BarcodeHelper.java

/* 
 * Copyright 2010-2013 Eric Kok et al.
 * 
 * Transdroid is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Transdroid is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with Transdroid.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.transdroid.core.gui.search;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.Intent;
import android.net.Uri;
import android.text.TextUtils;

import org.transdroid.R;
import org.transdroid.core.app.search.GoogleWebSearchBarcodeResolver;

public class BarcodeHelper {

	public static final int ACTIVITY_BARCODE_ADDTORRENT = 0x0000c0de;
	// A 'random' ID to identify torrent adding scan intents
	public static final int ACTIVITY_BARCODE_QRSETTINGS = 0x0000c0df;
	// A 'random' ID to identify QR-encoded settings scan intents
	public static final Uri SCANNER_MARKET_URI = Uri.parse("market://search?q=pname:com.google.zxing.client.android");

	/**
	 * Call this to start a bar code scanner intent. The calling activity will receive an Intent result with ID {@link
	 * #ACTIVITY_BARCODE_ADDTORRENT} or {@link #ACTIVITY_BARCODE_QRSETTINGS}. From there {@link #handleScanResult(int,
	 * android.content.Intent, boolean)} can be called to parse the result into a search query, in case of {@link
	 * #ACTIVITY_BARCODE_ADDTORRENT} scans.
	 * @param activity The calling activity, to which the result is returned or a dialog is bound that asks to install
	 * the bar code scanner
	 * @param requestCode {@link #ACTIVITY_BARCODE_ADDTORRENT} or {@link #ACTIVITY_BARCODE_QRSETTINGS
	 */
	public static void startBarcodeScanner(final Activity activity, int requestCode) {
		// Start a bar code scanner that can handle the SCAN intent (specifically ZXing)
		startBarcodeIntent(activity, new Intent("com.google.zxing.client.android.SCAN"), requestCode);
	}

	/**
	 * Call this to share content encoded in a QR code, specially used to share settings. The calling activity will
	 * receive an Intent result with ID {@link #ACTIVITY_BARCODE_QRSETTINGS}. From there the returned intent will
	 * contain the data as SCAN_RESULT String extra.
	 * @param activity The calling activity, to which the result is returned or a dialog is bound that asks to install
	 * the bar code scanner
	 * @param content The content to share, that is, the raw data (Transdroid settings encoded as JSON data structure)
	 * to share as QR code
	 */
	public static void shareContentBarcode(final Activity activity, final String content) {
		// Start a bar code encoded that can handle the ENCODE intent (specifically ZXing)
		Intent encodeIntent = new Intent("com.google.zxing.client.android.ENCODE");
		encodeIntent.putExtra("ENCODE_TYPE", "TEXT_TYPE");
		encodeIntent.putExtra("ENCODE_DATA", content);
		encodeIntent.putExtra("ENCODE_SHOW_CONTENTS", false);
		startBarcodeIntent(activity, encodeIntent, -1);
	}

	@SuppressLint("ValidFragment")
	private static void startBarcodeIntent(final Activity activity, final Intent intent, int requestCode) {
		try {
			activity.startActivityForResult(intent, requestCode);
		} catch (Exception e) {
			// Can't start the bar code scanner, for example with a SecurityException or when ZXing is not present
			new DialogFragment() {
				public android.app.Dialog onCreateDialog(android.os.Bundle savedInstanceState) {
					return new AlertDialog.Builder(activity).setIcon(android.R.drawable.ic_dialog_alert)
							.setMessage(activity.getString(R.string.search_barcodescannernotfound))
							.setPositiveButton(android.R.string.yes, new OnClickListener() {
								@Override
								public void onClick(DialogInterface dialog, int which) {
									if (activity != null) {
										activity.startActivity(new Intent(Intent.ACTION_VIEW, SCANNER_MARKET_URI));
									}
								}
							}).setNegativeButton(android.R.string.no, null).create();
				}

				;
			}.show(activity.getFragmentManager(), "installscanner");
		}
	}

	/**
	 * The activity that called {@link #startBarcodeScanner(android.app.Activity, int)} with {@link
	 * #ACTIVITY_BARCODE_ADDTORRENT} should call this after the scan result was returned. This will parse the scan data
	 * and return a query search query appropriate to the bar code.
	 * @param resultCode The raw result code as returned by the bar code scanner
	 * @param data The raw data as returned from the bar code scanner
	 * @param supportsSearch Whether the application has the search UI enabled, such that it can use the scanned barcode
	 * to find torrents
	 * @return A String that can be used as new search query, or null if the bar code could not be scanned or no query
	 * can be constructed for it
	 */
	public static String handleScanResult(int resultCode, Intent data, boolean supportsSearch) {
		String contents = data != null ? data.getStringExtra("SCAN_RESULT") : null;
		String formatName = data != null ? data.getStringExtra("SCAN_RESULT_FORMAT") : null;
		if (formatName != null && formatName.equals("QR_CODE")) {
			// Scanned barcode was a QR code: return the contents directly
			return contents;
		} else {
			if (TextUtils.isEmpty(contents) || !supportsSearch) {
				return null;
			}
			// Get a meaningful search query based on a Google Search product lookup
			return GoogleWebSearchBarcodeResolver.resolveBarcode(contents);
		}
	}

}