URL步驟

1. 獲取urlURL url = new URL(urlString);`
2. 打開鏈接HttpURLConnection connection = (HttpURLConnection) url.openConnection();
3. 設置響應時間connection.setConnectTimeout(30000);
4. 獲取方法connection.setRequestMethod("GET");
5. 開始連接connection.connect();
6. 獲取響應碼int responseCode = connection.getResponseCode();
7. 獲取響應messageString responseMessage = connection.getResponseMessage();

8. 判斷響應碼 輸入輸出流獲取數據
   if(responseCode == HttpURLConnection.HTTP_OK){
InputStreamReader inputStreamReader = new InputStreamReader(connection.getInputStream());
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder stringBuilder = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuilder.append(line);
}
result = stringBuilder.toString();
} else {
// TODO:
}

9. 解析json數據及數組

LessonResult lessonResult = new LessonResult();
            try {
                JSONObject jsonObject = new JSONObject(result);
                int status = jsonObject.getInt("status");
                String message = jsonObject.getString("msg");
                lessonResult.setStatus(status);
                lessonResult.setMessage(message);

                List<LessonInfo> lessonInfos = new ArrayList<>();
                JSONArray dataArray = jsonObject.getJSONArray("data");
                for (int i = 0; i < dataArray.length(); i++) {
                    LessonInfo lessonInfo = new LessonInfo();
                    JSONObject tempJsonObject = (JSONObject) dataArray.get(i);
                    lessonInfo.setID(tempJsonObject.getInt("id"));
                    lessonInfo.setName(tempJsonObject.getString("name"));
                    lessonInfos.add(lessonInfo);
                }
                lessonResult.setLessonInfos(lessonInfos);

            } catch (JSONException e) {
                e.printStackTrace();
            }
mListView.setAdapter(new AppListAdapter(RequestDataActivity.this, lessonResult.getLessonInfos()));

源代碼

public class RequestDataActivity  extends AppCompatActivity {
    private ListView mListView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView = (ListView) findViewById(R.id.list_view_demo);
        LayoutInflater layoutInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = layoutInflater.inflate(R.layout.header_list_demo, null);
        mListView.addFooterView(view);

        new AppAsyncTask().execute();
    }

    public class AppListAdapter extends BaseAdapter {

        private Context mContext;
        private List<LessonInfo> mInfos;

        public AppListAdapter(Context context, List<LessonInfo> infos) {
            mContext = context;
            mInfos = infos;
        }

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

        @Override
        public Object getItem(int position) {
            return mInfos.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            ViewHolder viewHolder;
            LayoutInflater layoutInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            if(convertView == null){
                viewHolder = new ViewHolder();
                convertView = layoutInflater.inflate(R.layout.item_demo_list, null);
                // 獲取控件
                viewHolder.nameTextView = (TextView) convertView.findViewById(R.id.title_text_view);
                viewHolder.avatarImageView = (ImageView) convertView.findViewById(R.id.icon_image_view);
                convertView.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder) convertView.getTag();
            }
            // 和數據之間進行綁定
            viewHolder.nameTextView.setText(mInfos.get(position).getName());
            viewHolder.avatarImageView.setVisibility(View.GONE);

            return convertView;
        }

        class ViewHolder {
            ImageView avatarImageView;
            TextView nameTextView;
        }
    }



    public class AppAsyncTask extends AsyncTask<Void,Integer, String> {

        @Override
        protected String doInBackground(Void... params) {

            return request("網址");
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);

        }LessonResult lessonResult = new LessonResult();
            try {
            JSONObject jsonObject = new JSONObject(result);
            int status = jsonObject.getInt("status");
            String message = jsonObject.getString("msg");
            lessonResult.setStatus(status);
            lessonResult.setMessage(message);

            List<LessonInfo> lessonInfos = new ArrayList<>();
            JSONArray dataArray = jsonObject.getJSONArray("data");
            for (int i = 0; i < dataArray.length(); i++) {
                LessonInfo lessonInfo = new LessonInfo();
                JSONObject tempJsonObject = (JSONObject) dataArray.get(i);
                lessonInfo.setID(tempJsonObject.getInt("id"));
                lessonInfo.setName(tempJsonObject.getString("name"));
                lessonInfos.add(lessonInfo);
            }
            lessonResult.setLessonInfos(lessonInfos);

        } catch (JSONException e) {
            e.printStackTrace();
        }
            mListView.setAdapter(new AppListAdapter(RequestDataActivity.this, lessonResult.getLessonInfos()));


        private String request(String urlString) {
            try {
                URL url = new URL(urlString);
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setConnectTimeout(30000);
                connection.setRequestMethod("GET");  // GET POST
                connection.connect();
                int responseCode = connection.getResponseCode();
                String responseMessage = connection.getResponseMessage();
                String result = null;
                if(responseCode == HttpURLConnection.HTTP_OK){
                    InputStreamReader inputStreamReader = new InputStreamReader(connection.getInputStream());
                    BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
                    StringBuilder stringBuilder = new StringBuilder();
                    String line;
                    while ((line = bufferedReader.readLine()) != null) {
                        stringBuilder.append(line);
                    }
                    result = stringBuilder.toString();
                } else {
                  // TODO:
                }
                return result;
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }
    }

}