自定义Listview实现横向的HorizontalListView
先看一下效果图
介可不是什么ScrollView哦,android系统自带的ListView都是竖着的,这个是横着的,自定义的ListView,不说了上代码
package com.zhangyu.activity; import java.util.LinkedList; import java.util.Queue; import android.content.Context; import android.database.DataSetObserver; import android.graphics.Rect; import android.util.AttributeSet; import android.util.Log; 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; public class HorizontialListView extends AdapterView{ 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 mRemovedViewQueue = new LinkedList (); private OnItemSelectedListener mOnItemSelected; private OnItemClickListener mOnItemClicked; private OnItemLongClickListener mOnItemLongClicked; private boolean mDataChanged = false; public HorizontialListView(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(HorizontialListView.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 上面这段代码是自定义的ListView
下面看一下adapter
package com.zhangyu.activity; import android.app.Activity; import android.os.Bundle; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.TextView; public class HorizontalListViewDemo extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); HorizontialListView listview = (HorizontialListView) findViewById(R.id.listview); listview.setAdapter(mAdapter); } private static String[] dataObjects = new String[]{ "Text #1", "Text #2", "Text #3" }; private BaseAdapter mAdapter = new BaseAdapter() { @Override public int getCount() { return dataObjects.length; } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return 0; } @Override public View getView(int position, View convertView, ViewGroup parent) { View retval = LayoutInflater.from(parent.getContext()).inflate(R.layout.viewitem, null); TextView title = (TextView) retval.findViewById(R.id.title); title.setText(dataObjects[position]); return retval; } }; }里面的数据自己填充哦 </GETCHILDCOUNT();I++){></view></view></listadapter></pre>
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