Android kotlin 用户点击更换头像 拍照和相册选择

以下是一个使用Kotlin编写的示例代码，用于允许用户更改其头像。它将打开一个对话框，让用户选择从相机拍照或从相册中选择。选择后，它将更新用户的头像。

private val REQUEST_IMAGE_CAPTURE = 1
private val REQUEST_IMAGE_SELECT = 2
private var mCurrentPhotoPath: String = ""

private fun changeAvatar() {
    val pictureDialog = AlertDialog.Builder(this)
    pictureDialog.setTitle("选择头像")
    val pictureDialogItems = arrayOf("从相册选择", "拍照")
    pictureDialog.setItems(pictureDialogItems
    ) { _, which ->
        when (which) {
            0 -> choosePhotoFromGallery()
            1 -> takePhoto()
        }
    }
    pictureDialog.show()
}

private fun choosePhotoFromGallery() {
    val galleryIntent = Intent(Intent.ACTION_PICK,
        MediaStore.Images.Media.EXTERNAL_CONTENT_URI)
    startActivityForResult(galleryIntent, REQUEST_IMAGE_SELECT)
}

private fun takePhoto() {
    val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
    if (takePictureIntent.resolveActivity(packageManager) != null) {
        val photoFile: File? = try {
            createImageFile()
        } catch (ex: IOException) {
            null
        }
        photoFile?.also {
            val photoURI: Uri = FileProvider.getUriForFile(
                this,
                "com.example.android.fileprovider",
                it
            )
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI)
            startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE)
        }
    }
}

@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
        mCurrentPhotoPath = absolutePath
    }
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)

    if (resultCode == Activity.RESULT_OK) {
        when (requestCode) {
            REQUEST_IMAGE_CAPTURE -> {
                val file = File(mCurrentPhotoPath)
                val uri = Uri.fromFile(file)
                updateAvatar(uri)
            }
            REQUEST_IMAGE_SELECT -> {
                val uri = data?.data
                updateAvatar(uri)
            }
        }
    }
}

private fun updateAvatar(uri: Uri?) {
    // Do something with the selected image
}

请注意，在使用相机拍照时，我们需要在`AndroidManifest.xml`文件中添加以下内容，以确保我们的应用程序具有访问相机的权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />

同时，我们还需要添加以下内容，以确保我们的应用程序具有访问存储的权限：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />