《Android SwipeToDismiss：左右滑动删除ListView条目Item》
Android的SwipeToDismiss是github上一个第三方开源框架（github上的项目链接地址：https://github.com/romannurik/Android-SwipeToDismiss ）。该开源项目旨在：使得一个ListView的item在用户的手指在屏幕上左滑或者右滑时候，删除当前的这个ListView Item。
1 package com.lixu.SwipeRefreshLayoutyongfa; 2 3 import java.util.ArrayList; 4 import java.util.HashMap; 5 6 import com.lixu.SwipeRefreshLayoutyongfa.SwipeDismissListViewTouchListener.DismissCallbacks; 7 import android.app.Activity; 8 import android.content.Context; 9 import android.os.AsyncTask; 10 import android.os.Bundle; 11 import android.support.v4.widget.SwipeRefreshLayout; 12 import android.support.v4.widget.SwipeRefreshLayout.OnRefreshListener; 13 import android.view.LayoutInflater; 14 import android.view.View; 15 import android.view.ViewGroup; 16 import android.widget.ArrayAdapter; 17 import android.widget.ImageView; 18 import android.widget.ListView; 19 import android.widget.TextView; 20 21 public class MainActivity extends Activity { 22 private ArrayAdapter<String> adapter; 23 private ArrayList<HashMap<String, Object>> data; 24 private int count = 0; 25 SwipeRefreshLayout srl; 26 private int[] image = { R.drawable.beijing, R.drawable.chengdu, R.drawable.guangzhou, R.drawable.hangzhou, 27 R.drawable.wuhan, R.drawable.xian, R.drawable.shenzhen }; 28 29 private String[] city = { "北京", "成都", "广州", "杭州", "武汉", "西安", "深圳" }; 30 private String KEY_IMAGE = "image"; 31 private String KEY_TXT = "txt"; 32 33 private int i = 0; 34 private int j = 0; 35 36 ListView lv; 37 38 SwipeDismissListViewTouchListener touchlistener; 39 40 @Override 41 protected void onCreate(Bundle savedInstanceState) { 42 super.onCreate(savedInstanceState); 43 setContentView(R.layout.activity_main); 44 45 data = new ArrayList<HashMap<String, Object>>(); 46 47 lv = (ListView) findViewById(R.id.lv); 48 49 srl = (SwipeRefreshLayout) findViewById(R.id.srl); 50 // 设置刷新动画的颜色. 51 srl.setColorSchemeResources(android.R.color.holo_green_light, android.R.color.holo_blue_bright, 52 android.R.color.holo_red_light); 53 54 srl.setOnRefreshListener(new OnRefreshListener() { 55 // SwipeRefreshLayout接管其包裹的ListView下拉事件。 56 // 每一次对ListView的下拉动作，将触发SwipeRefreshLayout的onRefresh()。 57 @SuppressWarnings("unchecked") 58 @Override 59 public void onRefresh() { 60 61 new MyAsyncTask().execute(); 62 63 } 64 }); 65 adapter = new MyAdapter(this, -1); 66 67 lv.setAdapter(adapter); 68 addSwipeDismissListView(); 69 // 往listview里面添加触摸事件 70 lv.setOnTouchListener(touchlistener); 71 } 72 73 private void addSwipeDismissListView() { 74 touchlistener = new SwipeDismissListViewTouchListener(lv, new DismissCallbacks() { 75 76 @Override 77 public void onDismiss(ListView listView, int[] reverseSortedPositions) { 78 for (int pos : reverseSortedPositions) 79 // 获取滑动的下标行后删除这一行 80 data.remove(pos); 81 // 每次要刷新适配器 82 adapter.notifyDataSetChanged();
Toast.makeText(getApplicationContext(), "删除成功！", 0).show(); 83 } 84 85 @Override 86 public boolean canDismiss(int position) { 87 return true; 88 } 89 }); 90 } 91 92 private class MyAdapter extends ArrayAdapter { 93 private LayoutInflater flater; 94 95 public MyAdapter(Context context, int resource) { 96 super(context, resource); 97 flater = LayoutInflater.from(context); 98 } 99 100 @Override 101 public int getCount() { 102 return data.size(); 103 } 104 105 @Override 106 public View getView(int position, View convertView, ViewGroup parent) { 107 if (convertView == null) 108 convertView = flater.inflate(R.layout.item, null); 109 110 TextView tv = (TextView) convertView.findViewById(R.id.tv); 111 tv.setText(data.get(position).get(KEY_TXT) + ""); 112 113 ImageView iv = (ImageView) convertView.findViewById(R.id.iv); 114 iv.setImageResource((Integer) data.get(position).get(KEY_IMAGE)); 115 116 return convertView; 117 } 118 } 119 120 @SuppressWarnings("rawtypes") 121 private class MyAsyncTask extends AsyncTask { 122 private HashMap<String, Object> map; 123 124 @Override 125 protected void onPreExecute() { 126 // 刷新开始 127 srl.setRefreshing(true); 128 map = new HashMap<String, Object>(); 129 } 130 131 @Override 132 protected Object doInBackground(Object... params) { 133 // 防止下标越界，到达数组长度后返回开始 134 if (i == image.length) 135 i = 0; 136 if (j == city.length) 137 j = 0; 138 139 map.put(KEY_IMAGE, image[i++]); 140 map.put(KEY_TXT, city[j++]); 141 142 // 处理一些耗时的事件 143 return map; 144 } 145 146 @SuppressWarnings("unchecked") 147 @Override 148 protected void onPostExecute(Object result) { 149 // 每次从头部添加 150 data.add(0, (HashMap<String, Object>) result); 151 // 刷新适配器 152 adapter.notifyDataSetChanged(); 153 // 刷新完毕 154 srl.setRefreshing(false); 155 } 156 157 } 158 159 }
需要用的SwipeDismissListViewTouchListener类
1 package com.lixu.SwipeRefreshLayoutyongfa; 2 3 /* 4 * Copyright 2013 Google Inc. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 import android.animation.Animator; 20 import android.animation.AnimatorListenerAdapter; 21 import android.animation.ValueAnimator; 22 import android.graphics.Rect; 23 import android.os.SystemClock; 24 import android.view.MotionEvent; 25 import android.view.VelocityTracker; 26 import android.view.View; 27 import android.view.ViewConfiguration; 28 import android.view.ViewGroup; 29 import android.view.ViewPropertyAnimator; 30 import android.widget.AbsListView; 31 import android.widget.ListView; 32 33 import java.util.ArrayList; 34 import java.util.Collections; 35 import java.util.List; 36 37 /** 38 * A {@link View.OnTouchListener} that makes the list items in a 39 * {@link ListView} dismissable. {@link ListView} is given special treatment 40 * because by default it handles touches for its list items... i.e. it's in 41 * charge of drawing the pressed state (the list selector), handling list item 42 * clicks, etc. 43 * 44 * <p> 45 * After creating the listener, the caller should also call 46 * {@link ListView#setOnScrollListener(AbsListView.OnScrollListener)}, passing 47 * in the scroll listener returned by {@link #makeScrollListener()}. If a scroll 48 * listener is already assigned, the caller should still pass scroll changes 49 * through to this listener. This will ensure that this 50 * {@link SwipeDismissListViewTouchListener} is paused during list view 51 * scrolling. 52 * </p> 53 * 54 * <p> 55 * Example usage: 56 * </p> 57 * 58 * <pre> 59 * SwipeDismissListViewTouchListener touchListener = new SwipeDismissListViewTouchListener( 60 * listView, new SwipeDismissListViewTouchListener.OnDismissCallback() { 61 * public void onDismiss(ListView listView, 62 * int[] reverseSortedPositions) { 63 * for (int position : reverseSortedPositions) { 64 * adapter.remove(adapter.getItem(position)); 65 * } 66 * adapter.notifyDataSetChanged(); 67 * } 68 * }); 69 * listView.setOnTouchListener(touchListener); 70 * listView.setOnScrollListener(touchListener.makeScrollListener()); 71 * </pre> 72 * 73 * <p> 74 * This class Requires API level 12 or later due to use of 75 * {@link ViewPropertyAnimator}. 76 * </p> 77 * 78 * <p> 79 * For a generalized {@link View.OnTouchListener} that makes any view 80 * dismissable, see {@link SwipeDismissTouchListener}. 81 * </p> 82 * 83 * @see SwipeDismissTouchListener 84 */ 85 public class SwipeDismissListViewTouchListener implements View.OnTouchListener { 86 // Cached ViewConfiguration and system-wide constant values 87 private int mSlop; 88 private int mMinFlingVelocity; 89 private int mMaxFlingVelocity; 90 private long mAnimationTime; 91 92 // Fixed properties 93 private ListView mListView; 94 private DismissCallbacks mCallbacks; 95 private int mViewWidth = 1; // 1 and not 0 to prevent dividing by zero 96 97 // Transient properties 98 private List<PendingDismissData> mPendingDismisses = new ArrayList<PendingDismissData>(); 99 private int mDismissAnimationRefCount = 0; 100 private float mDownX; 101 private float mDownY; 102 private boolean mSwiping; 103 private int mSwipingSlop; 104 private VelocityTracker mVelocityTracker; 105 private int mDownPosition; 106 private View mDownView; 107 private boolean mPaused; 108 109 /** 110 * The callback interface used by {@link SwipeDismissListViewTouchListener} 111 * to inform its client about a successful dismissal of one or more list 112 * item positions. 113 */ 114 public interface DismissCallbacks { 115 /** 116 * Called to determine whether the given position can be dismissed. 117 */ 118 boolean canDismiss(int position); 119 120 /** 121 * Called when the user has indicated they she would like to dismiss one 122 * or more list item positions. 123 * 124 * @param listView 125 * The originating {@link ListView}. 126 * @param reverseSortedPositions 127 * An array of positions to dismiss, sorted in descending 128 * order for convenience. 129 */ 130 void onDismiss(ListView listView, int[] reverseSortedPositions); 131 } 132 133 /** 134 * Constructs a new swipe-to-dismiss touch listener for the given list view. 135 * 136 * @param listView 137 * The list view whose items should be dismissable. 138 * @param callbacks 139 * The callback to trigger when the user has indicated that she 140 * would like to dismiss one or more list items. 141 */ 142 public SwipeDismissListViewTouchListener(ListView listView, 143 DismissCallbacks callbacks) { 144 ViewConfiguration vc = ViewConfiguration.get(listView.getContext()); 145 mSlop = vc.getScaledTouchSlop(); 146 mMinFlingVelocity = vc.getScaledMinimumFlingVelocity() * 16; 147 mMaxFlingVelocity = vc.getScaledMaximumFlingVelocity(); 148 mAnimationTime = listView.getContext().getResources() 149 .getInteger(android.R.integer.config_shortAnimTime); 150 mListView = listView; 151 mCallbacks = callbacks; 152 } 153 154 /** 155 * Enables or disables (pauses or resumes) watching for swipe-to-dismiss 156 * gestures. 157 * 158 * @param enabled 159 * Whether or not to watch for gestures. 160 */ 161 public void setEnabled(boolean enabled) { 162 mPaused = !enabled; 163 } 164 165 /** 166 * Returns an {@link AbsListView.OnScrollListener} to be added to the 167 * {@link ListView} using 168 * {@link ListView#setOnScrollListener(AbsListView.OnScrollListener)}. If a 169 * scroll listener is already assigned, the caller should still pass scroll 170 * changes through to this listener. This will ensure that this 171 * {@link SwipeDismissListViewTouchListener} is paused during list view 172 * scrolling.</p> 173 * 174 * @see SwipeDismissListViewTouchListener 175 */ 176 public AbsListView.OnScrollListener makeScrollListener() { 177 return new AbsListView.OnScrollListener() { 178 @Override 179 public void onScrollStateChanged(AbsListView absListView, 180 int scrollState) { 181 setEnabled(scrollState != AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL); 182 } 183 184 @Override 185 public void onScroll(AbsListView absListView, int i, int i1, int i2) { 186 } 187 }; 188 } 189 190 @Override 191 public boolean onTouch(View view, MotionEvent motionEvent) { 192 if (mViewWidth < 2) { 193 mViewWidth = mListView.getWidth(); 194 } 195 196 switch (motionEvent.getActionMasked()) { 197 case MotionEvent.ACTION_DOWN: { 198 if (mPaused) { 199 return false; 200 } 201 202 // TODO: ensure this is a finger, and set a flag 203 204 // Find the child view that was touched (perform a hit test) 205 Rect rect = new Rect(); 206 int childCount = mListView.getChildCount(); 207 int[] listViewCoords = new int[2]; 208 mListView.getLocationOnScreen(listViewCoords); 209 int x = (int) motionEvent.getRawX() - listViewCoords[0]; 210 int y = (int) motionEvent.getRawY() - listViewCoords[1]; 211 View child; 212 for (int i = 0; i < childCount; i++) { 213 child = mListView.getChildAt(i); 214 child.getHitRect(rect); 215 if (rect.contains(x, y)) { 216 mDownView = child; 217 break; 218 } 219 } 220 221 if (mDownView != null) { 222 mDownX = motionEvent.getRawX(); 223 mDownY = motionEvent.getRawY(); 224 mDownPosition = mListView.getPositionForView(mDownView); 225 if (mCallbacks.canDismiss(mDownPosition)) { 226 mVelocityTracker = VelocityTracker.obtain(); 227 mVelocityTracker.addMovement(motionEvent); 228 } else { 229 mDownView = null; 230 } 231 } 232 return false; 233 } 234 235 case MotionEvent.ACTION_CANCEL: { 236 if (mVelocityTracker == null) { 237 break; 238 } 239 240 if (mDownView != null && mSwiping) { 241 // cancel 242 mDownView.animate().translationX(0).alpha(1) 243 .setDuration(mAnimationTime).setListener(null); 244 } 245 mVelocityTracker.recycle(); 246 mVelocityTracker = null; 247 mDownX = 0; 248 mDownY = 0; 249 mDownView = null; 250 mDownPosition = ListView.INVALID_POSITION; 251 mSwiping = false; 252 break; 253 } 254 255 case MotionEvent.ACTION_UP: { 256 if (mVelocityTracker == null) { 257 break; 258 } 259 260 float deltaX = motionEvent.getRawX() - mDownX; 261 mVelocityTracker.addMovement(motionEvent); 262 mVelocityTracker.computeCurrentVelocity(1000); 263 float velocityX = mVelocityTracker.getXVelocity(); 264 float absVelocityX = Math.abs(velocityX); 265 float absVelocityY = Math.abs(mVelocityTracker.getYVelocity()); 266 boolean dismiss = false; 267 boolean dismissRight = false; 268 if (Math.abs(deltaX) > mViewWidth / 2 && mSwiping) { 269 dismiss = true; 270 dismissRight = deltaX > 0; 271 } else if (mMinFlingVelocity <= absVelocityX 272 && absVelocityX <= mMaxFlingVelocity 273 && absVelocityY < absVelocityX && mSwiping) { 274 // dismiss only if flinging in the same direction as dragging 275 dismiss = (velocityX < 0) == (deltaX < 0); 276 dismissRight = mVelocityTracker.getXVelocity() > 0; 277 } 278 if (dismiss && mDownPosition != ListView.INVALID_POSITION) { 279 // dismiss 280 final View downView = mDownView; // mDownView gets null'd before 281 // animation ends 282 final int downPosition = mDownPosition; 283 ++mDismissAnimationRefCount; 284 mDownView.animate() 285 .translationX(dismissRight ? mViewWidth : -mViewWidth) 286 .alpha(0).setDuration(mAnimationTime) 287 .setListener(new AnimatorListenerAdapter() { 288 @Override 289 public void onAnimationEnd(Animator animation) { 290 performDismiss(downView, downPosition); 291 } 292 }); 293 } else { 294 // cancel 295 mDownView.animate().translationX(0).alpha(1) 296 .setDuration(mAnimationTime).setListener(null); 297 } 298 mVelocityTracker.recycle(); 299 mVelocityTracker = null; 300 mDownX = 0; 301 mDownY = 0; 302 mDownView = null; 303 mDownPosition = ListView.INVALID_POSITION; 304 mSwiping = false; 305 break; 306 } 307 308 case MotionEvent.ACTION_MOVE: { 309 if (mVelocityTracker == null || mPaused) { 310 break; 311 } 312 313 mVelocityTracker.addMovement(motionEvent); 314 float deltaX = motionEvent.getRawX() - mDownX; 315 float deltaY = motionEvent.getRawY() - mDownY; 316 if (Math.abs(deltaX) > mSlop 317 && Math.abs(deltaY) < Math.abs(deltaX) / 2) { 318 mSwiping = true; 319 mSwipingSlop = (deltaX > 0 ? mSlop : -mSlop); 320 mListView.requestDisallowInterceptTouchEvent(true); 321 322 // Cancel ListView's touch (un-highlighting the item) 323 MotionEvent cancelEvent = MotionEvent.obtain(motionEvent); 324 cancelEvent 325 .setAction(MotionEvent.ACTION_CANCEL 326 | (motionEvent.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT)); 327 mListView.onTouchEvent(cancelEvent); 328 cancelEvent.recycle(); 329 } 330 331 if (mSwiping) { 332 mDownView.setTranslationX(deltaX - mSwipingSlop); 333 mDownView.setAlpha(Math.max(0f, 334 Math.min(1f, 1f - 2f * Math.abs(deltaX) / mViewWidth))); 335 return true; 336 } 337 break; 338 } 339 } 340 return false; 341 } 342 343 class PendingDismissData implements Comparable<PendingDismissData> { 344 public int position; 345 public View view; 346 347 public PendingDismissData(int position, View view) { 348 this.position = position; 349 this.view = view; 350 } 351 352 @Override 353 public int compareTo(PendingDismissData other) { 354 // Sort by descending position 355 return other.position - position; 356 } 357 } 358 359 private void performDismiss(final View dismissView, 360 final int dismissPosition) { 361 // Animate the dismissed list item to zero-height and fire the dismiss 362 // callback when 363 // all dismissed list item animations have completed. This triggers 364 // layout on each animation 365 // frame; in the future we may want to do something smarter and more 366 // performant. 367 368 final ViewGroup.LayoutParams lp = dismissView.getLayoutParams(); 369 final int originalHeight = dismissView.getHeight(); 370 371 ValueAnimator animator = ValueAnimator.ofInt(originalHeight, 1) 372 .setDuration(mAnimationTime); 373 374 animator.addListener(new AnimatorListenerAdapter() { 375 @Override 376 public void onAnimationEnd(Animator animation) { 377 --mDismissAnimationRefCount; 378 if (mDismissAnimationRefCount == 0) { 379 // No active animations, process all pending dismisses. 380 // Sort by descending position 381 Collections.sort(mPendingDismisses); 382 383 int[] dismissPositions = new int[mPendingDismisses.size()]; 384 for (int i = mPendingDismisses.size() - 1; i >= 0; i--) { 385 dismissPositions[i] = mPendingDismisses.get(i).position; 386 } 387 mCallbacks.onDismiss(mListView, dismissPositions); 388 389 // Reset mDownPosition to avoid MotionEvent.ACTION_UP trying 390 // to start a dismiss 391 // animation with a stale position 392 mDownPosition = ListView.INVALID_POSITION; 393 394 ViewGroup.LayoutParams lp; 395 for (PendingDismissData pendingDismiss : mPendingDismisses) { 396 // Reset view presentation 397 pendingDismiss.view.setAlpha(1f); 398 pendingDismiss.view.setTranslationX(0); 399 lp = pendingDismiss.view.getLayoutParams(); 400 lp.height = originalHeight; 401 pendingDismiss.view.setLayoutParams(lp); 402 } 403 404 // Send a cancel event 405 long time = SystemClock.uptimeMillis(); 406 MotionEvent cancelEvent = MotionEvent.obtain(time, time, 407 MotionEvent.ACTION_CANCEL, 0, 0, 0); 408 mListView.dispatchTouchEvent(cancelEvent); 409 410 mPendingDismisses.clear(); 411 } 412 } 413 }); 414 415 animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { 416 @Override 417 public void onAnimationUpdate(ValueAnimator valueAnimator) { 418 lp.height = (Integer) valueAnimator.getAnimatedValue(); 419 dismissView.setLayoutParams(lp); 420 } 421 }); 422 423 mPendingDismisses.add(new PendingDismissData(dismissPosition, 424 dismissView)); 425 animator.start(); 426 } 427 }
xml文件：
1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 xmlns:tools="http://schemas.android.com/tools" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 tools:context="com.lixu.SwipeRefreshLayoutyongfa.MainActivity" > 6 7 <android.support.v4.widget.SwipeRefreshLayout 8 android:id="@+id/srl" 9 android:layout_width="match_parent" 10 android:layout_height="match_parent" > 11 12 <ListView 13 android:id="@+id/lv" 14 android:layout_width="match_parent" 15 android:layout_height="match_parent" /> 16 </android.support.v4.widget.SwipeRefreshLayout> 17 18 </RelativeLayout>
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 android:orientation="vertical" > 6 7 <ImageView 8 android:id="@+id/iv" 9 android:layout_width="50dp" 10 android:layout_height="50dp" /> 11 12 <TextView 13 android:id="@+id/tv" 14 android:layout_width="wrap_content" 15 android:layout_height="wrap_content" 16 android:textSize="25sp" /> 17 18 </LinearLayout>
运行效果图：
