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在Android中，我们可以通过继承View来打造完全如我们所愿的组件，但是，有的时候，我们需要的组件是一个由现有的几个组件的组合实现的，那么我们就可以利用组件合成技术，呵呵，这个名字我自己起的。
在Android中打造复合组件，其实只需要继承Layout或者其子类，比如LinearLayout等，然后在其中定义需要完成该功能的现有的几个组件。
然后定义一个监听器（就是一个简单的接口，暴露给用户使用，获取返回的数据，给用户使用）
本文通过使用两个Spinner来打造一个省份城市信息联动的选择控件，省份和城市信息的联动是开发中经常遇到的，这里我们看看使用组件合成技术如何简单巧妙的实现该功能。本例是雏形，强大的功能待大家完善。
闲话少说，直接上实例：
1、自定义一个CitySpinner，代码：
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package org.widget.spinner;
import java.util.ArrayList;
import java.util.HashMap;
import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.Spinner;
/**
* 自定义复合组件，实现省份城市联动Spinner组件
* 定义复合组件通常继承自Layout，不必重写onDraw,onMesure等方法，除非有特殊的需求
* @author Administrator
*
*/
public class CitySpinner extends LinearLayout {
private Context context;
private Spinner mProvinceSpinner, mCitySpinner;
private HashMap<String, ArrayList<String>> proCities; //存放数据
private ArrayList<String> provinces;
private OnCitySelectListener cityListener;
private AdapterView.OnItemSelectedListener provinceSelectListener = new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> p, View v, int position,
long id) {
// 在选择了一个省份后，我们需要更新对应的城市列表
String currProvince = (String)p.getItemAtPosition(position);
switchCity(currProvince);
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
};
private AdapterView.OnItemSelectedListener citySelectListener = new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> p, View v, int position,
long id) {
if(cityListener != null){
//这里获取当前选择的省份和城市
String province = (String)mProvinceSpinner.getSelectedItem();
String city = (String)p.getItemAtPosition(position);
cityListener.onCitySelected(province, city);
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
//Do nothing;
}
};
public CitySpinner(Context context, HashMap<String, ArrayList<String>> data){
super(context);
this.context = context;
if(data != null){
init(data);
}
}
public CitySpinner(Context context, HashMap<String, ArrayList<String>> data, AttributeSet attrs){
super(context, attrs);
this.context = context;
if(data != null){
init(data);
}
}
private void init(HashMap<String, ArrayList<String>> data){
this.setOrientation(HORIZONTAL); //水平布局
this.setWeightSum(0.5f);
//然后设置省份Spinner的数据
//首先,我们直接在代码中定义组件
// mProvinceSpinner = new Spinner(context);
// mCitySpinner = new Spinner(context);
//我们看看从xml文件中获取
View v = LayoutInflater.from(context).inflate(R.layout.city, null);
mProvinceSpinner = (Spinner)v.findViewById(R.id.province);
mCitySpinner = (Spinner)v.findViewById(R.id.city);
//在将这两个组件添加到新的LinearLayout中时,需要首先将这两个组件从原来的Layout中删除
LinearLayout temp = (LinearLayout)v.findViewById(R.id.layout_city);
temp.removeAllViews();
//添加监听
mProvinceSpinner.setOnItemSelectedListener(provinceSelectListener);
mCitySpinner.setOnItemSelectedListener(citySelectListener);
//如何对其进行定制布局格式呢??待解决
this.proCities = data;
initProvince();
this.addView(mProvinceSpinner,LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
this.addView(mCitySpinner,LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
}
//初始化省份信息
private void initProvince(){
provinces = new ArrayList<String>();
Object[] temps = proCities.keySet().toArray();
for(int i=0; i<temps.length; i++){
provinces.add((String)temps);
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(context, android.R.layout.simple_spinner_item,provinces);
adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
mProvinceSpinner.setAdapter(adapter);
}
//根据当前指定的省份更新对应的城市信息
private void switchCity(String currProvince){
ArrayList<String> cities = proCities.get(currProvince);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(context, android.R.layout.simple_spinner_item,cities);
adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
mCitySpinner.setAdapter(adapter);
}
public Spinner getmProvinceSpinner() {
return mProvinceSpinner;
}
public void setmProvinceSpinner(Spinner mProvinceSpinner) {
this.mProvinceSpinner = mProvinceSpinner;
}
public Spinner getmCitySpinner() {
return mCitySpinner;
}
public void setmCitySpinner(Spinner mCitySpinner) {
this.mCitySpinner = mCitySpinner;
}
public void setOnCitySelectListener(OnCitySelectListener listener){
this.cityListener = listener;
}
}
package org.widget.spinner;import java.util.ArrayList;import java.util.HashMap;import android.content.Context;import android.util.AttributeSet;import android.view.LayoutInflater;import android.view.View;import android.widget.AdapterView;import android.widget.ArrayAdapter;import android.widget.LinearLayout;import android.widget.Spinner;/** * 自定义复合组件，实现省份城市联动Spinner组件 * 定义复合组件通常继承自Layout，不必重写onDraw,onMesure等方法，除非有特殊的需求 * @author Administrator * */public class CitySpinner extends LinearLayout { private Context context; private Spinner mProvinceSpinner, mCitySpinner; private HashMap<String, ArrayList<String>> proCities; //存放数据 private ArrayList<String> provinces; private OnCitySelectListener cityListener; private AdapterView.OnItemSelectedListener provinceSelectListener = new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> p, View v, int position, long id) { // 在选择了一个省份后，我们需要更新对应的城市列表 String currProvince = (String)p.getItemAtPosition(position); switchCity(currProvince); } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub } }; private AdapterView.OnItemSelectedListener citySelectListener = new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> p, View v, int position, long id) { if(cityListener != null){ //这里获取当前选择的省份和城市 String province = (String)mProvinceSpinner.getSelectedItem(); String city = (String)p.getItemAtPosition(position); cityListener.onCitySelected(province, city); } } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub //Do nothing; } }; public CitySpinner(Context context, HashMap<String, ArrayList<String>> data){ super(context); this.context = context; if(data != null){ init(data); } } public CitySpinner(Context context, HashMap<String, ArrayList<String>> data, AttributeSet attrs){ super(context, attrs); this.context = context; if(data != null){ init(data); } } private void init(HashMap<String, ArrayList<String>> data){ this.setOrientation(HORIZONTAL); //水平布局 this.setWeightSum(0.5f); //然后设置省份Spinner的数据 //首先,我们直接在代码中定义组件// mProvinceSpinner = new Spinner(context);// mCitySpinner = new Spinner(context); //我们看看从xml文件中获取 View v = LayoutInflater.from(context).inflate(R.layout.city, null); mProvinceSpinner = (Spinner)v.findViewById(R.id.province); mCitySpinner = (Spinner)v.findViewById(R.id.city); //在将这两个组件添加到新的LinearLayout中时,需要首先将这两个组件从原来的Layout中删除 LinearLayout temp = (LinearLayout)v.findViewById(R.id.layout_city); temp.removeAllViews(); //添加监听 mProvinceSpinner.setOnItemSelectedListener(provinceSelectListener); mCitySpinner.setOnItemSelectedListener(citySelectListener); //如何对其进行定制布局格式呢??待解决 this.proCities = data; initProvince(); this.addView(mProvinceSpinner,LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT); this.addView(mCitySpinner,LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); } //初始化省份信息 private void initProvince(){ provinces = new ArrayList<String>(); Object[] temps = proCities.keySet().toArray(); for(int i=0; i<temps.length; i++){ provinces.add((String)temps); } ArrayAdapter<String> adapter = new ArrayAdapter<String>(context, android.R.layout.simple_spinner_item,provinces); adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line); mProvinceSpinner.setAdapter(adapter); } //根据当前指定的省份更新对应的城市信息 private void switchCity(String currProvince){ ArrayList<String> cities = proCities.get(currProvince); ArrayAdapter<String> adapter = new ArrayAdapter<String>(context, android.R.layout.simple_spinner_item,cities); adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line); mCitySpinner.setAdapter(adapter); } public Spinner getmProvinceSpinner() { return mProvinceSpinner; } public void setmProvinceSpinner(Spinner mProvinceSpinner) { this.mProvinceSpinner = mProvinceSpinner; } public Spinner getmCitySpinner() { return mCitySpinner; } public void setmCitySpinner(Spinner mCitySpinner) { this.mCitySpinner = mCitySpinner; } public void setOnCitySelectListener(OnCitySelectListener listener){ this.cityListener = listener; }}
2、该代码中使用到了一个监听器OnCitySelectListener,其实就是一个简单的接口，在用户使用的时候，由用户来具体实现。
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/**
* 选择事件监听器
* @author Administrator
*
*/
public interface OnCitySelectListener {
public void onCitySelected(String province, String city);
}
/** * 选择事件监听器 * @author Administrator * */public interface OnCitySelectListener { public void onCitySelected(String province, String city);}
3、测试代码，目前不能再配置文件中使用该控件，只能在代码中使用，如何使其能在配置文件中使用，也很简单。后期待完成。代码：
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package demo.spinner;
import java.util.ArrayList;
import java.util.HashMap;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.Toast;
public class DemoActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
HashMap<String, ArrayList<String>> data = new HashMap<String, ArrayList<String>>();
for(int i=0; i<5; i++){
ArrayList<String> cities = new ArrayList<String>();
for(int j=0; j<5; j++){
cities.add("cities"+i+j);
}
data.put("province"+i, cities);
}
final CitySpinner spinner = new CitySpinner(this, data);
LinearLayout layout = (LinearLayout)this.findViewById(R.id.layout_demo);
layout.addView(spinner);
//CitySpinner spinner = (CitySpinner)this.findViewById(R.id.city_spinner);//在布局文件中加入,目前不行，待完善
spinner.setOnCitySelectListener(new OnCitySelectListener() {
@Override
public void onCitySelected(String province, String city) {
//
Toast.makeText(DemoActivity.this, "当前省市："+province+city, Toast.LENGTH_LONG).show();
}
});
}
}
package demo.spinner;import java.util.ArrayList;import java.util.HashMap;import android.app.Activity;import android.os.Bundle;import android.widget.LinearLayout;import android.widget.Toast;public class DemoActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); HashMap<String, ArrayList<String>> data = new HashMap<String, ArrayList<String>>(); for(int i=0; i<5; i++){ ArrayList<String> cities = new ArrayList<String>(); for(int j=0; j<5; j++){ cities.add("cities"+i+j); } data.put("province"+i, cities); } final CitySpinner spinner = new CitySpinner(this, data); LinearLayout layout = (LinearLayout)this.findViewById(R.id.layout_demo); layout.addView(spinner); //CitySpinner spinner = (CitySpinner)this.findViewById(R.id.city_spinner);//在布局文件中加入,目前不行，待完善 spinner.setOnCitySelectListener(new OnCitySelectListener() { @Override public void onCitySelected(String province, String city) { // Toast.makeText(DemoActivity.this, "当前省市："+province+city, Toast.LENGTH_LONG).show(); } }); }}
可以看到，组件合成技术，如此简单而已！ |
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发表于 2011-10-25 09:49:38