Make sample IME aware of language switching

This CL demonstrates how the new language switching functionality
should work by using the SoftKeyboard sample.

BUG: 15267645
Change-Id: I18ab25a0784979fe6028b97a22ff02bfd502d506

samples/SoftKeyboard/res/xml/method.xml

@@ -22,6 +22,7 @@
 
 <input-method xmlns:android="http://schemas.android.com/apk/res/android"
         android:settingsActivity="com.example.android.softkeyboard.ImePreferences"
+        android:supportsSwitchingToNextInputMethod="true"
 >
     <subtype
         android:label="@string/label_subtype_generic"

samples/SoftKeyboard/res/xml/qwerty.xml

@@ -69,8 +69,14 @@
     
     <Row android:rowEdgeFlags="bottom">
         <Key android:codes="-3" android:keyIcon="@drawable/sym_keyboard_done" 
-                android:keyWidth="20%p" android:keyEdgeFlags="left"/>
+                android:keyWidth="15%p" android:keyEdgeFlags="left"/>
-        <Key android:codes="-2" android:keyLabel="123" android:keyWidth="15%p"/>
+        <Key android:codes="-2" android:keyLabel="123" android:keyWidth="10%p"/>
+        <!--
+            android:codes: -101 is not a framework-defined key code but a key code that is
+            privately defined in com.example.android.softkeyboard.LatinKeyboardView.
+        -->
+        <Key android:codes="-101" android:keyIcon="@drawable/sym_keyboard_language_switch"
+                android:keyWidth="10%p"/>
         <Key android:codes="32" android:keyIcon="@drawable/sym_keyboard_space" 
                 android:keyWidth="30%p" android:isRepeatable="true"/>
         <Key android:codes="46,44" android:keyLabel=". ,"

samples/SoftKeyboard/res/xml/symbols.xml

@@ -69,8 +69,14 @@
     
     <Row  android:rowEdgeFlags="bottom">
         <Key android:codes="-3" android:keyIcon="@drawable/sym_keyboard_done"
-                android:keyWidth="20%p" android:keyEdgeFlags="left" />
+                android:keyWidth="15%p" android:keyEdgeFlags="left" />
-        <Key android:codes="-2" android:keyLabel="ABC" android:keyWidth="15%p" />
+        <Key android:codes="-2" android:keyLabel="ABC" android:keyWidth="10%p" />
+        <!--
+            android:codes: -101 is not a framework-defined key code but a key code that is
+            privately defined in com.example.android.softkeyboard.LatinKeyboardView.
+        -->
+        <Key android:codes="-101" android:keyIcon="@drawable/sym_keyboard_language_switch"
+                android:keyWidth="10%p" />
         <Key android:codes="32" android:keyIcon="@drawable/sym_keyboard_space" android:keyWidth="30%p" 
                 android:isRepeatable="true"/>
         <Key android:codes="44" android:keyLabel="," android:keyWidth="15%p" />

samples/SoftKeyboard/res/xml/symbols_shift.xml

@@ -69,8 +69,14 @@
     
     <Row android:rowEdgeFlags="bottom">
         <Key android:codes="-3" android:keyIcon="@drawable/sym_keyboard_done" 
-                android:keyWidth="20%p" android:keyEdgeFlags="left" />
+                android:keyWidth="15%p" android:keyEdgeFlags="left" />
-        <Key android:codes="-2" android:keyLabel="ABC" android:keyWidth="15%p" />
+        <Key android:codes="-2" android:keyLabel="ABC" android:keyWidth="10%p" />
+        <!--
+            android:codes: -101 is not a framework-defined key code but a key code that is
+            privately defined in com.example.android.softkeyboard.LatinKeyboardView.
+        -->
+        <Key android:codes="-101" android:keyIcon="@drawable/sym_keyboard_language_switch"
+                android:keyWidth="10%p" />
         <Key android:codes="32" android:keyIcon="@drawable/sym_keyboard_space" android:keyWidth="30%p" 
                 android:isRepeatable="true"/>
         <Key android:codes="8230" android:keyLabel="…" android:keyWidth="15%p" />

samples/SoftKeyboard/src/com/example/android/softkeyboard/LatinKeyboard.java

@@ -22,11 +22,35 @@ import android.content.res.XmlResourceParser;
 import android.graphics.drawable.Drawable;
 import android.inputmethodservice.Keyboard;
 import android.view.inputmethod.EditorInfo;
+import android.view.inputmethod.InputMethodManager;
 
 public class LatinKeyboard extends Keyboard {
 
     private Key mEnterKey;
     private Key mSpaceKey;
+    /**
+     * Stores the current state of the mode change key. Its width will be dynamically updated to
+     * match the region of {@link #mModeChangeKey} when {@link #mModeChangeKey} becomes invisible.
+     */
+    private Key mModeChangeKey;
+    /**
+     * Stores the current state of the language switch key (a.k.a. globe key). This should be
+     * visible while {@link InputMethodManager#shouldOfferSwitchingToNextInputMethod(IBinder)}
+     * returns true. When this key becomes invisible, its width will be shrunk to zero.
+     */
+    private Key mLanguageSwitchKey;
+    /**
+     * Stores the size and other information of {@link #mModeChangeKey} when
+     * {@link #mLanguageSwitchKey} is visible. This should be immutable and will be used only as a
+     * reference size when the visibility of {@link #mLanguageSwitchKey} is changed.
+     */
+    private Key mSavedModeChangeKey;
+    /**
+     * Stores the size and other information of {@link #mLanguageSwitchKey} when it is visible.
+     * This should be immutable and will be used only as a reference size when the visibility of
+     * {@link #mLanguageSwitchKey} is changed.
+     */
+    private Key mSavedLanguageSwitchKey;
     
     public LatinKeyboard(Context context, int xmlLayoutResId) {
         super(context, xmlLayoutResId);
@@ -45,10 +69,39 @@ public class LatinKeyboard extends Keyboard {
             mEnterKey = key;
         } else if (key.codes[0] == ' ') {
             mSpaceKey = key;
+        } else if (key.codes[0] == Keyboard.KEYCODE_MODE_CHANGE) {
+            mModeChangeKey = key;
+            mSavedModeChangeKey = new LatinKey(res, parent, x, y, parser);
+        } else if (key.codes[0] == LatinKeyboardView.KEYCODE_LANGUAGE_SWITCH) {
+            mLanguageSwitchKey = key;
+            mSavedLanguageSwitchKey = new LatinKey(res, parent, x, y, parser);
         }
         return key;
     }
-    
+
+    /**
+     * Dynamically change the visibility of the language switch key (a.k.a. globe key).
+     * @param visible True if the language switch key should be visible.
+     */
+    void setLanguageSwitchKeyVisibility(boolean visible) {
+        if (visible) {
+            // The language switch key should be visible. Restore the size of the mode change key
+            // and language switch key using the saved layout.
+            mModeChangeKey.width = mSavedModeChangeKey.width;
+            mModeChangeKey.x = mSavedModeChangeKey.x;
+            mLanguageSwitchKey.width = mSavedLanguageSwitchKey.width;
+            mLanguageSwitchKey.icon = mSavedLanguageSwitchKey.icon;
+            mLanguageSwitchKey.iconPreview = mSavedLanguageSwitchKey.iconPreview;
+        } else {
+            // The language switch key should be hidden. Change the width of the mode change key
+            // to fill the space of the language key so that the user will not see any strange gap.
+            mModeChangeKey.width = mSavedModeChangeKey.width + mSavedLanguageSwitchKey.width;
+            mLanguageSwitchKey.width = 0;
+            mLanguageSwitchKey.icon = null;
+            mLanguageSwitchKey.iconPreview = null;
+        }
+    }
+
     /**
      * This looks at the ime options given by the current editor, to set the
      * appropriate label on the keyboard's enter key (if it has one).
@@ -57,7 +110,7 @@ public class LatinKeyboard extends Keyboard {
         if (mEnterKey == null) {
             return;
         }
-        
+
         switch (options&(EditorInfo.IME_MASK_ACTION|EditorInfo.IME_FLAG_NO_ENTER_ACTION)) {
             case EditorInfo.IME_ACTION_GO:
                 mEnterKey.iconPreview = null;
@@ -93,7 +146,8 @@ public class LatinKeyboard extends Keyboard {
 
     static class LatinKey extends Keyboard.Key {
         
-        public LatinKey(Resources res, Keyboard.Row parent, int x, int y, XmlResourceParser parser) {
+        public LatinKey(Resources res, Keyboard.Row parent, int x, int y,
+                XmlResourceParser parser) {
             super(res, parent, x, y, parser);
         }
         

samples/SoftKeyboard/src/com/example/android/softkeyboard/LatinKeyboardView.java

@@ -26,6 +26,8 @@ import android.view.inputmethod.InputMethodSubtype;
 public class LatinKeyboardView extends KeyboardView {
 
     static final int KEYCODE_OPTIONS = -100;
+    // TODO: Move this into android.inputmethodservice.Keyboard
+    static final int KEYCODE_LANGUAGE_SWITCH = -101;
 
     public LatinKeyboardView(Context context, AttributeSet attrs) {
         super(context, attrs);

samples/SoftKeyboard/src/com/example/android/softkeyboard/SoftKeyboard.java

@@ -16,14 +16,17 @@
 
 package com.example.android.softkeyboard;
 
+import android.app.Dialog;
 import android.inputmethodservice.InputMethodService;
 import android.inputmethodservice.Keyboard;
 import android.inputmethodservice.KeyboardView;
+import android.os.IBinder;
 import android.text.InputType;
 import android.text.method.MetaKeyKeyListener;
 import android.view.KeyCharacterMap;
 import android.view.KeyEvent;
 import android.view.View;
+import android.view.Window;
 import android.view.inputmethod.CompletionInfo;
 import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputConnection;
@@ -114,10 +117,17 @@ public class SoftKeyboard extends InputMethodService
         mInputView = (LatinKeyboardView) getLayoutInflater().inflate(
                 R.layout.input, null);
         mInputView.setOnKeyboardActionListener(this);
-        mInputView.setKeyboard(mQwertyKeyboard);
+        setLatinKeyboard(mQwertyKeyboard);
         return mInputView;
     }
 
+    private void setLatinKeyboard(LatinKeyboard nextKeyboard) {
+        final boolean shouldSupportLanguageSwitchKey =
+                mInputMethodManager.shouldOfferSwitchingToNextInputMethod(getToken());
+        nextKeyboard.setLanguageSwitchKeyVisibility(shouldSupportLanguageSwitchKey);
+        mInputView.setKeyboard(nextKeyboard);
+    }
+
     /**
      * Called by the framework when your view for showing candidates needs to
      * be generated, like {@link #onCreateInputView}.
@@ -247,7 +257,7 @@ public class SoftKeyboard extends InputMethodService
     @Override public void onStartInputView(EditorInfo attribute, boolean restarting) {
         super.onStartInputView(attribute, restarting);
         // Apply the selected keyboard to the input view.
-        mInputView.setKeyboard(mCurKeyboard);
+        setLatinKeyboard(mCurKeyboard);
         mInputView.closing();
         final InputMethodSubtype subtype = mInputMethodManager.getCurrentInputMethodSubtype();
         mInputView.setSubtypeOnSpaceKey(subtype);
@@ -509,19 +519,19 @@ public class SoftKeyboard extends InputMethodService
         } else if (primaryCode == Keyboard.KEYCODE_CANCEL) {
             handleClose();
             return;
+        } else if (primaryCode == LatinKeyboardView.KEYCODE_LANGUAGE_SWITCH) {
+            handleLanguageSwitch();
+            return;
         } else if (primaryCode == LatinKeyboardView.KEYCODE_OPTIONS) {
             // Show a menu or somethin'
         } else if (primaryCode == Keyboard.KEYCODE_MODE_CHANGE
                 && mInputView != null) {
             Keyboard current = mInputView.getKeyboard();
             if (current == mSymbolsKeyboard || current == mSymbolsShiftedKeyboard) {
-                current = mQwertyKeyboard;
+                setLatinKeyboard(mQwertyKeyboard);
             } else {
-                current = mSymbolsKeyboard;
+                setLatinKeyboard(mSymbolsKeyboard);
-            }
+                mSymbolsKeyboard.setShifted(false);
-            mInputView.setKeyboard(current);
-            if (current == mSymbolsKeyboard) {
-                current.setShifted(false);
             }
         } else {
             handleCharacter(primaryCode, keyCodes);
@@ -597,11 +607,11 @@ public class SoftKeyboard extends InputMethodService
             mInputView.setShifted(mCapsLock || !mInputView.isShifted());
         } else if (currentKeyboard == mSymbolsKeyboard) {
             mSymbolsKeyboard.setShifted(true);
-            mInputView.setKeyboard(mSymbolsShiftedKeyboard);
+            setLatinKeyboard(mSymbolsShiftedKeyboard);
             mSymbolsShiftedKeyboard.setShifted(true);
         } else if (currentKeyboard == mSymbolsShiftedKeyboard) {
             mSymbolsShiftedKeyboard.setShifted(false);
-            mInputView.setKeyboard(mSymbolsKeyboard);
+            setLatinKeyboard(mSymbolsKeyboard);
             mSymbolsKeyboard.setShifted(false);
         }
     }
@@ -629,6 +639,22 @@ public class SoftKeyboard extends InputMethodService
         mInputView.closing();
     }
 
+    private IBinder getToken() {
+        final Dialog dialog = getWindow();
+        if (dialog == null) {
+            return null;
+        }
+        final Window window = dialog.getWindow();
+        if (window == null) {
+            return null;
+        }
+        return window.getAttributes().token;
+    }
+
+    private void handleLanguageSwitch() {
+        mInputMethodManager.switchToNextInputMethod(getToken(), false /* onlyCurrentIme */);
+    }
+
     private void checkToggleCapsLock() {
         long now = System.currentTimeMillis();
         if (mLastShiftTime + 800 > now) {