Java tutorial
/* * Copyright (C) 2014 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.damianhinch.sunshine; import android.content.Intent; import android.database.Cursor; import android.net.Uri; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.LoaderManager; import android.support.v4.content.CursorLoader; import android.support.v4.content.Loader; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.ListView; import com.damianhinch.sunshine.data.WeatherContract; import static com.damianhinch.sunshine.data.WeatherContract.*; /** * Encapsulates fetching the forecast and displaying it as a {@link android.widget.ListView} layout. */ public class ForecastFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor> { private static final int FORECAST_LOADER = 0; // For the forecast view we're showing only a small subset of the stored data. // Specify the columns we need. private static final String[] FORECAST_COLUMNS = { WeatherEntry.TABLE_NAME + "." + WeatherContract.WeatherEntry._ID, WeatherEntry.COLUMN_DATE, WeatherEntry.COLUMN_SHORT_DESC, WeatherEntry.COLUMN_MAX_TEMP, WeatherEntry.COLUMN_MIN_TEMP, LocationEntry.COLUMN_LOCATION_SETTING, WeatherEntry.COLUMN_WEATHER_ID, LocationEntry.COLUMN_COORD_LAT, LocationEntry.COLUMN_COORD_LONG }; // These indices are tied to FORECAST_COLUMNS. If FORECAST_COLUMNS changes, these // must change. static final int COL_WEATHER_ID = 0; static final int COL_WEATHER_DATE = 1; static final int COL_WEATHER_DESC = 2; static final int COL_WEATHER_MAX_TEMP = 3; static final int COL_WEATHER_MIN_TEMP = 4; static final int COL_LOCATION_SETTING = 5; static final int COL_WEATHER_CONDITION_ID = 6; static final int COL_COORD_LAT = 7; static final int COL_COORD_LONG = 8; private ForecastAdapter mForecastAdapter; public ForecastFragment() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Add this line in order for this fragment to handle menu events. setHasOptionsMenu(true); } @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { inflater.inflate(R.menu.forecastfragment, menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { int id = item.getItemId(); if (id == R.id.refresh_button) { updateWeather(); return true; } return super.onOptionsItemSelected(item); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // The CursorAdapter will take data from our cursor and populate the ListView. mForecastAdapter = new ForecastAdapter(getActivity(), null, 0); View rootView = inflater.inflate(R.layout.fragment_main, container, false); // Get a reference to the ListView, and attach this adapter to it. ListView listView = (ListView) rootView.findViewById(R.id.listview_forecast); listView.setAdapter(mForecastAdapter); // We'll call our MainActivity listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) { // CursorAdapter returns a cursor at the correct position for getItem(), or null // if it cannot seek to that position. Cursor cursor = (Cursor) adapterView.getItemAtPosition(position); if (cursor != null) { String locationSetting = Helpers.getUserPreferredLocation(getActivity()); Intent intent = new Intent(getActivity(), DetailView.class).setData(WeatherContract.WeatherEntry .buildWeatherLocationWithDate(locationSetting, cursor.getLong(COL_WEATHER_DATE))); startActivity(intent); } } }); return rootView; } @Override public void onActivityCreated(Bundle savedInstanceState) { getLoaderManager().initLoader(FORECAST_LOADER, null, this); super.onActivityCreated(savedInstanceState); } // since we read the location when we create the loader, all we need to do is restart things void onLocationChanged() { updateWeather(); getLoaderManager().restartLoader(FORECAST_LOADER, null, this); } private void updateWeather() { FetchWeatherTask weatherTask = new FetchWeatherTask(getActivity()); String location = Helpers.getUserPreferredLocation(getActivity()); weatherTask.execute(location); } @Override public Loader<Cursor> onCreateLoader(int i, Bundle bundle) { String locationSetting = Helpers.getUserPreferredLocation(getActivity()); // Sort order: Ascending, by date. String sortOrder = WeatherContract.WeatherEntry.COLUMN_DATE + " ASC"; Uri weatherForLocationUri = WeatherContract.WeatherEntry.buildWeatherLocationWithStartDate(locationSetting, System.currentTimeMillis()); return new CursorLoader(getActivity(), weatherForLocationUri, FORECAST_COLUMNS, null, null, sortOrder); } @Override public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) { mForecastAdapter.swapCursor(cursor); } @Override public void onLoaderReset(Loader<Cursor> cursorLoader) { mForecastAdapter.swapCursor(null); } }