Android应用上下拉刷新实现-优快云博客

本文介绍了一个基于Android平台的应用如何实现上下拉刷新功能。通过自定义PullToRefreshListView组件并结合异步任务来更新数据，同时展示了如何通过监听器响应用户的刷新操作。

BaseActivity

public abstract class BaseActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(getActivity());

initView();

initData();
}

//
public abstract int getActivity();
//获取ID
public abstract void initView();
//得到数据
public abstract void initData();

}

HttpUtils

public class HttpUtils {

private static HttpUtils httpUtils;

private HttpListener httpListener;

public static HttpUtils getInstance(){
if(httpUtils == null){
httpUtils = new HttpUtils();
}
return httpUtils;
}

//网络获得请求数据
public void getdata(String url){
Myasynctack asynctack = new Myasynctack();
asynctack.execute(url);

}

class Myasynctack extends AsyncTask<String,Void,String>{

@Override
protected String doInBackground(String... params) {

try {
HttpClient client = new DefaultHttpClient();
//设置请求方式
HttpGet get = new HttpGet(params[0]);

HttpResponse response = client.execute(get);

int statusCode = response.getStatusLine().getStatusCode();

if(statusCode == 200){

//得到请求到的数据
HttpEntity entity = response.getEntity();

String s = EntityUtils.toString(entity);

return s;
}

} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);

httpListener.getjsondata(s);

}

}

//定义接口
public interface HttpListener{

void getjsondata(String json);
}

//向外提供当前的接口
public void setHttpListener(HttpListener httpListener){
this.httpListener = httpListener;

}

}

MainActivity

public class MainActivity extends AppCompatActivity {

private PullToRefreshListView pullToRefreshListView;
private HttpUtils httpUtils = HttpUtils.getInstance();
private String path = "http://www.yulin520.com/a2a/impressApi/news/mergeList?pageSize=15&page=";
private int page =1;
private List<UserBean.DataBean> list = new ArrayList<>();
private MyBase adapter;
private Handler handler = new Handler();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//1.定义方法
initView();

getData();

}
//设置头部底部的视图
private void initView() {
//获取资源ID
pullToRefreshListView = (PullToRefreshListView) findViewById(R.id.pull_listView);

//2.设置模式 BOTH 可以上拉下拉 pull_from_end代表上拉，pull_from_start代表下拉
pullToRefreshListView.setMode(PullToRefreshBase.Mode.BOTH);

//3.都是布尔类型第一个如果为true 时当前设置的就是头部如果第二个为true设置的就是底部
final ILoadingLayout startLoadding = pullToRefreshListView.getLoadingLayoutProxy(true,false);
startLoadding.setPullLabel("下拉刷新");
startLoadding.setRefreshingLabel("正在刷新");
startLoadding.setReleaseLabel("放开刷新");
ILoadingLayout endLoadding = pullToRefreshListView.getLoadingLayoutProxy(false,true);
endLoadding.setPullLabel("上拉加载");
endLoadding.setRefreshingLabel("正在加载");
endLoadding.setReleaseLabel("放开加载");

//4.接口回调上拉下拉
pullToRefreshListView.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {
//11.在下拉完成后被回调
@Override
public void onPullDownToRefresh(PullToRefreshBase<ListView> pullToRefreshBase) {
page =1;
getData();
//12.
handler.postDelayed(new Runnable() {
@Override
public void run() {
//必须在异步中完成在列表没有数据的时候，不再请求接口，调用当前方法
pullToRefreshListView.onRefreshComplete();
}
},2000);

//可以设置刷新的时间....
startLoadding.setLastUpdatedLabel("上次更新时间:"+new SimpleDateFormat("HH:mm").format(new Date(System.currentTimeMillis())));//last最近的,最后一次update修改/更新

}
//11.在上拉完成后被回调
@Override
public void onPullUpToRefresh(PullToRefreshBase<ListView> pullToRefreshBase) {

page+=1;
getData();
//12.
handler.postDelayed(new Runnable() {
@Override
public void run() {

pullToRefreshListView.onRefreshComplete();
}
},2000);

}
});
//9.创建适配器
adapter = new MyBase(list,MainActivity.this);
pullToRefreshListView.setAdapter(adapter);

}

//5.得到数据
public void getData(){

final String url = path+page;

httpUtils.getdata(url);

//6.接口回调得到数据
httpUtils.setHttpListener(new HttpUtils.HttpListener() {
@Override
public void getjsondata(String json) {
//开始解析
Gson gson = new Gson();

UserBean userBean = gson.fromJson(json, UserBean.class);
//7.解析出来的数据
List<UserBean.DataBean> data = userBean.getData();

//8.在list集合中添加数据
Log.i("TAG",data.size()+"");
//如果是第一页的数据清空集合
if(page == 1){
list.clear();
}
//将请求到的数据刷新
list.addAll(data);
//10.刷新适配器
adapter.notifyDataSetChanged();

}
});

}

}

MyBase

public class MyBase extends BaseAdapter {

private List<UserBean.DataBean> list;
private Context context;

public MyBase(List<UserBean.DataBean> list, Context context) {
this.list = list;
this.context = context;
}

@Override
public int getCount() {
return list.size();
}

@Override
public Object getItem(int position) {
return null;
}

@Override
public long getItemId(int position) {
return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

ViewHolder holder;
if(convertView == null){
convertView = View.inflate(context,R.layout.mybase,null);
holder = new ViewHolder();
holder.textView = convertView.findViewById(R.id.textView);
convertView.setTag(holder);

}else{
holder = (ViewHolder) convertView.getTag();
}

holder.textView.setText(list.get(position).getTitle());

return convertView;
}

class ViewHolder{

TextView textView;

}

}

<com.handmark.pulltorefresh.library.PullToRefreshListView
xmlns:ptr="http://schemas.android.com/apk/res-auto"
android:id="@+id/pull_listView"
android:layout_width="match_parent"
android:layout_height="match_parent"
ptr:ptrDrawable="@drawable/default_ptr_flip"
ptr:ptrAnimationStyle="flip"
ptr:ptrHeaderBackground="#383838"
ptr:ptrHeaderTextColor="#FFFFFF"
></com.handmark.pulltorefresh.library.PullToRefreshListView>