Android 横向ListView实现

上面历史环境一栏这个是实现后的效果图，可以横向滑动的listView

核心代码类HorizontalListView：

package com.example.horizontallistviewdemo;

import android.content.Context;
import android.database.DataSetObserver;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.GestureDetector.OnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.Scroller;

import java.util.LinkedList;
import java.util.Queue;

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(OnItemSelectedListener listener) {
		mOnItemSelected = listener;
	}
	
	@Override
	public void setOnItemClickListener(OnItemClickListener listener){
		mOnItemClicked = listener;
	}
	
	@Override
	public void setOnItemLongClickListener(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();
		}
		
	};
	public boolean onInterceptTouchEvent(MotionEvent ev) {
		getParent().requestDisallowInterceptTouchEvent(true);
		return mGesture.onTouchEvent(ev);
	};
	@Override
	public ListAdapter getAdapter() {
		return mAdapter;
	}

	@Override
	public View getSelectedView() {
		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) {
	}
	
	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());
        }
	};

	

}

Activity 调用非常简单：

package com.example.horizontallistviewdemo;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends ActionBarActivity {
	
	private HorizontalListView mHorizontalListView;
	private HorizontalListViewAdapter mHorizontalListViewAdapter;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		initView();
	}

	private void initView() {
		  mHorizontalListView = (HorizontalListView) findViewById(R.id.horizontal_lv);
	        mHorizontalListViewAdapter = new HorizontalListViewAdapter(MainActivity.this);
	        mHorizontalListView.setAdapter(mHorizontalListViewAdapter);
		
	}


}

xml中引用

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.horizontallistviewdemo.MainActivity" >
  <com.example.horizontallistviewdemo.HorizontalListView
                android:id="@+id/horizontal_lv"
                android:layout_marginTop="1dp"
                android:background="@drawable/background_transparent_content"
                android:layout_width="wrap_content"
                android:layout_height="60dp" />

</RelativeLayout>

点击事件和ListView 一样

      mHorizontalListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

				@Override
				public void onItemClick(AdapterView<?> parent, View view,
						int position, long id) {
					// TODO Auto-generated method stub
					
				}

	        });

不是很复杂的东西，整理了一个DEMO

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文章来源: wukong.blog.csdn.net，作者：再见孙悟空_，版权归原作者所有，如需转载，请联系作者。

原文链接：wukong.blog.csdn.net/article/details/79441799