Android开发之多级下拉列表菜单实现（仿美团，淘宝等）

我们在常用的电商或者旅游APP中，例如美团，手机淘宝等等，都能够看的到有那种下拉式的二级列表菜单。具体如图所示：

上面两张图就是美团的一个二级列表菜单的一个展示。我相信很多人都想开发一个跟它一样的功能放到自己的APP中。好，接下来我们就开始动手，解决它。

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1）如上图所示，最外围的是一个Activity，顶部包含了一个View的容器，这个容器主要是装载ToggleButton来实现诸如美团里面的“美食，全城，理我最近，刷选”这一行。这一行一点就会弹出对应的下来菜单。

2）下拉菜单是如何实现的呢？，这里我们利用了PopupWindow来实现这一弹出式窗口。然后我们在弹出式窗口里面再定义我们的下来列表项，是单列还是二级菜单，都是由里面来定。

3）不同的菜单，需要一级或者需要二级，在这里根据我的需求而变动。我们在PopupWindow上面加一个自定义的LeftView，或者是MiddleView，RightView。主要是一个ToggleButton，你弹出一个窗口，你就定制一个窗口。

3）视图里面嵌入ListView，就形成了列表项。

好分析就到上面为止，接下来我们一步步的说明实现。

2，项目结构

本项目的项目结构如图所示：

1） Adapter。适配器，主要是为ListView提供数据适配的。

2）MainActivity。主活动页面。

3）ExpandTabView。本项目的核心类，它包含ToggleButton容器和PopupWindow，是控制弹出窗口的核心类。

4）ViewLeft,ViewMiddle,ViewRight。是弹出里面嵌套的类，实现不同的列表菜单。

3，MainActivity

承载所有元素。看代码比看文字实在。

package com.example.expandtabview;


import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.example.view.ExpandTabView;
import com.example.view.ViewLeft;
import com.example.view.ViewMiddle;
import com.example.view.ViewRight;

public class MainActivity extends Activity {
    private static final String TAG = "MainActivity" ;
    private ExpandTabView expandTabView;
    private ArrayList mViewArray = new ArrayList();
    private ViewLeft viewLeft;
    private ViewMiddle viewMiddle;
    private ViewRight viewRight;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super .onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initVaule();
        initListener();

    }

    private void initView() {
        Log.d(TAG, "initView" );
        expandTabView = (ExpandTabView) findViewById(R.id.expandtab_view);
        viewLeft = new ViewLeft( this );
        viewMiddle = new ViewMiddle( this );
        viewRight = new ViewRight( this );

    }

    private void initVaule() {
        Log.d(TAG, "initValue" );
        mViewArray.add(viewLeft);
        mViewArray.add(viewMiddle);
        mViewArray.add(viewRight);
        ArrayList mTextArray = new ArrayList();
        mTextArray.add( "距离" );
        mTextArray.add( "区域" );
        mTextArray.add( "距离" );
        expandTabView.setValue(mTextArray, mViewArray); //将三个下拉列表设置进去
        expandTabView.setTitle(viewLeft.getShowText(), 0 );
        expandTabView.setTitle(viewMiddle.getShowText(), 1 );
        expandTabView.setTitle(viewRight.getShowText(), 2 );

    }

    private void initListener() {
        Log.d(TAG, "initListener" );
        viewLeft.setOnSelectListener( new ViewLeft.OnSelectListener() {

            @Override
            public void getValue(String distance, String showText) {
                Log.d( "ViewLeft" , "OnSelectListener, getValue" );
                onRefresh(viewLeft, showText);
            }
        });

        viewMiddle.setOnSelectListener( new ViewMiddle.OnSelectListener() {

            @Override
            public void getValue(String showText) {
                Log.d( "ViewMiddle" , "OnSelectListener, getValue" );
                onRefresh(viewMiddle,showText);

            }
        });

        viewRight.setOnSelectListener( new ViewRight.OnSelectListener() {

            @Override
            public void getValue(String distance, String showText) {
                Log.d( "ViewRight" , "OnSelectListener, getValue" );
                onRefresh(viewRight, showText);
            }
        });

    }

    private void onRefresh(View view, String showText) {
        Log.d(TAG, "onRefresh,view:" +view+ ",showText:" +showText);
        expandTabView.onPressBack();
        int position = getPositon(view);
        if (position >= 0 && !expandTabView.getTitle(position).equals(showText)) {
            expandTabView.setTitle(showText, position);
        }
        Toast.makeText(MainActivity. this , showText, Toast.LENGTH_SHORT).show();

    }

    private int getPositon(View tView) {
        Log.d(TAG, "getPosition" );
        for ( int i = 0 ; i < mViewArray.size(); i++) {
            if (mViewArray.get(i) == tView) {
                return i;
            }
        }
        return - 1 ;
    }

    @Override
    public void onBackPressed() {

        if (!expandTabView.onPressBack()) {
            finish();
        }

    }

}

4 ，ExpandTabView

最主要就是如何处理当我们点击这些ToggleButton的时候要弹出或者收起这些PopupWindow。

package com.example.view;

import java.util.ArrayList;

import com.example.expandtabview.R;

import android.app.Activity;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.PopupWindow;
import android.widget.PopupWindow.OnDismissListener;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.ToggleButton;

/**
 * 菜单控件头部，封装了下拉动画，动态生成头部按钮个数
 *
 * @author zengjinlong
 */

public class ExpandTabView extends LinearLayout implements OnDismissListener {
    private static final String TAG = "ExpandTabView" ;
    private ToggleButton selectedButton;
    private ArrayList mTextArray = new ArrayList();
    private ArrayList mViewArray = new ArrayList();
    private ArrayList mToggleButton = new ArrayList();
    private Context mContext;
    private final int SMALL = 0 ;
    private int displayWidth;
    private int displayHeight;
    private PopupWindow popupWindow;
    private int selectPosition;

    public ExpandTabView(Context context) {
        super (context);
        init(context);
    }

    public ExpandTabView(Context context, AttributeSet attrs) {
        super (context, attrs);
        init(context);
    }

    /**
     * 根据选择的位置设置tabitem显示的值
     */
    public void setTitle(String valueText, int position) {
        if (position < mToggleButton.size()) {
            mToggleButton.get(position).setText(valueText);
        }
    }

    public void setTitle(String title){

    }
    /**
     * 根据选择的位置获取tabitem显示的值
     */
    public String getTitle( int position) {
        if (position < mToggleButton.size() && mToggleButton.get(position).getText() != null ) {
            return mToggleButton.get(position).getText().toString();
        }
        return "" ;
    }

    /**
     * 设置tabitem的个数和初始值
     * @param textArray 标题数组
     * @param viewArray 控件数组
     */
    public void setValue(ArrayList textArray, ArrayList viewArray) {
        if (mContext == null ) {
            return ;
        }
        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        Log.d(TAG, "setValue" );
        mTextArray = textArray;
        for ( int i = 0 ; i < viewArray.size(); i++) {
            final RelativeLayout r = new RelativeLayout(mContext);
            int maxHeight = ( int ) (displayHeight * 0.7 );
            RelativeLayout.LayoutParams rl = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, maxHeight);
            rl.leftMargin = 10 ;
            rl.rightMargin = 10 ;
            r.addView(viewArray.get(i), rl);
            mViewArray.add(r);
            r.setTag(SMALL);
            ToggleButton tButton = (ToggleButton) inflater.inflate(R.layout.toggle_button, this , false );
            addView(tButton);
            View line = new TextView(mContext);
            line.setBackgroundResource(R.drawable.choosebar_line);
            if (i < viewArray.size() - 1 ) {
                LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams( 2 , LinearLayout.LayoutParams.MATCH_PARENT);
                addView(line, lp);
            }
            mToggleButton.add(tButton);
            tButton.setTag(i);
            tButton.setText(mTextArray.get(i));

            r.setOnClickListener( new OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d( "RelativeLayout" , "view:" +v);
                    onPressBack();
                }
            });

            r.setBackgroundColor(mContext.getResources().getColor(R.color.popup_main_background));
            tButton.setOnClickListener( new OnClickListener() {
                @Override
                public void onClick(View view) {
                    Log.d( "tButton" , "setOnClickListener(l)" );
                    // initPopupWindow();
                    ToggleButton tButton = (ToggleButton) view;

                    if (selectedButton != null && selectedButton != tButton) {
                        selectedButton.setChecked( false );
                    }
                    selectedButton = tButton;
                    selectPosition = (Integer) selectedButton.getTag();
                    startAnimation();
                    if (mOnButtonClickListener != null && tButton.isChecked()) {
                        mOnButtonClickListener.onClick(selectPosition);
                    }
                }
            });
        } // for..
    }

    private void startAnimation() {
        Log.d(TAG, "startAnimation" );
        if (popupWindow == null ) {
            Log.d(TAG, "startAnimation(),new popupWindow now" );
            popupWindow = new PopupWindow(mViewArray.get(selectPosition), displayWidth, displayHeight);
            popupWindow.setAnimationStyle(R.style.PopupWindowAnimation);
            popupWindow.setFocusable( false );
            popupWindow.setOutsideTouchable( true );
        }
        Log.d(TAG, "startAnimation(),selectedButton:" +selectedButton+ ",isChecked:" +selectedButton.isChecked()+
                ",popupWindow.isShowing:" +popupWindow.isShowing());
        if (selectedButton.isChecked()) {

            if (!popupWindow.isShowing()) {
                showPopup(selectPosition);
            } else {
                popupWindow.setOnDismissListener( this );
                popupWindow.dismiss();
                hideView();
            }
        } else {
            if (popupWindow.isShowing()) {
                popupWindow.dismiss();
                hideView();
            }
        }
    }

    private void showPopup( int position) {
        View tView = mViewArray.get(selectPosition).getChildAt( 0 );
        if (tView instanceof ViewBaseAction) {
            ViewBaseAction f = (ViewBaseAction) tView;
            f.show();
        }
        if (popupWindow.getContentView() != mViewArray.get(position)) {
            popupWindow.setContentView(mViewArray.get(position));
        }
        popupWindow.showAsDropDown( this , 0 , 0 );
    }

    /**
     * 如果菜单成展开状态，则让菜单收回去
     */
    public boolean onPressBack() {
        Log.d(TAG, "onPressBack" );
        if (popupWindow != null && popupWindow.isShowing()) {
            popupWindow.dismiss();
            hideView();
            if (selectedButton != null ) {
                selectedButton.setChecked( false );
            }
            return true ;
        } else {
            return false ;
        }

    }

    private void hideView() {
        Log.d(TAG, "hide()" );
        View tView = mViewArray.get(selectPosition).getChildAt( 0 );
        if (tView