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我在 worklight 中使用 Cordova 文件 API 创建了一个文件。写事件完成后，我想读取文件。我尝试在 writer.onwriteend 事件中编写函数调用 readAsText()。但是文件没有被读取。“独家”选项与此有关吗？一切正常，直到读取（），然后没有错误，没有消息..但我认为它没有读取文件。但是一旦reader.onloadend 事件发生错误：

读取错误 {"type":"error","bubbles":false,"cancelBubble":false,"cancelable":false,"lengthComputable":false,"loaded":0,"total":0,"target" :{"fileName":"file://C:\Users\IBM_ADMIN\cordova\filesystem\persistent\RQM\ExecutionResult.xml","re​​adyState":2,"result":null,"error":{"code ":1},"onloadstart":null,"onprogress":null,"onload":null,"onabort":null}}

这是我的代码：

window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
        onFileSystemSuccess, fail);


function onFileSystemSuccess(fileSystem) {
alert("Created File system ");
fileSystem.root.getFile("ExecutionResult.xml", {
    create : true,
    exclusive : true
}, gotFileEntry, fail);
function gotFileEntry(fileEntry) {
fileEntry.createWriter(gotFileWriter, fail);
}
function gotFileWriter(writer) {
writer.write(JsonData);

writer.onwriteend = function(evt) {
    readAfterWriting();
};
}
function readAfterWriting(){
    fileSystem.root.getFile("ExecutionResult.xml", {
        create : false,
        exclusive : false
    }, gotFile, fail);

};
} 
function gotFile(file) {
readAsText(file);
}
function readAsText(file) {
var reader = new FileReader();
reader.onloadend = function(evt) {
    console.log("Read as text");
    console.log(evt.target.result);
};
reader.readAsText(file);
}

这是发生错误的代码。文件名显示为 22。这里是显示的行.. var callbackId = v.id;

window.addEventListener("message", function(e){
    _consoleLog("*****PG BC***** " + e.domain + " said: " + e.data);
    var r = e.data;

    // If a result was returned
    _consoleLog("typeof result=" + (typeof r) + " r=" + r);
    if (r.length > 0) {
        // if ((typeof r == "string") && (r.length > 0)) {
        _consoleLog("Result from exec=<" + dumpObj(r, '', ' ', 2) + ">");
        eval("var v=" + r + ";");
        var callbackId = v.id;
        var cast = v.cast;
        // var temp = "+cast+"("+this.getJSONString() + ");\n"
        if (cast) {
            // _consoleLog("CAST==="+"var
            // temp="+cast+"("+JSON.stringify(v.message)+");\n");
            // eval("var temp="+cast+"("+JSON.stringify(v.message)+");\n");
            // _consoleLog("***** CAST:"+" var temp="+cast+"("+r+");");
            eval("var temp=" + cast + "(" + r + ");");
            v = temp;
        }
        // _consoleLog("After CAST="+dumpObj(v, '', ' ', 3));

        // If status is OK, then return value back to caller
        if (v.status === Cordova.callbackStatus.OK) {

            // If there is a success callback, then call it now with
            // returned value
            if ((typeof(Cordova.callbacks[callbackId]) != 'undefined') 
                && (Cordova.callbacks[callbackId] != null)) {
                if (Cordova.callbacks[callbackId].success) {
                    try {
                        Cordova.callbacks[callbackId].success(v.message);
                    } catch (e) {
                        _consoleLog("Error in success callback: " + callbackId + " = " + e);
                    }

                    // Clear callback if not expecting any more results
                    if (!v.keepCallback) {
                        delete Cordova.callbacks[callbackId];
                    }
                }
            }
            return v.message;
        }
4

1 回答 1

1

这是一些符合您期望的代码：

<!DOCTYPE html>
<html>
<head>
<title>FileReader Example</title>
<meta name="viewport"
    content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">

<script type="text/javascript" charset="utf-8">

    onWLReady = function() {
        // Wait for PhoneGap to load
        document.addEventListener("deviceready", onDeviceReady, false);
    }

    var wlInitOptions = {
        onSuccess : onWLReady,
        connectOnStartup : false
    };

    if (window.addEventListener) {
        window.addEventListener('load', function() {
            WL.Client.init(wlInitOptions); }, false);
    } else if (window.attachEvent) {
        window.attachEvent('onload',  function() {
            WL.Client.init(wlInitOptions);
         });
    }

    function log(txt){
        var p = document.createElement('p');
        document.getElementById("log").appendChild(p);
        p.appendChild(document.createTextNode(txt));
    }

    // PhoneGap is ready
    //
    function onDeviceReady(){
        log("onDeviceReady");
    }

    function readFile() {
        window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
            function(fileSystem) {
                fileSystem.root.getFile("ExecutionResult.xml", {
                     create : false, exclusive: false
                },
                function(fileEntry){
                    fileEntry.file(function(file) {
                        readDataUrl(file);
                        readAsText(file);
                    },
                    fail);
                },
                fail);
        }, fail);
    }

    function writeFile() {
        window.requestFileSystem(LocalFileSystem.PERSISTENT, 0,
            function(fileSystem) {
            fileSystem.root.getFile("ExecutionResult.xml", {create: true,     exclusive: true},
                    function(fileEntry) {
                        fileEntry.createWriter(
                            function(writer) {
                                writer.onwriteend = function(evt) {
                                    readFile();
                                };
                            writer.onwritestart =     function(evt){
                                    log("onwritestart");
                                };
                                writer.onwrite = function(evt){
                                    log("onwrite");
                                };
                                writer.onerror = function(evt){
                                    log("onerror");
                                };
                                writer.write("JSonData");
                            },
                            fail);
                        }
                        , fail);
            },
            fail);
    }

    function readDataUrl(file){
        var reader = new FileReader();
        log("readDataUrl...");
        reader.onloadstart = function(evt){
            log("onloadstart: " + evt.target.result);
        };
        reader.onload = function(evt){
            log("onload: " + evt.target.result);
        };
        reader.onloadend = function(evt){
            log("onloadend: " + evt.target.result);
        };
        reader.onerror = function(evt){
            log("onerror: " + evt.target.result);
        };
        reader.readAsDataURL(file);
    }

    function readAsText(file) {
        var reader = new FileReader();
        log("readAsText...");
        reader.onloadstart = function(evt){
            log("onloadstart: " + evt.target.result);
        };
        reader.onload = function(evt){
            log("onload: " + evt.target.result);
        };
        reader.onloadend = function(evt){
            log("onloadend: " + evt.target.result);
        };
        reader.onerror = function(evt){
            log("onerror: " + evt.target.result);
        };
        reader.readAsText(file);
    }

    function fail(error) {
        log("fail: "+ evt.target.error.code);
    }
</script>
</head>
<body id="content">
    <button onclick="writeFile();">Write and read file</button>
    <p id="log"></p>
</body>
</html>

希望这可以帮助...

于 2013-04-18T16:44:33.547 回答