Android实战简易教程<十九>(SwipeRefreshLayout下拉刷新使用实例)
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我们来看SwipeRefreshLayout的具体用法,顾名思义此组件就是一个布局,只不过要注意的是此布局内只能有一个直接子View。其实通过文档我们可以知道SwipeRefreshLayout只不过是继承了ViewGroup。
查看文档,我们可以知道,在SwipRefreshLayout中存在一个接口,通过此接口我们可以监听滑动手势,其实使用此组件最重要的步骤就是实现此接口的onRefresh方法,在此方法中实现数据的更新操作。如下:
接口中的方法:
除了OnRefreshListener接口外,SwipRefreshLayout中还有一些其他重要的方法,具体如下:
1、setOnRefreshListener(SwipeRefreshLayout.OnRefreshListener listener):设置手势滑动监听器。
2、setProgressBackgroundColor(int colorRes):设置进度圈的背景色。
3、setColorSchemeResources(int… colorResIds):设置进度动画的颜色。
4、setRefreshing(Boolean refreshing):设置组件的刷新状态。
5、setSize(int size):设置进度圈的大小,只有两个值:DEFAULT、LARGE。
下面我们通过一个实例来看一下具体怎么用
1.main.xml:
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="match_parent"
- android:layout_height="match_parent" >
-
- <android.support.v4.widget.SwipeRefreshLayout
- android:id="@+id/swipe_refresh"
- android:layout_width="match_parent"
- android:layout_height="match_parent" >
-
- <ListView
- android:id="@+id/listview"
- android:layout_width="match_parent"
- android:layout_height="match_parent" >
- </ListView>
- </android.support.v4.widget.SwipeRefreshLayout>
-
- </LinearLayout>
2.list_item.xml:- <?xml version="1.0" encoding="utf-8"?>
- <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="match_parent"
- android:layout_height="wrap_content" >
-
- <TextView
- android:id="@+id/item_name"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_margin="15dp"
- android:gravity="center"
- android:singleLine="true"
- android:textSize="16sp"
- android:textStyle="bold" />
-
- </RelativeLayout>
3.ItemInfo.java:
- package com.demo.downrefresh;
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-
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- public class ItemInfo {
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-
-
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- private int id;
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-
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- private String name;
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- public int getId() {
- return id;
- }
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- public void setId(int id) {
- this.id = id;
- }
-
- public String getName() {
- return name;
- }
-
- public void setName(String name) {
- this.name = name;
- }
-
- }
4.ListViewAdapter.java:- package com.demo.downrefresh;
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- import java.util.List;
-
- import android.content.Context;
- import android.view.LayoutInflater;
- import android.view.View;
- import android.view.ViewGroup;
- import android.widget.ArrayAdapter;
- import android.widget.TextView;
-
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-
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- public class ListViewAdapter extends ArrayAdapter<ItemInfo> {
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- private LayoutInflater inflater;
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- public ListViewAdapter(Context context, List<ItemInfo> list) {
- super(context, 0, list);
- inflater = LayoutInflater.from(context);
- }
-
- @Override
- public View getView(int position, View convertView, ViewGroup parent) {
- ItemInfo info = getItem(position);
-
- if (convertView == null) {
- convertView = inflater.inflate(R.layout.item_listview, null);
- }
-
- TextView name = (TextView) convertView.findViewById(R.id.item_name);
- name.setText(info.getName());
-
- return convertView;
- }
-
- }
5.MainActivity.java:- package com.demo.downrefresh;
-
- import java.util.ArrayList;
- import java.util.List;
-
- import android.R.integer;
- import android.app.Activity;
- import android.os.Bundle;
- import android.os.Handler;
- import android.support.v4.widget.SwipeRefreshLayout;
- import android.widget.ListView;
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- public class MainActivity extends Activity implements SwipeRefreshLayout.OnRefreshListener {
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- private SwipeRefreshLayout swipeLayout;
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- private ListView listView;
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- private ListViewAdapter adapter;
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- private List<ItemInfo> infoList;
- private int i=0;
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- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
-
- swipeLayout = (SwipeRefreshLayout) this.findViewById(R.id.swipe_refresh);
- swipeLayout.setOnRefreshListener(this);
-
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- swipeLayout.setColorScheme(android.R.color.holo_red_light, android.R.color.holo_green_light,
- android.R.color.holo_blue_bright, android.R.color.holo_orange_light);
-
- infoList = new ArrayList<ItemInfo>();
- ItemInfo info = new ItemInfo();
- info.setName("coin");
- infoList.add(info);
- listView = (ListView) this.findViewById(R.id.listview);
- adapter = new ListViewAdapter(this, infoList);
- listView.setAdapter(adapter);
- }
-
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- public void onRefresh() {
- new Handler().postDelayed(new Runnable() {
- public void run() {
- swipeLayout.setRefreshing(false);
-
- ItemInfo info = new ItemInfo();
- info.setName("coin-refresh"+i);
- infoList.add(info);
- i++;
-
-
- adapter.notifyDataSetChanged();
- }
- }, 500);
- }
- }
6.运行实例如下:总结
1.此布局内只能有一个直接子View;
2.setOnRefreshListener(SwipeRefreshLayout.OnRefreshListener listener):设置手势滑动监听器;
3.覆写public void onRefresh()。
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