phonegap-plugins/Android/BarcodeScanner/BarcodeScanner.java

/**
 * Phonegap Barcode Scanner plugin
 * Copyright (c) Matt Kane 2010
 *
 */

package com.beetight.barcodescanner;



import org.json.JSONArray;
import org.json.JSONException;

import com.phonegap.DroidGap;
import com.phonegap.api.Plugin;
import com.phonegap.api.PluginResult;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;

import android.content.ActivityNotFoundException;

import android.net.Uri;

/**
 * This calls out to the ZXing barcode reader and returns the result.
 */
public class BarcodeScanner extends Plugin {
	public static final int REQUEST_CODE = 0x0ba7c0de;

	
	public static final String defaultInstallTitle = "Install Barcode Scanner?";
	public static final String defaultInstallMessage = "This requires the free Barcode Scanner app. Would you like to install it now?";
	public static final String defaultYesString = "Yes";
	public static final String defaultNoString = "No";
  
	public String callback;
	
    /**
     * Constructor.
     */
	public BarcodeScanner() {
	}

	/**
	 * Executes the request and returns PluginResult.
	 * 
	 * @param action 		The action to execute.
	 * @param args 			JSONArray of arguments for the plugin.
	 * @param callbackId	The callback id used when calling back into JavaScript.
	 * @return 				A PluginResult object with a status and message.
	 */
	public PluginResult execute(String action, JSONArray args, String callbackId) {
		this.callback = callbackId;
		
		try {
			if (action.equals("scan")) {
				String barcodeTypes = null;
				if(args.length() > 0) {
					barcodeTypes = args.getString(0);
				}
				
				String installTitle = defaultInstallTitle;
				if(args.length() > 1) {
					installTitle = args.getString(1);
				}

				String installMessage = defaultInstallMessage;
				if(args.length() > 2) {
					installMessage = args.getString(2);
				}

				String yesString = defaultYesString;
				if(args.length() > 3) {
					yesString = args.getString(3);
				}

				String noString = defaultNoString;
				if(args.length() > 4) {
					noString = args.getString(4);
				}

				scan(barcodeTypes, installTitle, installMessage, yesString, noString);
			} else {
	            return new PluginResult(PluginResult.Status.INVALID_ACTION);
			}
			PluginResult r = new PluginResult(PluginResult.Status.NO_RESULT);
			r.setKeepCallback(true);
			return r;
		} catch (JSONException e) {
			e.printStackTrace();
			return new PluginResult(PluginResult.Status.JSON_EXCEPTION);
		}
	} 
	
    
	/**
	 * Initiates a barcode scan. If the ZXing scanner isn't installed, the user 
	 * will be prompted to install it.
	 * @param types	The barcode types to accept
	 * @param installTitle The title for the dialog box that prompts the user to install the scanner
	 * @param installMessage The message prompting the user to install the barcode scanner
	 * @param yesString The string "Yes" or localised equivalent
	 * @param noString The string "No" or localised version
	 */
	public void scan(String barcodeFormats, String installTitle, String installMessage, String yesString, String noString ) {
	    Intent intentScan = new Intent("com.google.zxing.client.android.SCAN");
	    intentScan.addCategory(Intent.CATEGORY_DEFAULT);

	    // A null format means we scan for any type
	    if (barcodeFormats != null) {
	      // Tell the scanner what types we're after
	      intentScan.putExtra("SCAN_FORMATS", barcodeFormats);
	    }

	    try {  
	      this.ctx.startActivityForResult((Plugin) this, intentScan, REQUEST_CODE);
	    } catch (ActivityNotFoundException e) { 
	    	showDownloadDialog(installTitle, installMessage, yesString, noString);
	    }
	}

    /**
     * Called when the barcode scanner exits 
     * 
     * @param requestCode		The request code originally supplied to startActivityForResult(), 
     * 							allowing you to identify who this result came from.
     * @param resultCode		The integer result code returned by the child activity through its setResult().
     * @param intent			An Intent, which can return result data to the caller (various data can be attached to Intent "extras").
     */
	public void onActivityResult(int requestCode, int resultCode, Intent intent) {
		if (requestCode == REQUEST_CODE) {
			if (resultCode == Activity.RESULT_OK) {
				String contents = intent.getStringExtra("SCAN_RESULT");
				this.success(new PluginResult(PluginResult.Status.OK, contents), this.callback);
			} else {
				this.error(new PluginResult(PluginResult.Status.ERROR), this.callback);
			}
		}	
	}
	
	 private void showDownloadDialog(final String title, final String message, final String yesString, final String noString) {
		final DroidGap context = this.ctx;
		Runnable runnable = new Runnable() {
				public void run() {

					AlertDialog.Builder dialog = new AlertDialog.Builder(context);
					dialog.setTitle(title);
					dialog.setMessage(message);
					dialog.setPositiveButton(yesString, new DialogInterface.OnClickListener() {
						public void onClick(DialogInterface dlg, int i) {
							dlg.dismiss();
							Intent intent = new Intent(Intent.ACTION_VIEW, 
									Uri.parse("market://search?q=pname:com.google.zxing.client.android")
							);
							context.startActivity(intent);
						}
					});
					dialog.setNegativeButton(noString, new DialogInterface.OnClickListener() {
						public void onClick(DialogInterface dlg, int i) {
							dlg.dismiss();
						}
					});
					dialog.create();
					dialog.show();
				}
			};
			context.runOnUiThread(runnable);
		}
}