应用程序在使用Retrofit上传图像时崩溃，运行在KitKat 4.4.4 API 19上。

Question

根据需求，应用程序用户从设备相机中点击图像并将其上传到服务器。当我在Lollipop及以上版本上测试我的APK时，一切正常，但当我在Lollipop以下版本上测试（特别是KitKat 4.4.4 API 19）时，应用程序会崩溃并显示异常java.io.FileNotFoundException: /：open failed：EISDIR（是一个目录）。

在将intent传递给Camera之前，我创建了一个File并将其传递给Uri。同时，在创建File 时，我还将文件路径保存在某个变量中。

后来，在onActivityResult()中，我使用路径（保存在变量中）创建新文件，然后使用retrofit multipart将其传递给服务器。

这是我如何将Intent传递给Camera的方式。

Intent(MediaStore.ACTION_IMAGE_CAPTURE).also { takePictureIntent ->
                        takePictureIntent.resolveActivity(packageManager)?.also {
                            val photoFile = try {
                                createImageFile()
                            } catch (e: Exception) {
                                null
                            }

                            Log.e("file tag", photoFile!!.absolutePath)

                            photoFile?.also {
                                val photoUri = FileProvider.getUriForFile(this@PrintActivity, "$packageName.fileprovider", it)
                                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoUri)
                                if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP) {
                                    takePictureIntent.clipData = ClipData.newRawUri("", photoUri)
                                    takePictureIntent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
                                }
                                startActivityForResult(takePictureIntent, REQUEST_CAMERA)
                            }
                        }
                    }

createImageFile()方法如下：

@Throws(IOException::class)
    private fun createImageFile(): File {
        val timeStamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.ENGLISH).format(Date())
        val storageDir = getExternalFilesDir("Allocation")
        return File.createTempFile("JPEG_${timeStamp}_", ".jpg", storageDir).apply {
            printImageFilePath = absolutePath
        }
    }

这是我提供的file_paths。

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="my_images" path="Android/data/$packageName/files/Allocation" />
</paths>

这是我在 AndroidManifest 文件中的 application 标签下声明 Provider 的方式。

<provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="$packageName.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths" />
        </provider>

这是方法 OnActivityResult()。

 override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if (requestCode == REQUEST_CAMERA && resultCode == Activity.RESULT_OK) {
            try {
                val printedImageFile = File(printImageFilePath)
                doImageUpload(printedImageFile)
            } catch (e: Throwable) {
                e.stackTrace
            }
        }
}

这是我的doImageUpload()方法。

private fun doImageUpload(printedImageFile: File?) {
        if (networkUtil.isConnected()) {
            try {
                launch(UI) {
                    val response = dataManager.uploadImage(printedImageFile)
                    Log.v("ImageUploadSuccess", response.body())

}catch(e:Exception){

}

    }

这是我的dataManager.uploadImage(printedImageFile)方法。

suspend fun uploadImage(printImageFile: File?): Response<String> {

        val printImageBody: RequestBody
        val printImagePart: MultipartBody.Part

            printImageBody = 
 RequestBody.create(MediaType.parse("multipart/formdata"),printImageFile)
            printImagePart = MultipartBody.Part.createFormData("my_file1", printImageFile.name, printImageBody)
            restService.uploadImage(printImagePart).await()
}

最后，这是我的retrofit多部分接口方法：

@Multipart
    @POST
    fun uploadImage(@Part myFile2: MultipartBody.Part?): Deferred<Response<String>>

这是我收到的崩溃日志。

E/AndroidRuntime: FATAL EXCEPTION: main
Process: $packageName, PID: 24339
java.io.FileNotFoundException: /: open failed: EISDIR (Is a directory)
    at libcore.io.IoBridge.open(IoBridge.java:409)
    at java.io.FileInputStream.<init>(FileInputStream.java:78)
    at okio.Okio.source(Okio.java:168)
    at okhttp3.RequestBody$3.writeTo(RequestBody.java:119)
    at okhttp3.MultipartBody.writeOrCountBytes(MultipartBody.java:173)
    at okhttp3.MultipartBody.writeTo(MultipartBody.java:114)
    at com.readystatesoftware.chuck.ChuckInterceptor.intercept(ChuckInterceptor.java:154)
    at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147)
    at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121)
    at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:254)
    at okhttp3.RealCall$AsyncCall.execute(RealCall.java:200)
    at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
    at java.lang.Thread.run(Thread.java:841)
 Caused by: libcore.io.ErrnoException: open failed: EISDIR (Is a directory)
    at libcore.io.IoBridge.open(IoBridge.java:398)
    at java.io.FileInputStream.<init>(FileInputStream.java:78) 
    at okio.Okio.source(Okio.java:168) 
    at okhttp3.RequestBody$3.writeTo(RequestBody.java:119) 
    at okhttp3.MultipartBody.writeOrCountBytes(MultipartBody.java:173) 
    at okhttp3.MultipartBody.writeTo(MultipartBody.java:114) 
    at com.readystatesoftware.chuck.ChuckInterceptor.intercept(ChuckInterceptor.java:154) 
    at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
    at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) 
    at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:254) 
    at okhttp3.RealCall$AsyncCall.execute(RealCall.java:200) 
    at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
    at java.lang.Thread.run(Thread.java:841)

- iCantC

Answer 1

经过多次尝试并得到我的前辈和this的帮助，我终于解决了相关问题。

问题是，当我从后置摄像头拍照时，安卓系统会杀死我的Activity类以节省资源。当相机关闭并返回到我的Activity时，由于Activity被重新创建，用于保存捕获图像文件路径的实例变量为空。结果应用程序崩溃。

因此，为了保留实例变量，我在我的PrintActivity类（从中触发Camera Intent的Activity）中使用了以下onSaveInstanceState(outState: Bundle?)方法：

override fun onSaveInstanceState(outState: Bundle?) {
    super.onSaveInstanceState(outState)
    outState?.putString(Constants.PRINT_IMAGE_FILE_PATH,printImageFilePath) 
  // printImageFilePath is the path of the image file , 
 //  Constants.PRINT_IMAGE_FILE_PATH is my key for the bundle

}

然后在我的PrintActivity中，在onCreate(savedInstanceState: Bundle?)中重新分配实例变量，像这样：

override fun onCreate(savedInstanceState: Bundle?) {
    if(savedInstanceState?.get(Constants.PRINT_IMAGE_FILE_PATH)!=null){
    printImageFilePath = 
    savedInstanceState.get(Constants.PRINT_IMAGE_FILE_PATH)
  }
}

- iCantC