androidliststring
❶ android green怎么怎么在entity里保存list<String>
可以建立one-to-many的关系,但是个人觉得这种方式不是很合适,没有必要,建议还是让服务器端把返回的list<String>转换成 xxxx,xxx,xxxxx,这样的字符串 然后直接保存到数据库比较方便
❷ 如何在Android中使用listview
创建继承BaseAdapter并实现其抽象方法的类MyListViewAdapter
说明
下面的讲解中,只创建自定义的适配器类,如何使用请参考android中常用控件的使用之ListView
1.创建类MyListViewAdapter
创建类MyListViewAdapter,该类继承BaseAdapter,并实现其抽象方法:
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int getCount();
Object getItem(int position);
long getItemId(int position);
View getView(int position,View convertView,ViewGroup parent);
getCount需要返回有多少个item,也就是说如昌姿最会在listview中展示这么多行
getItem需要返回参数position位置的数据
getItemId返回position就行了
2.给MyListViewAdapter类添加成员变量和构造方法
两个成员变量
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List<String> list;
Context context;
list表示要显示的数据,context变量在生成View对象时需要用到
构造方法:构造方法是为了给两个成员变量赋值
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public MyListViewAdapter(List<String> list , Context context) {
this.list = list;
this.context = context;
}
3.给getCount,getItem,getItemId方法添加代码
getCount需要返回有多少个item,也就是说最会在listview中展示这么多行,所以返回list.size
getItem需要返回参数position位置的数据,也就是list中第position项的值list.get(position)
getItemId返回position就行了
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@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int position) {
return list.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
4.给getView方法添加代码
getView方法是返回位置为position的View对象,第迅明二个参数convertView考虑到资源重用问题,在上下滑动的过程中,需要显示某项的时候才会调用getView方法,而如果有某项被隐藏不显示,就会把不显示那一行的View作为convertView参数传入,如果没有某项被隐藏,convertView值为null。可以通过下面代码中的if(convertView!=null)中的输出来渣绝看哪一行被隐藏了。
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@Override
public View getView(int position, View convertView, ViewGroup parent) {
System.out.println("调用getView方法,显示position="+position+"项");
if(convertView!=null){
TextView t = (TextView) convertView.findViewById(R.id.firstTextView);
System.out.println(t.getText());
}else{
LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = layoutInflater.inflate(R.layout.item_mylistviewadapter, null);
}
TextView t = (TextView)(convertView.findViewById(R.id.firstTextView));
t.setText(list.get(position));
if(position%2==0)
{
t.setBackgroundColor(Color.WHITE);
}
else{
t.setBackgroundColor(Color.GRAY);
}
return convertView;
}
补充:通过xml生成View对象
通过Context对象生成一个LayoutInflater对象
调用LayoutInflater对象的inflate方法生成控件对象,inflate方法的第一个参数为xml文件,第二个参数一般为null。返回值为该xml文件最外层的标签对象。
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LayoutInflater layoutInflater =(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LinearLayout convertView =(LinearLayout)layoutInflater.inflate(R.layout.item_mylistvie
源代码下载
pan..com/s/1ntuQDdv
❸ android开发中如何讲一个list数组转换成String字符串的形式
public class SplitTest {
public static void main(String args[]) {
String str = "a1.png,a2.png,a3.png";// 原始字符串
String[] arrayStr = new String[] {};// 字符数组
List<String> list = new ArrayList<String>();// list
arrayStr = str.split(",");// 字符串转字符数组
list = java.util.Arrays.asList(arrayStr);// 字符数组转list
String[] storeStr = list.toArray(new String[list.size()]);// list转成字符数组
/* 输出字符数组的值 */
for (String s : arrayStr) {
System.out.println(s);
}
System.out.println("-------------");
/* 输出list值 */
for (String s : list) {
System.out.println(s);
}
System.out.println("-------------");
for (String s : storeStr) {
System.out.println(s);
}
System.out.println("-------------");
}
}
❹ android 怎么取list数据
按以下代码可获取到list数据:
package com.example.sdtg.sdsw;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.ksoap2.SoapEnvelope;
import org.ksoap2.SoapFault;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
import org.xmlpull.v1.XmlPullParserException;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
public class ListActivity extends Activity {
// 命名空间
// String nameSpace = "http://tempuri.org/";
// 调用的方法名称
// String methodName = "GetSjSearch";
// EndPoint
// String endPoint = "http://192.168.0.145/webservice2/gswebservice.asmx";
// SOAP Action
// String soapAction = "http://tempuri.org/GetSjSearch";
// List<Map<String, Object>> mList;
ListView ListV;
HashMap<String, Object> map = new HashMap<String, Object>();
private List<Map<String,String>> listItems;
SimpleAdapter mListAdapter;
String name="";
String addr="";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
listItems = new ArrayList<Map<String,String>>();
ListV=(ListView)findViewById(R.id.ListView01);
Handler indicate = new Handler();
//获取主页面传的值
final Intent data = getIntent();
name=data.getStringExtra("Name");
addr=data.getStringExtra("Addr");
new NetAsyncTask().execute();
ListV.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
//获得选中项的HashMap对象
TextView viewtmc = (TextView) arg1.findViewById(R.id.textListmc);
TextView viewdz = (TextView) arg1.findViewById(R.id.textlistdz);
TextView viewid = (TextView) arg1.findViewById(R.id.textlistid);
//String playerChanged = c.getText().toString();
Bundle bundle = new Bundle();
bundle.putString("Name", viewtmc.getText().toString());
bundle.putString("Addr", viewdz.getText().toString());
bundle.putString("ID", viewid.getText().toString());
final Intent data = getIntent();
data.putExtras(bundle);
//跳转回MainActivity
//注意下面的RESULT_OK常量要与回传接收的Activity中onActivityResult()方法一致
ListActivity.this.setResult(RESULT_OK, data);
//关闭当前activity
ListActivity.this.finish();
}
});
};
class NetAsyncTask extends AsyncTask<Object, Object, String> {
@Override
protected void onPostExecute(String result) {
if (result.equals("success")) {
mListAdapter = null;
mListAdapter = new SimpleAdapter(ListActivity.this, listItems, R.layout.item,new String[]{"title", "info", "img"}, new int[]{R.id.textListmc, R.id.textlistdz, R.id.textlistid});
ListV.setAdapter(mListAdapter);
}
super.onPostExecute(result);
}
@Override
protected String doInBackground(Object... params) {
// 命名空间
String nameSpace = "http://tempuri.org/";
// 调用的方法名称
String methodName = "GetSjSearch";
// EndPoint
String endPoint = "http://192.168.0.145/webservice2/gswebservice.asmx";
// SOAP Action
String soapAction = "http://tempuri.org/GetSjSearch";
// 指定WebService的命名空间和调用的方法名
SoapObject rpc = new SoapObject(nameSpace, methodName);
// 设置需调用WebService接口需要传入的两个参数mobileCode、userId
rpc.addProperty("name", name);
rpc.addProperty("address", addr);
// 生成调用WebService方法的SOAP请求信息,并指定SOAP的版本
SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(
SoapEnvelope.VER11);
// SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER12);
envelope.bodyOut = rpc;
// 设置是否调用的是dotNet开发的WebService
envelope.dotNet = true;
// 等价于envelope.bodyOut = rpc;
envelope.setOutputSoapObject(rpc);
HttpTransportSE transport = new HttpTransportSE(endPoint);
try {
// 调用WebService
transport.call(soapAction, envelope);
} catch (Exception e) {
e.printStackTrace();
}
SoapObject object;
// 开始调用远程方法
try {
object = (SoapObject) envelope.getResponse();
int count = object.getPropertyCount();
// 得到服务器传回的数据
int count1 = object.getPropertyCount();
if(count1>0)
{
for (int i = 0; i < count1; i++) {
Map<String,String> listItem = new HashMap<String, String>();
SoapObject soapProvince = (SoapObject)object.getProperty(i);
listItem.put("title", soapProvince.getProperty("DJXX_NSRMC").toString());
listItem.put("info", soapProvince.getProperty("DJXX_ZCDJ").toString());
//listItem.put("img", soapProvince.getProperty("DJXX_NSRSBH").toString());
listItems.add(listItem);
}}
} catch (IOException e) {
e.printStackTrace();
//return "IOException";
}
return "success";
}
}
}
❺ Android是怎么对对数据源中list<String>字段进行Parcelable序列化的
ArrayList<String> photos;
写入
dest.writeStringList(photos);
读取
this.photos=new ArrayList<>();
in.readStringList(this.photos);
注意加粗地方,另一个人回答错了!