首先要定义一个footer.xml作为进度条和提示加载中的底部布局,代码如下:
<LinearLayout android:id="@+id/load_layout" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center" android:orientation="horizontal" android:paddingBottom="10dip" android:paddingTop="10dip" tools:ignore="UselessParent" > <ProgressBar style="?android:attr/progressBarStyleLargeInverse" android:layout_width="30dp" android:layout_height="30dp" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="正在加载......" android:textSize="16sp" tools:ignore="HardcodedText" /> </LinearLayout>
这样的显示效果就是这样的:
然后自定义一个LoadListView,继承自ListView,实现其三个构造方法:
public LoadListView(Context context) { super(context); initView(context); } public LoadListView(Context context, AttributeSet attrs) { super(context, attrs); initView(context); } public LoadListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initView(context); }
其中initView()是通过inflater初始化布局的,代码:
private void initView(Context context){ LayoutInflater inflater = LayoutInflater.from(context); footer = inflater.inflate(R.layout.footer, null); footer.findViewById(R.id.load_layout).setVisibility(GONE); this.addFooterView(footer); this.setOnScrollListener(this); }
然后,实现实现它的滑动事件接口,(详见代码,这里只说过程),目的是为了监听ListView上滑到底部的时候,显示那个【加载更多...】提示信息,然后实现加载更多的函数运行,达到加载出更多数据。
那么问题来了,加在了更多数据是重新设置数据适配器吗?答案当然是不可以重新设置,这里我们首先判断adapter是否为空,如果是空的,就setAdaper(),如果不是,其实就是加载更多以后,我们不去重新设置,而是调用this.notifyDataSetChanged(); //当有数据变化的时候,ListView会自动刷新界面。这样很好的保证了数据不会重新设置,效果还不错。
if(adapter == null){ adapter = new FenleiAdapter(FenleiActivity.this, newsBeans); mListView.setAdapter(adapter); }else { adapter.onDateChange(newsBeans); }
public void onDateChange(List<FenleiBean> mList) { // TODO Auto-generated method stub this.mList = mList; this.notifyDataSetChanged(); //当有数据变化的时候,自动刷新界面 }
继续,这个时候我们会遇到一个问题,就是在自定义类LoadListView中,怎么去调用MainActivity中的方法,答案是接口回调,大概的意思就是在LoadListView中定义一个接口,然后去MainActivity具体实现这个接口,调用的时候,通过ListView变量来调用,具体我也只是大致明白这个意思,如果不明白可以再百度一下。
当ListView通过findViewById()找到控件id的时候,不要忘了将这个接口设置给ListView,代码是mListView.setInterface(this);
最后的最后要在加载完数据之后,去把提示消息设置为隐藏,这样,整个就大功告成了!!!
最后的效果如图:
[上滑效果] [加载更多以后的效果]
LoadListView.java源码(具体还要根据你的项目去写)
package com.tdyl.consult.fenlei; import com.tdyl.consult.R; import android.content.Context; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.View; import android.widget.AbsListView; import android.widget.AbsListView.OnScrollListener; import android.widget.ListView; public class LoadListView extends ListView implements OnScrollListener { View footer; int totalItemCount; int lastVisibleItem; boolean isLoading; ILoadListener2 iListener2; public LoadListView(Context context) { super(context); initView(context); } public LoadListView(Context context, AttributeSet attrs) { super(context, attrs); initView(context); } public LoadListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initView(context); } private void initView(Context context){ LayoutInflater inflater = LayoutInflater.from(context); footer = inflater.inflate(R.layout.footer, null); footer.findViewById(R.id.load_layout).setVisibility(GONE); this.addFooterView(footer); this.setOnScrollListener(this); } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { this.lastVisibleItem = firstVisibleItem + visibleItemCount; this.totalItemCount = totalItemCount; } @Override public void onScrollStateChanged(AbsListView view, int scrollStatus) { if(totalItemCount == lastVisibleItem && scrollStatus == SCROLL_STATE_IDLE){ if(!isLoading){ isLoading = true; footer.findViewById(R.id.load_layout).setVisibility(VISIBLE); //加载更多数据 iListener2.onLoad(); } } } public void loadComplete(){ isLoading = false; footer.findViewById(R.id.load_layout).setVisibility(GONE); } public void setInterface(ILoadListener2 iListener2){ this.iListener2 = iListener2; } public interface ILoadListener2{ public void onl oad(); } }
package com.tdyl.consult.fenlei; import com.tdyl.consult.R; import android.content.Context; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.View; import android.widget.AbsListView; import android.widget.AbsListView.OnScrollListener; import android.widget.ListView; public class LoadListView extends ListView implements OnScrollListener { View footer; int totalItemCount; int lastVisibleItem; boolean isLoading; ILoadListener2 iListener2; public LoadListView(Context context) { super(context); initView(context); } public LoadListView(Context context, AttributeSet attrs) { super(context, attrs); initView(context); } public LoadListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initView(context); } private void initView(Context context){ LayoutInflater inflater = LayoutInflater.from(context); footer = inflater.inflate(R.layout.footer, null); footer.findViewById(R.id.load_layout).setVisibility(GONE); this.addFooterView(footer); this.setOnScrollListener(this); } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { this.lastVisibleItem = firstVisibleItem + visibleItemCount; this.totalItemCount = totalItemCount; } @Override public void onScrollStateChanged(AbsListView view, int scrollStatus) { if(totalItemCount == lastVisibleItem && scrollStatus == SCROLL_STATE_IDLE){ if(!isLoading){ isLoading = true; footer.findViewById(R.id.load_layout).setVisibility(VISIBLE); //加载更多数据 iListener2.onLoad(); } } } public void loadComplete(){ isLoading = false; footer.findViewById(R.id.load_layout).setVisibility(GONE); } public void setInterface(ILoadListener2 iListener2){ this.iListener2 = iListener2; } public interface ILoadListener2{ public void onl oad(); } }
MainActivity.java源码(我这里叫FenleiActivity.java,道理是一样的)
package com.tdyl.consult.fenlei; import java.io.IOException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; 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.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.Intent; import android.os.AsyncTask; import android.os.Bundle; import android.os.Handler; import android.util.Log; import android.view.View; import android.view.Window; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.ListView; import android.widget.TextView; import com.tdyl.consult.R; import com.tdyl.consult.fenlei.LoadListView.ILoadListener2; import com.tdyl.consult.otochat.ChatOtoActivity; public class FenleiActivity extends Activity implements ILoadListener2 { private LoadListView mListView; private String user_fenlei = ""; private TextView title_name; int number = 10; FenleiAdapter adapter = null; ArrayList <HashMap<String,Object>> list=new ArrayList<HashMap<String,Object>>(); //用来存放用户信息 HashMap<String, Object> map = new HashMap<String, Object>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_fenlei); title_name = (TextView) findViewById(R.id.id_top_fenlei); mListView = (LoadListView) findViewById(R.id.lv_main); mListView.setInterface(this); Intent intent = getIntent(); user_fenlei = intent.getStringExtra("user_fenlei"); //----------------------------------------------------------------------------- title_name.setText(user_fenlei+"专家"); new NewsAsynkTask().execute(number); } /** * 将url对应的json格式数据转化为我们缩封装的NewsBean对象 * @param url * @return */ private List<FenleiBean> getJsonData(int number){ List<FenleiBean> newsBeanList = new ArrayList<FenleiBean>(); //----------------------------------------------------------------------------- searchTop10(number); FenleiBean newsBean; if(list.size() == 0) { new AlertDialog.Builder(this) .setIcon(R.drawable.icon_menu) .setTitle("温馨小提示") .setMessage("没有要搜寻的专家分类") .setPositiveButton("立刻返回搜索界面...", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { finish(); } }).show(); } for(int i=0;i<list.size();i++) { newsBean = new FenleiBean(); HashMap<String, Object> map1 = new HashMap<String, Object>(); map1 = list.get(i); newsBean.newsIconUrl = map1.get("user_touxiangURL").toString(); newsBean.newTitle = map1.get("username").toString(); newsBean.newsContent = map1.get("user_qianming").toString(); newsBean.newsJifen = map1.get("user_jifen").toString(); newsBeanList.add(newsBean); } return newsBeanList; } /** * 实现网络的异步访问 * @author Lenovo * */ class NewsAsynkTask extends AsyncTask<Integer,Void, List<FenleiBean>>{ @Override protected List<FenleiBean> doInBackground(Integer... params) { return getJsonData(params[0]); } @Override protected void onPostExecute(List<FenleiBean> newsBeans) { // TODO Auto-generated method stub super.onPostExecute(newsBeans); if(adapter == null){ adapter = new FenleiAdapter(FenleiActivity.this, newsBeans); mListView.setAdapter(adapter); }else { adapter.onDateChange(newsBeans); } mListView.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // TODO Auto-generated method stub HashMap<String, Object> map1 = list.get(position); Intent intent=new Intent(); intent.setClass(FenleiActivity.this,ChatOtoActivity.class); intent.putExtra("username", map1.get("username").toString()); //用户名传到另一个界面 System.out.println("username"+map1.get("username").toString()); intent.putExtra("touxiang", map1.get("user_touxiangURL").toString()); //头像地址 //启动 startActivity(intent); //Toast.makeText(FenleiActivity.this, "点击了"+newsBean.get("username"),Toast.LENGTH_SHORT).show(); } }); } } /** * 查询用户分类信息函数,放入list中,通过关键字key来取出 * */ public void searchTop10(int number) { //命名空间 String nameSpace = "http://wsServer.gnuhpc.org/"; //方法名字 String methodName = "SearchTeacherTop10"; // endPoint String endPoint = "http://10.0.2.2:8080/wsServerHello"; //soapAction String soapAction = "http://wsServer.gnuhpc.org/SearchTeacherTop10"; //指定调用方法命名空间和方法名字 SoapObject rpc = new SoapObject(nameSpace, methodName); //调用方法时需要传入一个参数 //为了与web service保持一致,需要设置为arg0,因为web service会自动将其转化为arg0 arg1 rpc.addProperty("arg0",user_fenlei); rpc.addProperty("arg1",number); try { //wsdl地址 HttpTransportSE transport = new HttpTransportSE(endPoint); transport.debug= true; //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); envelope.bodyOut = rpc; //设置是否调用的是dotNet开发的WebService,服务器是.net的需要设置为true,java不用 envelope.dotNet = false; envelope.setOutputSoapObject(rpc); System.out.println("rpc:"+rpc); System.out.println("enevlope:"+envelope); System.out.println("---基本服务设置完毕,下面开始调用服务"); Log.v("---调用消息:", "开始call函数"); transport.call(soapAction, envelope); Log.v("---函数结果:", ""+envelope.getResponse()); if(envelope.getResponse()!=null) { // 获取返回的数据 SoapObject object = (SoapObject) envelope.bodyIn; System.out.println("---object:"+object); System.out.println("---获取数据成功!"); System.out.println("object.toString():"+object.toString()); // 获取返回的结果 ,将结果存入到一个Map中 System.out.println(object.getProperty(0)); int count = object.getPropertyCount(); System.out.println("#######################"+count); for(int index = 0; index < count; index = index + 5) //表中有五个关键字,循环条件+5 { map = new HashMap<String, Object>(); map.put("username", object.getProperty(index).toString()); //用户名 map.put("user_fenlei", object.getProperty(index+1).toString()); //分类 map.put("user_qianming", object.getProperty(index+2).toString()); //签名 map.put("user_touxiangURL", object.getProperty(index+3).toString()); //在线状态 map.put("user_jifen", object.getProperty(index+4).toString()); //积分 list.add(map); } System.out.println("list的值为:"+list); } else{ Log.v("----连接消息:", "连接失败"); } } catch (SoapFault e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (XmlPullParserException e) { e.printStackTrace(); } } @Override public void onl oad() { //获取更多数据 Handler handler = new Handler(); handler.postDelayed(new Runnable() { @Override public void run() { number=number+2; //每次多显示两条数据 new NewsAsynkTask().execute(number); //通知listView显示更新,加载完毕 /** * 设置默认显示为Listview最后一行 */ mListView.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL); mListView.setStackFromBottom(true); //通知listView加载完毕,底部布局消失 mListView.loadComplete(); } }, 1000); } }
package com.tdyl.consult.fenlei; import java.io.IOException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; 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.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.Intent; import android.os.AsyncTask; import android.os.Bundle; import android.os.Handler; import android.util.Log; import android.view.View; import android.view.Window; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.ListView; import android.widget.TextView; import com.tdyl.consult.R; import com.tdyl.consult.fenlei.LoadListView.ILoadListener2; import com.tdyl.consult.otochat.ChatOtoActivity; public class FenleiActivity extends Activity implements ILoadListener2 { private LoadListView mListView; private String user_fenlei = ""; private TextView title_name; int number = 10; FenleiAdapter adapter = null; ArrayList <HashMap<String,Object>> list=new ArrayList<HashMap<String,Object>>(); //用来存放用户信息 HashMap<String, Object> map = new HashMap<String, Object>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_fenlei); title_name = (TextView) findViewById(R.id.id_top_fenlei); mListView = (LoadListView) findViewById(R.id.lv_main); mListView.setInterface(this); Intent intent = getIntent(); user_fenlei = intent.getStringExtra("user_fenlei"); //----------------------------------------------------------------------------- title_name.setText(user_fenlei+"专家"); new NewsAsynkTask().execute(number); } /** * 将url对应的json格式数据转化为我们缩封装的NewsBean对象 * @param url * @return */ private List<FenleiBean> getJsonData(int number){ List<FenleiBean> newsBeanList = new ArrayList<FenleiBean>(); //----------------------------------------------------------------------------- searchTop10(number); FenleiBean newsBean; if(list.size() == 0) { new AlertDialog.Builder(this) .setIcon(R.drawable.icon_menu) .setTitle("温馨小提示") .setMessage("没有要搜寻的专家分类") .setPositiveButton("立刻返回搜索界面...", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { finish(); } }).show(); } for(int i=0;i<list.size();i++) { newsBean = new FenleiBean(); HashMap<String, Object> map1 = new HashMap<String, Object>(); map1 = list.get(i); newsBean.newsIconUrl = map1.get("user_touxiangURL").toString(); newsBean.newTitle = map1.get("username").toString(); newsBean.newsContent = map1.get("user_qianming").toString(); newsBean.newsJifen = map1.get("user_jifen").toString(); newsBeanList.add(newsBean); } return newsBeanList; } /** * 实现网络的异步访问 * @author Lenovo * */ class NewsAsynkTask extends AsyncTask<Integer,Void, List<FenleiBean>>{ @Override protected List<FenleiBean> doInBackground(Integer... params) { return getJsonData(params[0]); } @Override protected void onPostExecute(List<FenleiBean> newsBeans) { // TODO Auto-generated method stub super.onPostExecute(newsBeans); if(adapter == null){ adapter = new FenleiAdapter(FenleiActivity.this, newsBeans); mListView.setAdapter(adapter); }else { adapter.onDateChange(newsBeans); } mListView.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // TODO Auto-generated method stub HashMap<String, Object> map1 = list.get(position); Intent intent=new Intent(); intent.setClass(FenleiActivity.this,ChatOtoActivity.class); intent.putExtra("username", map1.get("username").toString()); //用户名传到另一个界面 System.out.println("username"+map1.get("username").toString()); intent.putExtra("touxiang", map1.get("user_touxiangURL").toString()); //头像地址 //启动 startActivity(intent); //Toast.makeText(FenleiActivity.this, "点击了"+newsBean.get("username"),Toast.LENGTH_SHORT).show(); } }); } } /** * 查询用户分类信息函数,放入list中,通过关键字key来取出 * */ public void searchTop10(int number) { //命名空间 String nameSpace = "http://wsServer.gnuhpc.org/"; //方法名字 String methodName = "SearchTeacherTop10"; // endPoint String endPoint = "http://10.0.2.2:8080/wsServerHello"; //soapAction String soapAction = "http://wsServer.gnuhpc.org/SearchTeacherTop10"; //指定调用方法命名空间和方法名字 SoapObject rpc = new SoapObject(nameSpace, methodName); //调用方法时需要传入一个参数 //为了与web service保持一致,需要设置为arg0,因为web service会自动将其转化为arg0 arg1 rpc.addProperty("arg0",user_fenlei); rpc.addProperty("arg1",number); try { //wsdl地址 HttpTransportSE transport = new HttpTransportSE(endPoint); transport.debug= true; //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); envelope.bodyOut = rpc; //设置是否调用的是dotNet开发的WebService,服务器是.net的需要设置为true,java不用 envelope.dotNet = false; envelope.setOutputSoapObject(rpc); System.out.println("rpc:"+rpc); System.out.println("enevlope:"+envelope); System.out.println("---基本服务设置完毕,下面开始调用服务"); Log.v("---调用消息:", "开始call函数"); transport.call(soapAction, envelope); Log.v("---函数结果:", ""+envelope.getResponse()); if(envelope.getResponse()!=null) { // 获取返回的数据 SoapObject object = (SoapObject) envelope.bodyIn; System.out.println("---object:"+object); System.out.println("---获取数据成功!"); System.out.println("object.toString():"+object.toString()); // 获取返回的结果 ,将结果存入到一个Map中 System.out.println(object.getProperty(0)); int count = object.getPropertyCount(); System.out.println("#######################"+count); for(int index = 0; index < count; index = index + 5) //表中有五个关键字,循环条件+5 { map = new HashMap<String, Object>(); map.put("username", object.getProperty(index).toString()); //用户名 map.put("user_fenlei", object.getProperty(index+1).toString()); //分类 map.put("user_qianming", object.getProperty(index+2).toString()); //签名 map.put("user_touxiangURL", object.getProperty(index+3).toString()); //在线状态 map.put("user_jifen", object.getProperty(index+4).toString()); //积分 list.add(map); } System.out.println("list的值为:"+list); } else{ Log.v("----连接消息:", "连接失败"); } } catch (SoapFault e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (XmlPullParserException e) { e.printStackTrace(); } } @Override public void onl oad() { //获取更多数据 Handler handler = new Handler(); handler.postDelayed(new Runnable() { @Override public void run() { number=number+2; //每次多显示两条数据 new NewsAsynkTask().execute(number); //通知listView显示更新,加载完毕 /** * 设置默认显示为Listview最后一行 */ mListView.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL); mListView.setStackFromBottom(true); //通知listView加载完毕,底部布局消失 mListView.loadComplete(); } }, 1000); } }
感谢这门视频课程,汲取营养,继续努力......
标签:int,public,context,new,import,Android,ListView,android,加载 From: https://www.cnblogs.com/Alex80/p/17998149