Phonegap相机插件获取临时缓存图片后如何获取永久imageURI？

Hey there! I see you're running into the common issue where temporary image URIs from the PhoneGap Camera plugin get cleaned up by the system over time. Since you already have saveToPhotoAlbum: true enabled, we have a couple solid options to get persistent image URIs that won't disappear. Let's break them down:

Option 1: Copy the Image to Your App's Persistent Storage Directory #

This method takes the temporary image from the cache and copies it to a private, system-protected directory that won't be automatically cleaned up. We'll use the cordova-plugin-file for this.

First, install the required plugin:

cordova plugin add cordova-plugin-file

Then modify your onSuccess function to handle the file copy:

$('.photo').click(function() {
    navigator.camera.getPicture(onSuccess, onFail, {
        quality: 50,
        destinationType: Camera.DestinationType.FILE_URI,
        saveToPhotoAlbum: true
    });

    function onSuccess(imageURI) {
        // Resolve the temporary file entry from the camera
        window.resolveLocalFileSystemURL(imageURI, function(tempFileEntry) {
            // Access your app's persistent data directory
            window.resolveLocalFileSystemURL(cordova.file.dataDirectory, function(persistentDir) {
                // Generate a unique filename to avoid overwriting existing photos
                var fileName = "persistent_photo_" + Date.now() + ".jpg";
                
                // Copy the temp file to the persistent directory
                tempFileEntry.copyTo(persistentDir, fileName, function(newFileEntry) {
                    var persistentImageURI = newFileEntry.toURL();
                    
                    // Update your UI and save the permanent URI to localStorage
                    $.mobile.changePage("#four", { transition: "slide", reverse: true, changeHash: false});
                    $('img').remove();
                    var img = $('<img />');
                    img.attr('src', persistentImageURI);
                    img.attr('width', "200");
                    img.attr('height', "200");
                    img.appendTo('#photos');
                    
                    // Save to localStorage array
                    var savedPhotos = JSON.parse(localStorage.getItem('photos')) || [];
                    savedPhotos.push(persistentImageURI);
                    localStorage.setItem('photos', JSON.stringify(savedPhotos));
                }, function(copyError) {
                    console.error("Failed to copy file: ", copyError);
                });
            }, function(dirError) {
                console.error("Failed to access persistent directory: ", dirError);
            });
        }, function(fileError) {
            console.error("Failed to resolve temp file URI: ", fileError);
        });
    }

    function onFail(message) {
        console.log('Camera failed because: ' + message);
    }
});

The cordova.file.dataDirectory is a private space for your app—files here won't be deleted unless your app is uninstalled.

Option 2: Retrieve the Permanent URI from the Photo Album #

Since you're already saving photos to the system album, you can fetch the permanent URI directly from the photo library using the cordova-plugin-photo-library plugin. This avoids duplicating files, but note that users could delete the photo from their album later, breaking the URI.

First, install the plugin:

cordova plugin add cordova-plugin-photo-library

Then update your onSuccess function to fetch the latest photo from the album:

$('.photo').click(function() {
    navigator.camera.getPicture(onSuccess, onFail, {
        quality: 50,
        destinationType: Camera.DestinationType.FILE_URI,
        saveToPhotoAlbum: true
    });

    function onSuccess(imageURI) {
        // Fetch the most recently added photo from the library
        window.PhotoLibrary.getPhotos({
            limit: 1,
            sortBy: 'creationDate',
            sortOrder: 'desc'
        }, function(photos) {
            if (photos.length > 0) {
                var albumImageURI = photos[0].photoURL;
                
                // Update UI and save the album URI to localStorage
                $.mobile.changePage("#four", { transition: "slide", reverse: true, changeHash: false});
                $('img').remove();
                var img = $('<img />');
                img.attr('src', albumImageURI);
                img.attr('width', "200");
                img.attr('height', "200");
                img.appendTo('#photos');
                
                // Save to localStorage array
                var savedPhotos = JSON.parse(localStorage.getItem('photos')) || [];
                savedPhotos.push(albumImageURI);
                localStorage.setItem('photos', JSON.stringify(savedPhotos));
            }
        }, function(libraryError) {
            console.error("Failed to fetch photo from library: ", libraryError);
        });
    }

    function onFail(message) {
        console.log('Camera failed because: ' + message);
    }
});

Key Notes: #

• Permissions: Both plugins require proper permissions. For iOS, add NSPhotoLibraryUsageDescription to your config.xml; for Android, ensure you have READ_EXTERNAL_STORAGE and WRITE_EXTERNAL_STORAGE permissions configured.
• Tradeoffs: Option 1 keeps files under your app's control but uses more storage. Option 2 saves space but relies on users not deleting the photo from their album.

内容的提问来源于stack exchange，提问作者J.Doe