Phonegap - Send message to Javascript from Objective-c in a plugin delegate

Question

I have a Phonegap Cordova plugin. In this plugin I receive a click event from javascript.This click triggers a file download using my client library. This file download sends events and calls methods in my plugin, as I have set it to be delegate.

I can't manage to sends those events back to the javascript using 'stringByEvaluatingJavaScriptFromString' It seems like it doesn't triggers the call.

It's working when I try to call it after a javascript click to the echo Plugin method.

Here is the .m plugin class :

#import "CCDataBundlePlugin.h"
#import <Cordova/CDV.h>

@implementation CCDataBundlePlugin


-(id)init{

[MYCLIENTLIB sharedInstance].delegate = self;

self = [super init];
    return self;
}

- (void)echo:(CDVInvokedUrlCommand*)command
{
NSLog(@"------ Received click");
    CDVPluginResult* pluginResult = nil;
    NSString* echo = [command.arguments objectAtIndex:0];

    if (echo != nil && [echo length] > 0) {
        pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsString:echo];
    } else {
        pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR];
    }

// When latest extraction succeeded, call next download
[[MYCLIENTLIB sharedInstance] downloadBundlesForChannel:@"myChannel"];
// When latest download succeeded, call next extraction
[[MYCLIENTLIB sharedInstance] extractBundlesForChannel:@"myChannel"];

    [self.commandDelegate sendPluginResult:pluginResult callbackId:command.callbackId];
}

-(void)callJavascriptMethodWithString:(NSString*)stringParameter{

NSString* jsString = [NSString stringWithFormat:@"CN.Interface.Recepter.receiveWithString(\"%@\");", stringParameter];

    //The line under is not working, I don't get the function call in JS
[self.webView stringByEvaluatingJavaScriptFromString:jsString];

}

// DOWNLOAD EVENTS Called from the Library
- (void)dataBundle:(MYCLIENTLIB *)dataBundle downloadDidStartForChannelIdentifier:(NSString *)channelIdentifier  {

NSLog(@"download in progress..."); // this is logged

[self callJavascriptMethodWithString:@"download in progress..."];
    // The line above do calls the method

}

ezekielDFM · Accepted Answer · 2013-07-23 14:37:56Z

1

I wrote a cordova plugin tutorial not to long ago here: http://www.zen-sign.com/writing-a-cordova-plugin/. It should be a good help to you. In the meantime, here is the basic structure i have used with success inside my init/congifure methods for my native-side plugin wrapper:

- (void)configurePlugin:(CDVInvokedUrlCommand*)command
{
      // Cordova Result object and stirng to send to JS
      CDVPluginResult* pluginResult = nil;
      NSString* javaScript = nil;

      @try
      {
           // Create an instance of the class we want to wrap. This could be your 3rd party    library or whatever you want.
           wrappedClass = [[WrapMeUp alloc] init];

           pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsString:@"{'success' : '1'}"];
           javaScript = [pluginResult toSuccessCallbackString:command.callbackId];

      }
      @catch (NSException* exception)
      {
           //Sumptin went worng!
           pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_JSON_EXCEPTION messageAsString:[exception reason]];
           javaScript = [pluginResult toErrorCallbackString:command.callbackId];
      }

      // Write plugin results back to JS callback
      [self writeJavascript:javaScript];
 }

answered Jul 23, 2013 at 14:37

ezekielDFM

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7 Comments

arlg Over a year ago

I don't want to have something to call Obj-c methods in a plugin, I already have that. I want to call JS functions from Obj-c methods. I've seen that you use [self writeJavascript:javaScript]; It's working for me, but only once, that's strange !

arlg Over a year ago

Actually its working when I put it into the echo method. But in another method, like downloadDidStartForChannelIdentifier, it doesnt

ezekielDFM Over a year ago

You need to always have a callback ID for it to send/write the javascript to. This is received from the calling js method. I'm pretty sure that callback id only has a lifespan form the time the js method is fired to when it receives a callback success/error.

arlg Over a year ago

So If I understand well I can't call [self writeJavascript:jsString]; anywhere in the plugin ?

ezekielDFM Over a year ago

@PeterPiper Sorry, my server needed cycled. The article should be back up.

|

arlg · Accepted Answer · 2013-07-25 11:53:12Z

1

Just If someone want to do the same, I managed to do it by calling a native plugin method using a javascript timer. I'll search If I can find a cleaner way

answered Jul 25, 2013 at 11:53

arlg

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