android中的下拉菜单联动应用非常普遍,android中的下拉菜单用Spinner就能实现,以下列子通过简单的代码实现三级菜单联动。
一 样式文件
<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="com.example.spinner.MainActivity" > <Spinner android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/spn" android:dropDownWidth="200dp"/> <Spinner android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@id/spn" android:id="@+id/city" android:dropDownWidth="200dp"/> <Spinner android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@id/city" android:id="@+id/counstryside" android:dropDownWidth="200dp"/> </RelativeLayout>
二 联动逻辑代码
package com.example.spinner; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.AdapterView; import android.widget.AdapterView.OnItemSelectedListener; import android.widget.ArrayAdapter; import android.widget.Spinner; /** * @author ZMC * 三级联动主要是灵活的应用三维数组 */ public class MainActivity extends Activity { private String province[] = new String[]{"江西","湖南"}; private Spinner spinner1,spinner2,spinner3; private int provinceindex; private String city [][] = {{"南昌","赣州"},{"长沙","湘潭"}}; private String counstryside [][][] = {{{"青山湖区","南昌县"},{"章贡区","赣县"}},{{"长沙县","沙县"},{"湘潭县","象限"}}}; ArrayAdapter<String> adapter1,adapter2,adapter3; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); spinner1 = (Spinner) findViewById(R.id.spn); adapter1 = new ArrayAdapter<>(this,android.R.layout.simple_dropdown_item_1line,province); spinner1.setAdapter(adapter1); spinner2 = (Spinner)findViewById(R.id.city); adapter2 = new ArrayAdapter<>(this,city[0]); spinner2.setAdapter(adapter2); spinner3 = (Spinner)findViewById(R.id.counstryside); adapter3 = new ArrayAdapter<>(this,counstryside[0][0]); spinner3.setAdapter(adapter3); spinner1.setOnItemSelectedListener(new OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent,View view,int position,long id) { // TODO Auto-generated method stub provinceindex = position; adapter2 = new ArrayAdapter<>(MainActivity.this,city[position]); spinner2.setAdapter(adapter2); } @Override public void onNothingSelected(AdapterView<?> parent) { // TODO Auto-generated method stub } }); spinner2.setOnItemSelectedListener(new OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent,long id) { // TODO Auto-generated method stub adapter3 = new ArrayAdapter<>(MainActivity.this,counstryside[provinceindex][position]); //adapter3.notifyDataSetChanged(); spinner3.setAdapter(adapter3); } @Override public void onNothingSelected(AdapterView<?> parent) { // TODO Auto-generated method stub //当时据为空的时候触发的 } }); } }
三 结果
四 总结
三级联动主要是灵活的应用三维数组,这样能很方便的通过数组索引将三个菜单关联,同时通过设置Spinner的setOnItemSelectedListener来监听选择的动作,动态设置下拉菜单的内容。