TextEditingDelta support for Android #28175
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| // Copyright 2013 The Flutter Authors. All rights reserved. | ||
| // Use of this source code is governed by a BSD-style license that can be | ||
| // found in the LICENSE file. | ||
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| package io.flutter.plugin.editing; | ||
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| import androidx.annotation.VisibleForTesting; | ||
| import io.flutter.Log; | ||
| import org.json.JSONException; | ||
| import org.json.JSONObject; | ||
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| /// A representation of the change that occured to an editing state, along with the resulting | ||
| /// composing and selection regions. | ||
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Contributor
There was a problem hiding this comment. Do we explicitly differentiate between text content changes and selection/composing region index only changes? However it is handled, it should be documented.
Contributor
There was a problem hiding this comment. Never mind, that is under the umbrella of TextEditingDeltaNonTextUpdate
Contributor
Author
There was a problem hiding this comment. On the framework we do, but on the engine there is no differentiation. This differentiation is documented on the framework side, should it also have something here? Edit: didn't see your comment before this, disregard. |
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| public final class TextEditingDelta { | ||
| private CharSequence oldText; | ||
| private CharSequence deltaText; | ||
| private int deltaStart; | ||
| private int deltaEnd; | ||
| private int newSelectionStart; | ||
| private int newSelectionEnd; | ||
| private int newComposingStart; | ||
| private int newComposingEnd; | ||
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| private static final String TAG = "TextEditingDelta"; | ||
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| public TextEditingDelta( | ||
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Contributor
There was a problem hiding this comment. I was expecting that we can just extract the
Contributor
Author
There was a problem hiding this comment. That wouldn't work in some cases. Say the case where we are typing "world". Current state: "worl|" or for a deletion Current state: "world|" If typing at the end of the composing region the text in the composing region is replaced with the entire new composing text. If we move the cursor inside the word currently being composed like below we get this call. Here we are actually given the insertion point and the character inserted, where when it is at the end of the composing region we must do some reasoning. On iOS we have something slightly different as well. Current state: "world|" another thing iOS does is when typing with a CJK keyboard it will exhibit behavior similar to Android composing region where the entire composing region is replaced on input. Because these values can vary a bit by platform for the same operation I think it is important to unify them into one format. I'm unsure if a replacement of "world" with "worl" would have the same result as replacing "d" in "world" with an empty string regarding if ranges of "world" where bolded/styled. Would these ranges still have the information needed to contract/expand as expected?
Contributor
There was a problem hiding this comment. Ah makes sense, thank you for the clarification! Do you think we'll be able to extract that info directly from the
Contributor
Author
There was a problem hiding this comment. Unfortunately from my research of the API I don't think so. Even the
Maybe I missed something but this is my conclusion after my research.
Contributor
There was a problem hiding this comment. I see. So
Contributor
There was a problem hiding this comment. I'd prefer a bit more documentation in this class. If this were the entrypoint for someone learning about this feature, the documentation here is a bit lacking to properly introduce what this does and find the rest of the code. |
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| CharSequence oldEditable, | ||
| int replacementDestinationStart, | ||
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Contributor
There was a problem hiding this comment. Since in this system, we have a Delta type called Also, what is the difference between that testing constructor and this one? They seem to do the same thing, but parameter naming is out of sync.
Contributor
Author
There was a problem hiding this comment. The reason I don't call it Your right the testing constructor can be eliminated. |
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| int replacementDestinationEnd, | ||
| CharSequence replacementSource, | ||
| int selectionStart, | ||
| int selectionEnd, | ||
| int composingStart, | ||
| int composingEnd) { | ||
| newSelectionStart = selectionStart; | ||
| newSelectionEnd = selectionEnd; | ||
| newComposingStart = composingStart; | ||
| newComposingEnd = composingEnd; | ||
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| setDeltas( | ||
| oldEditable, | ||
| replacementSource.toString(), | ||
| replacementDestinationStart, | ||
| replacementDestinationEnd); | ||
| } | ||
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| // Non text update delta constructor. | ||
| public TextEditingDelta( | ||
| CharSequence oldText, | ||
| int selectionStart, | ||
| int selectionEnd, | ||
| int composingStart, | ||
| int composingEnd) { | ||
| newSelectionStart = selectionStart; | ||
| newSelectionEnd = selectionEnd; | ||
| newComposingStart = composingStart; | ||
| newComposingEnd = composingEnd; | ||
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| setDeltas(oldText, "", -1, -1); | ||
| } | ||
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| @VisibleForTesting | ||
| public CharSequence getOldText() { | ||
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Contributor
There was a problem hiding this comment. Do you need these getters? The text input plugin only need to be able to build deltas and serialize them to JSON right? Are these for writing tests?
Contributor
Author
There was a problem hiding this comment. Yes there are now purely for tests.
Contributor
There was a problem hiding this comment. Nit: Maybe write a comment or comments stating that these are for testing only.
Contributor
There was a problem hiding this comment. I don't know java too well but do you need expose them as
Contributor
Author
There was a problem hiding this comment. Yeah I think we do. I just tried to switch them to private and it complained. |
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| return oldText; | ||
| } | ||
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| @VisibleForTesting | ||
| public CharSequence getDeltaText() { | ||
| return deltaText; | ||
| } | ||
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| @VisibleForTesting | ||
| public int getDeltaStart() { | ||
| return deltaStart; | ||
| } | ||
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| @VisibleForTesting | ||
| public int getDeltaEnd() { | ||
| return deltaEnd; | ||
| } | ||
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| @VisibleForTesting | ||
| public int getNewSelectionStart() { | ||
| return newSelectionStart; | ||
| } | ||
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| @VisibleForTesting | ||
| public int getNewSelectionEnd() { | ||
| return newSelectionEnd; | ||
| } | ||
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| @VisibleForTesting | ||
| public int getNewComposingStart() { | ||
| return newComposingStart; | ||
| } | ||
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| @VisibleForTesting | ||
| public int getNewComposingEnd() { | ||
| return newComposingEnd; | ||
| } | ||
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| private void setDeltas(CharSequence oldText, CharSequence newText, int newStart, int newExtent) { | ||
| this.oldText = oldText; | ||
| deltaText = newText; | ||
| deltaStart = newStart; | ||
| deltaEnd = newExtent; | ||
| } | ||
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| public JSONObject toJSON() { | ||
| JSONObject delta = new JSONObject(); | ||
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| try { | ||
| delta.put("oldText", oldText.toString()); | ||
| delta.put("deltaText", deltaText.toString()); | ||
| delta.put("deltaStart", deltaStart); | ||
| delta.put("deltaEnd", deltaEnd); | ||
| delta.put("selectionBase", newSelectionStart); | ||
| delta.put("selectionExtent", newSelectionEnd); | ||
| delta.put("composingBase", newComposingStart); | ||
| delta.put("composingExtent", newComposingEnd); | ||
| } catch (JSONException e) { | ||
| Log.e(TAG, "unable to create JSONObject: " + e); | ||
| } | ||
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| return delta; | ||
| } | ||
| } | ||
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