Update Android port

* doc/emacs/android.texi (Android Environment): Document
notifications permission.
* java/org/gnu/emacs/EmacsEditable.java (EmacsEditable):
* java/org/gnu/emacs/EmacsInputConnection.java
(EmacsInputConnection): New files.
* java/org/gnu/emacs/EmacsNative.java (EmacsNative): Load
library dependencies in a less verbose fashion.
* java/org/gnu/emacs/EmacsView.java (EmacsView): Make imManager
public.
(onCreateInputConnection): Set InputType to TYPE_NULL for now.
* java/org/gnu/emacs/EmacsWindow.java (EmacsWindow, onKeyDown)
(onKeyUp, getEventUnicodeChar): Correctly handle key events with
strings.
* lisp/term/android-win.el (android-clear-preedit-text)
(android-preedit-text): New special event handlers.
* src/android.c (struct android_emacs_window): Add function
lookup_string.
(android_init_emacs_window): Adjust accordingly.
(android_wc_lookup_string): New function.
* src/androidgui.h (struct android_key_event): Improve
commentary.
(enum android_lookup_status): New enum.
* src/androidterm.c (handle_one_android_event): Synchronize IM
lookup code with X.
* src/coding.c (from_unicode_buffer): Implement on Android.
* src/coding.h:
* src/sfnt.c: Fix commentary.

java/org/gnu/emacs/EmacsInputConnection.java

@@ -0,0 +1,175 @@
+/* Communication module for Android terminals.  -*- c-file-style: "GNU" -*-
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+package org.gnu.emacs;
+
+import android.view.inputmethod.BaseInputConnection;
+import android.view.inputmethod.CompletionInfo;
+import android.view.inputmethod.ExtractedText;
+import android.view.inputmethod.ExtractedTextRequest;
+import android.view.inputmethod.InputMethodManager;
+import android.view.inputmethod.SurroundingText;
+import android.view.KeyEvent;
+
+import android.text.Editable;
+
+import android.util.Log;
+
+/* Android input methods, take number six.
+
+   See EmacsEditable for more details.  */
+
+public class EmacsInputConnection extends BaseInputConnection
+{
+  private static final String TAG = "EmacsInputConnection";
+  public EmacsView view;
+  private EmacsEditable editable;
+
+  /* The length of the last string to be committed.  */
+  private int lastCommitLength;
+
+  int currentLargeOffset;
+
+  public
+  EmacsInputConnection (EmacsView view)
+  {
+    super (view, false);
+    this.view = view;
+    this.editable = new EmacsEditable (this);
+  }
+
+  @Override
+  public Editable
+  getEditable ()
+  {
+    return editable;
+  }
+
+  @Override
+  public boolean
+  setComposingText (CharSequence text, int newCursorPosition)
+  {
+    editable.compositionStart ();
+    super.setComposingText (text, newCursorPosition);
+    return true;
+  }
+
+  @Override
+  public boolean
+  setComposingRegion (int start, int end)
+  {
+    int i;
+
+    if (lastCommitLength != 0)
+      {
+	Log.d (TAG, "Restarting composition for: " + lastCommitLength);
+
+	for (i = 0; i < lastCommitLength; ++i)
+	  sendKeyEvent (new KeyEvent (KeyEvent.ACTION_DOWN,
+				      KeyEvent.KEYCODE_DEL));
+
+	lastCommitLength = 0;
+      }
+
+    editable.compositionStart ();
+    super.setComposingRegion (start, end);
+    return true;
+  }
+  
+  @Override
+  public boolean
+  finishComposingText ()
+  {
+    editable.compositionEnd ();
+    return super.finishComposingText ();
+  }
+
+  @Override
+  public boolean
+  beginBatchEdit ()
+  {
+    editable.beginBatchEdit ();
+    return super.beginBatchEdit ();
+  }
+
+  @Override
+  public boolean
+  endBatchEdit ()
+  {
+    editable.endBatchEdit ();
+    return super.endBatchEdit ();
+  }
+  
+  @Override
+  public boolean
+  commitText (CharSequence text, int newCursorPosition)
+  {
+    editable.compositionEnd ();
+    super.commitText (text, newCursorPosition);
+
+    /* An observation is that input methods rarely recompose trailing
+       spaces.  Avoid re-setting the commit length in that case.  */
+
+    if (text.toString ().equals (" "))
+      lastCommitLength += 1;
+    else
+      /* At this point, the editable is now empty.
+	 
+	 The input method may try to cancel the edit upon a subsequent
+	 backspace by calling setComposingRegion with a region that is
+	 the length of TEXT.
+	 
+	 Record this length in order to be able to send backspace
+	 events to ``delete'' the text in that case.  */
+      lastCommitLength = text.length ();
+
+    Log.d (TAG, "commitText: \"" + text + "\"");
+
+    return true;
+  }
+
+  /* Return a large offset, cycling through 100000, 30000, 0.
+     The offset is typically used to force the input method to update
+     its notion of ``surrounding text'', bypassing any caching that
+     it might have in progress.
+
+     There must be another way to do this, but I can't find it.  */
+
+  public int
+  largeSelectionOffset ()
+  {
+    switch (currentLargeOffset)
+      {
+      case 0:
+	currentLargeOffset = 100000;
+	return 100000;
+
+      case 100000:
+	currentLargeOffset = 30000;
+	return 30000;
+
+      case 30000:
+	currentLargeOffset = 0;
+	return 0;
+      }
+
+    currentLargeOffset = 0;
+    return -1;
+  }
+}