利用Handler实现网络数据下载Json并转换成实体类的封装

本文主要是介绍利用Handler实现网络数据下载Json并转换成实体类的封装，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

NetWorkRunable类

用于实现子线程下载网络数据, 并转换成Json字符串, 然后通过Gson实现与实体类的转换, 所以必须导入Google的Gson包, 并写自己的实体类(记得加上注解)

/*** Created by Lulu on 2016/9/1.* 封装访问网络的类, Handler实现*/
public class NetWorkRunable<T> implements Runnable, Handler.Callback {private final Handler handler;private String url;private Class<T> t;private MyCallback<T> callback;public NetWorkRunable(String url, Class<T> t, MyCallback<T> callback) {this.url = url;this.t = t;this.callback = callback;//Looper.getMainLooper(): 因为Handler如果不指定, 得到的是当前线程的looper//现在直接将主线程的Looper传入!!!handler = new Handler(Looper.getMainLooper(), this);//现在它一定在主线程中执行}@Overridepublic boolean handleMessage(Message msg) {Object o = msg.obj;switch (msg.what) {case 0:callback.onSuccess((T) o);break;case 1:callback.onFailed((Exception) o);break;}//消息不再传递, 被截获return true;}public interface MyCallback<S> {void onSuccess(S s);void onFailed(Exception e);}@Overridepublic void run() {try {HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();connection.setRequestMethod("GET");connection.setDoInput(true);int code = connection.getResponseCode();if (code == 200) {InputStream is = connection.getInputStream();ByteArrayOutputStream bos = new ByteArrayOutputStream();byte[] buffer = new byte[102400];int length;while ((length = is.read(buffer)) != -1) {bos.write(buffer, 0, length);}String str = bos.toString("UTF-8");Gson gson = new Gson();handler.obtainMessage(0, gson.fromJson(str, t)).sendToTarget();} else {handler.obtainMessage(1, new RuntimeException("服务器异常"));}} catch (IOException e) {handler.obtainMessage(1, new RuntimeException("IO出现异常")).sendToTarget();e.printStackTrace();}}
}

测试实体类

public class Entry {@SerializedName("title")private String title;@SerializedName("message")private String message;...//省略getter和setter方法
}

测试Activity

class MainActivity extends AppCompatActivity implements NetWorkRunable.MyCallback<Entry> {private static final String TAG = MainActivity.class.getSimpleName();private WebView webView;private static final String CSS = "<style>img{max-width:100%} </style>";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);webView = (WebView) findViewById(R.id.main_web);String url = "http://www.tngou.net/api/top/show?id=106";new Thread(new NetWorkRunable<>(url, Entry.class, this)).start();}@Overridepublic void onSuccess(Entry entry) {Log.d(TAG, "onSuccess: " + entry.getTitle());setTitle(entry.getTitle());webView.loadDataWithBaseURL("", CSS + entry.getMessage(), "text/html; charset=utf-8", "UTF-8", null);}@Overridepublic void onFailed(Exception e) {webView.loadDataWithBaseURL("", e.getMessage(), "text/html; charset=utf-8", "UTF-8", null);}
}