Android example source code file (BaseInputConnection.java)

This example Android source code file (BaseInputConnection.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, baseinputconnection, charsequence, composing, composingtext, content, debug, editable, get_text_with_styles, keyevent, logprinter, object, os, spannable, spannablestringbuilder, spanned, tag, text, ui, view

The BaseInputConnection.java Android example source code

/*
 * Copyright (C) 2008 The Android Open Source Project
 * 
 * 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 android.view.inputmethod;

import android.content.Context;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;
import android.text.Editable;
import android.text.NoCopySpan;
import android.text.Selection;
import android.text.Spannable;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.TextUtils;
import android.text.method.MetaKeyKeyListener;
import android.util.Log;
import android.util.LogPrinter;
import android.view.KeyCharacterMap;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewRoot;

class ComposingText implements NoCopySpan {
}

/**
 * Base class for implementors of the InputConnection interface, taking care
 * of most of the common behavior for providing a connection to an Editable.
 * Implementors of this class will want to be sure to implement
 * {@link #getEditable} to provide access to their own editable object.
 */
public class BaseInputConnection implements InputConnection {
    private static final boolean DEBUG = false;
    private static final String TAG = "BaseInputConnection";
    static final Object COMPOSING = new ComposingText();
    
    final InputMethodManager mIMM;
    final View mTargetView;
    final boolean mDummyMode;
    
    private Object[] mDefaultComposingSpans;
    
    Editable mEditable;
    KeyCharacterMap mKeyCharacterMap;
    
    BaseInputConnection(InputMethodManager mgr, boolean fullEditor) {
        mIMM = mgr;
        mTargetView = null;
        mDummyMode = !fullEditor;
    }
    
    public BaseInputConnection(View targetView, boolean fullEditor) {
        mIMM = (InputMethodManager)targetView.getContext().getSystemService(
                Context.INPUT_METHOD_SERVICE);
        mTargetView = targetView;
        mDummyMode = !fullEditor;
    }
    
    public static final void removeComposingSpans(Spannable text) {
        text.removeSpan(COMPOSING);
        Object[] sps = text.getSpans(0, text.length(), Object.class);
        if (sps != null) {
            for (int i=sps.length-1; i>=0; i--) {
                Object o = sps[i];
                if ((text.getSpanFlags(o)&Spanned.SPAN_COMPOSING) != 0) {
                    text.removeSpan(o);
                }
            }
        }
    }
    
    public static void setComposingSpans(Spannable text) {
        final Object[] sps = text.getSpans(0, text.length(), Object.class);
        if (sps != null) {
            for (int i=sps.length-1; i>=0; i--) {
                final Object o = sps[i];
                if (o == COMPOSING) {
                    text.removeSpan(o);
                    continue;
                }
                final int fl = text.getSpanFlags(o);
                if ((fl&(Spanned.SPAN_COMPOSING|Spanned.SPAN_POINT_MARK_MASK)) 
                        != (Spanned.SPAN_COMPOSING|Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)) {
                    text.setSpan(o, text.getSpanStart(o), text.getSpanEnd(o),
                            (fl&Spanned.SPAN_POINT_MARK_MASK)
                                    | Spanned.SPAN_COMPOSING
                                    | Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
                }
            }
        }
        
        text.setSpan(COMPOSING, 0, text.length(),
                Spanned.SPAN_EXCLUSIVE_EXCLUSIVE | Spanned.SPAN_COMPOSING);
    }
    
    public static int getComposingSpanStart(Spannable text) {
        return text.getSpanStart(COMPOSING);
    }
    
    public static int getComposingSpanEnd(Spannable text) {
        return text.getSpanEnd(COMPOSING);
    }
    
    /**
     * Return the target of edit operations.  The default implementation
     * returns its own fake editable that is just used for composing text;
     * subclasses that are real text editors should override this and
     * supply their own.
     */
    public Editable getEditable() {
        if (mEditable == null) {
            mEditable = Editable.Factory.getInstance().newEditable("");
            Selection.setSelection(mEditable, 0);
        }
        return mEditable;
    }
    
    /**
     * Default implementation does nothing.
     */
    public boolean beginBatchEdit() {
        return false;
    }

    /**
     * Default implementation does nothing.
     */
    public boolean endBatchEdit() {
        return false;
    }

    /**
     * Default implementation uses
     * {@link MetaKeyKeyListener#clearMetaKeyState(long, int)
     * MetaKeyKeyListener.clearMetaKeyState(long, int)} to clear the state.
     */
    public boolean clearMetaKeyStates(int states) {
        final Editable content = getEditable();
        if (content == null) return false;
        MetaKeyKeyListener.clearMetaKeyState(content, states);
        return true;
    }

    /**
     * Default implementation does nothing.
     */
    public boolean commitCompletion(CompletionInfo text) {
        return false;
    }

    /**
     * Default implementation replaces any existing composing text with
     * the given text.  In addition, only if dummy mode, a key event is
     * sent for the new text and the current editable buffer cleared.
     */
    public boolean commitText(CharSequence text, int newCursorPosition) {
        if (DEBUG) Log.v(TAG, "commitText " + text);
        replaceText(text, newCursorPosition, false);
        sendCurrentText();
        return true;
    }

    /**
     * The default implementation performs the deletion around the current
     * selection position of the editable text.
     */
    public boolean deleteSurroundingText(int leftLength, int rightLength) {
        if (DEBUG) Log.v(TAG, "deleteSurroundingText " + leftLength
                + " / " + rightLength);
        final Editable content = getEditable();
        if (content == null) return false;

        beginBatchEdit();
        
        int a = Selection.getSelectionStart(content);
        int b = Selection.getSelectionEnd(content);

        if (a > b) {
            int tmp = a;
            a = b;
            b = tmp;
        }

        // ignore the composing text.
        int ca = getComposingSpanStart(content);
        int cb = getComposingSpanEnd(content);
        if (cb < ca) {
            int tmp = ca;
            ca = cb;
            cb = tmp;
        }
        if (ca != -1 && cb != -1) {
            if (ca < a) a = ca;
            if (cb > b) b = cb;
        }

        int deleted = 0;

        if (leftLength > 0) {
            int start = a - leftLength;
            if (start < 0) start = 0;
            content.delete(start, a);
            deleted = a - start;
        }

        if (rightLength > 0) {
            b = b - deleted;

            int end = b + rightLength;
            if (end > content.length()) end = content.length();

            content.delete(b, end);
        }
        
        endBatchEdit();
        
        return true;
    }

    /**
     * The default implementation removes the composing state from the
     * current editable text.  In addition, only if dummy mode, a key event is
     * sent for the new text and the current editable buffer cleared.
     */
    public boolean finishComposingText() {
        if (DEBUG) Log.v(TAG, "finishComposingText");
        final Editable content = getEditable();
        if (content != null) {
            beginBatchEdit();
            removeComposingSpans(content);
            endBatchEdit();
            sendCurrentText();
        }
        return true;
    }

    /**
     * The default implementation uses TextUtils.getCapsMode to get the
     * cursor caps mode for the current selection position in the editable
     * text, unless in dummy mode in which case 0 is always returned.
     */
    public int getCursorCapsMode(int reqModes) {
        if (mDummyMode) return 0;
        
        final Editable content = getEditable();
        if (content == null) return 0;
        
        int a = Selection.getSelectionStart(content);
        int b = Selection.getSelectionEnd(content);

        if (a > b) {
            int tmp = a;
            a = b;
            b = tmp;
        }

        return TextUtils.getCapsMode(content, a, reqModes);
    }

    /**
     * The default implementation always returns null.
     */
    public ExtractedText getExtractedText(ExtractedTextRequest request, int flags) {
        return null;
    }

    /**
     * The default implementation returns the given amount of text from the
     * current cursor position in the buffer.
     */
    public CharSequence getTextBeforeCursor(int length, int flags) {
        final Editable content = getEditable();
        if (content == null) return null;

        int a = Selection.getSelectionStart(content);
        int b = Selection.getSelectionEnd(content);

        if (a > b) {
            int tmp = a;
            a = b;
            b = tmp;
        }

        if (a <= 0) {
            return "";
        }
        
        if (length > a) {
            length = a;
        }

        if ((flags&GET_TEXT_WITH_STYLES) != 0) {
            return content.subSequence(a - length, a);
        }
        return TextUtils.substring(content, a - length, a);
    }

    /**
     * The default implementation returns the given amount of text from the
     * current cursor position in the buffer.
     */
    public CharSequence getTextAfterCursor(int length, int flags) {
        final Editable content = getEditable();
        if (content == null) return null;

        int a = Selection.getSelectionStart(content);
        int b = Selection.getSelectionEnd(content);

        if (a > b) {
            int tmp = a;
            a = b;
            b = tmp;
        }

        // Guard against the case where the cursor has not been positioned yet.
        if (b < 0) {
            b = 0;
        }

        if (b + length > content.length()) {
            length = content.length() - b;
        }


        if ((flags&GET_TEXT_WITH_STYLES) != 0) {
            return content.subSequence(b, b + length);
        }
        return TextUtils.substring(content, b, b + length);
    }

    /**
     * The default implementation turns this into the enter key.
     */
    public boolean performEditorAction(int actionCode) {
        long eventTime = SystemClock.uptimeMillis();
        sendKeyEvent(new KeyEvent(eventTime, eventTime,
                KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_ENTER, 0, 0, 0, 0,
                KeyEvent.FLAG_SOFT_KEYBOARD | KeyEvent.FLAG_KEEP_TOUCH_MODE
                | KeyEvent.FLAG_EDITOR_ACTION));
        sendKeyEvent(new KeyEvent(SystemClock.uptimeMillis(), eventTime,
                KeyEvent.ACTION_UP, KeyEvent.KEYCODE_ENTER, 0, 0, 0, 0,
                KeyEvent.FLAG_SOFT_KEYBOARD | KeyEvent.FLAG_KEEP_TOUCH_MODE
                | KeyEvent.FLAG_EDITOR_ACTION));
        return true;
    }

    /**
     * The default implementation does nothing.
     */
    public boolean performContextMenuAction(int id) {
        return false;
    }

    /**
     * The default implementation does nothing.
     */
    public boolean performPrivateCommand(String action, Bundle data) {
        return false;
    }

    /**
     * The default implementation places the given text into the editable,
     * replacing any existing composing text.  The new text is marked as
     * in a composing state with the composing style.
     */
    public boolean setComposingText(CharSequence text, int newCursorPosition) {
        if (DEBUG) Log.v(TAG, "setComposingText " + text);
        replaceText(text, newCursorPosition, true);
        return true;
    }

    /**
     * The default implementation changes the selection position in the
     * current editable text.
     */
    public boolean setSelection(int start, int end) {
        if (DEBUG) Log.v(TAG, "setSelection " + start + ", " + end);
        final Editable content = getEditable();
        if (content == null) return false;
        int len = content.length();
        if (start > len || end > len) {
            // If the given selection is out of bounds, just ignore it.
            // Most likely the text was changed out from under the IME,
            // the the IME is going to have to update all of its state
            // anyway.
            return true;
        }
        if (start == end && MetaKeyKeyListener.getMetaState(content,
                MetaKeyKeyListener.META_SELECTING) != 0) {
            // If we are in selection mode, then we want to extend the
            // selection instead of replacing it.
            Selection.extendSelection(content, start);
        } else {
            Selection.setSelection(content, start, end);
        }
        return true;
    }

    /**
     * Provides standard implementation for sending a key event to the window
     * attached to the input connection's view.
     */
    public boolean sendKeyEvent(KeyEvent event) {
        synchronized (mIMM.mH) {
            Handler h = mTargetView != null ? mTargetView.getHandler() : null;
            if (h == null) {
                if (mIMM.mServedView != null) {
                    h = mIMM.mServedView.getHandler();
                }
            }
            if (h != null) {
                h.sendMessage(h.obtainMessage(ViewRoot.DISPATCH_KEY_FROM_IME,
                        event));
            }
        }
        return false;
    }
    
    /**
     * Updates InputMethodManager with the current fullscreen mode.
     */
    public boolean reportFullscreenMode(boolean enabled) {
        mIMM.setFullscreenMode(enabled);
        return true;
    }
    
    private void sendCurrentText() {
        if (!mDummyMode) {
            return;
        }
        
        Editable content = getEditable();
        if (content != null) {
            final int N = content.length();
            if (N == 0) {
                return;
            }
            if (N == 1) {
                // If it's 1 character, we have a chance of being
                // able to generate normal key events...
                if (mKeyCharacterMap == null) {
                    mKeyCharacterMap = KeyCharacterMap.load(
                            KeyCharacterMap.BUILT_IN_KEYBOARD);
                }
                char[] chars = new char[1];
                content.getChars(0, 1, chars, 0);
                KeyEvent[] events = mKeyCharacterMap.getEvents(chars);
                if (events != null) {
                    for (int i=0; i<events.length; i++) {
                        if (DEBUG) Log.v(TAG, "Sending: " + events[i]);
                        sendKeyEvent(events[i]);
                    }
                    content.clear();
                    return;
                }
            }
            
            // Otherwise, revert to the special key event containing
            // the actual characters.
            KeyEvent event = new KeyEvent(SystemClock.uptimeMillis(),
                    content.toString(), KeyCharacterMap.BUILT_IN_KEYBOARD, 0);
            sendKeyEvent(event);
            content.clear();
        }
    }
    
    private void replaceText(CharSequence text, int newCursorPosition,
            boolean composing) {
        final Editable content = getEditable();
        if (content == null) {
            return;
        }
        
        beginBatchEdit();
        
        // delete composing text set previously.
        int a = getComposingSpanStart(content);
        int b = getComposingSpanEnd(content);

        if (DEBUG) Log.v(TAG, "Composing span: " + a + " to " + b);
        
        if (b < a) {
            int tmp = a;
            a = b;
            b = tmp;
        }

        if (a != -1 && b != -1) {
            removeComposingSpans(content);
        } else {
            a = Selection.getSelectionStart(content);
            b = Selection.getSelectionEnd(content);
            if (a < 0) a = 0;
            if (b < 0) b = 0;
            if (b < a) {
                int tmp = a;
                a = b;
                b = tmp;
            }
        }

        if (composing) {
            Spannable sp = null;
            if (!(text instanceof Spannable)) {
                sp = new SpannableStringBuilder(text);
                text = sp;
                if (mDefaultComposingSpans == null) {
                    Context context;
                    if (mTargetView != null) {
                        context = mTargetView.getContext();
                    } else if (mIMM.mServedView != null) {
                        context = mIMM.mServedView.getContext();
                    } else {
                        context = null;
                    }
                    if (context != null) {
                        TypedArray ta = context.getTheme()
                                .obtainStyledAttributes(new int[] {
                                        com.android.internal.R.attr.candidatesTextStyleSpans
                                });
                        CharSequence style = ta.getText(0);
                        ta.recycle();
                        if (style != null && style instanceof Spanned) {
                            mDefaultComposingSpans = ((Spanned)style).getSpans(
                                    0, style.length(), Object.class);
                        }
                    }
                }
                if (mDefaultComposingSpans != null) {
                    for (int i = 0; i < mDefaultComposingSpans.length; ++i) {
                        sp.setSpan(mDefaultComposingSpans[i], 0, sp.length(),
                                Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
                    }
                }
            } else {
                sp = (Spannable)text;
            }
            setComposingSpans(sp);
        }
        
        if (DEBUG) Log.v(TAG, "Replacing from " + a + " to " + b + " with \""
                + text + "\", composing=" + composing
                + ", type=" + text.getClass().getCanonicalName());
        
        if (DEBUG) {
            LogPrinter lp = new LogPrinter(Log.VERBOSE, TAG);
            lp.println("Current text:");
            TextUtils.dumpSpans(content, lp, "  ");
            lp.println("Composing text:");
            TextUtils.dumpSpans(text, lp, "  ");
        }
        
        // Position the cursor appropriately, so that after replacing the
        // desired range of text it will be located in the correct spot.
        // This allows us to deal with filters performing edits on the text
        // we are providing here.
        if (newCursorPosition > 0) {
            newCursorPosition += b - 1;
        } else {
            newCursorPosition += a;
        }
        if (newCursorPosition < 0) newCursorPosition = 0;
        if (newCursorPosition > content.length())
            newCursorPosition = content.length();
        Selection.setSelection(content, newCursorPosition);

        content.replace(a, b, text);
        
        if (DEBUG) {
            LogPrinter lp = new LogPrinter(Log.VERBOSE, TAG);
            lp.println("Final text:");
            TextUtils.dumpSpans(content, lp, "  ");
        }
        
        endBatchEdit();
    }
}