javascript - Cordova媒体，如何获取循环播放的回调？

Question

我有以下 Angular JS 服务，它正在访问 cordova 媒体插件。

MediaSrv.loadMedia(filePath, mediaSuccess, null, status).then(function(media, status, test, status1){
                    media.play({ numberOfLoops: 999 });
                    media.setVolume(volume);
                    $scope.selectedSounds[index].state = 1;
                    $scope.selectedSounds[index].mediaInstance = media;
                    $scope.someSoundsArePlaying = true;
                });

我想问一下，如何循环播放选定的文件，并在将mediaInstance传递给stop函数后停止播放？

我尝试了mediaSuccess回调和status回调，但无法正常工作。

服务如下:

'use strict';

angular.module('MaxRelax')
  .factory('MediaSrv', function($q, $ionicPlatform, $window){
        var service = {
            loadMedia: loadMedia,
            getStatusMessage: getStatusMessage,
            getErrorMessage: getErrorMessage
        };

        function loadMedia(src, onError, onStatus, onStop){
            var defer = $q.defer();
            $ionicPlatform.ready(function(){
                var mediaSuccess = function(){
                    if(onStop){onStop();}
                };
                var mediaError = function(err){
                    _logError(src, err);
                    if(onError){onError(err);}
                };
                var mediaStatus = function(status){
                    console.log(status);
                    if(onStatus){onStatus(status);}
                };

                if($ionicPlatform.is('android')){src = '/android_asset/www/' + src;}
                defer.resolve(new $window.Media(src, mediaSuccess, mediaError, mediaStatus));
            });
            return defer.promise;
        }

        function _logError(src, err){
            console.error('media error', {
                code: err.code,
                message: getErrorMessage(err.code)
            });
        }

        function getStatusMessage(status){
            if(status === 0){return 'Media.MEDIA_NONE';}
            else if(status === 1){return 'Media.MEDIA_STARTING';}
            else if(status === 2){return 'Media.MEDIA_RUNNING';}
            else if(status === 3){return 'Media.MEDIA_PAUSED';}
            else if(status === 4){return 'Media.MEDIA_STOPPED';}
            else {return 'Unknown status <'+status+'>';}
        }

        function getErrorMessage(code){
            if(code === 1){return 'MediaError.MEDIA_ERR_ABORTED';}
            else if(code === 2){return 'MediaError.MEDIA_ERR_NETWORK';}
            else if(code === 3){return 'MediaError.MEDIA_ERR_DECODE';}
            else if(code === 4){return 'MediaError.MEDIA_ERR_NONE_SUPPORTED';}
            else {return 'Unknown code <'+code+'>';}
        }

        return service;
    });

非常非常感谢您的帮助。

编辑:

项目的播放通过以下方法处理:

  $scope.playSelectedItem = function(index) {
            try {
                var fileName = $scope.selectedSounds[index].file;
                var volume = $scope.selectedSounds[index].defaultVolume;
                var filePath  = "sounds/" +fileName+".mp3";
                console.log(filePath);
                MediaSrv.loadMedia(
                    filePath,
                    function onError(err){ console.log('onError', MediaSrv.getErrorMessage(err)); },
                    function onStatus(status){ console.log('onStatus', MediaSrv.getStatusMessage(status)); },
                    function onStop(){ console.log('onStop'); myMedia.play(); }
                ).then(function(media){
                    myMedia = media;
                    media.play({ numberOfLoops: 999 });
                    media.setVolume(volume);
                    $scope.selectedSounds[index].state = 1;
                    $scope.selectedSounds[index].mediaInstance = media;
                    $scope.someSoundsArePlaying = true;
                });
            } catch(e) {
                alert(JSON.stringify(e));
                console.log(e);
                $scope.showAlert("Error", "Error during the playing item");
            }
        };

停止:

$scope.stopSelectedItem = function(index) {
            try {
                var leng = 0;
                if($scope.selectedSounds[index].state == 1) {
                    var mediaInstance = $scope.selectedSounds[index].mediaInstance;
                    mediaInstance.stop();
                    $scope.selectedSounds[index].state = 0;
                    $scope.selectedSounds[index].mediaInstance = "";
                    myMedia.stop();
                }

                angular.forEach($scope.selectedSounds, function loadMedia(selectedSound, idx){
                    if($scope.selectedSounds[idx].state == 1) {
                        leng ++;
                    }
                });

                if(leng <= 0) {
                    $scope.someSoundsArePlaying = false;
                    console.log("No sound are playing");
                }
                if(leng > 0) {
                    $scope.someSoundsArePlaying = true;
                    console.log("Some sound are playing");
                }
                console.log("Leng is:");
                console.log(leng);
            } catch(e) {
                alert(JSON.stringify(e));
                console.log(e);
                $scope.showAlert("Error", "Cannot stop playing of item");
            }
        };

编辑2:

我最终通过将 myMedia 实例存储在简单数组中解决了这个问题。

$scope.playSelectedItem = function(index) {
            try {
                var fileName = $scope.selectedSounds[index].file;
                var volume = $scope.selectedSounds[index].defaultVolume;
                var filePath  = "sounds/" +fileName+".mp3";
                console.log(filePath);
                MediaSrv.loadMedia(
                    filePath,
                    function onError(err){ console.log('onError', MediaSrv.getErrorMessage(err)); },
                    function onStatus(status){ console.log('onStatus', MediaSrv.getStatusMessage(status)); },
                    function onStop(){
                        console.log('onStop');
                        if($scope.selectedSounds[index].state == 1) {
                            console.log('For index ' +index+' is state '+$scope.selectedSounds[index].state);
                            myMedia[index].play();
                        }

                    }
                ).then(function(media){
                    myMedia[index] = media;
                    media.play({ numberOfLoops: 999 });
                    media.setVolume(volume);
                    $scope.selectedSounds[index].state = 1;
                    $scope.selectedSounds[index].mediaInstance = media;
                    $scope.someSoundsArePlaying = true;
                });
            } catch(e) {
                alert(JSON.stringify(e));
                console.log(e);
                $scope.showAlert("Error", "Error during the playing item");
            }
        };

Answer 1

我很高兴您发现我的 Angular 服务很有用。

在您的示例中，您似乎搞乱了参数顺序:
MediaSrv.loadMedia(filePath, mediaSuccess, null, status) vs
函数loadMedia(src, onError, onStatus, onStop)

顺便说一句，播放参数numberOfLoops似乎不起作用(至少在我的nexus4上)。如果您想循环播放，则需要在每次 mp3 结束时调用 play()。

这是一个简短的示例:

var myMedia = null;
MediaSrv.loadMedia(
    'sounds/1023.mp3', 
    function onError(err){ console.log('onError', MediaSrv.getErrorMessage(err)); },
    function onStatus(status){ console.log('onStatus', MediaSrv.getStatusMessage(status)); },
    function onStop(){ console.log('onError'); myMedia.play(); },
).then(function(media){
    myMedia = media;
    myMedia.play();
});

使用此代码，您的声音应该永远播放...要控制声音何时停止，我建议您添加一个控制参数，如下所示:

var myMedia = null;
var shouldPlay = false;
MediaSrv.loadMedia(
    'sounds/1023.mp3', 
    function onError(err){ console.log('onError', MediaSrv.getErrorMessage(err)); },
    function onStatus(status){ console.log('onStatus', MediaSrv.getStatusMessage(status)); },
    function onStop(){ console.log('onError'); if(shouldPlay){myMedia.play();} },
).then(function(media){
    myMedia = media;
});

function playStart(){
    shouldPlay = true;
    myMedia.play();
}
function playStop(){
    shouldPlay = false;
    myMedia.stop();
}

要循环播放多个文件，您必须存储所有媒体引用并连续播放它们。参见那里:

var shouldPlay = false;
var playingMedia = null;
var soundFiles = ['sounds/1.mp3', 'sounds/2.mp3', 'sounds/3.mp3'];
var mediaInstances = [];
var onPlayStop = function(){
    if(shouldPlay){
        if(playingMedia === null){
            playingMedia = 0;
        } else {
            playingMedia = (playingMedia+1) % mediaInstances.length;
        }
        mediaInstances[playingMedia].play();
    }
};
for(var i in soundFiles){
    MediaSrv.loadMedia(soundFiles[i], null, null, onPlayStop).then(function(media){
        mediaInstances.push(media);
    });
}

function playStart(){
    shouldPlay = true;
    onPlayStop();
}
function playStop(){
    shouldPlay = false;
    mediaInstances[playingMedia].stop();
}

我希望这会有所帮助:D