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.replicaappforyou.app; import android.content.Context; import android.content.Intent; import android.net.Uri; import android.support.v4.app.ShareCompat; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.text.TextUtils; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.BaseAdapter; import android.widget.GridView; import android.widget.ImageView; import android.widget.TextView; import java.util.ArrayList; import java.util.List; /** * Activity to display a grid of coupons. The number of columns varies based on * screen width and goes down to a one-column grid on a small devicde such as a phone. * * <p>A coupon consists of a photo, title, and subtitle</p> * * <p>Tapping on a coupon to redeem it brings up the Android "share" * dialog with a pre-populated message based on the coupon text</p> */ public class MainActivity extends ActionBarActivity implements AdapterView.OnItemClickListener { //Name of person giving out these coupons. When the user clicks on a coupon and //shares to another app, this name will be part of the pre-populated text //TODO: Fill in your name here private static final String SENDER_NAME = "John"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //Fetch the {@link LayoutInflater} service so that new views can be created LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); //TODO: create grid layout //Find the {@link GridView} that was already defined in the XML layout GridView gridView = (GridView) findViewById(R.id.grid); //Initialize the adapter with all the coupons setting the adapter on the {@link GridView} gridView.setAdapter(new CouponAdapter(inflater, createAllCoupons())); //Set a click listener for each coupon in the grid gridView.setOnItemClickListener(this); } /** * Generate the list of all coupons * @return The list of coupons */ private List<Coupon> createAllCoupons() { //TODO: Customize this list of coupons for your personal use List<Coupon> coupons = new ArrayList<Coupon>(); coupons.add(new Coupon("Walk in the park", "Take a stroll in the flower garden", "park.jpg")); coupons.add(new Coupon("Trip to the zoo", "See the cute zoo animals", "zoo.jpg")); coupons.add(new Coupon("Watch sunrise", "Drive out to the vista point and watch the sunrise at 6am", "sunrise.jpg")); coupons.add(new Coupon("Hawaii getaway", "Relax in Hawaii by going to the beach and attending luaus", "hawaii.jpg")); coupons.add(new Coupon("Spa day", "Receive a massage and enjoy the peace and quiet", "spa.jpg")); coupons.add(new Coupon("Homemade dinner", "Your favorite meal cooked by yours truly", "dinner.jpg")); coupons.add(new Coupon("Day on the water", "Boat ride down the river on a breezy day", "boat.jpg")); coupons.add(new Coupon("Flowers", "Delivered to your front door", "rose.jpg")); coupons.add(new Coupon("Picnic", "Wine, bread, and cheese at the vineyard", "picnic.jpg")); coupons.add(new Coupon("Surprise gift", "Won't be revealed until redeemed", "present.jpg")); return coupons; } /** * Callback method for when a coupon is clicked. A new share Intent is created with the * coupon title. The the user can select which app to share the content of the coupon with * @param parent The AdapterView where the click happened * @param view The view within the AdapterView that was clicked (this will be a mvi provided * by the adapter) * @param position The position of the view in the adapter that was clicked * @param id The row ID of the item that was clicked */ @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { //Find coupon that was clicked based off of position in adapter Coupon coupon = (Coupon) parent.getItemAtPosition(position); //Create the share Intent Intent shareIntent = ShareCompat.IntentBuilder.from(this).setText(getShareText(coupon)) .setType("image/jpeg").setStream(coupon.mImageUri).setChooserTitle("Redeem using") .createChooserIntent(); startActivity(shareIntent); } /** * Create the share Intent text based on the coupon title, subtitle and whether or not * there is a SENDER_NAME * @param coupon to create the intent text for * @return string to be used in the share intent */ private String getShareText(Coupon coupon) { //If there is no sender name, just use the coupon title and subtitl //TODO: Create the strings in string.xml if (TextUtils.isEmpty(SENDER_NAME)) { return getString(R.string.message_format_without_sender, coupon.mTitle, coupon.mSubtitle); } else { return getString(R.string.message_format_with_sender, SENDER_NAME, coupon.mTitle, coupon.mSubtitle); } } /** * Adapter for grid of coupons */ private static class CouponAdapter extends BaseAdapter { private LayoutInflater mInflater; private List<Coupon> mAllCoupons; /** * Constructs a new {@link CouponAdapter} * * @param mInflater to create new views * @param mAllCoupons for the list of all coupons to be displayed */ private CouponAdapter(LayoutInflater mInflater, List<Coupon> mAllCoupons) { if (mAllCoupons == null) { throw new IllegalStateException("Can't have null list of coupons"); } this.mInflater = mInflater; this.mAllCoupons = mAllCoupons; } @Override public int getCount() { return mAllCoupons.size(); } @Override public Coupon getItem(int position) { return mAllCoupons.get(position); } @Override public long getItemId(int position) { return position; } /** * Get a View that displays the data at the specified position in the data set. * You can either create a View manually or inflate it from an XML layout file. * When the View is inflated, the parent View (GridView, ListView...) will * apply default layout parameters unless you use * inflate(int, android.view.ViewGroup, boolean) to specify a root view * and to prevent attachment to the root. * @param position of the element we are parsing * @param convertView the view we are going to customize * @param parent the parent in where our list is stored * @return */ @Override public View getView(int position, View convertView, ViewGroup parent) { View result = convertView; if (result == null) { //TODO: Create grid_item layout result = mInflater.inflate(R.layout.grid_item, parent, false); } //Try to get view cache or create a new one if needed ViewCache viewCache = (ViewCache) result.getTag(); if (viewCache == null) { viewCache = new ViewCache(result); result.setTag(viewCache); } //Fetch item Coupon coupon = getItem(position); //Bind the data viewCache.mTitleView.setText(coupon.mTitle); viewCache.mSubtitleView.setText(coupon.mSubtitle); viewCache.mImageView.setImageURI(coupon.mImageUri); return result; } } /** * Cache of views in the grid item view to make recycling of views quicker. This avoids * additional {@link View#findViewById(int)}} calls after the {@link com.replicaappforyou.app.MainActivity.ViewCache} * is first created for a view. See: * {@link CouponAdapter#getView(int position, View convertView, ViewGroup parent)} */ private static class ViewCache { //View that displays the title of the coupon private final TextView mTitleView; //View that displays the description of the coupon private final TextView mSubtitleView; //View that displays tha image associated with the coupon private final ImageView mImageView; //TODO: Modify your layout in order to have these fields private ViewCache(View view) { this.mTitleView = (TextView) view.findViewById(R.id.title); this.mSubtitleView = (TextView) view.findViewById(R.id.subtitle); this.mImageView = (ImageView) view.findViewById(R.id.image); } } /** * Model object for coupons */ private static class Coupon { //Title of the coupon private final String mTitle; //Description del coupon private final String mSubtitle; //Content URI of the image for the coupon private final Uri mImageUri; /** * Constructs a new {@link Coupon} * @param mTitle is the title * @param mSubtitle is the description * @param mImageUri is the file path from the application's assets folder for * the image associated with this coupon */ private Coupon(String mTitle, String mSubtitle, String mImageUri) { this.mTitle = mTitle; this.mSubtitle = mSubtitle; this.mImageUri = Uri.parse("content://" + AssetProvider.CONTENT_URI + "/" + mImageUri); } } }