Added!: Convert extra-keys to agnosticism

The termux `extra-keys` have been moved to `termux-shared` library so that they can be imported and used by other apps for their own needs as long as they comply with GPLv3 license.

Almost everything is customizable and has no dependency on termux specific logic. Check the javadocs of files of `com.termux.shared.terminal.io.extrakeys` package for more info, specially, `ExtraKeysView`, `ExtraKeysInfo`, `ExtraKeyButton`, `TerminalExtraKeys` and  `TermuxTerminalExtraKeys`.

Moreover, you can now long hold on `CTRL`, `ALT`, `SHIFT` and `FN` to lock those control keys. They will not be released when you press another key and will only be released by pressing the respective control key again.

Closes termux#2049, Closes termux#1861

app/src/main/java/com/termux/app/TermuxActivity.java

@@ -44,7 +44,7 @@
 import com.termux.app.terminal.io.TerminalToolbarViewPager;
 import com.termux.app.terminal.TermuxTerminalSessionClient;
 import com.termux.app.terminal.TermuxTerminalViewClient;
-import com.termux.app.terminal.io.extrakeys.ExtraKeysView;
+import com.termux.shared.terminal.io.extrakeys.ExtraKeysView;
 import com.termux.app.settings.properties.TermuxAppSharedProperties;
 import com.termux.shared.interact.TextInputDialogUtils;
 import com.termux.shared.logger.Logger;

app/src/main/java/com/termux/app/settings/properties/TermuxAppSharedProperties.java

@@ -3,7 +3,9 @@
 import android.content.Context;
 
 import com.termux.app.terminal.io.KeyboardShortcut;
-import com.termux.app.terminal.io.extrakeys.ExtraKeysInfo;
+import com.termux.shared.terminal.io.extrakeys.ExtraKeysConstants;
+import com.termux.shared.terminal.io.extrakeys.ExtraKeysConstants.EXTRA_KEY_DISPLAY_MAPS;
+import com.termux.shared.terminal.io.extrakeys.ExtraKeysInfo;
 import com.termux.shared.logger.Logger;
 import com.termux.shared.settings.properties.TermuxPropertyConstants;
 import com.termux.shared.settings.properties.TermuxSharedProperties;
@@ -50,13 +52,20 @@ private void setExtraKeys() {
             // {@link #getExtraKeysStyleInternalPropertyValueFromValue(String)}
             String extrakeys = (String) getInternalPropertyValue(TermuxPropertyConstants.KEY_EXTRA_KEYS, true);
             String extraKeysStyle = (String) getInternalPropertyValue(TermuxPropertyConstants.KEY_EXTRA_KEYS_STYLE, true);
-            mExtraKeysInfo = new ExtraKeysInfo(extrakeys, extraKeysStyle);
+
+            ExtraKeysConstants.ExtraKeyDisplayMap extraKeyDisplayMap = ExtraKeysInfo.getCharDisplayMapForStyle(extraKeysStyle);
+            if (EXTRA_KEY_DISPLAY_MAPS.DEFAULT_CHAR_DISPLAY.equals(extraKeyDisplayMap) && !TermuxPropertyConstants.DEFAULT_IVALUE_EXTRA_KEYS_STYLE.equals(extraKeysStyle)) {
+                Logger.logError(TermuxSharedProperties.LOG_TAG, "The style \"" + extraKeysStyle + "\" for the key \"" + TermuxPropertyConstants.KEY_EXTRA_KEYS_STYLE + "\" is invalid. Using default style instead.");
+                extraKeysStyle = TermuxPropertyConstants.DEFAULT_IVALUE_EXTRA_KEYS_STYLE;
+            }
+
+            mExtraKeysInfo = new ExtraKeysInfo(extrakeys, extraKeysStyle, ExtraKeysConstants.CONTROL_CHARS_ALIASES);
         } catch (JSONException e) {
             Logger.showToast(mContext, "Could not load and set the \"" + TermuxPropertyConstants.KEY_EXTRA_KEYS + "\" property from the properties file: " + e.toString(), true);
             Logger.logStackTraceWithMessage(LOG_TAG, "Could not load and set the \"" + TermuxPropertyConstants.KEY_EXTRA_KEYS + "\" property from the properties file: ", e);
 
             try {
-                mExtraKeysInfo = new ExtraKeysInfo(TermuxPropertyConstants.DEFAULT_IVALUE_EXTRA_KEYS, TermuxPropertyConstants.DEFAULT_IVALUE_EXTRA_KEYS_STYLE);
+                mExtraKeysInfo = new ExtraKeysInfo(TermuxPropertyConstants.DEFAULT_IVALUE_EXTRA_KEYS, TermuxPropertyConstants.DEFAULT_IVALUE_EXTRA_KEYS_STYLE, ExtraKeysConstants.CONTROL_CHARS_ALIASES);
             } catch (JSONException e2) {
                 Logger.showToast(mContext, "Can't create default extra keys",true);
                 Logger.logStackTraceWithMessage(LOG_TAG, "Could create default extra keys: ", e);

app/src/main/java/com/termux/app/terminal/TermuxTerminalViewClient.java

@@ -27,13 +27,13 @@
 import com.termux.shared.interact.MessageDialogUtils;
 import com.termux.shared.shell.ShellUtils;
 import com.termux.shared.terminal.TermuxTerminalViewClientBase;
+import com.termux.shared.terminal.io.extrakeys.SpecialButton;
 import com.termux.shared.termux.AndroidUtils;
 import com.termux.shared.termux.TermuxConstants;
 import com.termux.shared.activities.ReportActivity;
 import com.termux.shared.models.ReportInfo;
 import com.termux.app.models.UserAction;
 import com.termux.app.terminal.io.KeyboardShortcut;
-import com.termux.app.terminal.io.extrakeys.ExtraKeysView;
 import com.termux.shared.settings.properties.TermuxPropertyConstants;
 import com.termux.shared.data.DataUtils;
 import com.termux.shared.logger.Logger;
@@ -289,12 +289,22 @@ private boolean handleVirtualKeys(int keyCode, KeyEvent event, boolean down) {
 
     @Override
     public boolean readControlKey() {
-        return (mActivity.getExtraKeysView() != null && mActivity.getExtraKeysView().readSpecialButton(ExtraKeysView.SpecialButton.CTRL)) || mVirtualControlKeyDown;
+        return readExtraKeysSpecialButton(SpecialButton.CTRL) || mVirtualControlKeyDown;
     }
 
     @Override
     public boolean readAltKey() {
-        return (mActivity.getExtraKeysView() != null && mActivity.getExtraKeysView().readSpecialButton(ExtraKeysView.SpecialButton.ALT));
+        return readExtraKeysSpecialButton(SpecialButton.ALT);
+    }
+
+    public boolean readExtraKeysSpecialButton(SpecialButton specialButton) {
+        if (mActivity.getExtraKeysView() == null) return false;
+        Boolean state = mActivity.getExtraKeysView().readSpecialButton(specialButton, true);
+        if (state == null) {
+            Logger.logError(LOG_TAG,"Failed to read an unregistered " + specialButton + " special button value from extra keys.");
+            return false;
+        }
+        return state;
     }
 
     @Override

app/src/main/java/com/termux/app/terminal/io/TerminalToolbarViewPager.java

@@ -11,7 +11,7 @@
 
 import com.termux.R;
 import com.termux.app.TermuxActivity;
-import com.termux.app.terminal.io.extrakeys.ExtraKeysView;
+import com.termux.shared.terminal.io.extrakeys.ExtraKeysView;
 import com.termux.terminal.TerminalSession;
 
 public class TerminalToolbarViewPager {
@@ -44,8 +44,8 @@ public Object instantiateItem(@NonNull ViewGroup collection, int position) {
             if (position == 0) {
                 layout = inflater.inflate(R.layout.view_terminal_toolbar_extra_keys, collection, false);
                 ExtraKeysView extraKeysView = (ExtraKeysView) layout;
-                extraKeysView.setTermuxTerminalViewClient(mActivity.getTermuxTerminalViewClient());
-                extraKeysView.setTermuxTerminalSessionClient(mActivity.getTermuxTerminalSessionClient());
+                extraKeysView.setExtraKeysViewClient(new TermuxTerminalExtraKeys(mActivity.getTerminalView(),
+                    mActivity.getTermuxTerminalViewClient(), mActivity.getTermuxTerminalSessionClient()));
                 mActivity.setExtraKeysView(extraKeysView);
                 extraKeysView.reload(mActivity.getProperties().getExtraKeysInfo());
 

app/src/main/java/com/termux/app/terminal/io/TermuxTerminalExtraKeys.java

@@ -0,0 +1,47 @@
+package com.termux.app.terminal.io;
+
+import android.annotation.SuppressLint;
+import android.view.Gravity;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.drawerlayout.widget.DrawerLayout;
+
+import com.termux.R;
+import com.termux.app.terminal.TermuxTerminalSessionClient;
+import com.termux.app.terminal.TermuxTerminalViewClient;
+import com.termux.shared.terminal.io.TerminalExtraKeys;
+import com.termux.view.TerminalView;
+
+public class TermuxTerminalExtraKeys extends TerminalExtraKeys {
+
+
+    TermuxTerminalViewClient mTermuxTerminalViewClient;
+    TermuxTerminalSessionClient mTermuxTerminalSessionClient;
+
+    public TermuxTerminalExtraKeys(@NonNull TerminalView terminalView,
+                                   TermuxTerminalViewClient termuxTerminalViewClient,
+                                   TermuxTerminalSessionClient termuxTerminalSessionClient) {
+        super(terminalView);
+        mTermuxTerminalViewClient = termuxTerminalViewClient;
+        mTermuxTerminalSessionClient = termuxTerminalSessionClient;
+    }
+
+    @SuppressLint("RtlHardcoded")
+    @Override
+    public void onTerminalExtraKeyButtonClick(View view, String key, boolean ctrlDown, boolean altDown, boolean shiftDown, boolean fnDown) {
+        if ("KEYBOARD".equals(key)) {
+            if(mTermuxTerminalViewClient != null)
+                mTermuxTerminalViewClient.onToggleSoftKeyboardRequest();
+        } else if ("DRAWER".equals(key)) {
+            DrawerLayout drawer = view.findViewById(R.id.drawer_layout);
+            drawer.openDrawer(Gravity.LEFT);
+        } else if ("PASTE".equals(key)) {
+            if(mTermuxTerminalSessionClient != null)
+                mTermuxTerminalSessionClient.onPasteTextFromClipboard(null);
+        } else {
+            super.onTerminalExtraKeyButtonClick(view, key, ctrlDown, altDown, shiftDown, fnDown);
+        }
+    }
+
+}