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最新推荐文章于 2024-09-09 15:18:36 发布

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最新推荐文章于 2024-09-09 15:18:36 发布

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分类专栏： Android

本文链接：https://blog.youkuaiyun.com/u012360634/article/details/47166591

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本文介绍了一款Android新闻应用如何实现从服务器加载数据、解析JSON格式数据，并展示如何在不同Fragment间传递数据，实现新闻分类浏览等功能。

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1.服务器位置：tomcat--webapp-Root---

2.Json格式化工具：HiJson

3.网络连接的URl放在一个类中，方便管理(放在一个独立的包下)

<span style="font-size:14px;">/**
 * 定义全局参数
 * 
 * @author Kevin
 * 
 */
public class GlobalContants {

	public static final String SERVER_URL = "http://10.0.2.2:8080/zhbj";
	public static final String CATEGORIES_URL = SERVER_URL + "/categories.json";// 获取分类信息的接口

}</span>

4.从服务器获取数据

开源框架：XUtils

需要权限：

<span style="font-size:14px;">    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /></span>

<span style="font-size:14px;">	/**
	 * 从服务器获取数据
	 */
	private void getDataFromServer() {
		HttpUtils utils = new HttpUtils();

		// 使用xutils发送请求
		utils.send(HttpMethod.GET, GlobalContants.CATEGORIES_URL,
				new RequestCallBack<String>() {  //返还的Json数据为String，如果是文件就是File

					// 访问成功
					@Override
					public void onSuccess(ResponseInfo responseInfo) {
						String result = (String) responseInfo.result;
						System.out.println("返回结果:" + result);

						parseData(result);      //解析网络数据
					}

					// 访问失败
					@Override
					public void onFailure(HttpException error, String msg) {
						Toast.makeText(mActivity, msg, Toast.LENGTH_SHORT)
								.show();
						error.printStackTrace();
					}

				});
	}</span>

5.使用Gson解析Json

(1)写一个javabean接收解析结果

包名一般为domain

javabean严格按照Json中结构命名，字段名要完全一致，Gson是按照名称存放数据的

<span style="font-size:14px;">{
    "data": [
        {
            "children": [
                {
                    "id": 10007,
                    "title": "北京",
                    "type": 1,
                    "url": "/10007/list_1.json"
                },
                {
                    "id": 10006,
                    "title": "中国",
                    "type": 1,
                    "url": "/10006/list_1.json"
                },
                {
                    "id": 10008,
                    "title": "国际",
                    "type": 1,
                    "url": "/10008/list_1.json"
                },
                {
                    "id": 10010,
                    "title": "体育",
                    "type": 1,
                    "url": "/10010/list_1.json"
                },
                {
                    "id": 10091,
                    "title": "生活",
                    "type": 1,
                    "url": "/10091/list_1.json"
                },
                {
                    "id": 10012,
                    "title": "旅游",
                    "type": 1,
                    "url": "/10012/list_1.json"
                },
                {
                    "id": 10095,
                    "title": "科技",
                    "type": 1,
                    "url": "/10095/list_1.json"
                },
                {
                    "id": 10009,
                    "title": "军事",
                    "type": 1,
                    "url": "/10009/list_1.json"
                },
                {
                    "id": 10093,
                    "title": "时尚",
                    "type": 1,
                    "url": "/10093/list_1.json"
                },
                {
                    "id": 10011,
                    "title": "财经",
                    "type": 1,
                    "url": "/10011/list_1.json"
                },
                {
                    "id": 10094,
                    "title": "育儿",
                    "type": 1,
                    "url": "/10094/list_1.json"
                },
                {
                    "id": 10105,
                    "title": "汽车",
                    "type": 1,
                    "url": "/10105/list_1.json"
                }
            ],
            "id": 10000,
            "title": "新闻",
            "type": 1
        },
        {
            "id": 10002,
            "title": "专题",
            "type": 10,
            "url": "/10006/list_1.json",
            "url1": "/10007/list1_1.json"
        },
        {
            "id": 10003,
            "title": "组图",
            "type": 2,
            "url": "/10008/list_1.json"
        },
        {
            "dayurl": "",
            "excurl": "",
            "id": 10004,
            "title": "互动",
            "type": 3,
            "weekurl": ""
        }
    ],
    "extend": [
        10007,
        10006,
        10008,
        10014,
        10012,
        10091,
        10009,
        10010,
        10095
    ],
    "retcode": 200
}</span>

a.使用HiJson工具了解Json结构

*：数组一般用ArrayList表示

*：String可以接收Int型

*：解析不到就置空

*：原则：首先定义一个类，如果是数组就用ArrayList，否则就是对象

bean：

<span style="font-size:14px;">/**
 * 网络分类信息的封装
 * 
 * 字段名字必须和服务器返回的字段名一致, 方便gson解析
 * 
 * @author Kevin
 * 
 */
public class NewsData {

	public int retcode;
	public ArrayList<NewsMenuData> data;

	// 侧边栏数据对象
	public class NewsMenuData {
		public String id;
		public String title;
		public int type;
		public String url;

		public ArrayList<NewsTabData> children;

		@Override
		public String toString() {
			return "NewsMenuData [title=" + title + ", children=" + children
					+ "]";
		}
	}

	// 新闻页面下11个子页签的数据对象
	public class NewsTabData {
		public String id;
		public String title;
		public int type;
		public String url;

		@Override
		public String toString() {
			return "NewsTabData [title=" + title + "]";
		}
	}

	@Override
	public String toString() {
		return "NewsData [data=" + data + "]";
	}

}
</span>

(2)解析，使用开源框架Gson

临时代码：

<span style="font-size:14px;">	/**
	 * 解析网络数据
	 * 
	 * @param result
	 */
	protected void parseData(String result) {
		Gson gson = new Gson();
		mNewsData = gson.fromJson(result, NewsData.class);
		System.out.println("解析结果:" + mNewsData);
	}
</span>

6.不同Fragment中传递数据

(1)定义第一个fragment时获取getActivity----对应的activity对象

并标记对应的fragment

<span style="font-size:14px;">transaction.replace(R.id.fl_left_menu, new LeftMenuFragment(),
				FRAGMENT_LEFT_MENU);// 用fragment替换framelayout
		transaction.replace(R.id.fl_content, new ContentFragment(),
				FRAGMENT_CONTENT);</span>

通过activity对象的传递，可以在不同fragment中传递数据，中枢纽带为该Activity

通过标记获得对应fragment

<span style="font-size:14px;">	// 获取主页面fragment
	public ContentFragment getContentFragment() {
		FragmentManager fm = getSupportFragmentManager();
		ContentFragment fragment = (ContentFragment) fm
				.findFragmentByTag(FRAGMENT_CONTENT);

		return fragment;
	}</span>

(2)传递，调用LeftMenusFragment中的set方法传递

<span style="font-size:14px;">		// 刷新测边栏的数据
		MainActivity mainUi = (MainActivity) mActivity;
		LeftMenuFragment leftMenuFragment = mainUi.getLeftMenuFragment();
		leftMenuFragment.setMenuData(mNewsData);</span>

7.点击listview某个item时，保持不变，状态选择器

<span style="font-size:14px;"><selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_enabled="true" android:color="#f00"/>
    <item android:color="@android:color/white"/>

</selector></span>

8.点击侧边栏切换(新闻中)

基类BaseMenuDetailPager

<span style="font-size:14px;">/**
 * 菜单详情页基类
 * 
 * @author Kevin
 * 
 */
public abstract class BaseMenuDetailPager {

	public Activity mActivity;

	public View mRootView;// 根布局对象

	public BaseMenuDetailPager(Activity activity) {
		mActivity = activity;
		mRootView = initViews();
	}

	/**
	 * 初始化界面
	 */
	public abstract View initViews();

	/**
	 * 初始化数据
	 */
	public void initData() {

	}

}</span>

----------------------------------------------简单版-------详细见下-----------------------
(1)新闻 NewsMenuDetailPager

<span style="font-size:14px;">/**
 * 菜单详情页-新闻
 * 
 * @author Kevin
 * 
 */
public class NewsMenuDetailPager extends BaseMenuDetailPager {

	public InteractMenuDetailPager(Activity activity) {
		super(activity);
	}

	@Override
	public View initViews() {
		TextView text = new TextView(mActivity);
		text.setText("菜单详情页-新闻");
		text.setTextColor(Color.RED);
		text.setTextSize(25);
		text.setGravity(Gravity.CENTER);

		return text;
	}

}</span>

(2)互动 InteractMenuDetailPager

<span style="font-size:14px;">/**
 * 菜单详情页-互动
 * 
 * @author Kevin
 * 
 */
public class InteractMenuDetailPager extends BaseMenuDetailPager {

	public InteractMenuDetailPager(Activity activity) {
		super(activity);
	}

	@Override
	public View initViews() {
		TextView text = new TextView(mActivity);
		text.setText("菜单详情页-互动");
		text.setTextColor(Color.RED);
		text.setTextSize(25);
		text.setGravity(Gravity.CENTER);

		return text;
	}

}</span>

(3)组图 PhotoMenuDetailPager

<span style="font-size:14px;">/**
 * 菜单详情页-组图
 * 
 * @author Kevin
 * 
 */
public class PhotoMenuDetailPager extends BaseMenuDetailPager {

	public PhotoMenuDetailPager(Activity activity) {
		super(activity);
	}

	@Override
	public View initViews() {
		TextView text = new TextView(mActivity);
		text.setText("菜单详情页-组图");
		text.setTextColor(Color.RED);
		text.setTextSize(25);
		text.setGravity(Gravity.CENTER);

		return text;
	}

}
</span>

(4)专题 TopicMenuDetailPager

<span style="font-size:14px;">/**
 * 菜单详情页-专题
 * 
 * @author Kevin
 * 
 */
public class TopicMenuDetailPager extends BaseMenuDetailPager {

	public TopicMenuDetailPager(Activity activity) {
		super(activity);
	}

	@Override
	public View initViews() {
		TextView text = new TextView(mActivity);
		text.setText("菜单详情页-专题");
		text.setTextColor(Color.RED);
		text.setTextSize(25);
		text.setGravity(Gravity.CENTER);

		return text;
	}

}</span>

(5)NewCenterPager中的FramLayout填充对应的view

<span style="font-size:14px;"> private ArrayList<BaseMenuDetailPager> mPagers;// 4个菜单详情页的集合
// 准备4个菜单详情页
                mPagers = new ArrayList<BaseMenuDetailPager>();
		mPagers.add(new NewsMenuDetailPager(mActivity,
				mNewsData.data.get(0).children));
		mPagers.add(new TopicMenuDetailPager(mActivity));
		mPagers.add(new PhotoMenuDetailPager(mActivity));
		mPagers.add(new InteractMenuDetailPager(mActivity));

		setCurrentMenuDetailPager(0);// 设置菜单详情页-新闻为默认当前页


	/**
	 * 设置当前菜单详情页,----------------在Left_fragment中调用
	 */
	public void setCurrentMenuDetailPager(int position) {
		BaseMenuDetailPager pager = mPagers.get(position);// 获取当前要显示的菜单详情页
		flContent.removeAllViews();// 清除之前的布局
		flContent.addView(pager.mRootView);// 将菜单详情页的布局设置给帧布局

		// 设置当前页的标题
		NewsMenuData menuData = mNewsData.data.get(position);
		tvTitle.setText(menuData.title);

		pager.initData();// 初始化当前页面的数据
	}</span>

在left_fragment中横跨几个fragment调用NewsCenterPager-------------------MainActivity为中枢

left_fragment：

	/**
	 * 设置当前菜单详情页
	 * 
	 * @param position
	 */
	protected void setCurrentMenuDetailPager(int position) {
		MainActivity mainUi = (MainActivity) mActivity;
		ContentFragment fragment = mainUi.getContentFragment();// 获取主页面fragment
		NewsCenterPager pager = fragment.getNewsCenterPager();// 获取新闻中心页面
		pager.setCurrentMenuDetailPager(position);// 设置当前菜单详情页
	}

MainActivity中：有标记

	// 获取主页面fragment
	public ContentFragment getContentFragment() {
		FragmentManager fm = getSupportFragmentManager();
		ContentFragment fragment = (ContentFragment) fm
				.findFragmentByTag(FRAGMENT_CONTENT);

		return fragment;
	}

ContentFragment中：

	/**
	 * 获取新闻中心页面
	 * 
	 * @return
	 */
	public NewsCenterPager getNewsCenterPager() {
		return (NewsCenterPager) mPagerList.get(1);
	}

成功调用

9.隐藏菜单

 	private void toggleSlidingMenu() {
		MainActivity mainUi = (MainActivity) mActivity;
		SlidingMenu slidingMenu = mainUi.getSlidingMenu();
		slidingMenu.toggle();// 切换状态, 显示时隐藏, 隐藏时显示
	}

10. 新闻中心中的新闻(详细)

(1)添加一个ViewPager

public class NewsMenuDetailPager extends BaseMenuDetailPager {

	private ViewPager mViewPager;

	private ArrayList<TabDetailPager> mPagerList;

	private ArrayList<NewsTabData> mNewsTabData;// 页签网络数据

	public NewsMenuDetailPager(Activity activity,
			ArrayList<NewsTabData> children) {
		super(activity);

		mNewsTabData = children;
	}

	@Override
	public View initViews() {
		View view = View.inflate(mActivity, R.layout.news_menu_detail, null);
		mViewPager = (ViewPager) view.findViewById(R.id.vp_menu_detail);
		return view;
	}

	@Override
	public void initData() {
		mPagerList = new ArrayList<TabDetailPager>();

		// 初始化页签数据
		for (int i = 0; i < mNewsTabData.size(); i++) {
			TabDetailPager pager = new TabDetailPager(mActivity, mNewsTabData.get(i));
			mPagerList.add(pager);
		}

		mViewPager.setAdapter(new MenuDetailAdapter());
	}

	class MenuDetailAdapter extends PagerAdapter {

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

		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			return arg0 == arg1;
		}

		@Override
		public Object instantiateItem(ViewGroup container, int position) {
			TabDetailPager pager = mPagerList.get(position);
			container.addView(pager.mRootView);
			pager.initData();
			return pager.mRootView;
		}

		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			container.removeView((View) object);
		}
	}

}

(2)在ViewPager中添加若干个view