拍照时意图始终为空

Posted 2023-04-17

【中文标题】拍照时意图始终为空

【英文标题】：Intent is always null when taking a picture

【发布时间】：2021-07-15 17:28:27

【问题描述】：

我是 Kotlin 和 android Studio 的新手，在从相机中检索图片时遇到了问题。

onActivityResult 中的 Intent 始终为 null，因此不会显示任何图像。当我删除数据时！==null，我得到以下错误

将结果 ResultInfowho=null, request=1, result=-1, data=null 传递给活动失败

这是我的代码：

MainActivity.kt：

class MainActivity : AppCompatActivity() 
    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) 
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        binding.startButton.setOnClickListener
            dispatchTakePictureIntent()
        
    

    val REQUEST_IMAGE_CAPTURE = 1

    private fun dispatchTakePictureIntent() 
        Intent(MediaStore.ACTION_IMAGE_CAPTURE).also  takePictureIntent ->
            // Ensure that there's a camera activity to handle the intent
            takePictureIntent.resolveActivity(packageManager)?.also 
                // Create the File where the photo should go
                val photoFile: File? = try 
                    createImageFile()
                 catch (ex: IOException) 
                    // Error occurred while creating the File
                    Log.d("ERROR", "An error occured")
                    null
                
                // Continue only if the File was successfully created
                photoFile?.also 
                    val photoURI: Uri = FileProvider.getUriForFile(
                            this,
                            "pim.android.photoapp.fileprovider",
                            it
                    )
                    takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI)
                    startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE)
                
            
        
    

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) 
        super.onActivityResult(requestCode, resultCode, data)
//        Log.d("DATA", data.toString())

        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK && data !== null) 
            val imageBitmap = data.extras?.get("data") as Bitmap
            binding.imageView.setImageBitmap(imageBitmap)
        
    

    lateinit var currentPhotoPath: String

    @Throws(IOException::class)
    private fun createImageFile(): File 
        // Create an image file name
        val timeStamp: String = SimpleDateFormat("yyyyMMdd_HHmmss").format(Date())
        val storageDir: File? = getExternalFilesDir(Environment.DIRECTORY_PICTURES)
        return File.createTempFile(
                "JPEG_$timeStamp_", /* prefix */
                ".jpg", /* suffix */
                storageDir /* directory */
        ).apply 
            // Save a file: path for use with ACTION_VIEW intents
            currentPhotoPath = absolutePath
        
    

清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="pim.android.photoapp">

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-feature android:name="android.hardware.camera"
        android:required="true" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.PhotoApp">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="pim.android.photoapp.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths"></meta-data>
        </provider>
    </application>

</manifest>

@xml/file_paths：

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

有人知道我在这里做错了什么吗？任何答案将不胜感激

【问题讨论】：

ACTION_IMAGE_CAPTURE 不应返回Intent。您的照片应位于EXTRA_OUTPUT 中指定的位置。

@CommonsWare 你的意思是我必须将 putExtra 中的 EXTRA_OUTPUT 更改为 ACTION_IMAGE_CAPTURE？因为那有点用，只有图片不会很清晰

"您的意思是我必须将 putExtra 中的 EXTRA_OUTPUT 更改为 ACTION_IMAGE_CAPTURE？" ——你已经有了。不过，您没有在onActivityResult() 中使用它。我之前的评论并不清楚：当您使用EXTRA_OUTPUT 时，不要假设ACTION_IMAGE_CAPTURE 会返回Intent，并且从不在@ 中寻找data 额外987654332@。这就是你现在正在做的事情。相反，在onActivityResult() 中，使用应写入您在EXTRA_OUTPUT 中请求的位置的照片。

【参考方案1】：

onActivityResult 上的 Intent 不会返回 Image 数据，而是保存在创建的文件路径上（如果文件创建成功，考虑到不同 android 版本的权限方面）

步骤 1. 将照片文件设为全局变量

    private var photoFile: File? = null

第 2 步。使用 glabal photofile 更新您的 dispath 方法

private fun dispatchTakePictureIntent() 
    Intent(MediaStore.ACTION_IMAGE_CAPTURE).also  takePictureIntent ->
        // Ensure that there's a camera activity to handle the intent
        takePictureIntent.resolveActivity(packageManager)?.also 
            // Create the File where the photo should go
             photoFile: File? = try 
                createImageFile()
             catch (ex: IOException) 
                // Error occurred while creating the File
                Log.d("ERROR", "An error occured")
                null
            
            // Continue only if the File was successfully created
            photoFile?.also 
                val photoURI: Uri = FileProvider.getUriForFile(
                        this,
                        "pim.android.photoapp.fileprovider",
                        it
                )
                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI)
                startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE)
            
        
    

第 3 步。更新您的活动结果

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) 
        super.onActivityResult(requestCode, resultCode, data)
//        Log.d("DATA", data.toString())

        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) 
photoFile?.let 
                val imageBitmap: Bitmap=  BitmapFactory.decodeFile(it.absolutePath)
binding.imageView.setImageBitmap(imageBitmap)