android UI 往右滑动,滑动到最后一页就自动加载数据并显示
如图:
Java代码
package cn.anycall.ju; import java.util.ArrayList; import java.util.List; import java.util.Map; import android.content.Context; import android.content.pm.PackageManager; import android.content.pm.ResolveInfo; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; import cn.anycall.ju.R; public class AppAdapter extends BaseAdapter { private List<Map> mList; private Context mContext; public static final int APP_PAGE_SIZE = 4; private PackageManager pm; public AppAdapter(Context context, List<Map> list, int page) { mContext = context; pm = context.getPackageManager(); mList = new ArrayList<Map>(); int i = page * APP_PAGE_SIZE; int iEnd = i+APP_PAGE_SIZE; while ((i<list.size()) && (i<iEnd)) { mList.add(list.get(i)); i++; } } public int getCount() { // TODO Auto-generated method stub return mList.size(); } public Object getItem(int position) { // TODO Auto-generated method stub return mList.get(position); } public long getItemId(int position) { // TODO Auto-generated method stub return position; } public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub Map appInfo = mList.get(position); AppItem appItem; if (convertView == null) { View v = LayoutInflater.from(mContext).inflate(R.layout.app_item, null); appItem = new AppItem(); appItem.mAppIcon = (ImageView)v.findViewById(R.id.imgdetail); appItem.mAppName = (TextView)v.findViewById(R.id.tuaninfo); v.setTag(appItem); convertView = v; } else { appItem = (AppItem)convertView.getTag(); } // set the icon appItem.mAppIcon.setImageResource(R.drawable.icon); // set the app name appItem.mAppName.setText(appInfo.get("name").toString()); return convertView; } /** * 每个应用显示的内容,包括图标和名称 * @author Yao.GUET * */ class AppItem { ImageView mAppIcon; TextView mAppName; } }
package cn.anycall.ju; import android.content.Context; import android.graphics.Canvas; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.Scroller; /** * 仿Launcher中的WorkSapce,可以左右滑动切换屏幕的类 * */ public class ScrollLayout extends ViewGroup { private static final String TAG = "ScrollLayout"; private Scroller mScroller; private VelocityTracker mVelocityTracker; private int mCurScreen; private int mDefaultScreen = 0; private static final int TOUCH_STATE_REST = 0; private static final int TOUCH_STATE_SCROLLING = 1; private static final int SNAP_VELOCITY = 600; private int mTouchState = TOUCH_STATE_REST; private int mTouchSlop; private float mLastMotionX; private float mLastMotionY; private int currentScreenIndex = 0; public int getCurrentScreenIndex() { return currentScreenIndex; } public void setCurrentScreenIndex(int currentScreenIndex) { this.currentScreenIndex = currentScreenIndex; } public ScrollLayout(Context context, AttributeSet attrs) { this(context, attrs, 0); // TODO Auto-generated constructor stub } public ScrollLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); // TODO Auto-generated constructor stub mScroller = new Scroller(context); mCurScreen = mDefaultScreen; mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop(); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { // TODO Auto-generated method stub int childLeft = 0; final int childCount = getChildCount(); System.out.println("childCount=" + childCount); for (int i = 0; i < childCount; i++) { final View childView = getChildAt(i); if (childView.getVisibility() != View.GONE) { final int childWidth = childView.getMeasuredWidth(); childView.layout(childLeft, 0, childLeft + childWidth, childView.getMeasuredHeight()); childLeft += childWidth; } } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { Log.e(TAG, "onMeasure"); super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int width = MeasureSpec.getSize(widthMeasureSpec); final int widthMode = MeasureSpec.getMode(widthMeasureSpec); if (widthMode != MeasureSpec.EXACTLY) { throw new IllegalStateException( "ScrollLayout only canmCurScreen run at EXACTLY mode!"); } final int heightMode = MeasureSpec.getMode(heightMeasureSpec); if (heightMode != MeasureSpec.EXACTLY) { throw new IllegalStateException( "ScrollLayout only can run at EXACTLY mode!"); } // The children are given the same width and height as the scrollLayout final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); } System.out.println("moving to screen " + mCurScreen); scrollTo(mCurScreen * width, 0); } /** * According to the position of current layout scroll to the destination * page. */ public void snapToDestination() { final int screenWidth = getWidth(); final int destScreen = (getScrollX() + screenWidth / 2) / screenWidth; snapToScreen(destScreen); } public void snapToScreen(int whichScreen) { // get the valid layout page whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1)); if (getScrollX() != (whichScreen * getWidth())) { final int delta = whichScreen * getWidth() - getScrollX(); mScroller.startScroll(getScrollX(), 0, delta, 0, Math.abs(delta) * 2); mCurScreen = whichScreen; invalidate(); // Redraw the layout } } public void setToScreen(int whichScreen) { whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1)); mCurScreen = whichScreen; scrollTo(whichScreen * getWidth(), 0); } public int getCurScreen() { return mCurScreen; } @Override public void computeScroll() { // TODO Auto-generated method stub if (mScroller.computeScrollOffset()) { scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(event); final int action = event.getAction(); final float x = event.getX(); final float y = event.getY(); switch (action) { case MotionEvent.ACTION_DOWN: Log.e(TAG, "event down!"); if (!mScroller.isFinished()) { mScroller.abortAnimation(); } mLastMotionX = x; break; case MotionEvent.ACTION_MOVE: int deltaX = (int) (mLastMotionX - x); mLastMotionX = x; scrollBy(deltaX, 0); break; case MotionEvent.ACTION_UP: Log.e(TAG, "event : up"); // if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000); int velocityX = (int) velocityTracker.getXVelocity(); Log.e(TAG, "velocityX:" + velocityX); if (velocityX > SNAP_VELOCITY && mCurScreen > 0) { // Fling enough to move left Log.e(TAG, "snap left"); onScreenChangeListener.onScreenChange(mCurScreen - 1); System.out.println("mCurScreen=" + (mCurScreen - 1)); snapToScreen(mCurScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurScreen < getChildCount() - 1) { // Fling enough to move right Log.e(TAG, "snap right"); onScreenChangeListener.onScreenChange(mCurScreen + 1); //只往右移动才加载数据 onScreenChangeListenerDataLoad.onScreenChange(mCurScreen+1); snapToScreen(mCurScreen + 1); } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } // } mTouchState = TOUCH_STATE_REST; break; case MotionEvent.ACTION_CANCEL: mTouchState = TOUCH_STATE_REST; break; } return true; } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { // TODO Auto-generated method stub Log.e(TAG, "onInterceptTouchEvent-slop:" + mTouchSlop); final int action = ev.getAction(); if ((action == MotionEvent.ACTION_MOVE) && (mTouchState != TOUCH_STATE_REST)) { return true; } final float x = ev.getX(); final float y = ev.getY(); switch (action) { case MotionEvent.ACTION_MOVE: final int xDiff = (int) Math.abs(mLastMotionX - x); if (xDiff > mTouchSlop) { mTouchState = TOUCH_STATE_SCROLLING; } break; case MotionEvent.ACTION_DOWN: mLastMotionX = x; mLastMotionY = y; mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; break; case MotionEvent.ACTION_CANCEL: case MotionEvent.ACTION_UP: mTouchState = TOUCH_STATE_REST; break; } return mTouchState != TOUCH_STATE_REST; } //分页监听 public interface OnScreenChangeListener { void onScreenChange(int currentIndex); } private OnScreenChangeListener onScreenChangeListener; public void setOnScreenChangeListener( OnScreenChangeListener onScreenChangeListener) { this.onScreenChangeListener = onScreenChangeListener; } //动态数据监听 public interface OnScreenChangeListenerDataLoad { void onScreenChange(int currentIndex); } private OnScreenChangeListenerDataLoad onScreenChangeListenerDataLoad; public void setOnScreenChangeListenerDataLoad(OnScreenChangeListenerDataLoad onScreenChangeListenerDataLoad) { this.onScreenChangeListenerDataLoad = onScreenChangeListenerDataLoad; } }
app_item.xml