in the composition state, it can be freely changed, these changes are considered as a batch operation, and are submitted as one update at the end of the composition, so the whole text modification is stored as one action in the edit history. | |||
GeckoInputConnection tracks the composing state using mComposing flag. When it receives a text modification request from Android it sets this flag and sends IME_COMPOSITION_BEGIN event to Gecko. While in that state the mComposingText variable contains the current composing text, and mCompositionStart points to a start index of the composition within the text body. mCompositionSelStart/mCompositionSelLen track the text selection during the composition, as Gecko selection is not supposed to change while in the composing state. | |||
= Bugs = | |||
[https://bugzilla.mozilla.org/buglist.cgi?cmdtype=dorem&remaction=run&namedcmd=Fennec%20IME%20bugs&sharer_id=350513 Bugzilla query to get all Fennec IME-related bugs] | |||
[[Mobile/IME_Bugs]] | |||