MainFragment.java是做什么用的？能否详细解释一下它的功能？

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javapackage net.wequick.example.small.app.home;

import android.app.ProgressDialog;import android.content.Context;import android.databinding.DataBindingUtil;import android.os.Bundle;import android.os.Handler;

MainFragment.java

package net.wequick.example.small.app.home; import android.app.ProgressDialog; import android.content.Context; import android.databinding.DataBindingUtil; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.support.annotation.Keep; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.Toast; import net.wequick.example.small.app.home.databinding.FragmentMainBinding; import net.wequick.small.Small; import net.wequick.example.small.lib.utils.UIUtils; import org.json.JSONArray; import org.json.JSONObject; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.ArrayList; import java.util.List; import java.util.Map; /** * Created by galen on 15/11/16. */ @Keep public class MainFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // View rootView = inflater.inflate(R.layout.fragment_main, container, false); FragmentMainBinding binding = DataBindingUtil.inflate(inflater, R.layout.fragment_main, container, false); binding.setHandlers(new MyHandler()); View rootView = binding.getRoot(); // Button button = (Button) rootView.findViewById(R.id.btnDetail); // button.setOnClickListener(new View.OnClickListener() { // @Override // public void onClick(View v) { // Small.openUri("detail?from=app.home", getContext()); // } // }); Button button = (Button) rootView.findViewById(R.id.btnSubDetail); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Small.openUri("detail/sub", getContext()); } }); button = (Button) rootView.findViewById(R.id.btnAbout); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Small.openUri("about", getContext()); } }); button = (Button) rootView.findViewById(R.id.btnLib); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { UIUtils.showToast(getContext(), "Hello World!"); } }); button = (Button) rootView.findViewById(R.id.btnUpgrade); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { checkUpgrade(); } }); return rootView; } private void checkUpgrade() { new UpgradeManager(getContext()).checkUpgrade(); } private static class UpgradeManager { private static class UpdateInfo { public String packageName; public String downloadUrl; } private static class UpgradeInfo { public JSONObject manifest; public List updates; } private interface OnResponseListener { void onResponse(UpgradeInfo info); } private interface OnUpgradeListener { void onUpgrade(boolean succeed); } private static class ResponseHandler extends Handler { private OnResponseListener mListener; public ResponseHandler(OnResponseListener listener) { mListener = listener; } @Override public void handleMessage(Message msg) { switch (msg.what) { case 1: mListener.onResponse((UpgradeInfo) msg.obj); break; } } } private ResponseHandler mResponseHandler; private Context mContext; private ProgressDialog mProgressDlg; public UpgradeManager(Context context) { mContext = context; } public void checkUpgrade() { mProgressDlg = ProgressDialog.show(mContext, "Small", "Checking for updates..."); requestUpgradeInfo(Small.getBundleVersions(), new OnResponseListener() { @Override public void onResponse(UpgradeInfo info) { mProgressDlg.setMessage("Upgrading..."); upgradeBundles(info, new OnUpgradeListener() { @Override public void onUpgrade(boolean succeed) { mProgressDlg.dismiss(); mProgressDlg = null; String text = succeed ? "Upgrade Success! Switch to background and back to foreground to see changes." : "Upgrade Failed!"; Toast.makeText(mContext, text, Toast.LENGTH_SHORT).show(); } }); } }); } /** * * @param versions * @param listener */ private void requestUpgradeInfo(Map versions, OnResponseListener listener) { System.out.println(versions); // this should be passed as HTTP parameters mResponseHandler = new ResponseHandler(listener); new Thread() { @Override public void run() { try { // Example HTTP request to get the upgrade bundles information. // Json format see wequick.github.io/small/upgrade/bundles.json URL url = new URL("wequick.github.io/small/upgrade/bundles.json"); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); StringBuilder sb = new StringBuilder(); InputStream is = conn.getInputStream(); byte[] buffer = new byte[1024]; int length; while ((length = is.read(buffer)) != -1) { sb.append(new String(buffer, 0, length)); } // Parse json JSONObject jo = new JSONObject(sb.toString()); JSONObject mf = jo.has("manifest") ? jo.getJSONObject("manifest") : null; JSONArray updates = jo.getJSONArray("updates"); int N = updates.length(); List infos = new ArrayList (N); for (int i = 0; i < N; i++) { JSONObject o = updates.getJSONObject(i); UpdateInfo info = new UpdateInfo(); info.packageName = o.getString("pkg"); info.downloadUrl = o.getString("url"); infos.add(info); } // Post message UpgradeInfo ui = new UpgradeInfo(); ui.manifest = mf; ui.updates = infos; Message.obtain(mResponseHandler, 1, ui).sendToTarget(); } catch (Exception e) { e.printStackTrace(); } } }.start(); } private static class DownloadHandler extends Handler { private OnUpgradeListener mListener; public DownloadHandler(OnUpgradeListener listener) { mListener = listener; } @Override public void handleMessage(Message msg) { switch (msg.what) { case 1: mListener.onUpgrade((Boolean) msg.obj); break; } } } private DownloadHandler mHandler; private void upgradeBundles(final UpgradeInfo info, final OnUpgradeListener listener) { // Just for example, you can do this by OkHttp or something. mHandler = new DownloadHandler(listener); new Thread() { @Override public void run() { try { // Update manifest if (info.manifest != null) { if (!Small.updateManifest(info.manifest, false)) { Message.obtain(mHandler, 1, false).sendToTarget(); return; } } // Download bundles List updates = info.updates; for (UpdateInfo u : updates) { // Get the patch file for downloading net.wequick.small.Bundle bundle = Small.getBundle(u.packageName); File file = bundle.getPatchFile(); // Download URL url = new URL(u.downloadUrl); HttpURLConnection urlConn = (HttpURLConnection) url.openConnection(); InputStream is = urlConn.getInputStream(); OutputStream os = new FileOutputStream(file); byte[] buffer = new byte[1024]; int length; while ((length = is.read(buffer)) != -1) { os.write(buffer, 0, length); } os.flush(); os.close(); is.close(); // Upgrade bundle.upgrade(); } Message.obtain(mHandler, 1, true).sendToTarget(); } catch (IOException e) { e.printStackTrace(); Message.obtain(mHandler, 1, false).sendToTarget(); } } }.start(); } } }