如何实现拍照按钮并将拍摄照片传递至另一Activity？

Hey there, sorry this has been bugging you for two weeks—let’s get this sorted out! Showing a captured photo in another Activity is totally doable, and I’ll walk you through the most reliable approaches below.

Directly passing large bitmaps between Activities can cause OutOfMemoryErrors, so using a file path is the safest bet. Here's how to do it step by step:

Step 1: Save the Captured Photo to a Local File #

When you trigger the camera, first create a dedicated file to save the photo (using your app's private external storage to avoid permission headaches on Android 10+):

private lateinit var currentPhotoPath: String

private fun createImageFile(): File {
    val timeStamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(Date())
    val storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES)
    return File.createTempFile(
        "JPEG_${timeStamp}_",
        ".jpg",
        storageDir
    ).apply {
        currentPhotoPath = absolutePath // Save the path for later use
    }
}

Then launch the camera intent with this file's URI (using FileProvider to comply with Android's security rules):

val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
val photoFile: File? = try {
    createImageFile()
} catch (ex: IOException) {
    // Handle file creation errors here
    null
}

photoFile?.also {
    val photoURI = FileProvider.getUriForFile(
        this,
        "com.your.app.package.fileprovider", // Replace with your app's FileProvider authority
        it
    )
    takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI)
    // Use Activity Result API (modern approach) instead of startActivityForResult
    takePictureLauncher.launch(takePictureIntent)
}

Step 2: Pass the File Path to the Second Activity #

Once the photo is captured and saved, pass the file path via Intent when launching your target Activity:

// Register the Activity Result Launcher in your onCreate
val takePictureLauncher = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
    if (result.resultCode == RESULT_OK) {
        // Photo is saved at currentPhotoPath
        val intent = Intent(this, YourSecondActivity::class.java)
        intent.putExtra("IMAGE_FILE_PATH", currentPhotoPath)
        startActivity(intent)
    }
}

Step 3: Load the Image in the Second Activity #

Retrieve the path and load the image into an ImageView. For better performance, use an image loading library like Glide or Picasso instead of BitmapFactory directly (to avoid OOM):

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_second)

    val imagePath = intent.getStringExtra("IMAGE_FILE_PATH")
    imagePath?.let {
        // Option 1: Using BitmapFactory (simpler but riskier for large images)
        val bitmap = BitmapFactory.decodeFile(it)
        findViewById<ImageView>(R.id.target_image_view).setImageBitmap(bitmap)

        // Option 2: Using Glide (recommended for efficiency)
        // Glide.with(this).load(File(it)).into(findViewById(R.id.target_image_view))
    }
}

Important Setup: FileProvider #

Don't forget to configure FileProvider in your AndroidManifest.xml to allow the camera app to write to your app's private files:

<application ...>
    <provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="com.your.app.package.fileprovider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths" />
    </provider>
</application>

Then create res/xml/file_paths.xml to define the directory your FileProvider can access:

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-files-path name="captured_photos" path="Pictures" />
</paths>

If you're working with small images (like thumbnails), you can pass the Bitmap directly via Intent, but be warned—this can cause memory issues for high-resolution photos:

// In your first Activity after capturing the photo
val bitmap = BitmapFactory.decodeFile(currentPhotoPath)
val intent = Intent(this, YourSecondActivity::class.java)
intent.putExtra("IMAGE_BITMAP", bitmap)
startActivity(intent)

// In the second Activity
val bitmap = intent.getParcelableExtra<Bitmap>("IMAGE_BITMAP")
bitmap?.let { findViewById<ImageView>(R.id.target_image_view).setImageBitmap(it) }

Give these methods a try—chances are the issue was either not saving the photo to a persistent location or mishandling the data transfer between Activities. Let me know if you run into any specific errors!

内容的提问来源于stack exchange，提问作者Bodie