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ANDROID: Fix for buggy backspace behavior in TYPE_NULL inputType

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Code taken from https://stackoverflow.com/a/19980975
This commit is contained in:
antoniou 2020-10-01 00:05:01 +03:00
parent 303d4681f0
commit bf54ea041b
4 changed files with 281 additions and 13 deletions
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1
backends/platform/android/events.cpp
View file

@ -89,6 +89,7 @@ void OSystem_Android::pushEvent(int type, int arg1, int arg2, int arg3,
// map special keys to 'our' ascii codes
switch (e.kbd.keycode) {
case Common::KEYCODE_BACKSPACE:
LOGD("received BACKSPACE");
e.kbd.ascii = Common::ASCII_BACKSPACE;
break;
case Common::KEYCODE_TAB:

53
backends/platform/android/org/scummvm/scummvm/EditableAccommodatingLatinIMETypeNullIssues.java Normal file
View file

@ -0,0 +1,53 @@
package org.scummvm.scummvm;
import android.text.SpannableStringBuilder;
public class EditableAccommodatingLatinIMETypeNullIssues extends SpannableStringBuilder {
EditableAccommodatingLatinIMETypeNullIssues(CharSequence source) {
super(source);
}
//This character must be ignored by your onKey() code.
public static CharSequence ONE_UNPROCESSED_CHARACTER = "/";
@Override
public SpannableStringBuilder replace(final int spannableStringStart, final int spannableStringEnd, CharSequence replacementSequence, int replacementStart, int replacementEnd) {
if (replacementEnd > replacementStart) {
//In this case, there is something in the replacementSequence that the IME
// is attempting to replace part of the editable with.
//We don't really care about whatever might already be in the editable;
// we only care about making sure that SOMETHING ends up in it,
// so that the backspace key will continue to work.
// So, start by zeroing out whatever is there to begin with.
super.replace(0, length(), "", 0, 0);
//We DO care about preserving the new stuff that is replacing the stuff in the
// editable, because this stuff might be sent to us as a keydown event. So, we
// insert the new stuff (typically, a single character) into the now-empty editable,
// and return the result to the caller.
return super.replace(0, 0, replacementSequence, replacementStart, replacementEnd);
} else if (spannableStringEnd > spannableStringStart) {
//In this case, there is NOTHING in the replacementSequence, and something is
// being replaced in the editable.
// This is characteristic of a DELETION.
// So, start by zeroing out whatever is being replaced in the editable.
super.replace(0, length(), "", 0, 0);
//And now, we will place our ONE_UNPROCESSED_CHARACTER into the editable buffer, and return it.
return super.replace(0, 0, ONE_UNPROCESSED_CHARACTER, 0, 1);
}
// In this case, NOTHING is being replaced in the editable. This code assumes that there
// is already something there. This assumption is probably OK because in our
// InputConnectionAccommodatingLatinIMETypeNullIssues.getEditable() method
// we PLACE a ONE_UNPROCESSED_CHARACTER into the newly-created buffer. So if there
// is nothing replacing the identified part
// of the editable, and no part of the editable that is being replaced, then we just
// leave whatever is in the editable ALONE,
// and we can be confident that there will be SOMETHING there. This call to super.replace()
// in that case will be a no-op, except
// for the value it returns.
return super.replace(spannableStringStart, spannableStringEnd,
replacementSequence, replacementStart, replacementEnd);
}
}

228
backends/platform/android/org/scummvm/scummvm/EditableSurfaceView.java
View file

@ -1,15 +1,18 @@
package org.scummvm.scummvm;
import android.content.Context;
import android.os.Build;
import android.text.Editable;
import android.text.InputType;
import android.text.Selection;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.PointerIcon;
import android.view.SurfaceView;
import android.view.inputmethod.BaseInputConnection;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.view.inputmethod.InputMethodManager;
import android.annotation.TargetApi;
public class EditableSurfaceView extends SurfaceView {
@ -25,7 +28,8 @@ public class EditableSurfaceView extends SurfaceView {
_context = context;
}
public EditableSurfaceView(Context context, AttributeSet attrs,
public EditableSurfaceView(Context context,
AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
_context = context;
@ -44,23 +48,227 @@ public class EditableSurfaceView extends SurfaceView {
super(EditableSurfaceView.this, false);
}
// Bug fixes for backspace behavior in TYPE_NULL input type
// ref: https://stackoverflow.com/a/19980975
// This holds the Editable text buffer that the LatinIME mistakenly *thinks*
// that it is editing, even though the views that employ this class are
// completely driven by key events.
Editable _myEditable = null;
//This method is called by the IME whenever the view that returned an
// instance of this class to the IME from its onCreateInputConnection()
// gains focus.
@Override
public boolean performEditorAction(int actionCode) {
if (actionCode == EditorInfo.IME_ACTION_DONE) {
InputMethodManager imm = (InputMethodManager)
getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(getWindowToken(), 0);
public Editable getEditable() {
// Some versions of the Google Keyboard (LatinIME) were delivered with a
// bug that causes KEYCODE_DEL to no longer be generated once the number
// of KEYCODE_DEL taps equals the number of other characters that have
// been typed. This bug was reported here as issue 62306.
//
// As of this writing (1/7/2014), it is fixed in the AOSP code, but that
// fix has not yet been released. Even when it is released, there will
// be many devices having versions of the Google Keyboard that include the bug
// in the wild for the indefinite future. Therefore, a workaround is required.
//
// This is a workaround for that bug which just jams a single garbage character
// into the internal buffer that the keyboard THINKS it is editing even
// though we have specified TYPE_NULL which *should* cause LatinIME to
// generate key events regardless of what is in that buffer. We have other
// code that attempts to ensure as the user edites that there is always
// one character remaining.
//
// The problem arises because when this unseen buffer becomes empty, the IME
// thinks that there is nothing left to delete, and therefore stops
// generating KEYCODE_DEL events, even though the app may still be very
// interested in receiving them.
//
// So, for example, if the user taps in ABCDE and then positions the
// (app-based) cursor to the left of A and taps the backspace key three
// times without any evident effect on the letters (because the app's own
// UI code knows that there are no letters to the left of the
// app-implemented cursor), and then moves the cursor to the right of the
// E and hits backspace five times, then, after E and D have been deleted,
// no more KEYCODE_DEL events will be generated by the IME because the
// unseen buffer will have become empty from five letter key taps followed
// by five backspace key taps (as the IME is unaware of the app-based cursor
// movements performed by the user).
//
// In other words, if your app is processing KEYDOWN events itself, and
// maintaining its own cursor and so on, and not telling the IME anything
// about the user's cursor position, this buggy processing of the hidden
// buffer will stop KEYCODE_DEL events when your app actually needs them -
// in whatever Android releases incorporate this LatinIME bug.
//
// By creating this garbage characters in the Editable that is initially
// returned to the IME here, we make the IME think that it still has
// something to delete, which causes it to keep generating KEYCODE_DEL
// events in response to backspace key presses.
//
// A specific keyboard version that I tested this on which HAS this
// problem but does NOT have the "KEYCODE_DEL completely gone" (issue 42904)
// problem that is addressed by the deleteSurroundingText() override below
// (the two problems are not both present in a single version) is
// 2.0.19123.914326a, tested running on a Nexus7 2012 tablet.
// There may be other versions that have issue 62306.
//
// A specific keyboard version that I tested this on which does NOT have
// this problem but DOES have the "KEYCODE_DEL completely gone" (issue
// 42904) problem that is addressed by the deleteSurroundingText()
// override below is 1.0.1800.776638, tested running on the Nexus10
// tablet. There may be other versions that also have issue 42904.
//
// The bug that this addresses was first introduced as of AOSP commit tag
// 4.4_r0.9, and the next RELEASED Android version after that was
// android-4.4_r1, which is the first release of Android 4.4. So, 4.4 will
// be the first Android version that would have included, in the original
// RELEASED version, a Google Keyboard for which this bug was present.
//
// Note that this bug was introduced exactly at the point that the OTHER bug
// (the one that is addressed in deleteSurroundingText(), below) was first
// FIXED.
//
// Despite the fact that the above are the RELEASES associated with the bug,
// the fact is that any 4.x Android release could have been upgraded by the
// user to a later version of Google Keyboard than was present when the
// release was originally installed to the device. I have checked the
// www.archive.org snapshots of the Google Keyboard listing page on the Google
// Play store, and all released updates listed there (which go back to early
// June of 2013) required Android 4.0 and up, so we can be pretty sure that
// this bug is not present in any version earlier than 4.0 (ICS), which means
// that we can limit this fix to API level 14 and up. And once the LatinIME
// problem is fixed, we can limit the scope of this workaround to end as of
// the last release that included the problem, since we can assume that
// users will not upgrade Google Keyboard to an EARLIER version than was
// originally included in their Android release.
//
// The bug that this addresses was FIXED but NOT RELEASED as of this AOSP
// commit:
//https://android.googlesource.com/platform/packages/inputmethods/LatinIME/+
// /b41bea65502ce7339665859d3c2c81b4a29194e4/java/src/com/android
// /inputmethod/latin/LatinIME.java
// so it can be assumed to affect all of KitKat released thus far
// (up to 4.4.2), and could even affect beyond KitKat, although I fully
// expect it to be incorporated into the next release *after* API level 19.
//
// When it IS released, this method should be changed to limit it to no
// higher than API level 19 (assuming that the fix is released before API
// level 20), just in order to limit the scope of this fix, since poking
// 1024 characters into the Editable object returned here is of course a
// kluge. But right now the safest thing is just to not have an upper limit
// on the application of this kluge, since the fix for the problem it
// addresses has not yet been released (as of 1/7/2014).
if(Build.VERSION.SDK_INT >= 14) {
if (_myEditable == null) {
_myEditable = new EditableAccommodatingLatinIMETypeNullIssues(EditableAccommodatingLatinIMETypeNullIssues.ONE_UNPROCESSED_CHARACTER);
Selection.setSelection(_myEditable, 1);
} else {
int _myEditableLength = _myEditable.length();
if (_myEditableLength == 0) {
// I actually HAVE seen this be zero on the Nexus 10 with the keyboard
// that came with Android 4.4.2
// On the Nexus 10 4.4.2 if I tapped away from the view and then back to it, the
// _myEditable would come back as null and I would create a new one. This is also
// what happens on other devices (e.g., the Nexus 6 with 4.4.2,
// which has a slightly later version of the Google Keyboard). But for the
// Nexus 10 4.4.2, the keyboard had a strange behavior
// when I tapped on the rack, and then tapped Done on the keyboard to close it,
// and then tapped on the rack AGAIN. In THAT situation,
// the _myEditable would NOT be set to NULL but its LENGTH would be ZERO. So, I
// just append to it in that situation.
_myEditable.append(EditableAccommodatingLatinIMETypeNullIssues.ONE_UNPROCESSED_CHARACTER);
Selection.setSelection(_myEditable, 1);
}
}
return _myEditable;
}
else {
//Default behavior for keyboards that do not require any fix
return super.getEditable();
}
}
// Sends enter key
return super.performEditorAction(actionCode);
// This method is called INSTEAD of generating a KEYCODE_DEL event, by
// versions of Latin IME that have the bug described in Issue 42904.
@Override
public boolean deleteSurroundingText(int beforeLength, int afterLength) {
// If targetSdkVersion is set to anything AT or ABOVE API level 16
// then for the GOOGLE KEYBOARD versions DELIVERED
// with Android 4.1.x, 4.2.x or 4.3.x, NO KEYCODE_DEL EVENTS WILL BE
// GENERATED BY THE GOOGLE KEYBOARD (LatinIME) EVEN when TYPE_NULL
// is being returned as the InputType by your view from its
// onCreateInputMethod() override, due to a BUG in THOSE VERSIONS.
//
// When TYPE_NULL is specified (as this entire class assumes is being done
// by the views that use it, what WILL be generated INSTEAD of a KEYCODE_DEL
// is a deleteSurroundingText(1,0) call. So, by overriding this
// deleteSurroundingText() method, we can fire the KEYDOWN/KEYUP events
// ourselves for KEYCODE_DEL. This provides a workaround for the bug.
//
// The specific AOSP RELEASES involved are 4.1.1_r1 (the very first 4.1
// release) through 4.4_r0.8 (the release just prior to Android 4.4).
// This means that all of KitKat should not have the bug and will not
// need this workaround.
//
// Although 4.0.x (ICS) did not have this bug, it was possible to install
// later versions of the keyboard as an app on anything running 4.0 and up,
// so those versions are also potentially affected.
//
// The first version of separately-installable Google Keyboard shown on the
// Google Play store site by www.archive.org is Version 1.0.1869.683049,
// on June 6, 2013, and that version (and probably other, later ones)
// already had this bug.
//
//Since this required at least 4.0 to install, I believe that the bug will
// not be present on devices running versions of Android earlier than 4.0.
//
// AND, it should not be present on versions of Android at 4.4 and higher,
// since users will not "upgrade" to a version of Google Keyboard that
// is LOWER than the one they got installed with their version of Android
// in the first place, and the bug will have been fixed as of the 4.4 release.
//
// The above scope of the bug is reflected in the test below, which limits
// the application of the workaround to Android versions between 4.0.x and 4.3.x.
//
// UPDATE: A popular third party keyboard was found that exhibits this same issue. It
// was not fixed at the same time as the Google Play keyboard, and so the bug in that case
// is still in place beyond API LEVEL 19. So, even though the Google Keyboard fixed this
// as of level 19, we cannot take out the fix based on that version number. And so I've
// removed the test for an upper limit on the version; the fix will remain in place ad
// infinitum - but only when TYPE_NULL is used, so it *should* be harmless even when
// the keyboard does not have the problem...
if ((Build.VERSION.SDK_INT >= 14) // && (Build.VERSION.SDK_INT < 19)
&& (beforeLength == 1 && afterLength == 0)) {
//Send Backspace key down and up events to replace the ones omitted
// by the LatinIME keyboard.
return super.sendKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DEL))
&& super.sendKeyEvent(new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_DEL));
} else {
//Really, I can't see how this would be invoked, given that we're using
// TYPE_NULL, for non-buggy versions, but in order to limit the impact
// of this change as much as possible (i.e., to versions at and above 4.0)
// I am using the original behavior here for non-affected versions.
return super.deleteSurroundingText(beforeLength, afterLength);
}
}
// @Override
// public boolean performEditorAction(int actionCode) {
// if (actionCode == EditorInfo.IME_ACTION_DONE) {
// InputMethodManager imm = (InputMethodManager)
// getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
// imm.hideSoftInputFromWindow(getWindowToken(), 0);
// }
//
// // Sends enter key
// return super.performEditorAction(actionCode);
// }
}
@Override
public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
outAttrs.initialCapsMode = 0;
outAttrs.initialSelEnd = outAttrs.initialSelStart = -1;
outAttrs.actionLabel = null;
// Per the documentation for InputType.TYPE_NULL:
// "This should be interpreted to mean that the target input connection is not rich,
@ -70,7 +278,7 @@ public class EditableSurfaceView extends SurfaceView {
// We lose auto-complete, but that is ok, because we *really* want direct input key handling
outAttrs.inputType = InputType.TYPE_NULL;
// IME_FLAG_NO_EXTRACT_UI used to specify that the IME does not need to show its extracted text UI
// IME_FLAG_NO_EXTRACT_UI used to specify that the IME does not need to show its extracted text UI. Extract UI means the fullscreen editing mode.
// IME_ACTION_NONE Bits of IME_MASK_ACTION: there is no available action.
// TODO should we have a IME_ACTION_DONE?
outAttrs.imeOptions = (EditorInfo.IME_ACTION_NONE |

6
backends/platform/android/org/scummvm/scummvm/ScummVMEvents.java
View file

@ -114,6 +114,12 @@ public class ScummVMEvents implements
final public boolean onKey(View v, int keyCode, KeyEvent e) {
final int action = e.getAction();
if (e.getUnicodeChar() == (int)EditableAccommodatingLatinIMETypeNullIssues.ONE_UNPROCESSED_CHARACTER.charAt(0)) {
//We are ignoring this character, and we want everyone else to ignore it, too, so
// we return true indicating that we have handled it (by ignoring it).
return true;
}
if (keyCode == 238) {
// this (undocumented) event is sent when ACTION_HOVER_ENTER or ACTION_HOVER_EXIT occurs
return false;