Android example source code file (SoftKeyboard.java)

This example Android source code file (SoftKeyboard.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, arraylist, candidateview, completioninfo, debug, input, inputconnection, inputmethod, inputmethodservice, keyboardview, keyevent, latinkeyboard, override, process_hard_keys, softkeyboard, string, stringbuilder, ui, util, view

The SoftKeyboard.java Android example source code

/*
 * Copyright (C) 2008-2009 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.example.android.softkeyboard;

import android.inputmethodservice.InputMethodService;
import android.inputmethodservice.Keyboard;
import android.inputmethodservice.KeyboardView;
import android.text.method.MetaKeyKeyListener;
import android.util.Log;
import android.view.KeyCharacterMap;
import android.view.KeyEvent;
import android.view.View;
import android.view.inputmethod.CompletionInfo;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.view.inputmethod.InputMethodManager;

import java.util.ArrayList;
import java.util.List;

/**
 * Example of writing an input method for a soft keyboard.  This code is
 * focused on simplicity over completeness, so it should in no way be considered
 * to be a complete soft keyboard implementation.  Its purpose is to provide
 * a basic example for how you would get started writing an input method, to
 * be fleshed out as appropriate.
 */
public class SoftKeyboard extends InputMethodService 
        implements KeyboardView.OnKeyboardActionListener {
    static final boolean DEBUG = false;
    
    /**
     * This boolean indicates the optional example code for performing
     * processing of hard keys in addition to regular text generation
     * from on-screen interaction.  It would be used for input methods that
     * perform language translations (such as converting text entered on 
     * a QWERTY keyboard to Chinese), but may not be used for input methods
     * that are primarily intended to be used for on-screen text entry.
     */
    static final boolean PROCESS_HARD_KEYS = true;
    
    private KeyboardView mInputView;
    private CandidateView mCandidateView;
    private CompletionInfo[] mCompletions;
    
    private StringBuilder mComposing = new StringBuilder();
    private boolean mPredictionOn;
    private boolean mCompletionOn;
    private int mLastDisplayWidth;
    private boolean mCapsLock;
    private long mLastShiftTime;
    private long mMetaState;
    
    private LatinKeyboard mSymbolsKeyboard;
    private LatinKeyboard mSymbolsShiftedKeyboard;
    private LatinKeyboard mQwertyKeyboard;
    
    private LatinKeyboard mCurKeyboard;
    
    private String mWordSeparators;
    
    /**
     * Main initialization of the input method component.  Be sure to call
     * to super class.
     */
    @Override public void onCreate() {
        super.onCreate();
        mWordSeparators = getResources().getString(R.string.word_separators);
    }
    
    /**
     * This is the point where you can do all of your UI initialization.  It
     * is called after creation and any configuration change.
     */
    @Override public void onInitializeInterface() {
        if (mQwertyKeyboard != null) {
            // Configuration changes can happen after the keyboard gets recreated,
            // so we need to be able to re-build the keyboards if the available
            // space has changed.
            int displayWidth = getMaxWidth();
            if (displayWidth == mLastDisplayWidth) return;
            mLastDisplayWidth = displayWidth;
        }
        mQwertyKeyboard = new LatinKeyboard(this, R.xml.qwerty);
        mSymbolsKeyboard = new LatinKeyboard(this, R.xml.symbols);
        mSymbolsShiftedKeyboard = new LatinKeyboard(this, R.xml.symbols_shift);
    }
    
    /**
     * Called by the framework when your view for creating input needs to
     * be generated.  This will be called the first time your input method
     * is displayed, and every time it needs to be re-created such as due to
     * a configuration change.
     */
    @Override public View onCreateInputView() {
        mInputView = (KeyboardView) getLayoutInflater().inflate(
                R.layout.input, null);
        mInputView.setOnKeyboardActionListener(this);
        mInputView.setKeyboard(mQwertyKeyboard);
        return mInputView;
    }

    /**
     * Called by the framework when your view for showing candidates needs to
     * be generated, like {@link #onCreateInputView}.
     */
    @Override public View onCreateCandidatesView() {
        mCandidateView = new CandidateView(this);
        mCandidateView.setService(this);
        return mCandidateView;
    }

    /**
     * This is the main point where we do our initialization of the input method
     * to begin operating on an application.  At this point we have been
     * bound to the client, and are now receiving all of the detailed information
     * about the target of our edits.
     */
    @Override public void onStartInput(EditorInfo attribute, boolean restarting) {
        super.onStartInput(attribute, restarting);
        
        // Reset our state.  We want to do this even if restarting, because
        // the underlying state of the text editor could have changed in any way.
        mComposing.setLength(0);
        updateCandidates();
        
        if (!restarting) {
            // Clear shift states.
            mMetaState = 0;
        }
        
        mPredictionOn = false;
        mCompletionOn = false;
        mCompletions = null;
        
        // We are now going to initialize our state based on the type of
        // text being edited.
        switch (attribute.inputType&EditorInfo.TYPE_MASK_CLASS) {
            case EditorInfo.TYPE_CLASS_NUMBER:
            case EditorInfo.TYPE_CLASS_DATETIME:
                // Numbers and dates default to the symbols keyboard, with
                // no extra features.
                mCurKeyboard = mSymbolsKeyboard;
                break;
                
            case EditorInfo.TYPE_CLASS_PHONE:
                // Phones will also default to the symbols keyboard, though
                // often you will want to have a dedicated phone keyboard.
                mCurKeyboard = mSymbolsKeyboard;
                break;
                
            case EditorInfo.TYPE_CLASS_TEXT:
                // This is general text editing.  We will default to the
                // normal alphabetic keyboard, and assume that we should
                // be doing predictive text (showing candidates as the
                // user types).
                mCurKeyboard = mQwertyKeyboard;
                mPredictionOn = true;
                
                // We now look for a few special variations of text that will
                // modify our behavior.
                int variation = attribute.inputType &  EditorInfo.TYPE_MASK_VARIATION;
                if (variation == EditorInfo.TYPE_TEXT_VARIATION_PASSWORD ||
                        variation == EditorInfo.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD) {
                    // Do not display predictions / what the user is typing
                    // when they are entering a password.
                    mPredictionOn = false;
                }
                
                if (variation == EditorInfo.TYPE_TEXT_VARIATION_EMAIL_ADDRESS 
                        || variation == EditorInfo.TYPE_TEXT_VARIATION_URI
                        || variation == EditorInfo.TYPE_TEXT_VARIATION_FILTER) {
                    // Our predictions are not useful for e-mail addresses
                    // or URIs.
                    mPredictionOn = false;
                }
                
                if ((attribute.inputType&EditorInfo.TYPE_TEXT_FLAG_AUTO_COMPLETE) != 0) {
                    // If this is an auto-complete text view, then our predictions
                    // will not be shown and instead we will allow the editor
                    // to supply their own.  We only show the editor's
                    // candidates when in fullscreen mode, otherwise relying
                    // own it displaying its own UI.
                    mPredictionOn = false;
                    mCompletionOn = isFullscreenMode();
                }
                
                // We also want to look at the current state of the editor
                // to decide whether our alphabetic keyboard should start out
                // shifted.
                updateShiftKeyState(attribute);
                break;
                
            default:
                // For all unknown input types, default to the alphabetic
                // keyboard with no special features.
                mCurKeyboard = mQwertyKeyboard;
                updateShiftKeyState(attribute);
        }
        
        // Update the label on the enter key, depending on what the application
        // says it will do.
        mCurKeyboard.setImeOptions(getResources(), attribute.imeOptions);
    }

    /**
     * This is called when the user is done editing a field.  We can use
     * this to reset our state.
     */
    @Override public void onFinishInput() {
        super.onFinishInput();
        
        // Clear current composing text and candidates.
        mComposing.setLength(0);
        updateCandidates();
        
        // We only hide the candidates window when finishing input on
        // a particular editor, to avoid popping the underlying application
        // up and down if the user is entering text into the bottom of
        // its window.
        setCandidatesViewShown(false);
        
        mCurKeyboard = mQwertyKeyboard;
        if (mInputView != null) {
            mInputView.closing();
        }
    }
    
    @Override public void onStartInputView(EditorInfo attribute, boolean restarting) {
        super.onStartInputView(attribute, restarting);
        // Apply the selected keyboard to the input view.
        mInputView.setKeyboard(mCurKeyboard);
        mInputView.closing();
    }
    
    /**
     * Deal with the editor reporting movement of its cursor.
     */
    @Override public void onUpdateSelection(int oldSelStart, int oldSelEnd,
            int newSelStart, int newSelEnd,
            int candidatesStart, int candidatesEnd) {
        super.onUpdateSelection(oldSelStart, oldSelEnd, newSelStart, newSelEnd,
                candidatesStart, candidatesEnd);
        
        // If the current selection in the text view changes, we should
        // clear whatever candidate text we have.
        if (mComposing.length() > 0 && (newSelStart != candidatesEnd
                || newSelEnd != candidatesEnd)) {
            mComposing.setLength(0);
            updateCandidates();
            InputConnection ic = getCurrentInputConnection();
            if (ic != null) {
                ic.finishComposingText();
            }
        }
    }

    /**
     * This tells us about completions that the editor has determined based
     * on the current text in it.  We want to use this in fullscreen mode
     * to show the completions ourself, since the editor can not be seen
     * in that situation.
     */
    @Override public void onDisplayCompletions(CompletionInfo[] completions) {
        if (mCompletionOn) {
            mCompletions = completions;
            if (completions == null) {
                setSuggestions(null, false, false);
                return;
            }
            
            List<String> stringList = new ArrayList();
            for (int i=0; i<(completions != null ? completions.length : 0); i++) {
                CompletionInfo ci = completions[i];
                if (ci != null) stringList.add(ci.getText().toString());
            }
            setSuggestions(stringList, true, true);
        }
    }
    
    /**
     * This translates incoming hard key events in to edit operations on an
     * InputConnection.  It is only needed when using the
     * PROCESS_HARD_KEYS option.
     */
    private boolean translateKeyDown(int keyCode, KeyEvent event) {
        mMetaState = MetaKeyKeyListener.handleKeyDown(mMetaState,
                keyCode, event);
        int c = event.getUnicodeChar(MetaKeyKeyListener.getMetaState(mMetaState));
        mMetaState = MetaKeyKeyListener.adjustMetaAfterKeypress(mMetaState);
        InputConnection ic = getCurrentInputConnection();
        if (c == 0 || ic == null) {
            return false;
        }
        
        boolean dead = false;

        if ((c & KeyCharacterMap.COMBINING_ACCENT) != 0) {
            dead = true;
            c = c & KeyCharacterMap.COMBINING_ACCENT_MASK;
        }
        
        if (mComposing.length() > 0) {
            char accent = mComposing.charAt(mComposing.length() -1 );
            int composed = KeyEvent.getDeadChar(accent, c);

            if (composed != 0) {
                c = composed;
                mComposing.setLength(mComposing.length()-1);
            }
        }
        
        onKey(c, null);
        
        return true;
    }
    
    /**
     * Use this to monitor key events being delivered to the application.
     * We get first crack at them, and can either resume them or let them
     * continue to the app.
     */
    @Override public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_BACK:
                // The InputMethodService already takes care of the back
                // key for us, to dismiss the input method if it is shown.
                // However, our keyboard could be showing a pop-up window
                // that back should dismiss, so we first allow it to do that.
                if (event.getRepeatCount() == 0 && mInputView != null) {
                    if (mInputView.handleBack()) {
                        return true;
                    }
                }
                break;
                
            case KeyEvent.KEYCODE_DEL:
                // Special handling of the delete key: if we currently are
                // composing text for the user, we want to modify that instead
                // of let the application to the delete itself.
                if (mComposing.length() > 0) {
                    onKey(Keyboard.KEYCODE_DELETE, null);
                    return true;
                }
                break;
                
            case KeyEvent.KEYCODE_ENTER:
                // Let the underlying text editor always handle these.
                return false;
                
            default:
                // For all other keys, if we want to do transformations on
                // text being entered with a hard keyboard, we need to process
                // it and do the appropriate action.
                if (PROCESS_HARD_KEYS) {
                    if (keyCode == KeyEvent.KEYCODE_SPACE
                            && (event.getMetaState()&KeyEvent.META_ALT_ON) != 0) {
                        // A silly example: in our input method, Alt+Space
                        // is a shortcut for 'android' in lower case.
                        InputConnection ic = getCurrentInputConnection();
                        if (ic != null) {
                            // First, tell the editor that it is no longer in the
                            // shift state, since we are consuming this.
                            ic.clearMetaKeyStates(KeyEvent.META_ALT_ON);
                            keyDownUp(KeyEvent.KEYCODE_A);
                            keyDownUp(KeyEvent.KEYCODE_N);
                            keyDownUp(KeyEvent.KEYCODE_D);
                            keyDownUp(KeyEvent.KEYCODE_R);
                            keyDownUp(KeyEvent.KEYCODE_O);
                            keyDownUp(KeyEvent.KEYCODE_I);
                            keyDownUp(KeyEvent.KEYCODE_D);
                            // And we consume this event.
                            return true;
                        }
                    }
                    if (mPredictionOn && translateKeyDown(keyCode, event)) {
                        return true;
                    }
                }
        }
        
        return super.onKeyDown(keyCode, event);
    }

    /**
     * Use this to monitor key events being delivered to the application.
     * We get first crack at them, and can either resume them or let them
     * continue to the app.
     */
    @Override public boolean onKeyUp(int keyCode, KeyEvent event) {
        // If we want to do transformations on text being entered with a hard
        // keyboard, we need to process the up events to update the meta key
        // state we are tracking.
        if (PROCESS_HARD_KEYS) {
            if (mPredictionOn) {
                mMetaState = MetaKeyKeyListener.handleKeyUp(mMetaState,
                        keyCode, event);
            }
        }
        
        return super.onKeyUp(keyCode, event);
    }

    /**
     * Helper function to commit any text being composed in to the editor.
     */
    private void commitTyped(InputConnection inputConnection) {
        if (mComposing.length() > 0) {
            inputConnection.commitText(mComposing, mComposing.length());
            mComposing.setLength(0);
            updateCandidates();
        }
    }

    /**
     * Helper to update the shift state of our keyboard based on the initial
     * editor state.
     */
    private void updateShiftKeyState(EditorInfo attr) {
        if (attr != null 
                && mInputView != null && mQwertyKeyboard == mInputView.getKeyboard()) {
            int caps = 0;
            EditorInfo ei = getCurrentInputEditorInfo();
            if (ei != null && ei.inputType != EditorInfo.TYPE_NULL) {
                caps = getCurrentInputConnection().getCursorCapsMode(attr.inputType);
            }
            mInputView.setShifted(mCapsLock || caps != 0);
        }
    }
    
    /**
     * Helper to determine if a given character code is alphabetic.
     */
    private boolean isAlphabet(int code) {
        if (Character.isLetter(code)) {
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * Helper to send a key down / key up pair to the current editor.
     */
    private void keyDownUp(int keyEventCode) {
        getCurrentInputConnection().sendKeyEvent(
                new KeyEvent(KeyEvent.ACTION_DOWN, keyEventCode));
        getCurrentInputConnection().sendKeyEvent(
                new KeyEvent(KeyEvent.ACTION_UP, keyEventCode));
    }
    
    /**
     * Helper to send a character to the editor as raw key events.
     */
    private void sendKey(int keyCode) {
        switch (keyCode) {
            case '\n':
                keyDownUp(KeyEvent.KEYCODE_ENTER);
                break;
            default:
                if (keyCode >= '0' && keyCode <= '9') {
                    keyDownUp(keyCode - '0' + KeyEvent.KEYCODE_0);
                } else {
                    getCurrentInputConnection().commitText(String.valueOf((char) keyCode), 1);
                }
                break;
        }
    }

    // Implementation of KeyboardViewListener

    public void onKey(int primaryCode, int[] keyCodes) {
        if (isWordSeparator(primaryCode)) {
            // Handle separator
            if (mComposing.length() > 0) {
                commitTyped(getCurrentInputConnection());
            }
            sendKey(primaryCode);
            updateShiftKeyState(getCurrentInputEditorInfo());
        } else if (primaryCode == Keyboard.KEYCODE_DELETE) {
            handleBackspace();
        } else if (primaryCode == Keyboard.KEYCODE_SHIFT) {
            handleShift();
        } else if (primaryCode == Keyboard.KEYCODE_CANCEL) {
            handleClose();
            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;
            } else {
                current = mSymbolsKeyboard;
            }
            mInputView.setKeyboard(current);
            if (current == mSymbolsKeyboard) {
                current.setShifted(false);
            }
        } else {
            handleCharacter(primaryCode, keyCodes);
        }
    }

    public void onText(CharSequence text) {
        InputConnection ic = getCurrentInputConnection();
        if (ic == null) return;
        ic.beginBatchEdit();
        if (mComposing.length() > 0) {
            commitTyped(ic);
        }
        ic.commitText(text, 0);
        ic.endBatchEdit();
        updateShiftKeyState(getCurrentInputEditorInfo());
    }

    /**
     * Update the list of available candidates from the current composing
     * text.  This will need to be filled in by however you are determining
     * candidates.
     */
    private void updateCandidates() {
        if (!mCompletionOn) {
            if (mComposing.length() > 0) {
                ArrayList<String> list = new ArrayList();
                list.add(mComposing.toString());
                setSuggestions(list, true, true);
            } else {
                setSuggestions(null, false, false);
            }
        }
    }
    
    public void setSuggestions(List<String> suggestions, boolean completions,
            boolean typedWordValid) {
        if (suggestions != null && suggestions.size() > 0) {
            setCandidatesViewShown(true);
        } else if (isExtractViewShown()) {
            setCandidatesViewShown(true);
        }
        if (mCandidateView != null) {
            mCandidateView.setSuggestions(suggestions, completions, typedWordValid);
        }
    }
    
    private void handleBackspace() {
        final int length = mComposing.length();
        if (length > 1) {
            mComposing.delete(length - 1, length);
            getCurrentInputConnection().setComposingText(mComposing, 1);
            updateCandidates();
        } else if (length > 0) {
            mComposing.setLength(0);
            getCurrentInputConnection().commitText("", 0);
            updateCandidates();
        } else {
            keyDownUp(KeyEvent.KEYCODE_DEL);
        }
        updateShiftKeyState(getCurrentInputEditorInfo());
    }

    private void handleShift() {
        if (mInputView == null) {
            return;
        }
        
        Keyboard currentKeyboard = mInputView.getKeyboard();
        if (mQwertyKeyboard == currentKeyboard) {
            // Alphabet keyboard
            checkToggleCapsLock();
            mInputView.setShifted(mCapsLock || !mInputView.isShifted());
        } else if (currentKeyboard == mSymbolsKeyboard) {
            mSymbolsKeyboard.setShifted(true);
            mInputView.setKeyboard(mSymbolsShiftedKeyboard);
            mSymbolsShiftedKeyboard.setShifted(true);
        } else if (currentKeyboard == mSymbolsShiftedKeyboard) {
            mSymbolsShiftedKeyboard.setShifted(false);
            mInputView.setKeyboard(mSymbolsKeyboard);
            mSymbolsKeyboard.setShifted(false);
        }
    }
    
    private void handleCharacter(int primaryCode, int[] keyCodes) {
        if (isInputViewShown()) {
            if (mInputView.isShifted()) {
                primaryCode = Character.toUpperCase(primaryCode);
            }
        }
        if (isAlphabet(primaryCode) && mPredictionOn) {
            mComposing.append((char) primaryCode);
            getCurrentInputConnection().setComposingText(mComposing, 1);
            updateShiftKeyState(getCurrentInputEditorInfo());
            updateCandidates();
        } else {
            getCurrentInputConnection().commitText(
                    String.valueOf((char) primaryCode), 1);
        }
    }

    private void handleClose() {
        commitTyped(getCurrentInputConnection());
        requestHideSelf(0);
        mInputView.closing();
    }

    private void checkToggleCapsLock() {
        long now = System.currentTimeMillis();
        if (mLastShiftTime + 800 > now) {
            mCapsLock = !mCapsLock;
            mLastShiftTime = 0;
        } else {
            mLastShiftTime = now;
        }
    }
    
    private String getWordSeparators() {
        return mWordSeparators;
    }
    
    public boolean isWordSeparator(int code) {
        String separators = getWordSeparators();
        return separators.contains(String.valueOf((char)code));
    }

    public void pickDefaultCandidate() {
        pickSuggestionManually(0);
    }
    
    public void pickSuggestionManually(int index) {
        if (mCompletionOn && mCompletions != null && index >= 0
                && index < mCompletions.length) {
            CompletionInfo ci = mCompletions[index];
            getCurrentInputConnection().commitCompletion(ci);
            if (mCandidateView != null) {
                mCandidateView.clear();
            }
            updateShiftKeyState(getCurrentInputEditorInfo());
        } else if (mComposing.length() > 0) {
            // If we were generating candidate suggestions for the current
            // text, we would commit one of them here.  But for this sample,
            // we will just commit the current text.
            commitTyped(getCurrentInputConnection());
        }
    }
    
    public void swipeRight() {
        if (mCompletionOn) {
            pickDefaultCandidate();
        }
    }
    
    public void swipeLeft() {
        handleBackspace();
    }

    public void swipeDown() {
        handleClose();
    }

    public void swipeUp() {
    }
    
    public void onPress(int primaryCode) {
    }
    
    public void onRelease(int primaryCode) {
    }
}