Android下拉菜单效果
一、效果图
二、主要技术点:
1.PopupWindow的使用
2.ListView的使用
三、示例代码
1.布局文件:activity_main.xml
<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" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <EditText android:id="@+id/et" android:layout_width="200dp" android:layout_height="wrap_content" android:inputType="text" /> <ImageView android:id="@+id/iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignRight="@id/et" android:src="@drawable/down_arrow" /> </RelativeLayout>
2.ListView的布局文件:list_item.xml
<?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:gravity="center_vertical" android:orientation="horizontal" > <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/user" /> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:gravity="center" android:text="内容" android:id="@+id/tv_listitem_content"/> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/delete" android:id="@+id/iv_listitem_delete"/> </LinearLayout>
3.主界面MainActivity.java
package com.gnnuit.dropdownlist; import java.util.ArrayList; import java.util.List; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.EditText; import android.widget.ImageView; import android.widget.ListView; import android.widget.PopupWindow; import android.widget.TextView; import android.app.Activity; public class MainActivity extends Activity { private ImageView iv; private PopupWindow popupWindow; private ListView lv; private EditText et; private List<String> strs = new ArrayList<String>(); private MyAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initListView();// 初始化ListView et = (EditText) findViewById(R.id.et); iv = (ImageView) findViewById(R.id.iv); iv.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if (popupWindow == null) { popupWindow = new PopupWindow(MainActivity.this); popupWindow.setContentView(lv); // PopupWindow必须设置高度和宽度 popupWindow.setWidth(et.getWidth()); // 设置宽度 popupWindow.setHeight(200); // 设置popWin 高度 popupWindow.showAsDropDown(et, 0, 0); popupWindow.setOutsideTouchable(true);// 设置后点击其他位置PopupWindow将消失 } else if (popupWindow != null && popupWindow.isShowing()) { popupWindow.dismiss(); } else { popupWindow.showAsDropDown(et); } } }); } /** * 初始化ListView */ private void initListView() { for (int i = 0; i < 10; i++) { strs.add("第" + i + "条记录"); } lv = new ListView(this); if (adapter == null) { adapter = new MyAdapter(); lv.setAdapter(adapter); } else { adapter.notifyDataSetChanged(); } lv.setBackgroundResource(R.drawable.listview_background); lv.setDividerHeight(2); lv.setVerticalScrollBarEnabled(false); } private class MyAdapter extends BaseAdapter { @Override public int getCount() { return strs.size(); } @Override public Object getItem(int position) { return strs.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(final int position, View convertView, ViewGroup parent) { View view; ViewHolder holder; if (convertView == null) { view = View.inflate(MainActivity.this, R.layout.list_item, null); holder = new ViewHolder(); holder.iv = (ImageView) view.findViewById(R.id.iv_listitem_delete); holder.tv = (TextView) view.findViewById(R.id.tv_listitem_content); view.setTag(holder); } else { view = convertView; holder = (ViewHolder) view.getTag(); } holder.tv.setText(strs.get(position)); holder.tv.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { et.setText(strs.get(position)); popupWindow.dismiss(); } }); holder.iv.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // 从List中移除 strs.remove(position); // 更新ListView adapter.notifyDataSetChanged(); } }); return view; } } private class ViewHolder { private TextView tv; private ImageView iv; } }
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