Andro、id中实现水平滑动（横向滑动）ListView示例

2019-11-02 14:27:01

字体：大中小

来源：转载

供稿：网友

　　这篇文章主要介绍了Android中实现水平滑动(横向滑动)ListView示例,本文用自己封装一个控件的方法解决了这个需求,需要的朋友可以参考下

　　水平的ListView-HorizontalListView的使用

　　Android中ListView默认的是竖直方向的滑动，由于项目的需求，需要ListView是水平滑动的。有很多的方式可以实现，但是比较好的一种方式就是自己封装一个控件，使用方式和ListView的使用方式是一样的。需要完善的地方：获取到的图片大小没有处理。在界面上展示的是图片的原大小。为了更好的展示效果，应该压缩成统一的尺寸。

　　HorizontalListView.java 代码如下：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148

世界近代史[www.9-39.com/html/world/]

149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 /** * 横向的ListView * * * @author scd * */ public class HorizontalListView extends AdapterView<ListAdapter> { public boolean mAlwaysOverrideTouch = true; protected ListAdapter mAdapter; private int mLeftViewIndex = -1; private int mRightViewIndex = 0; protected int mCurrentX; protected int mNextX; private int mMaxX = Integer.MAX_VALUE; private int mDisplayOffset = 0; protected Scroller mScroller; private GestureDetector mGesture; private Queue<View> mRemovedViewQueue = new LinkedList<View>(); private OnItemSelectedListener mOnItemSelected; private OnItemClickListener mOnItemClicked; private OnItemLongClickListener mOnItemLongClicked; private boolean mDataChanged = false; public HorizontalListView(Context context, AttributeSet attrs) { super(context, attrs); initView(); } private synchronized void initView() { mLeftViewIndex = -1; mRightViewIndex = 0; mDisplayOffset = 0; mCurrentX = 0; mNextX = 0; mMaxX = Integer.MAX_VALUE; mScroller = new Scroller(getContext()); mGesture = new GestureDetector(getContext(), mOnGesture); } @Override public void setOnItemSelectedListener( AdapterView.OnItemSelectedListener listener) { mOnItemSelected = listener; } @Override public void setOnItemClickListener(AdapterView.OnItemClickListener listener) { mOnItemClicked = listener; } @Override public void setOnItemLongClickListener( AdapterView.OnItemLongClickListener listener) { mOnItemLongClicked = listener; } private DataSetObserver mDataObserver = new DataSetObserver() { @Override public void onChanged() { synchronized (HorizontalListView.this) { mDataChanged = true; } invalidate(); requestLayout(); } @Override public void onInvalidated() { reset(); invalidate(); requestLayout(); } }; @Override public ListAdapter getAdapter() { return mAdapter; } @Override public View getSelectedView() { // TODO: implement return null; } @Override public void setAdapter(ListAdapter adapter) { if (mAdapter != null) { mAdapter.unregisterDataSetObserver(mDataObserver); } mAdapter = adapter; mAdapter.registerDataSetObserver(mDataObserver); reset(); } private synchronized void reset() { initView(); removeAllViewsInLayout(); requestLayout(); } @Override public void setSelection(int position) { // TODO: implement } private void addAndMeasureChild(final View child, int viewPos) { LayoutParams params = child.getLayoutParams(); if (params == null) { params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT); } addViewInLayout(child, viewPos, params, true); child.measure( MeasureSpec.makeMeasureSpec(getWidth(), MeasureSpec.AT_MOST), MeasureSpec.makeMeasureSpec(getHeight(), MeasureSpec.AT_MOST)); } @Override protected synchronized void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); if (mAdapter == null) { return; } if (mDataChanged) { int oldCurrentX = mCurrentX; initView(); removeAllViewsInLayout(); mNextX = oldCurrentX; mDataChanged = false; } if (mScroller.computeScrollOffset()) { int scrollx = mScroller.getCurrX(); mNextX = scrollx; } if (mNextX <= 0) { mNextX = 0; mScroller.forceFinished(true); } if (mNextX >= mMaxX) { mNextX = mMaxX; mScroller.forceFinished(true); } int dx = mCurrentX - mNextX; removeNonVisibleItems(dx); fillList(dx); positionItems(dx); mCurrentX = mNextX; if (!mScroller.isFinished()) { post(new Runnable() { @Override public void run() { requestLayout(); } }); } } private void fillList(final int dx) { int edge = 0; View child = getChildAt(getChildCount() - 1); if (child != null) { edge = child.getRight(); } fillListRight(edge, dx); edge = 0; child = getChildAt(0); if (child != null) { edge = child.getLeft(); } fillListLeft(edge, dx); } private void fillListRight(int rightEdge, final int dx) { while (rightEdge + dx < getWidth() && mRightViewIndex < mAdapter.getCount()) { View child = mAdapter.getView(mRightViewIndex, mRemovedViewQueue.poll(), this); addAndMeasureChild(child, -1); rightEdge += child.getMeasuredWidth(); if (mRightViewIndex == mAdapter.getCount() - 1) { mMaxX = mCurrentX + rightEdge - getWidth(); } if (mMaxX < 0) { mMaxX = 0; } mRightViewIndex++; } } private void fillListLeft(int leftEdge, final int dx) { while (leftEdge + dx > 0 && mLeftViewIndex >= 0) { View child = mAdapter.getView(mLeftViewIndex, mRemovedViewQueue.poll(), this); addAndMeasureChild(child, 0); leftEdge -= child.getMeasuredWidth(); mLeftViewIndex--; mDisplayOffset -= child.getMeasuredWidth(); } } private void removeNonVisibleItems(final int dx) { View child = getChildAt(0); while (child != null && child.getRight() + dx <= 0) { mDisplayOffset += child.getMeasuredWidth(); mRemovedViewQueue.offer(child); removeViewInLayout(child); mLeftViewIndex++; child = getChildAt(0); } child = getChildAt(getChildCount() - 1); while (child != null && child.getLeft() + dx >= getWidth()) { mRemovedViewQueue.offer(child); removeViewInLayout(child); mRightViewIndex--; child = getChildAt(getChildCount() - 1); } } private void positionItems(final int dx) { if (getChildCount() > 0) { mDisplayOffset += dx; int left = mDisplayOffset; for (int i = 0; i < getChildCount(); i++) { View child = getChildAt(i); int childWidth = child.getMeasuredWidth(); child.layout(left, 0, left + childWidth, child.getMeasuredHeight()); left += childWidth + child.getPaddingRight(); } } } public synchronized void scrollTo(int x) { mScroller.startScroll(mNextX, 0, x - mNextX, 0); requestLayout(); } @Override public boolean dispatchTouchEvent(MotionEvent ev) { boolean handled = super.dispatchTouchEvent(ev); handled |= mGesture.onTouchEvent(ev); return handled; } protected boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { synchronized (HorizontalListView.this) { mScroller.fling(mNextX, 0, (int) -velocityX, 0, 0, mMaxX, 0, 0); } requestLayout(); return true; } protected boolean onDown(MotionEvent e) { mScroller.forceFinished(true); return true; } private OnGestureListener mOnGesture = new GestureDetector.SimpleOnGestureListener() { @Override public boolean onDown(MotionEvent e) { return HorizontalListView.this.onDown(e); } @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { return HorizontalListView.this .onFling(e1, e2, velocityX, velocityY); } @Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { synchronized (HorizontalListView.this) { mNextX += (int) distanceX; } requestLayout(); return true; } @Override public boolean onSingleTapConfirmed(MotionEvent e) { for (int i = 0; i < getChildCount(); i++) { View child = getChildAt(i); if (isEventWithinView(e, child)) { if (mOnItemClicked != null) { mOnItemClicked.onItemClick(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i)); } if (mOnItemSelected != null) { mOnItemSelected.onItemSelected(HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i)); } break; } } return true; } @Override public void onLongPress(MotionEvent e) { int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { View child = getChildAt(i); if (isEventWithinView(e, child)) { if (mOnItemLongClicked != null) { mOnItemLongClicked.onItemLongClick( HorizontalListView.this, child, mLeftViewIndex + 1 + i, mAdapter.getItemId(mLeftViewIndex + 1 + i)); } break; } } } private boolean isEventWithinView(MotionEvent e, View child) { Rect viewRect = new Rect(); int[] childPosition = new int[2]; child.getLocationOnScreen(childPosition); int left = childPosition[0]; int right = left + child.getWidth(); int top = childPosition[1]; int bottom = top + child.getHeight(); viewRect.set(left, top, right, bottom); return viewRect.contains((int) e.getRawX(), (int) e.getRawY()); } }; }

上一篇：Acc-ess数据库创建宏组

下一篇：程序员新手指南之如何编写技术文档