1 /* 2 * Copyright (C) 2007 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 17 package android.widget; 18 19 import android.content.Context; 20 import android.content.res.TypedArray; 21 import android.graphics.drawable.shapes.RectShape; 22 import android.graphics.drawable.shapes.Shape; 23 import android.util.AttributeSet; 24 25 import com.android.internal.R; 26 27 /** 28 * A RatingBar is an extension of SeekBar and ProgressBar that shows a rating in 29 * stars. The user can touch/drag or use arrow keys to set the rating when using 30 * the default size RatingBar. The smaller RatingBar style ( 31 * {@link android.R.attr#ratingBarStyleSmall}) and the larger indicator-only 32 * style ({@link android.R.attr#ratingBarStyleIndicator}) do not support user 33 * interaction and should only be used as indicators. 34 * <p> 35 * When using a RatingBar that supports user interaction, placing widgets to the 36 * left or right of the RatingBar is discouraged. 37 * <p> 38 * The number of stars set (via {@link #setNumStars(int)} or in an XML layout) 39 * will be shown when the layout width is set to wrap content (if another layout 40 * width is set, the results may be unpredictable). 41 * <p> 42 * The secondary progress should not be modified by the client as it is used 43 * internally as the background for a fractionally filled star. 44 * 45 * @attr ref android.R.styleable#RatingBar_numStars 46 * @attr ref android.R.styleable#RatingBar_rating 47 * @attr ref android.R.styleable#RatingBar_stepSize 48 * @attr ref android.R.styleable#RatingBar_isIndicator 49 */ 50 public class RatingBar extends AbsSeekBar { 51 52 /** 53 * A callback that notifies clients when the rating has been changed. This 54 * includes changes that were initiated by the user through a touch gesture 55 * or arrow key/trackball as well as changes that were initiated 56 * programmatically. 57 */ 58 public interface OnRatingBarChangeListener { 59 60 /** 61 * Notification that the rating has changed. Clients can use the 62 * fromUser parameter to distinguish user-initiated changes from those 63 * that occurred programmatically. This will not be called continuously 64 * while the user is dragging, only when the user finalizes a rating by 65 * lifting the touch. 66 * 67 * @param ratingBar The RatingBar whose rating has changed. 68 * @param rating The current rating. This will be in the range 69 * 0..numStars. 70 * @param fromUser True if the rating change was initiated by a user's 71 * touch gesture or arrow key/horizontal trackbell movement. 72 */ 73 void onRatingChanged(RatingBar ratingBar, float rating, boolean fromUser); 74 75 } 76 77 private int mNumStars = 5; 78 79 private int mProgressOnStartTracking; 80 81 private OnRatingBarChangeListener mOnRatingBarChangeListener; 82 83 public RatingBar(Context context, AttributeSet attrs, int defStyle) { 84 super(context, attrs, defStyle); 85 86 TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RatingBar, 87 defStyle, 0); 88 final int numStars = a.getInt(R.styleable.RatingBar_numStars, mNumStars); 89 setIsIndicator(a.getBoolean(R.styleable.RatingBar_isIndicator, !mIsUserSeekable)); 90 final float rating = a.getFloat(R.styleable.RatingBar_rating, -1); 91 final float stepSize = a.getFloat(R.styleable.RatingBar_stepSize, -1); 92 a.recycle(); 93 94 if (numStars > 0 && numStars != mNumStars) { 95 setNumStars(numStars); 96 } 97 98 if (stepSize >= 0) { 99 setStepSize(stepSize); 100 } else { 101 setStepSize(0.5f); 102 } 103 104 if (rating >= 0) { 105 setRating(rating); 106 } 107 108 // A touch inside a star fill up to that fractional area (slightly more 109 // than 1 so boundaries round up). 110 mTouchProgressOffset = 1.1f; 111 } 112 113 public RatingBar(Context context, AttributeSet attrs) { 114 this(context, attrs, com.android.internal.R.attr.ratingBarStyle); 115 } 116 117 public RatingBar(Context context) { 118 this(context, null); 119 } 120 121 /** 122 * Sets the listener to be called when the rating changes. 123 * 124 * @param listener The listener. 125 */ 126 public void setOnRatingBarChangeListener(OnRatingBarChangeListener listener) { 127 mOnRatingBarChangeListener = listener; 128 } 129 130 /** 131 * @return The listener (may be null) that is listening for rating change 132 * events. 133 */ 134 public OnRatingBarChangeListener getOnRatingBarChangeListener() { 135 return mOnRatingBarChangeListener; 136 } 137 138 /** 139 * Whether this rating bar should only be an indicator (thus non-changeable 140 * by the user). 141 * 142 * @param isIndicator Whether it should be an indicator. 143 */ 144 public void setIsIndicator(boolean isIndicator) { 145 mIsUserSeekable = !isIndicator; 146 setFocusable(!isIndicator); 147 } 148 149 /** 150 * @return Whether this rating bar is only an indicator. 151 */ 152 public boolean isIndicator() { 153 return !mIsUserSeekable; 154 } 155 156 /** 157 * Sets the number of stars to show. In order for these to be shown 158 * properly, it is recommended the layout width of this widget be wrap 159 * content. 160 * 161 * @param numStars The number of stars. 162 */ 163 public void setNumStars(final int numStars) { 164 if (numStars <= 0) { 165 return; 166 } 167 168 mNumStars = numStars; 169 170 // This causes the width to change, so re-layout 171 requestLayout(); 172 } 173 174 /** 175 * Returns the number of stars shown. 176 * @return The number of stars shown. 177 */ 178 public int getNumStars() { 179 return mNumStars; 180 } 181 182 /** 183 * Sets the rating (the number of stars filled). 184 * 185 * @param rating The rating to set. 186 */ 187 public void setRating(float rating) { 188 setProgress(Math.round(rating * getProgressPerStar())); 189 } 190 191 /** 192 * Gets the current rating (number of stars filled). 193 * 194 * @return The current rating. 195 */ 196 public float getRating() { 197 return getProgress() / getProgressPerStar(); 198 } 199 200 /** 201 * Sets the step size (granularity) of this rating bar. 202 * 203 * @param stepSize The step size of this rating bar. For example, if 204 * half-star granularity is wanted, this would be 0.5. 205 */ 206 public void setStepSize(float stepSize) { 207 if (stepSize <= 0) { 208 return; 209 } 210 211 final float newMax = mNumStars / stepSize; 212 final int newProgress = (int) (newMax / getMax() * getProgress()); 213 setMax((int) newMax); 214 setProgress(newProgress); 215 } 216 217 /** 218 * Gets the step size of this rating bar. 219 * 220 * @return The step size. 221 */ 222 public float getStepSize() { 223 return (float) getNumStars() / getMax(); 224 } 225 226 /** 227 * @return The amount of progress that fits into a star 228 */ 229 private float getProgressPerStar() { 230 if (mNumStars > 0) { 231 return 1f * getMax() / mNumStars; 232 } else { 233 return 1; 234 } 235 } 236 237 @Override 238 Shape getDrawableShape() { 239 // TODO: Once ProgressBar's TODOs are fixed, this won't be needed 240 return new RectShape(); 241 } 242 243 @Override 244 void onProgressRefresh(float scale, boolean fromUser) { 245 super.onProgressRefresh(scale, fromUser); 246 247 // Keep secondary progress in sync with primary 248 updateSecondaryProgress(getProgress()); 249 250 if (!fromUser) { 251 // Callback for non-user rating changes 252 dispatchRatingChange(false); 253 } 254 } 255 256 /** 257 * The secondary progress is used to differentiate the background of a 258 * partially filled star. This method keeps the secondary progress in sync 259 * with the progress. 260 * 261 * @param progress The primary progress level. 262 */ 263 private void updateSecondaryProgress(int progress) { 264 final float ratio = getProgressPerStar(); 265 if (ratio > 0) { 266 final float progressInStars = progress / ratio; 267 final int secondaryProgress = (int) (Math.ceil(progressInStars) * ratio); 268 setSecondaryProgress(secondaryProgress); 269 } 270 } 271 272 @Override 273 protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 274 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 275 276 if (mSampleTile != null) { 277 // TODO: Once ProgressBar's TODOs are gone, this can be done more 278 // cleanly than mSampleTile 279 final int width = mSampleTile.getWidth() * mNumStars; 280 setMeasuredDimension(resolveSize(width, widthMeasureSpec), mMeasuredHeight); 281 } 282 } 283 284 @Override 285 void onStartTrackingTouch() { 286 mProgressOnStartTracking = getProgress(); 287 288 super.onStartTrackingTouch(); 289 } 290 291 @Override 292 void onStopTrackingTouch() { 293 super.onStopTrackingTouch(); 294 295 if (getProgress() != mProgressOnStartTracking) { 296 dispatchRatingChange(true); 297 } 298 } 299 300 @Override 301 void onKeyChange() { 302 super.onKeyChange(); 303 dispatchRatingChange(true); 304 } 305 306 void dispatchRatingChange(boolean fromUser) { 307 if (mOnRatingBarChangeListener != null) { 308 mOnRatingBarChangeListener.onRatingChanged(this, getRating(), 309 fromUser); 310 } 311 } 312 313 @Override 314 public synchronized void setMax(int max) { 315 // Disallow max progress = 0 316 if (max <= 0) { 317 return; 318 } 319 320 super.setMax(max); 321 } 322 323 } 324
