Java tutorial
/* * Copyright (C) 2016 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.example.scb.quakereport_l3; import android.content.Context; import android.graphics.drawable.GradientDrawable; import android.support.v4.content.ContextCompat; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.TextView; import java.text.DecimalFormat; import java.text.SimpleDateFormat; import java.util.Date; import java.util.List; /** * An {@link EarthquakeAdapter} knows how to create a list item layout for each earthquake * in the data source (a list of {@link Earthquake} objects). * * These list item layouts will be provided to an adapter view like ListView * to be displayed to the user. */ public class EarthquakeAdapter extends ArrayAdapter<Earthquake> { /** * The part of the location string from the USGS service that we use to determine * whether or not there is a location offset present ("5km N of Cairo, Egypt"). */ private static final String LOCATION_SEPARATOR = " of "; /** * Constructs a new {@link EarthquakeAdapter}. * * @param context of the app * @param earthquakes is the list of earthquakes, which is the data source of the adapter */ public EarthquakeAdapter(Context context, List<Earthquake> earthquakes) { super(context, 0, earthquakes); } /** * Returns a list item view that displays information about the earthquake at the given position * in the list of earthquakes. */ @Override public View getView(int position, View convertView, ViewGroup parent) { // Check if there is an existing list item view (called convertView) that we can reuse, // otherwise, if convertView is null, then inflate a new list item layout. View listItemView = convertView; if (listItemView == null) { listItemView = LayoutInflater.from(getContext()).inflate(R.layout.earthquake_list_item, parent, false); } // Find the earthquake at the given position in the list of earthquakes Earthquake currentEarthquake = getItem(position); // Find the TextView with view ID magnitude TextView magnitudeView = (TextView) listItemView.findViewById(R.id.magnitude); // Format the magnitude to show 1 decimal place String formattedMagnitude = formatMagnitude(currentEarthquake.getMagnitude()); // Display the magnitude of the current earthquake in that TextView magnitudeView.setText(formattedMagnitude); // Set the proper background color on the magnitude circle. // Fetch the background from the TextView, which is a GradientDrawable. GradientDrawable magnitudeCircle = (GradientDrawable) magnitudeView.getBackground(); // Get the appropriate background color based on the current earthquake magnitude int magnitudeColor = getMagnitudeColor(currentEarthquake.getMagnitude()); // Set the color on the magnitude circle magnitudeCircle.setColor(magnitudeColor); // Get the original location string from the Earthquake object, // which can be in the format of "5km N of Cairo, Egypt" or "Pacific-Antarctic Ridge". String originalLocation = currentEarthquake.getLocation(); // If the original location string (i.e. "5km N of Cairo, Egypt") contains // a primary location (Cairo, Egypt) and a location offset (5km N of that city) // then store the primary location separately from the location offset in 2 Strings, // so they can be displayed in 2 TextViews. String primaryLocation; String locationOffset; // Check whether the originalLocation string contains the " of " text if (originalLocation.contains(LOCATION_SEPARATOR)) { // Split the string into different parts (as an array of Strings) // based on the " of " text. We expect an array of 2 Strings, where // the first String will be "5km N" and the second String will be "Cairo, Egypt". String[] parts = originalLocation.split(LOCATION_SEPARATOR); // Location offset should be "5km N " + " of " --> "5km N of" locationOffset = parts[0] + LOCATION_SEPARATOR; // Primary location should be "Cairo, Egypt" primaryLocation = parts[1]; } else { // Otherwise, there is no " of " text in the originalLocation string. // Hence, set the default location offset to say "Near the". locationOffset = getContext().getString(R.string.near_the); // The primary location will be the full location string "Pacific-Antarctic Ridge". primaryLocation = originalLocation; } // Find the TextView with view ID location TextView primaryLocationView = (TextView) listItemView.findViewById(R.id.primary_location); // Display the location of the current earthquake in that TextView primaryLocationView.setText(primaryLocation); // Find the TextView with view ID location offset TextView locationOffsetView = (TextView) listItemView.findViewById(R.id.location_offset); // Display the location offset of the current earthquake in that TextView locationOffsetView.setText(locationOffset); // Create a new Date object from the time in milliseconds of the earthquake Date dateObject = new Date(currentEarthquake.getTimeInMilliseconds()); // Find the TextView with view ID date TextView dateView = (TextView) listItemView.findViewById(R.id.date); // Format the date string (i.e. "Mar 3, 1984") String formattedDate = formatDate(dateObject); // Display the date of the current earthquake in that TextView dateView.setText(formattedDate); // Find the TextView with view ID time TextView timeView = (TextView) listItemView.findViewById(R.id.time); // Format the time string (i.e. "4:30PM") String formattedTime = formatTime(dateObject); // Display the time of the current earthquake in that TextView timeView.setText(formattedTime); // Return the list item view that is now showing the appropriate data return listItemView; } /** * Return the color for the magnitude circle based on the intensity of the earthquake. * * @param magnitude of the earthquake */ private int getMagnitudeColor(double magnitude) { int magnitudeColorResourceId; int magnitudeFloor = (int) Math.floor(magnitude); switch (magnitudeFloor) { case 0: case 1: magnitudeColorResourceId = R.color.magnitude1; break; case 2: magnitudeColorResourceId = R.color.magnitude2; break; case 3: magnitudeColorResourceId = R.color.magnitude3; break; case 4: magnitudeColorResourceId = R.color.magnitude4; break; case 5: magnitudeColorResourceId = R.color.magnitude5; break; case 6: magnitudeColorResourceId = R.color.magnitude6; break; case 7: magnitudeColorResourceId = R.color.magnitude7; break; case 8: magnitudeColorResourceId = R.color.magnitude8; break; case 9: magnitudeColorResourceId = R.color.magnitude9; break; default: magnitudeColorResourceId = R.color.magnitude10plus; break; } return ContextCompat.getColor(getContext(), magnitudeColorResourceId); } /** * Return the formatted magnitude string showing 1 decimal place (i.e. "3.2") * from a decimal magnitude value. */ private String formatMagnitude(double magnitude) { DecimalFormat magnitudeFormat = new DecimalFormat("0.0"); return magnitudeFormat.format(magnitude); } /** * Return the formatted date string (i.e. "Mar 3, 1984") from a Date object. */ private String formatDate(Date dateObject) { SimpleDateFormat dateFormat = new SimpleDateFormat("LLL dd, yyyy"); return dateFormat.format(dateObject); } /** * Return the formatted date string (i.e. "4:30 PM") from a Date object. */ private String formatTime(Date dateObject) { SimpleDateFormat timeFormat = new SimpleDateFormat("h:mm a"); return timeFormat.format(dateObject); } }