利用Handler实现网络数据下载Json并转换成实体类的封装

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    }    @Override    public 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);    }    @Override    public 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>";    @Override    protected 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();    }    @Override    public 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);    }    @Override    public void onFailed(Exception e) {        webView.loadDataWithBaseURL("", e.getMessage(), "text/html; charset=utf-8", "UTF-8", null);    }}

效果图