Refactor TermuxActivity

This commit majorly refactors `TermuxActivity` and moves its view components and functions into dedicated classes.

- The view layouts and ids have been given meaningful names, like `termux_activity.xml`.
- The `TerminalToolbarViewPager` class has been created to handle the now called toolbar that shows on the bottom of the terminal view. It currently contains extra keys view defined by `terminal_toolbar_extra_keys_view.xml` file and a text input view defined by `terminal_toolbar_text_input_view.xml` file when user can switch to by swiping left. The input text will now be preserved if android destroys the activity or its recreated.
- The `TermuxSessionsListViewController` class has been created to handle view related functionality of the termux sessions list shown in the left drawer, namely view creation, `onItemClick()`, `onItemLongClick()`, etc. Its list view is defined by `termux_activity.xml` file and each item's layout is defined by the `terminal_sessions_list_item.xml` file.
- The `TextDataUtils` class has been added to the `com.termux.app.utils` package for text utils.
- The design for the `SessionChangedCallback` interface for `TerminalSession` has been majorly changed. Firstly, it has been renamed and moved from `TerminalSession` to the dedicated `TerminalSessionClient` class file. The interface now also supports the termux app centralized logging framework so that `TerminalSession` and `TerminalEmulator` can use them. Previously, `TermuxService` was implementing a wrapper interface, which would then call the real interface defined by the `TermuxActivity` if it was currently bound to the service. This cluttered and partially duplicated the code. Now, the implementation is defined by the `TermuxSessionClientBase` and `TermuxSessionClient` classes. The `TermuxSessionClientBase` implements the `TerminalSessionClient` interface but the definition of the activity related functions do not do anything, only the background ones like the logging functions are fully implemented. The `TermuxSessionClient` class inherits from the `TermuxSessionClientBase` class and provides the implementation for the activity related functions. The design for how this works is that if the `TermuxService` is not bound to `TermuxActivity`, it just passes the `TermuxSessionClientBase` implementation to `TerminalSession`. If the activity is bound at some point, then in `onServiceConnected()` it replaces/updates the client objects stored in `TerminalSession` and `TerminalEmulator` with `TermuxSessionClient`, and then replaces them back with `TermuxSessionClientBase` in `onDestroy()`. This seems to be working for now without an issue.

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

@@ -24,9 +24,12 @@
 import com.termux.app.TermuxConstants.TERMUX_APP.TERMUX_ACTIVITY;
 import com.termux.app.TermuxConstants.TERMUX_APP.TERMUX_SERVICE;
 import com.termux.app.settings.preferences.TermuxSharedPreferences;
+import com.termux.app.terminal.TermuxSessionClient;
+import com.termux.app.terminal.TermuxSessionClientBase;
 import com.termux.app.utils.Logger;
+import com.termux.terminal.TerminalEmulator;
 import com.termux.terminal.TerminalSession;
-import com.termux.terminal.TerminalSession.SessionChangedCallback;
+import com.termux.terminal.TerminalSessionClient;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -44,13 +47,11 @@
  * Optionally may hold a wake and a wifi lock, in which case that is shown in the notification - see
  * {@link #buildNotification()}.
  */
-public final class TermuxService extends Service implements SessionChangedCallback {
+public final class TermuxService extends Service {
 
     private static final String NOTIFICATION_CHANNEL_ID = "termux_notification_channel";
     private static final int NOTIFICATION_ID = 1337;
 
-    private static final String LOG_TAG = "TermuxService";
-
     /** This service is only bound from inside the same process and never uses IPC. */
     class LocalBinder extends Binder {
         public final TermuxService service = TermuxService.this;
@@ -63,15 +64,23 @@ class LocalBinder extends Binder {
     /**
      * The terminal sessions which this service manages.
      * <p/>
-     * Note that this list is observed by {@link TermuxActivity#mListViewAdapter}, so any changes must be made on the UI
+     * Note that this list is observed by {@link TermuxActivity#mTermuxSessionListViewController}, so any changes must be made on the UI
      * thread and followed by a call to {@link ArrayAdapter#notifyDataSetChanged()} }.
      */
     final List<TerminalSession> mTerminalSessions = new ArrayList<>();
 
     final List<BackgroundJob> mBackgroundTasks = new ArrayList<>();
 
-    /** Note that the service may often outlive the activity, so need to clear this reference. */
-    SessionChangedCallback mSessionChangeCallback;
+    /** The full implementation of the {@link TerminalSessionClient} interface to be used by {@link TerminalSession}
+     * that holds activity references for activity related functions.
+     * Note that the service may often outlive the activity, so need to clear this reference.
+     */
+    TermuxSessionClient mTermuxSessionClient;
+
+    /** The basic implementation of the {@link TerminalSessionClient} interface to be used by {@link TerminalSession}
+     * that does not hold activity references.
+     */
+    final TermuxSessionClientBase mTermuxSessionClientBase = new TermuxSessionClientBase();;
 
     /** The wake lock and wifi lock are always acquired and released together. */
     private PowerManager.WakeLock mWakeLock;
@@ -80,6 +89,8 @@ class LocalBinder extends Binder {
     /** If the user has executed the {@link TermuxConstants.TERMUX_APP.TERMUX_SERVICE#ACTION_STOP_SERVICE} intent. */
     boolean mWantsToStop = false;
 
+    private static final String LOG_TAG = "TermuxService";
+
     @SuppressLint("Wakelock")
     @Override
     public int onStartCommand(Intent intent, int flags, int startId) {
@@ -266,7 +277,7 @@ public List<TerminalSession> getSessions() {
         return mTerminalSessions;
     }
 
-    TerminalSession createTermSession(String executablePath, String[] arguments, String cwd, boolean failSafe) {
+    public TerminalSession createTermSession(String executablePath, String[] arguments, String cwd, boolean failSafe) {
         TermuxConstants.TERMUX_HOME_DIR.mkdirs();
 
         if (cwd == null || cwd.isEmpty()) cwd = TermuxConstants.TERMUX_HOME_DIR_PATH;
@@ -302,7 +313,7 @@ TerminalSession createTermSession(String executablePath, String[] arguments, Str
         args[0] = processName;
         if (processArgs.length > 1) System.arraycopy(processArgs, 1, args, 1, processArgs.length - 1);
 
-        TerminalSession session = new TerminalSession(executablePath, cwd, args, env, this);
+        TerminalSession session = new TerminalSession(executablePath, cwd, args, env, getTermuxSessionClient());
         mTerminalSessions.add(session);
         updateNotification();
 
@@ -327,35 +338,48 @@ public int removeTermSession(TerminalSession sessionToRemove) {
         return indexOfRemoved;
     }
 
-    @Override
-    public void onTitleChanged(TerminalSession changedSession) {
-        if (mSessionChangeCallback != null) mSessionChangeCallback.onTitleChanged(changedSession);
-    }
-
-    @Override
-    public void onSessionFinished(final TerminalSession finishedSession) {
-        if (mSessionChangeCallback != null)
-            mSessionChangeCallback.onSessionFinished(finishedSession);
+    /** If {@link TermuxActivity} has not bound to the {@link TermuxService} yet or is destroyed, then
+     * interface functions requiring the activity should not be available to the terminal sessions,
+     * so we just return the {@link #mTermuxSessionClientBase}. Once {@link TermuxActivity} bind
+     * callback is received, it should call {@link #setTermuxSessionClient} to set the
+     * {@link TermuxService#mTermuxSessionClient} so that further terminal sessions are directly
+     * passed the {@link TermuxSessionClient} object which fully implements the
+     * {@link TerminalSessionClient} interface.
+     *
+     * @return Returns the {@link TermuxSessionClient} if {@link TermuxActivity} has bound with
+     * {@link TermuxService}, otherwise {@link TermuxSessionClientBase}.
+     */
+    public TermuxSessionClientBase getTermuxSessionClient() {
+        if (mTermuxSessionClient != null)
+            return mTermuxSessionClient;
+        else
+            return mTermuxSessionClientBase;
     }
 
-    @Override
-    public void onTextChanged(TerminalSession changedSession) {
-        if (mSessionChangeCallback != null) mSessionChangeCallback.onTextChanged(changedSession);
-    }
+    /** This should be called when {@link TermuxActivity#onServiceConnected} is called to set the
+     * {@link TermuxService#mTermuxSessionClient} variable and update the {@link TerminalSession}
+     * and {@link TerminalEmulator} clients in case they were passed {@link TermuxSessionClientBase}
+     * earlier.
+     *
+     * @param termuxSessionClient The {@link TermuxSessionClient} object that fully
+     * implements the {@link TerminalSessionClient} interface.
+     */
+    public void setTermuxSessionClient(TermuxSessionClient termuxSessionClient) {
+        mTermuxSessionClient = termuxSessionClient;
 
-    @Override
-    public void onClipboardText(TerminalSession session, String text) {
-        if (mSessionChangeCallback != null) mSessionChangeCallback.onClipboardText(session, text);
+        for (int i = 0; i < mTerminalSessions.size(); i++)
+            mTerminalSessions.get(i).updateTerminalSessionClient(mTermuxSessionClient);
     }
 
-    @Override
-    public void onBell(TerminalSession session) {
-        if (mSessionChangeCallback != null) mSessionChangeCallback.onBell(session);
-    }
+    /** This should be called when {@link TermuxActivity} has been destroyed so that the
+     * {@link TermuxService} and {@link TerminalSession} and {@link TerminalEmulator} clients do not
+     * hold an activity references.
+     */
+    public void unsetTermuxSessionClient() {
+        mTermuxSessionClient = null;
 
-    @Override
-    public void onColorsChanged(TerminalSession session) {
-        if (mSessionChangeCallback != null) mSessionChangeCallback.onColorsChanged(session);
+        for (int i = 0; i < mTerminalSessions.size(); i++)
+            mTerminalSessions.get(i).updateTerminalSessionClient(mTermuxSessionClientBase);
     }
 
     public void onBackgroundJobExited(final BackgroundJob task) {

app/src/main/java/com/termux/app/settings/preferences/TermuxPreferenceConstants.java

@@ -26,9 +26,9 @@
  */
 public final class TermuxPreferenceConstants {
 
-    /** Defines the key for whether to show extra keys in termux terminal view */
-    public static final String KEY_SHOW_EXTRA_KEYS = "show_extra_keys";
-    public static final boolean DEFAULT_VALUE_SHOW_EXTRA_KEYS = true;
+    /** Defines the key for whether to show terminal toolbar containing extra keys and text input field */
+    public static final String KEY_SHOW_TERMINAL_TOOLBAR = "show_extra_keys";
+    public static final boolean DEFAULT_VALUE_SHOW_TERMINAL_TOOLBAR = true;
 
 
 

app/src/main/java/com/termux/app/settings/preferences/TermuxSharedPreferences.java

@@ -33,17 +33,17 @@ private static SharedPreferences getSharedPreferences(Context context) {
 
 
 
-    public boolean getShowExtraKeys() {
-        return mSharedPreferences.getBoolean(TermuxPreferenceConstants.KEY_SHOW_EXTRA_KEYS, TermuxPreferenceConstants.DEFAULT_VALUE_SHOW_EXTRA_KEYS);
+    public boolean getShowTerminalToolbar() {
+        return mSharedPreferences.getBoolean(TermuxPreferenceConstants.KEY_SHOW_TERMINAL_TOOLBAR, TermuxPreferenceConstants.DEFAULT_VALUE_SHOW_TERMINAL_TOOLBAR);
     }
 
-    public void setShowExtraKeys(boolean value) {
-        mSharedPreferences.edit().putBoolean(TermuxPreferenceConstants.KEY_SHOW_EXTRA_KEYS, value).apply();
+    public void setShowTerminalToolbar(boolean value) {
+        mSharedPreferences.edit().putBoolean(TermuxPreferenceConstants.KEY_SHOW_TERMINAL_TOOLBAR, value).apply();
     }
 
-    public boolean toggleShowExtraKeys() {
-        boolean currentValue = getShowExtraKeys();
-        setShowExtraKeys(!currentValue);
+    public boolean toogleShowTerminalToolbar() {
+        boolean currentValue = getShowTerminalToolbar();
+        setShowTerminalToolbar(!currentValue);
         return !currentValue;
     }
 
@@ -108,13 +108,6 @@ public void changeFontSize(Context context, boolean increase) {
         setFontSize(Integer.toString(fontSize));
     }
 
-    /**
-     * If value is not in the range [min, max], set it to either min or max.
-     */
-    static int clamp(int value, int min, int max) {
-        return Math.min(Math.max(value, min), max);
-    }
-
 
 
     public String getCurrentSession() {
@@ -152,4 +145,13 @@ public void setTerminalViewKeyLoggingEnabled(boolean value) {
         mSharedPreferences.edit().putBoolean(TermuxPreferenceConstants.KEY_TERMINAL_VIEW_KEY_LOGGING_ENABLED, value).apply();
     }
 
+
+
+    /**
+     * If value is not in the range [min, max], set it to either min or max.
+     */
+    static int clamp(int value, int min, int max) {
+        return Math.min(Math.max(value, min), max);
+    }
+
 }