ArrowKeyMovementMethod.java revision e193fd14346e6e808c6c266d2bb13c0c0cc6890e
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.text.method; 18 19import android.graphics.Rect; 20import android.text.Layout; 21import android.text.Selection; 22import android.text.Spannable; 23import android.view.KeyEvent; 24import android.view.MotionEvent; 25import android.view.View; 26import android.widget.TextView; 27 28/** 29 * A movement method that provides cursor movement and selection. 30 * Supports displaying the context menu on DPad Center. 31 */ 32public class ArrowKeyMovementMethod extends BaseMovementMethod implements MovementMethod { 33 private static boolean isSelecting(Spannable buffer) { 34 return ((MetaKeyKeyListener.getMetaState(buffer, MetaKeyKeyListener.META_SHIFT_ON) == 1) || 35 (MetaKeyKeyListener.getMetaState(buffer, MetaKeyKeyListener.META_SELECTING) != 0)); 36 } 37 38 private int getCurrentLineTop(Spannable buffer, Layout layout) { 39 return layout.getLineTop(layout.getLineForOffset(Selection.getSelectionEnd(buffer))); 40 } 41 42 private int getPageHeight(TextView widget) { 43 // This calculation does not take into account the view transformations that 44 // may have been applied to the child or its containers. In case of scaling or 45 // rotation, the calculated page height may be incorrect. 46 final Rect rect = new Rect(); 47 return widget.getGlobalVisibleRect(rect) ? rect.height() : 0; 48 } 49 50 @Override 51 protected boolean handleMovementKey(TextView widget, Spannable buffer, int keyCode, 52 int movementMetaState, KeyEvent event) { 53 switch (keyCode) { 54 case KeyEvent.KEYCODE_DPAD_CENTER: 55 if (KeyEvent.metaStateHasNoModifiers(movementMetaState)) { 56 if (event.getAction() == KeyEvent.ACTION_DOWN 57 && event.getRepeatCount() == 0 58 && MetaKeyKeyListener.getMetaState(buffer, 59 MetaKeyKeyListener.META_SELECTING) != 0) { 60 return widget.showContextMenu(); 61 } 62 } 63 break; 64 } 65 return super.handleMovementKey(widget, buffer, keyCode, movementMetaState, event); 66 } 67 68 @Override 69 protected boolean left(TextView widget, Spannable buffer) { 70 final Layout layout = widget.getLayout(); 71 if (isSelecting(buffer)) { 72 return Selection.extendLeft(buffer, layout); 73 } else { 74 return Selection.moveLeft(buffer, layout); 75 } 76 } 77 78 @Override 79 protected boolean right(TextView widget, Spannable buffer) { 80 final Layout layout = widget.getLayout(); 81 if (isSelecting(buffer)) { 82 return Selection.extendRight(buffer, layout); 83 } else { 84 return Selection.moveRight(buffer, layout); 85 } 86 } 87 88 @Override 89 protected boolean up(TextView widget, Spannable buffer) { 90 final Layout layout = widget.getLayout(); 91 if (isSelecting(buffer)) { 92 return Selection.extendUp(buffer, layout); 93 } else { 94 return Selection.moveUp(buffer, layout); 95 } 96 } 97 98 @Override 99 protected boolean down(TextView widget, Spannable buffer) { 100 final Layout layout = widget.getLayout(); 101 if (isSelecting(buffer)) { 102 return Selection.extendDown(buffer, layout); 103 } else { 104 return Selection.moveDown(buffer, layout); 105 } 106 } 107 108 @Override 109 protected boolean pageUp(TextView widget, Spannable buffer) { 110 final Layout layout = widget.getLayout(); 111 final boolean selecting = isSelecting(buffer); 112 final int targetY = getCurrentLineTop(buffer, layout) - getPageHeight(widget); 113 boolean handled = false; 114 for (;;) { 115 final int previousSelectionEnd = Selection.getSelectionEnd(buffer); 116 if (selecting) { 117 Selection.extendUp(buffer, layout); 118 } else { 119 Selection.moveUp(buffer, layout); 120 } 121 if (Selection.getSelectionEnd(buffer) == previousSelectionEnd) { 122 break; 123 } 124 handled = true; 125 if (getCurrentLineTop(buffer, layout) <= targetY) { 126 break; 127 } 128 } 129 return handled; 130 } 131 132 @Override 133 protected boolean pageDown(TextView widget, Spannable buffer) { 134 final Layout layout = widget.getLayout(); 135 final boolean selecting = isSelecting(buffer); 136 final int targetY = getCurrentLineTop(buffer, layout) + getPageHeight(widget); 137 boolean handled = false; 138 for (;;) { 139 final int previousSelectionEnd = Selection.getSelectionEnd(buffer); 140 if (selecting) { 141 Selection.extendDown(buffer, layout); 142 } else { 143 Selection.moveDown(buffer, layout); 144 } 145 if (Selection.getSelectionEnd(buffer) == previousSelectionEnd) { 146 break; 147 } 148 handled = true; 149 if (getCurrentLineTop(buffer, layout) >= targetY) { 150 break; 151 } 152 } 153 return handled; 154 } 155 156 @Override 157 protected boolean top(TextView widget, Spannable buffer) { 158 if (isSelecting(buffer)) { 159 Selection.extendSelection(buffer, 0); 160 } else { 161 Selection.setSelection(buffer, 0); 162 } 163 return true; 164 } 165 166 @Override 167 protected boolean bottom(TextView widget, Spannable buffer) { 168 if (isSelecting(buffer)) { 169 Selection.extendSelection(buffer, buffer.length()); 170 } else { 171 Selection.setSelection(buffer, buffer.length()); 172 } 173 return true; 174 } 175 176 @Override 177 protected boolean lineStart(TextView widget, Spannable buffer) { 178 final Layout layout = widget.getLayout(); 179 if (isSelecting(buffer)) { 180 return Selection.extendToLeftEdge(buffer, layout); 181 } else { 182 return Selection.moveToLeftEdge(buffer, layout); 183 } 184 } 185 186 @Override 187 protected boolean lineEnd(TextView widget, Spannable buffer) { 188 final Layout layout = widget.getLayout(); 189 if (isSelecting(buffer)) { 190 return Selection.extendToRightEdge(buffer, layout); 191 } else { 192 return Selection.moveToRightEdge(buffer, layout); 193 } 194 } 195 196 /** {@hide} */ 197 @Override 198 protected boolean leftWord(TextView widget, Spannable buffer) { 199 mWordIterator.setCharSequence(buffer); 200 return Selection.moveToPreceding(buffer, mWordIterator, isSelecting(buffer)); 201 } 202 203 /** {@hide} */ 204 @Override 205 protected boolean rightWord(TextView widget, Spannable buffer) { 206 mWordIterator.setCharSequence(buffer); 207 return Selection.moveToFollowing(buffer, mWordIterator, isSelecting(buffer)); 208 } 209 210 @Override 211 protected boolean home(TextView widget, Spannable buffer) { 212 return lineStart(widget, buffer); 213 } 214 215 @Override 216 protected boolean end(TextView widget, Spannable buffer) { 217 return lineEnd(widget, buffer); 218 } 219 220 @Override 221 public boolean onTouchEvent(TextView widget, Spannable buffer, MotionEvent event) { 222 int initialScrollX = -1; 223 int initialScrollY = -1; 224 final int action = event.getAction(); 225 226 if (action == MotionEvent.ACTION_UP) { 227 initialScrollX = Touch.getInitialScrollX(widget, buffer); 228 initialScrollY = Touch.getInitialScrollY(widget, buffer); 229 } 230 231 boolean handled = Touch.onTouchEvent(widget, buffer, event); 232 233 if (widget.isFocused() && !widget.didTouchFocusSelect()) { 234 if (action == MotionEvent.ACTION_DOWN) { 235 boolean cap = isSelecting(buffer); 236 if (cap) { 237 int offset = widget.getOffset((int) event.getX(), (int) event.getY()); 238 239 buffer.setSpan(LAST_TAP_DOWN, offset, offset, Spannable.SPAN_POINT_POINT); 240 241 // Disallow intercepting of the touch events, so that 242 // users can scroll and select at the same time. 243 // without this, users would get booted out of select 244 // mode once the view detected it needed to scroll. 245 widget.getParent().requestDisallowInterceptTouchEvent(true); 246 } 247 } else if (action == MotionEvent.ACTION_MOVE) { 248 boolean cap = isSelecting(buffer); 249 250 if (cap && handled) { 251 // Before selecting, make sure we've moved out of the "slop". 252 // handled will be true, if we're in select mode AND we're 253 // OUT of the slop 254 255 // Turn long press off while we're selecting. User needs to 256 // re-tap on the selection to enable long press 257 widget.cancelLongPress(); 258 259 // Update selection as we're moving the selection area. 260 261 // Get the current touch position 262 int offset = widget.getOffset((int) event.getX(), (int) event.getY()); 263 264 Selection.extendSelection(buffer, offset); 265 return true; 266 } 267 } else if (action == MotionEvent.ACTION_UP) { 268 // If we have scrolled, then the up shouldn't move the cursor, 269 // but we do need to make sure the cursor is still visible at 270 // the current scroll offset to avoid the scroll jumping later 271 // to show it. 272 if ((initialScrollY >= 0 && initialScrollY != widget.getScrollY()) || 273 (initialScrollX >= 0 && initialScrollX != widget.getScrollX())) { 274 widget.moveCursorToVisibleOffset(); 275 return true; 276 } 277 278 int offset = widget.getOffset((int) event.getX(), (int) event.getY()); 279 if (isSelecting(buffer)) { 280 buffer.removeSpan(LAST_TAP_DOWN); 281 Selection.extendSelection(buffer, offset); 282 } else { 283 Selection.setSelection(buffer, offset); 284 } 285 286 MetaKeyKeyListener.adjustMetaAfterKeypress(buffer); 287 MetaKeyKeyListener.resetLockedMeta(buffer); 288 289 return true; 290 } 291 } 292 293 return handled; 294 } 295 296 @Override 297 public boolean canSelectArbitrarily() { 298 return true; 299 } 300 301 @Override 302 public void initialize(TextView widget, Spannable text) { 303 Selection.setSelection(text, 0); 304 } 305 306 @Override 307 public void onTakeFocus(TextView view, Spannable text, int dir) { 308 if ((dir & (View.FOCUS_FORWARD | View.FOCUS_DOWN)) != 0) { 309 if (view.getLayout() == null) { 310 // This shouldn't be null, but do something sensible if it is. 311 Selection.setSelection(text, text.length()); 312 } 313 } else { 314 Selection.setSelection(text, text.length()); 315 } 316 } 317 318 public static MovementMethod getInstance() { 319 if (sInstance == null) { 320 sInstance = new ArrowKeyMovementMethod(); 321 } 322 323 return sInstance; 324 } 325 326 private WordIterator mWordIterator = new WordIterator(); 327 328 private static final Object LAST_TAP_DOWN = new Object(); 329 private static ArrowKeyMovementMethod sInstance; 330} 331