Question

我写了一个缓存系统。它使用平台/ Android方法将数据保存到App的缓存文件夹中以查找文件夹。我有一个问题，我无法在Apps缓存文件夹中创建新文件夹。

此错误在某些设备的Crashlytics（通过非致命错误报告）中报告，而对于大多数不是。

包含该问题的方法是我的getCacheFolder()方法。

在这些设备上无效的示例文件夹路径：/storage/emulated/0/Android/data/app.package.name/cache/stream-cache。

受影响的报告版本：4.4.2; 5.0.1; 6.0，6.0.1。

受影响的报告设备：LENOVO YOGA Tablet 2-1050L，MOTOROLA MotoE2(4G-LTE)，Samsung SM-N910F（报告的故障占98％）。

我怀疑可能存在与可移动sdcards相关的问题。

@NonNull
public File getCacheFolder() {
    // If this is the first run of this library function, we should get our cache folder
    if (mCacheFolder == null || !mCacheFolder.exists()) {
        File dir = null;

        // Prioritise the external sdcard to store cached files
        dir = mContext.get().getExternalCacheDir();
        if(dir == null) {
            // There was no external sdcard - instead use internal storage
            dir = mContext.get().getCacheDir();
        }

        // Still couldn't get a cache location, go to fallback plan and throw exception
        if(dir == null) {
            throw new IllegalStateException("Could not create a location to cache. " +
                    "This leaves the caching library in a bad state.");
        }

        // Point to our specific caching folder for this system
        mCacheFolder = new File(dir, "stream-cache");
    }

    // If it doesn't exist, we will need to make it
    if (!mCacheFolder.exists()) {
        // If we cannot make the directory, go to fallback plan and throw an exception
        if (!mCacheFolder.mkdirs()) {
            // HERE IS WHERE THE FAULT IS REPORTED
            throw new IllegalStateException("Could not create a location to cache. " +
                    "This leaves the caching library in a bad state.: "+mCacheFolder);
        }
    }

    return mCacheFolder;
}

更新1

我更新了代码以写出有关状态的各种信息：

@NonNull
public File getCacheFolder() {
    if (mCacheFolder == null || !mCacheFolder.exists()) {
        File dir = mContext.get().getExternalCacheDir();
        if(dir == null || !Utils.isExternalStorageWritable()) {
            dir = mContext.get().getCacheDir();
        }

        mCacheFolder = new File(dir, "stream-cache");
    }

    if (!mCacheFolder.exists()) {
        if (!mCacheFolder.mkdirs()) {
            // Problems writing to cache - test writing to file path.
            File filePath = mContext.get().getExternalFilesDir(null);
            File cachePath = new File(filePath, "stream-cache");

            throw new IllegalStateException("Could not create a location to cache. " +
                    "This leaves the caching library in a bad state.: "+mCacheFolder+ ". " +
                    "filePath="+filePath+". " +
                    "cachePath="+cachePath+". " +
                    "cachePath-exists="+cachePath.exists()+". " +
                    "cachePath-mkdirs="+cachePath.mkdirs());
        }
    }

    return mCacheFolder;
}

由此产生的重要结果：

filePath = null - Context.getExternalFilesDir(null);返回null。打破其余的测试。

Answer 1

而不是使用

// Point to our specific caching folder for this system
mCacheFolder = new File(dir, "stream-cache");

尝试使用：

// Point to our specific caching folder for this system
mCacheFolder = new File(dir + "/stream-cache");

在您的第一个代码段中。

无法在Apps缓存文件夹中创建新文件夹

更新1

1 个答案: