android左右滑动加载分页以及动态加载数据

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;
    }

}