Android自定义控件——仿饿了么联动ListView

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Android自定义控件——仿饿了么联动ListView


前几天,群里一哥们儿私聊我,问我会不会二级联动,当时的我是一脸懵逼啊,曾经听人提起过,但是自己也没用过,也没尝试着去做,正好趁这个机会就学学呗,Demo还是这哥们儿给我的呢,诺,github链接:DoubleListViewLinkage,简书链接:羊皮书APP(Android版)开发系列(二十一)双联动分组ListView,类似于外卖点餐,但是很头疼的,一个Android小白,要看没有一行注释的代码,Oh My God!不多说了,开车吧~


我们先来看下效果哈,然后来分析是怎么实现的,如下图:

看到后,或许会感到一头雾水,首先,标题是怎么变的,然后左边的item又是怎么变的,然后我们的自定义到底在哪儿?

ListView的自定义是哪一块儿?

一开始我也不知道ListView的自定义,到底是自定义的哪一块儿,毕竟这个概念是比较重要的,因为既然我们都要自定义ListView了,但是不知道自定义哪里,岂不是很尴尬?我们先来一张静态的图哈,来看看到底是哪里需要自定义如下图:

再来看下自定义后的ListView,如下图:

右边的是哈,然后我们可以发现他们的Item是不同的,所以说,自定义ListView其实就是自定义Item,然后我们来分析下哈,自定义Item,说到底,要想实现这个效果的自定义Item就是加了一个头部,也就是标题啦,然后我们看效果图的时候,可以发现当第一个标题内的内容向上移动,消失的时候,那个标题也就消失了,所以我们还要实现这个随着标题内的最后一个内容消失的时候,该标题也要消失。


总结一下呢,我们自定义Item要完成的就是,“标题+内容”,从开始出现到消失,且显示第二个“标题+内容”的过程。


那就具体的来实现吧!


在上一环节我们分析了,到底要自定义哪里,且是怎样的一个过程,那么这一环节我们就来再深入一点儿哈,我们要自定义ListView那么肯定是要继承ListView的啦,况且我们要监听一下内容是什么时候消失的,那么我们就必须要实现AbsListView.OnScrollListener这个接口喽~然后alt+回车,把抽象方法都实现,还要实现那必须的三个构造方法哈,最终如下:

public class HaveHeaderListView extends ListView implements AbsListView.OnScrollListener {    public HaveHeaderListView(Context context) {        super(context);    }    public HaveHeaderListView(Context context, AttributeSet attrs) {        super(context, attrs);    }    public HaveHeaderListView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    @Override    public void onScrollStateChanged(AbsListView view, int scrollState) {    }    @Override    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {    }}

然后我们在构造方法中super下那个滑动监听哈。就是这句super.setOnScrollListener(this);
这样完事儿后,我们来写一下我们的这个Adapter,因为这个属于我们自定义的了,若是想以前那样写Adapter是肯定不可以的,所以来写下我们自己的Adapter吧。Adapter代码如下:

    public interface HaveHeaderAdapter {        boolean isSectionHeader(int position);        int getSectionForPosition(int position);        View getSectionHeaderView(int section, View convertView, ViewGroup parent);        int getSectionHeaderViewType(int section);        int getCount();    }

这个Adapter其实就是和我们的那个标题相对应的,看名字大家应该都知道,也就是仿着我们的那个BaseAdapter写的。然后我们需要几个变量,如下:

    private HaveHeaderAdapter mAdapter;    //标题    private View mCurrentHeader;    //默认显示第几个标题    private int mCurrentHeaderViewType = 0;    //标题距顶部的距离    private float mHeaderOffset;    //是否显示    private boolean mShouldPin = true;    //当前部分    private int mCurrentSection = 0;    //宽度    private int mWidthMode;    //高度    private int mHeightMode;

注释已经说明了哈,这里也就不啰嗦了,嘿嘿。
OK,所用的变量都有了,那么我们就来实现吧,既然是通过向上滑动和向下滑动来让mCurrentHeader(也就是标题既然这里我们都有相应的变量了,那么我们就用它在代码中真实的名字吧!)显示和隐藏的,那么主要逻辑和代码实现肯定是在onScroll里面了,先贴代码:

    @Override    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {        if (mOnScrollListener != null) {            mOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);        }        if (mAdapter == null || mAdapter.getCount() == 0 || !mShouldPin) {            //当适配器为空或适配器中无数据或mShouldPin为false或者可见视同中第一个索引小于0则return            return;        }        //根据可见视图的第一个索引去获取section        int section = mAdapter.getSectionForPosition(firstVisibleItem);        //根据获取到的section去获取viewType        int viewType = mAdapter.getSectionHeaderViewType(section);        //获取标题        mCurrentHeader = getSectionHeaderView(section, mCurrentHeader);        //更换标题        ensureHaveHeaderLayout(mCurrentHeader);        //改成当前标题所对应的值        mCurrentHeaderViewType = viewType;        //设置标题距顶部距离        mHeaderOffset = 0.0f;        for (int i = firstVisibleItem; i < firstVisibleItem + visibleItemCount; i++) {            if (mAdapter.isSectionHeader(i)) {                //得到真实的子Item的值                View ChildView = getChildAt(i - firstVisibleItem);                //得到子Item距顶部的距离                float ChildViewTop = ChildView.getTop();                //得到子Item的高度                float ChildViewHeight = ChildView.getMeasuredHeight();                //将子Item设置为显示                ChildView.setVisibility(VISIBLE);                if (ChildViewHeight >= ChildViewTop && ChildViewTop > 0) {                    //当子Item的高度>子Item距顶部的距离时,则标题应该逐步消失                    mHeaderOffset = ChildViewTop - ChildViewHeight;                } else if (ChildViewTop <= 0) {                    //子Item距离小于0则将头部设置为不显示                    ChildView.setVisibility(INVISIBLE);                }            }        }        //刷新        invalidate();    }

先来解释下firstVisibleItemvisibleItemCounttotalItemCount这三个变量是什么意思哈,挺重要的。
firstVisibleItem,官方文档是这样写的:int: the index of the first visible cell (ignore if visibleItemCount == 0)
由于本人英语渣渣,经过不靠谱的有道翻译,再加上自己打log试,大致懂了,它其实就是可见View中的第一个索引,也就是在可见View中的第一个视图的索引值,再用下图来解释下,如下:

在该图中的firstVisibleItem就是“面食类”的索引值,它的索引就是0了,所以firstVisibleItem就是0了。
visibleItemCount,这个值想半天想不懂,然后经过刘某人的指点懂了,哈哈,就这个界面log值出来的和我数的值总是差1(我数的少),很纳闷儿,因为我们都知道计算机计数都是从0开始的,但是我若是从0开始数(面食类算第0个元素)就和log值出来的少1了,问刘某人后,老刘说最上面的那个也算,也就是说,visibleItemCount计数是从最上面的那个ListViewLinkage开始计的,恍然大悟啊~
totalItemCount,就简单了totalItemCount = firstVisibleItem + visibleItemCount;
然后剩下的……就是代码注释的那样了…
getSectionHeaderView()代码如下:

    private View getSectionHeaderView(int section, View oldView) {        //是否显示,即,section不等于当前显示的section,且View不为空        boolean shouldLayout = section != mCurrentSection || oldView == null;        //获取View        View view = mAdapter.getSectionHeaderView(section, oldView, this);        if (shouldLayout) {            //显示标头            ensureHaveHeaderLayout(view);            //并将section赋值给mCurrentSection            mCurrentSection = section;        }        //返回加载好的View        return view;    }

ensureHaveHeaderLayout()代码如下:

    private void ensureHaveHeaderLayout(View header) {        if (header.isLayoutRequested()) {            //设置宽(返回值是测量值+mode值)            int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), mWidthMode);            int heightSpec;            //父布局参数            ViewGroup.LayoutParams layoutParams = header.getLayoutParams();            if (layoutParams != null && layoutParams.height > 0) {                //若有父布局则header高为父布局的                heightSpec = MeasureSpec.makeMeasureSpec(layoutParams.height, MeasureSpec.EXACTLY);            } else {                //否则,header高为自适应大小                heightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);            }            //设置header宽高            header.measure(widthSpec, heightSpec);            //设置header相对于父布局的位置,左,上,右,下            header.layout(0, 0, header.getMeasuredWidth(), header.getMeasuredHeight());        }    }

只有这样还是不行的,虽然这里的逻辑有了,但是最重要的绘制还没有呢,重写dispatchDraw()方法,代码如下:

    @Override    protected void dispatchDraw(Canvas canvas) {        super.dispatchDraw(canvas);        if (mAdapter == null || !mShouldPin || mCurrentHeader == null) {            //adapter为空,mShouldPin为false,mCurrentHeader为空,则不绘制            return;        }        //保存Canvas状态        int saveCount = canvas.save();        //平移        canvas.translate(0, mHeaderOffset);        //设置显示范围,左,上,右,下        canvas.clipRect(0, 0, getWidth(), mCurrentHeader.getMeasuredHeight());        mCurrentHeader.draw(canvas);        //恢复Canvas状态        canvas.restoreToCount(saveCount);    }

同样,注释都写上了……

自定义控件怎么能少的了测量呢,重写onMeasure()方法,代码如下:

    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        //宽        mWidthMode = MeasureSpec.getMode(widthMeasureSpec);        //高        mHeightMode = MeasureSpec.getMode(heightMeasureSpec);    }

当然,setAdapter()方法也要重写,代码如下:

    public void setAdapter(ListAdapter adapter) {        mCurrentHeader = null;        mAdapter = (HaveHeaderAdapter) adapter;        super.setAdapter(adapter);    }

由于现在的点击事件不同了,所以点击事件的代码如下:

    public static abstract class OnItemClickListener implements AdapterView.OnItemClickListener {        @Override        public void onItemClick(AdapterView<?> parent, View view, int rawPosition, long id) {            CustomizeLVBaseAdapter adapter;            if (parent.getAdapter().getClass().equals(HeaderViewListAdapter.class)) {                HeaderViewListAdapter wrapperAdapter = (HeaderViewListAdapter) parent.getAdapter();                adapter = (CustomizeLVBaseAdapter) wrapperAdapter.getWrappedAdapter();            } else {                adapter = (CustomizeLVBaseAdapter) parent.getAdapter();            }            int section = adapter.getSectionForPosition(rawPosition);            int position = adapter.getPositionInSectionForPosition(rawPosition);            if (position == -1) {                onSectionClick(parent, view, section, id);            } else {                onItemClick(parent, view, section, position, id);            }        }        public abstract void onItemClick(AdapterView<?> adapterView, View view, int section, int position, long id);        public abstract void onSectionClick(AdapterView<?> adapterView, View view, int section, long id);    }

最后该自定义ListView的完整代码如下:

import android.content.Context;import android.graphics.Canvas;import android.util.AttributeSet;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.AdapterView;import android.widget.HeaderViewListAdapter;import android.widget.ListAdapter;import android.widget.ListView;import com.example.lilinxiong.listviewlinkage.Adapter.CustomizeLVBaseAdapter;/** * 项目名:  ListViewLinkage * 包名:    com.example.lilinxiong.listviewlinkage.View * 文件名:   HaveHeaderListView * 创建者:   LLX * 创建时间:  2017/4/17 16:56 * 描述:    带有标题的ListView */public class HaveHeaderListView extends ListView implements AbsListView.OnScrollListener {    //滑动监听    private OnScrollListener mOnScrollListener;    //相对应的适配器    public interface HaveHeaderAdapter {        boolean isSectionHeader(int position);        int getSectionForPosition(int position);        View getSectionHeaderView(int section, View convertView, ViewGroup parent);        int getSectionHeaderViewType(int section);        int getCount();    }    private HaveHeaderAdapter mAdapter;    //标题    private View mCurrentHeader;    //默认显示第几个标题    private int mCurrentHeaderViewType = 0;    //标题距顶部的距离    private float mHeaderOffset;    //是否显示    private boolean mShouldPin = true;    //当前部分    private int mCurrentSection = 0;    //宽度    private int mWidthMode;    //高度    private int mHeightMode;    public HaveHeaderListView(Context context) {        super(context);        super.setOnScrollListener(this);    }    public HaveHeaderListView(Context context, AttributeSet attrs) {        super(context, attrs);        super.setOnScrollListener(this);    }    public HaveHeaderListView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        super.setOnScrollListener(this);    }    //重写绑定适配器    @Override    public void setAdapter(ListAdapter adapter) {        mCurrentHeader = null;        mAdapter = (HaveHeaderAdapter) adapter;        super.setAdapter(adapter);    }    //滚动    @Override    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {        if (mOnScrollListener != null) {            mOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);        }        if (mAdapter == null || mAdapter.getCount() == 0 || !mShouldPin) {            //当适配器为空或适配器中无数据或mShouldPin为false或者可见视同中第一个索引小于0则return            return;        }        //根据可见视图的第一个索引去获取section        int section = mAdapter.getSectionForPosition(firstVisibleItem);        //根据获取到的section去获取viewType        int viewType = mAdapter.getSectionHeaderViewType(section);        //获取标题        mCurrentHeader = getSectionHeaderView(section, mCurrentHeader);        //更换标题        ensureHaveHeaderLayout(mCurrentHeader);        //改成当前标题所对应的值        mCurrentHeaderViewType = viewType;        //设置标题距顶部距离        mHeaderOffset = 0.0f;        for (int i = firstVisibleItem; i < firstVisibleItem + visibleItemCount; i++) {            if (mAdapter.isSectionHeader(i)) {                //得到真实的子Item的值                View ChildView = getChildAt(i - firstVisibleItem);                //得到子Item距顶部的距离                float ChildViewTop = ChildView.getTop();                //得到子Item的高度                float ChildViewHeight = ChildView.getMeasuredHeight();                //将子Item设置为显示                ChildView.setVisibility(VISIBLE);                if (ChildViewHeight >= ChildViewTop && ChildViewTop > 0) {                    //当子Item的高度>子Item距顶部的距离时,则标题应该逐步消失                    mHeaderOffset = ChildViewTop - ChildViewHeight;                } else if (ChildViewTop <= 0) {                    //子Item距离小于0则将头部设置为不显示                    ChildView.setVisibility(INVISIBLE);                }            }        }        //刷新        invalidate();    }    //滑动状态改变    @Override    public void onScrollStateChanged(AbsListView view, int scrollState) {        if (mOnScrollListener != null) {            mOnScrollListener.onScrollStateChanged(view, scrollState);        }    }    //事件分发子组件绘制    @Override    protected void dispatchDraw(Canvas canvas) {        super.dispatchDraw(canvas);        if (mAdapter == null || !mShouldPin || mCurrentHeader == null) {            //adapter为空,mShouldPin为false,mCurrentHeader为空,则不绘制            return;        }        //保存Canvas状态        int saveCount = canvas.save();        //平移        canvas.translate(0, mHeaderOffset);        //设置显示范围,左,上,右,下        canvas.clipRect(0, 0, getWidth(), mCurrentHeader.getMeasuredHeight());        mCurrentHeader.draw(canvas);        //恢复Canvas状态        canvas.restoreToCount(saveCount);    }    //测量    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        //宽        mWidthMode = MeasureSpec.getMode(widthMeasureSpec);        //高        mHeightMode = MeasureSpec.getMode(heightMeasureSpec);    }    //设置滑动监听    @Override    public void setOnScrollListener(OnScrollListener l) {        mOnScrollListener = l;    }    private View getSectionHeaderView(int section, View oldView) {        //是否显示,即,section不等于当前显示的section,且View不为空        boolean shouldLayout = section != mCurrentSection || oldView == null;        //获取View        View view = mAdapter.getSectionHeaderView(section, oldView, this);        if (shouldLayout) {            //显示标头            ensureHaveHeaderLayout(view);            //并将section赋值给mCurrentSection            mCurrentSection = section;        }        //返回加载好的View        return view;    }    //显示标题    private void ensureHaveHeaderLayout(View header) {        if (header.isLayoutRequested()) {            //设置宽(返回值是测量值+mode值)            int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), mWidthMode);            int heightSpec;            //父布局参数            ViewGroup.LayoutParams layoutParams = header.getLayoutParams();            if (layoutParams != null && layoutParams.height > 0) {                //若有父布局则header高为父布局的                heightSpec = MeasureSpec.makeMeasureSpec(layoutParams.height, MeasureSpec.EXACTLY);            } else {                //否则,header高为自适应大小                heightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);            }            //设置header宽高            header.measure(widthSpec, heightSpec);            //设置header相对于父布局的位置,左,上,右,下            header.layout(0, 0, header.getMeasuredWidth(), header.getMeasuredHeight());        }    }    //设置点击监听    public void setOnItemClickListener(OnItemClickListener listener) {        super.setOnItemClickListener(listener);    }    public static abstract class OnItemClickListener implements AdapterView.OnItemClickListener {        @Override        public void onItemClick(AdapterView<?> parent, View view, int rawPosition, long id) {            CustomizeLVBaseAdapter adapter;            if (parent.getAdapter().getClass().equals(HeaderViewListAdapter.class)) {                HeaderViewListAdapter wrapperAdapter = (HeaderViewListAdapter) parent.getAdapter();                adapter = (CustomizeLVBaseAdapter) wrapperAdapter.getWrappedAdapter();            } else {                adapter = (CustomizeLVBaseAdapter) parent.getAdapter();            }            int section = adapter.getSectionForPosition(rawPosition);            int position = adapter.getPositionInSectionForPosition(rawPosition);            if (position == -1) {                onSectionClick(parent, view, section, id);            } else {                onItemClick(parent, view, section, position, id);            }        }        public abstract void onItemClick(AdapterView<?> adapterView, View view, int section, int position, long id);        public abstract void onSectionClick(AdapterView<?> adapterView, View view, int section, long id);    }}

自定义ListView完了,那么该相对应的自定义Adapter了吧~


普通的ListView的Adapter直接继承BaseAdapter就好了,但是我们这个自定义ListView的Adapter再继承BaseAdapter就不行了,因为有那个mCurrentHeader贼烦,好气啊,刚出一坑就又入一坑了,但是这个自定义Adapter的坑并不大,比起上面的那个ListView简单多了,首先我们要了解我们要写一个什么样的Adapter的,肯定是希望把我们那个有mCurrentHeader的相关数据加进去呗,并且我们在刚才的这个自定义ListView中已经都写了相应的Adapter了,现在只要实现就好了,即,自定义的Adapter应该extends BaseAdapter且!implements HaveHeaderListView.HaveHeaderAdapter,不多说,上代码啦~:

import android.util.SparseArray;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import com.example.lilinxiong.listviewlinkage.View.HaveHeaderListView;/** * 项目名:  ListViewLinkage * 包名:    com.example.lilinxiong.listviewlinkage.Adapter * 文件名:   CustomizeLVBaseAdapter * 创建者:   LLX * 创建时间:  2017/4/17 18:42 * 描述:    带有标题ListView的Adapter */public abstract class CustomizeLVBaseAdapter extends BaseAdapter implements HaveHeaderListView.HaveHeaderAdapter {    private static int HEADER_VIEW_TYPE = 0;    private static int ITEM_VIEW_TYPE = 0;    private SparseArray<Integer> mSectionPositionCache;    private SparseArray<Integer> mSectionCache;    private SparseArray<Integer> mSectionCountCache;    private int mCount;    private int mSectionCount;    public CustomizeLVBaseAdapter() {        super();        mSectionPositionCache = new SparseArray<Integer>();        mSectionCache = new SparseArray<Integer>();        mSectionCountCache = new SparseArray<Integer>();        mCount = -1;        mSectionCount = -1;    }    @Override    public void notifyDataSetChanged() {        mSectionCache.clear();        mSectionPositionCache.clear();        mSectionCountCache.clear();        mCount = -1;        mSectionCount = -1;        super.notifyDataSetChanged();    }    @Override    public void notifyDataSetInvalidated() {        mSectionCache.clear();        mSectionPositionCache.clear();        mSectionCountCache.clear();        mCount = -1;        mSectionCount = -1;        super.notifyDataSetInvalidated();    }    @Override    public final int getCount() {        if (mCount >= 0) {            return mCount;        }        int count = 0;        for (int i = 0; i < internalGetSectionCount(); i++) {            count += internalGetCountForSection(i);            count++;        }        mCount = count;        return count;    }    @Override    public final Object getItem(int position) {        return getItem(getSectionForPosition(position), getPositionInSectionForPosition(position));    }    @Override    public final long getItemId(int position) {        return getItemId(getSectionForPosition(position), getPositionInSectionForPosition(position));    }    @Override    public final View getView(int position, View convertView, ViewGroup parent) {        if (isSectionHeader(position)) {            return getSectionHeaderView(getSectionForPosition(position), convertView, parent);        }        return getItemView(getSectionForPosition(position), getPositionInSectionForPosition(position), convertView, parent);    }    @Override    public final int getItemViewType(int position) {        if (isSectionHeader(position)) {            return getItemViewTypeCount() + getSectionHeaderViewType(getSectionForPosition(position));        }        return getItemViewType(getSectionForPosition(position), getPositionInSectionForPosition(position));    }    @Override    public final int getViewTypeCount() {        return getItemViewTypeCount() + getSectionHeaderViewTypeCount();    }    public final int getSectionForPosition(int position) {        Integer cachedSection = mSectionCache.get(position);        if (cachedSection != null) {            return cachedSection;        }        int sectionStart = 0;        for (int i = 0; i < internalGetSectionCount(); i++) {            int sectionCount = internalGetCountForSection(i);            int sectionEnd = sectionStart + sectionCount + 1;            if (position >= sectionStart && position < sectionEnd) {                mSectionCache.put(position, i);                return i;            }            sectionStart = sectionEnd;        }        return 0;    }    public int getPositionInSectionForPosition(int position) {        Integer cachedPosition = mSectionPositionCache.get(position);        if (cachedPosition != null) {            return cachedPosition;        }        int sectionStart = 0;        for (int i = 0; i < internalGetSectionCount(); i++) {            int sectionCount = internalGetCountForSection(i);            int sectionEnd = sectionStart + sectionCount + 1;            if (position >= sectionStart && position < sectionEnd) {                int positionInSection = position - sectionStart - 1;                mSectionPositionCache.put(position, positionInSection);                return positionInSection;            }            sectionStart = sectionEnd;        }        return 0;    }    public final boolean isSectionHeader(int position) {        int sectionStart = 0;        for (int i = 0; i < internalGetSectionCount(); i++) {            if (position == sectionStart) {                return true;            } else if (position < sectionStart) {                return false;            }            sectionStart += internalGetCountForSection(i) + 1;        }        return false;    }    public int getItemViewType(int section, int position) {        return ITEM_VIEW_TYPE;    }    public int getItemViewTypeCount() {        return 1;    }    public int getSectionHeaderViewType(int section) {        return HEADER_VIEW_TYPE;    }    public int getSectionHeaderViewTypeCount() {        return 1;    }    public abstract Object getItem(int section, int position);    public abstract long getItemId(int section, int position);    public abstract int getSectionCount();    public abstract int getCountForSection(int section);    public abstract View getItemView(int section, int position, View convertView, ViewGroup parent);    public abstract View getSectionHeaderView(int section, View convertView, ViewGroup parent);    private int internalGetCountForSection(int section) {        Integer cachedSectionCount = mSectionCountCache.get(section);        if (cachedSectionCount != null) {            return cachedSectionCount;        }        int sectionCount = getCountForSection(section);        mSectionCountCache.put(section, sectionCount);        return sectionCount;    }    private int internalGetSectionCount() {        if (mSectionCount >= 0) {            return mSectionCount;        }        mSectionCount = getSectionCount();        return mSectionCount;    }}

就不多解释了哈,因为这个……实在是没什么可解释的了。

布局!


布局……直接上代码吧,没啥说的。
activity_main.xml如下:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="horizontal">    <ListView        android:id="@+id/lv_left"        android:layout_width="0dp"        android:layout_height="match_parent"        android:layout_weight="2"        android:divider="@null"        android:scrollbars="none" />    <com.example.lilinxiong.listviewlinkage.View.HaveHeaderListView        android:id="@+id/lv_right"        android:layout_width="0dp"        android:layout_height="match_parent"        android:layout_marginLeft="10dp"        android:layout_weight="5"        android:background="@android:color/white" /></LinearLayout>

左侧ListView的Item,lv_item_left.xml如下:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#EBEDF0"    android:orientation="vertical">    <TextView        android:id="@+id/lv_left_item_text"        android:layout_width="match_parent"        android:layout_height="60dp"        android:layout_gravity="center"        android:gravity="center"        android:padding="10dp"        android:text="面食类"        android:textColor="#444444" /></LinearLayout>

右侧ListView的标题Item,lv_customize_item_header.xml如下:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:background="#EBEDF0"    android:orientation="horizontal">    <TextView        android:id="@+id/lv_customize_item_header_text"        android:layout_width="match_parent"        android:layout_height="30dp"        android:layout_gravity="center_vertical"        android:layout_marginLeft="10dp"        android:gravity="center_vertical"        android:paddingLeft="6dp"        android:text="面食类"        android:textColor="#444444" /></LinearLayout>

右侧ListView的内容Item,lv_customize_item_right.xml如下:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#FFFFFF"    android:orientation="horizontal">    <ImageView        android:id="@+id/lv_customize_item_image"        android:layout_width="50dp"        android:layout_height="50dp"        android:layout_gravity="center"        android:scaleType="fitXY"        android:src="@mipmap/ic_launcher" />    <TextView        android:id="@+id/lv_customize_item_text"        android:layout_width="match_parent"        android:layout_height="50dp"        android:layout_gravity="center"        android:gravity="center_vertical"        android:paddingLeft="6dp"        android:text="热干面"        android:textColor="#2F333A" /></LinearLayout>

两个ListView的Adapter!


左侧ListView的Adapter,LeftAdapter.java如下:

import android.content.Context;import android.graphics.Color;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.TextView;import com.example.lilinxiong.listviewlinkage.R;import java.util.List;/** * 项目名:  ListViewLinkage * 包名:    com.example.lilinxiong.listviewlinkage.Adapter * 文件名:   LeftAdapter * 创建者:   LLX * 创建时间:  2017/4/17 19:04 * 描述:    左侧Adapter */public class LeftAdapter extends BaseAdapter {    //标题    private List<String> leftStr;    //标志    private List<Boolean> flagArray;    private LayoutInflater inflater;    public LeftAdapter(Context mContext, List<String> leftStr, List<Boolean> flagArray) {        this.leftStr = leftStr;        this.flagArray = flagArray;        inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);    }    @Override    public int getCount() {        return leftStr.size();    }    @Override    public Object getItem(int position) {        return position;    }    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ViewHolder holder = null;        if (convertView == null) {            holder = new ViewHolder();            //加载            convertView = inflater.inflate(R.layout.lv_item_left, parent, false);            //绑定            holder.lv_left_item_text = (TextView) convertView.findViewById(R.id.lv_left_item_text);            convertView.setTag(holder);        } else {            holder = (ViewHolder) convertView.getTag();        }        //设置数据        holder.lv_left_item_text.setText(leftStr.get(position));        //根据标志位,设置背景颜色        if (flagArray.get(position)) {            holder.lv_left_item_text.setBackgroundColor(Color.rgb(255, 255, 255));        } else {            holder.lv_left_item_text.setBackgroundColor(Color.TRANSPARENT);        }        return convertView;    }    class ViewHolder {        private TextView lv_left_item_text;    }}

右侧ListView的Adapter,RightAdapter.java如下:

import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;import com.example.lilinxiong.listviewlinkage.R;import java.util.List;/** * 项目名:  ListViewLinkage * 包名:    com.example.lilinxiong.listviewlinkage.Adapter * 文件名:   RightAdapter * 创建者:   LLX * 创建时间:  2017/4/17 19:03 * 描述:    右侧ListViewAdapter */public class RightAdapter extends CustomizeLVBaseAdapter {    //上下文    private Context mContext;    //标题    private List<String> leftStr;    //内容    private List<List<String>> rightStr;    private LayoutInflater inflater;    public RightAdapter(Context mContext, List<String> leftStr, List<List<String>> rightStr) {        this.mContext = mContext;        this.leftStr = leftStr;        this.rightStr = rightStr;        //系统服务        inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);    }    @Override    public Object getItem(int section, int position) {        return rightStr.get(section).get(position);    }    @Override    public long getItemId(int section, int position) {        return position;    }    @Override    public int getSectionCount() {        return leftStr.size();    }    @Override    public int getCountForSection(int section) {        return rightStr.get(section).size();    }    @Override    public View getItemView(final int section, final int position, View convertView, ViewGroup parent) {        ChildViewHolder holder = null;        if (convertView == null) {            holder = new ChildViewHolder();            //加载            convertView = inflater.inflate(R.layout.lv_customize_item_right, parent, false);            //绑定            holder.lv_customize_item_image = (ImageView) convertView.findViewById(R.id.lv_customize_item_image);            holder.lv_customize_item_text = (TextView) convertView.findViewById(R.id.lv_customize_item_text);            convertView.setTag(holder);        } else {            holder = (ChildViewHolder) convertView.getTag();        }        //设置内容        holder.lv_customize_item_text.setText(rightStr.get(section).get(position));        //点击事件        convertView.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                Toast.makeText(mContext, rightStr.get(section).get(position), Toast.LENGTH_SHORT).show();            }        });        return convertView;    }    @Override    public View getSectionHeaderView(int section, View convertView, ViewGroup parent) {        HeaderViewHolder holder = null;        if (convertView == null) {            holder = new HeaderViewHolder();            //加载            convertView = inflater.inflate(R.layout.lv_customize_item_header, parent, false);            //绑定            holder.lv_customize_item_header_text = (TextView) convertView.findViewById(R.id.lv_customize_item_header_text);            convertView.setTag(holder);        } else {            holder = (HeaderViewHolder) convertView.getTag();        }        //不可点击        convertView.setClickable(false);        //设置标题        holder.lv_customize_item_header_text.setText(leftStr.get(section));        return convertView;    }    class ChildViewHolder {        //Item图片        private ImageView lv_customize_item_image;        //Item内容        private TextView lv_customize_item_text;    }    class HeaderViewHolder {        //标题        private TextView lv_customize_item_header_text;    }}

最后一步,MainActivity


所有的都准备好了,布局,Adapter,最后让我们在MainActivity中实现吧~


声明所需的变量:

    //左边的ListView    private ListView lv_left;    //左边ListView的Adapter    private LeftAdapter leftAdapter;    //左边的数据存储    private List<String> leftStr;    //左边数据的标志    private List<Boolean> flagArray;    //右边的ListView    private HaveHeaderListView lv_right;    //右边的ListView的Adapter    private RightAdapter rightAdapter;    //右边的数据存储    private List<List<String>> rightStr;    //是否滑动标志位    private Boolean isScroll = false;

初始化控件**initView();**initView代码如下:

    private void initView() {        lv_left = (ListView) findViewById(R.id.lv_left);        leftStr = new ArrayList<>();        flagArray = new ArrayList<>();        leftAdapter = new LeftAdapter(MainActivity.this, leftStr, flagArray);        lv_left.setAdapter(leftAdapter);        lv_right = (HaveHeaderListView) findViewById(R.id.lv_right);        rightStr = new ArrayList<List<String>>();        rightAdapter = new RightAdapter(MainActivity.this, leftStr, rightStr);        lv_right.setAdapter(rightAdapter);    }

初始化数据**initData();**initData代码如下:

    private void initData() {        //左边相关数据        leftStr.add("面食类");        leftStr.add("盖饭");        leftStr.add("寿司");        leftStr.add("烧烤");        leftStr.add("酒水");        leftStr.add("凉菜");        leftStr.add("小吃");        leftStr.add("粥");        flagArray.add(true);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        leftAdapter.notifyDataSetChanged();        //右边相关数据        //面食类        List<String> food1 = new ArrayList<>();        food1.add("热干面");        food1.add("臊子面");        food1.add("烩面");        //盖饭        List<String> food2 = new ArrayList<>();        food2.add("番茄鸡蛋");        food2.add("红烧排骨");        food2.add("农家小炒肉");        //寿司        List<String> food3 = new ArrayList<>();        food3.add("芝士");        food3.add("丑小丫");        food3.add("金枪鱼");        //烧烤        List<String> food4 = new ArrayList<>();        food4.add("羊肉串");        food4.add("烤鸡翅");        food4.add("烤羊排");        //酒水        List<String> food5 = new ArrayList<>();        food5.add("长城干红");        food5.add("燕京鲜啤");        food5.add("青岛鲜啤");        //凉菜        List<String> food6 = new ArrayList<>();        food6.add("拌粉丝");        food6.add("大拌菜");        food6.add("菠菜花生");        //小吃        List<String> food7 = new ArrayList<>();        food7.add("小食组");        food7.add("紫薯");        //粥        List<String> food8 = new ArrayList<>();        food8.add("小米粥");        food8.add("大米粥");        food8.add("南瓜粥");        food8.add("玉米粥");        food8.add("紫米粥");        rightStr.add(food1);        rightStr.add(food2);        rightStr.add(food3);        rightStr.add(food4);        rightStr.add(food5);        rightStr.add(food6);        rightStr.add(food7);        rightStr.add(food8);        rightAdapter.notifyDataSetChanged();    }

凑合看哈,实际开发中绝对不能这么干的,但是现在为了省事儿,为了数据不同,请各位大佬允许我这么干哈,嘿嘿!


现在控件绑定了,数据也有了,那就来处理下左边ListView的点击事件吧,逻辑就是,点击后,相应的标志位置为true,其他的为false,然后右边的ListView显示相应的位置,大致逻辑就是这个了,代码如下:

        lv_left.setOnItemClickListener(new AdapterView.OnItemClickListener() {            @Override            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {                isScroll = false;                for (int i = 0; i < leftStr.size(); i++) {                    if (i == position) {                        flagArray.set(i, true);                    } else {                        flagArray.set(i, false);                    }                }                //更新                leftAdapter.notifyDataSetChanged();                int rightSection = 0;                for (int i = 0; i < position; i++) {                    //查找                    rightSection += rightAdapter.getCountForSection(i) + 1;                }                //显示到rightSection所代表的标题                lv_right.setSelection(rightSection);            }        });

右边的ListView的就比较简单了,通过上下滑动来判断该显示那个标题,且!相对应的标志位置为true,左边ListView根据标志位flagArray更新,具体代码如下:

        lv_right.setOnScrollListener(new AbsListView.OnScrollListener() {            @Override            public void onScrollStateChanged(AbsListView view, int scrollState) {                switch (scrollState) {                    // 当不滚动时                    case AbsListView.OnScrollListener.SCROLL_STATE_IDLE:                        // 判断滚动到底部                        if (lv_right.getLastVisiblePosition() == (lv_right.getCount() - 1)) {                            lv_left.setSelection(ListView.FOCUS_DOWN);                        }                        // 判断滚动到顶部                        if (lv_right.getFirstVisiblePosition() == 0) {                            lv_left.setSelection(0);                        }                        break;                }            }            int y = 0;            int x = 0;            @Override            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {                if (isScroll) {                    for (int i = 0; i < rightStr.size(); i++) {                        if (i == rightAdapter.getSectionForPosition(lv_right.getFirstVisiblePosition())) {                            flagArray.set(i, true);                            //获取当前标题的标志位                            x = i;                        } else {                            flagArray.set(i, false);                        }                    }                    if (x != y) {                        leftAdapter.notifyDataSetChanged();                        //将之前的标志位赋值给y,下次判断                        y = x;                    }                } else {                    isScroll = true;                }            }        });

OK,这样就好了,最后,MainActivity.java的完整代码如下:

import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.AbsListView;import android.widget.AdapterView;import android.widget.ListView;import com.example.lilinxiong.listviewlinkage.Adapter.LeftAdapter;import com.example.lilinxiong.listviewlinkage.Adapter.RightAdapter;import com.example.lilinxiong.listviewlinkage.View.HaveHeaderListView;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    //左边的ListView    private ListView lv_left;    //左边ListView的Adapter    private LeftAdapter leftAdapter;    //左边的数据存储    private List<String> leftStr;    //左边数据的标志    private List<Boolean> flagArray;    //右边的ListView    private HaveHeaderListView lv_right;    //右边的ListView的Adapter    private RightAdapter rightAdapter;    //右边的数据存储    private List<List<String>> rightStr;    //是否滑动标志位    private Boolean isScroll = false;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //初始化控件        initView();        //初始化数据        initData();        lv_left.setOnItemClickListener(new AdapterView.OnItemClickListener() {            @Override            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {                isScroll = false;                for (int i = 0; i < leftStr.size(); i++) {                    if (i == position) {                        flagArray.set(i, true);                    } else {                        flagArray.set(i, false);                    }                }                //更新                leftAdapter.notifyDataSetChanged();                int rightSection = 0;                for (int i = 0; i < position; i++) {                    //查找                    rightSection += rightAdapter.getCountForSection(i) + 1;                }                //显示到rightSection所代表的标题                lv_right.setSelection(rightSection);            }        });        lv_right.setOnScrollListener(new AbsListView.OnScrollListener() {            @Override            public void onScrollStateChanged(AbsListView view, int scrollState) {                switch (scrollState) {                    // 当不滚动时                    case AbsListView.OnScrollListener.SCROLL_STATE_IDLE:                        // 判断滚动到底部                        if (lv_right.getLastVisiblePosition() == (lv_right.getCount() - 1)) {                            lv_left.setSelection(ListView.FOCUS_DOWN);                        }                        // 判断滚动到顶部                        if (lv_right.getFirstVisiblePosition() == 0) {                            lv_left.setSelection(0);                        }                        break;                }            }            int y = 0;            int x = 0;            @Override            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {                if (isScroll) {                    for (int i = 0; i < rightStr.size(); i++) {                        if (i == rightAdapter.getSectionForPosition(lv_right.getFirstVisiblePosition())) {                            flagArray.set(i, true);                            //获取当前标题的标志位                            x = i;                        } else {                            flagArray.set(i, false);                        }                    }                    if (x != y) {                        leftAdapter.notifyDataSetChanged();                        //将之前的标志位赋值给y,下次判断                        y = x;                    }                } else {                    isScroll = true;                }            }        });    }    private void initData() {        //左边相关数据        leftStr.add("面食类");        leftStr.add("盖饭");        leftStr.add("寿司");        leftStr.add("烧烤");        leftStr.add("酒水");        leftStr.add("凉菜");        leftStr.add("小吃");        leftStr.add("粥");        flagArray.add(true);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        flagArray.add(false);        leftAdapter.notifyDataSetChanged();        //右边相关数据        //面食类        List<String> food1 = new ArrayList<>();        food1.add("热干面");        food1.add("臊子面");        food1.add("烩面");        //盖饭        List<String> food2 = new ArrayList<>();        food2.add("番茄鸡蛋");        food2.add("红烧排骨");        food2.add("农家小炒肉");        //寿司        List<String> food3 = new ArrayList<>();        food3.add("芝士");        food3.add("丑小丫");        food3.add("金枪鱼");        //烧烤        List<String> food4 = new ArrayList<>();        food4.add("羊肉串");        food4.add("烤鸡翅");        food4.add("烤羊排");        //酒水        List<String> food5 = new ArrayList<>();        food5.add("长城干红");        food5.add("燕京鲜啤");        food5.add("青岛鲜啤");        //凉菜        List<String> food6 = new ArrayList<>();        food6.add("拌粉丝");        food6.add("大拌菜");        food6.add("菠菜花生");        //小吃        List<String> food7 = new ArrayList<>();        food7.add("小食组");        food7.add("紫薯");        //粥        List<String> food8 = new ArrayList<>();        food8.add("小米粥");        food8.add("大米粥");        food8.add("南瓜粥");        food8.add("玉米粥");        food8.add("紫米粥");        rightStr.add(food1);        rightStr.add(food2);        rightStr.add(food3);        rightStr.add(food4);        rightStr.add(food5);        rightStr.add(food6);        rightStr.add(food7);        rightStr.add(food8);        rightAdapter.notifyDataSetChanged();    }    private void initView() {        lv_left = (ListView) findViewById(R.id.lv_left);        leftStr = new ArrayList<>();        flagArray = new ArrayList<>();        leftAdapter = new LeftAdapter(MainActivity.this, leftStr, flagArray);        lv_left.setAdapter(leftAdapter);        lv_right = (HaveHeaderListView) findViewById(R.id.lv_right);        rightStr = new ArrayList<List<String>>();        rightAdapter = new RightAdapter(MainActivity.this, leftStr, rightStr);        lv_right.setAdapter(rightAdapter);    }}

这是第一个自己理解(当然也有那个Demo的帮助哈)的自定义控件,一开始感觉好难,好难,但是最后写出来后,发现也挺有趣的,但是说真的,坑真不少啊!

然后在布局的ImageView中用了android:scaleType属性,不懂的小伙伴可以去这里[Android] ImageView.ScaleType设置图解
在Adapter中使用了SparseArray<>不懂的小伙伴可以去这里Android编程之SparseArray详解
其他的就是大家常用的了,最后我们再来看下我们的效果图吧:


大家若是有什么不懂的,可以在下面评论区中留言哈,我看到后会回的,另外对android有兴趣的同学可以加我们程序员刘某人的群:555974449(若满则加后面的)、484167109,群里面有很多大神的,而且很热情,很热心的,大家不懂的可以问的。


到这里车开完了~~~送你到终点站源码地址,欢迎各位吐槽……

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