判斷網路獲取+資料庫+頁面展示
阿新 • • 發佈：2018-12-05
Activity頁面切換
public class MainActivity extends AppCompatActivity { private ViewPager pager; private RadioGroup group; private ArrayList<Fragment> list; private Dao dao; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); dao = new Dao(this); pager = (ViewPager) findViewById(R.id.pager); group = (RadioGroup) findViewById(R.id.group); group.check(group.getChildAt(0).getId()); list = new ArrayList<Fragment>(); list.add(new Fragment01()); list.add(new Fragment02()); list.add(new Fragment03()); pager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) { @Override public int getCount() { return list.size(); } @Override public Fragment getItem(int i) { return list.get(i); } }); pager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int i, float v, int i1) { group.check(group.getChildAt(i).getId()); } @Override public void onPageSelected(int i) { } @Override public void onPageScrollStateChanged(int i) { } }); group.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { @Override public void onCheckedChanged(RadioGroup group, int checkedId) { switch (checkedId){ case R.id.radio0: pager.setCurrentItem(0); break; case R.id.radio1: pager.setCurrentItem(1); break; case R.id.radio2: pager.setCurrentItem(2); break; } } }); } public Dao getDao(){ return dao; }; }
ImageLoader框架
image依賴 ：compile ‘com.nostra13.universalimageloader:universal-image-loader:1.9.5’
繼承 Application
一定記得要匯入依賴，一定記得要匯入依賴，一定記得要匯入依賴
public class MApp extends Application { @Override public void onCreate() { super.onCreate(); ImageLoaderConfiguration build = new ImageLoaderConfiguration.Builder(this).build(); ImageLoader instance = ImageLoader.getInstance(); instance.init(build); } }
判斷網路是否連結 使用AsyncTask
public class Fragment01 extends Fragment { String urlString = "http://api.expoon.com/AppNews/getNewsList/type/1/p/1"; private TextView text; private List<Bean.DataBean> list; private Dao dao; private ListView listvv; @Nullable @Override public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment01, container, false); text = (TextView) view.findViewById(R.id.text); dao = ((MainActivity) getActivity()).getDao(); if (NutilStateutil.iscoon(getActivity())) { listvv = (ListView)view.findViewById(R.id.listvv); new MyAnacs().execute(urlString); } else { text.setText("我沒有網"); Toast.makeText(getActivity(), "我沒有網", Toast.LENGTH_LONG).show(); } return view; } private class MyAnacs extends AsyncTask<String, Void, String> { private long insert; @Override protected String doInBackground(String... strings) { String jsonString = NutUtil.getJson(strings[0]); return jsonString; } @Override protected void onPostExecute(String s) { super.onPostExecute(s); Gson gson = new Gson(); Bean fromJson = gson.fromJson(s, Bean.class); list = fromJson.getData(); listvv.setAdapter(new BaseAdapter() { @Override public int getCount() { return list.size(); } @Override public Object getItem(int position) { return list.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; if(convertView == null){ convertView = View.inflate(getActivity(),R.layout.item,null); holder = new ViewHolder(); holder.ids = (TextView) convertView.findViewById(R.id.ids); holder.title = (TextView) convertView.findViewById(R.id.title); holder.url = (ImageView) convertView.findViewById(R.id.url); convertView.setTag(holder); }else{ holder =(ViewHolder)convertView.getTag(); } holder.ids.setText(list.get(position).getNews_id()); holder.title.setText(list.get(position).toString().trim()); ImageLoader instance = ImageLoader.getInstance(); instance.displayImage(list.get(position).getPic_url(),holder.url); return convertView; } class ViewHolder{ TextView ids; TextView title; ImageView url; } }); Log.e("Yxx", "資料json__list" + list.size()); for (int i = 0; i < list.size(); i++) { ContentValues values = new ContentValues(); values.put("ids", list.get(i).getNews_id()); values.put("title", list.get(i).getNews_summary()); insert = dao.insert("student", null, values); } Log.e("Yxx", "資料json__" + insert); } } }
判斷網路 在清單檔案一定要記得寫許可權
public class NutilStateutil {
public static boolean iscoon(Context context) {
boolean available = false;
ConnectivityManager systemService = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = systemService.getActiveNetworkInfo();
if (networkInfo != null) {
available = networkInfo.isAvailable();
}
return available;
}
}
網路讀取工具類
public class NutUtil {
public static String getJson(String urlString) {
URL url = null;
try {
url = new URL(urlString);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
int responseCode = httpURLConnection.getResponseCode();
if(responseCode == 200){
InputStream inputStream = httpURLConnection.getInputStream();
InputStreamReader streamReader = new InputStreamReader(inputStream);
BufferedReader reader = new BufferedReader(streamReader);
StringBuffer buffer = new StringBuffer();
String temp = "";
if((temp = reader.readLine())!=null){
buffer.append(temp);
}
return buffer.toString();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return "";
}
}
listview優化
public class MyAdapter extends BaseAdapter {
private Context context;
private ArrayList<baaa> list1;
//String urlBitmap="http://img.my.csdn.net/uploads/201407/26/1406383265_8550.jpg";
public MyAdapter(Context context, ArrayList<baaa> list1) {
this.context = context;
this.list1 = list1;
}
@Override
public int getCount() {
return list1.size();
}
@Override
public Object getItem(int position) {
return list1.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if(convertView == null){
convertView = View.inflate(context,R.layout.item,null);
holder = new ViewHolder();
holder.ids = (TextView) convertView.findViewById(R.id.ids);
holder.title = (TextView) convertView.findViewById(R.id.title);
holder.url = convertView.findViewById(R.id.url);
convertView.setTag(holder);
}else{
holder =(ViewHolder)convertView.getTag();
}
holder.ids.setText(list1.get(position).getId());
holder.title.setText(list1.get(position).getTitle());
ImageLoader instance = ImageLoader.getInstance();
instance.displayImage(list1.get(position).getImage_url(),holder.url);
return convertView;
}
class ViewHolder{
TextView ids;
TextView title;
ImageView url;
}
}
清單檔案
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.yxx.yxx1130_lianxi">
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
android:name=".Nutil.MApp"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>