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首页 > 解决方案 > 如何将图像转换为 base64 并在 androidX 中使用 kotlin 对其进行压缩？

android - 如何将图像转换为 base64 并在 androidX 中使用 kotlin 对其进行压缩？

问题描述

我正在创建一个离线短信应用程序。我想知道如何将用户选择的图像转换为字符串 base64 并对其进行压缩。

我搜索了很多但没有找到太多材料。我找到的所有数据都是Java。但我需要 Kotlin 语言。

活动文件

class MainActivity1 :AppCompatActivity(){

    private val requestReceiveSms: Int = 1
    private val requestSendSms: Int = 2
    private var mMessageRecycler: RecyclerView? = null
    private var mMessageAdapter: MessageAdapter? = null

    val SELECT_PICTURE = 5

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

        btn1.setOnClickListener {
            dispatchGalleryIntent()
        }



        seupRecycler()

        val bundle: Bundle? = intent.extras

        bundle?.let {
            val NUm = bundle.getString("address")



            phone.text = NUm
        }



        btnSend.setOnClickListener {

            if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.SEND_SMS) !=
                PackageManager.PERMISSION_GRANTED
            ) {
                ActivityCompat.requestPermissions(
                    this, arrayOf(android.Manifest.permission.SEND_SMS),
                    requestSendSms
                )
            } else {
                SendSms()
            }
        }

        if(ActivityCompat.checkSelfPermission(this,android.Manifest.permission.RECEIVE_SMS) !=
            PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(this, arrayOf(android.Manifest.permission.RECEIVE_SMS),
                requestReceiveSms)
        }
    }

    private fun seupRecycler() {
        mMessageRecycler = this.reyclerview_message_list as RecyclerView
        mMessageAdapter = MessageAdapter(this)
        val layoutManager = LinearLayoutManager(this)
        layoutManager.orientation = RecyclerView.VERTICAL
    }

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>,
                                            grantResults: IntArray) {
        if(requestCode == requestSendSms)SendSms()
    }

    private fun SendSms() {


        val str_address = phone
        val str_message = txtMessage.text.toString()



        SmsManager.getDefault().sendTextMessage(str_address.toString(),null,str_message,null,null)

        Toast.makeText(this,"SMS Sent", Toast.LENGTH_SHORT).show()



    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if(requestCode == SELECT_PICTURE && resultCode == Activity.RESULT_OK){
            try {

                val uri = data!!.data
                imageView2.setImageURI(uri)

            }catch (e : IOException){
                e.printStackTrace()
            }
        }
    }
    fun dispatchGalleryIntent(){
        val intent = Intent(
            Intent.ACTION_PICK,
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI)
        //intent.type = "image/*"
        //intent.action = Intent.ACTION_GET_CONTENT
        //startActivityForResult(Intent.createChooser(intent,"SELECT IMAGE"), SELECT_PICTURE)
        startActivityForResult(intent,SELECT_PICTURE)
    }

}

预期的

将图像转换为base64并压缩。

实际的

没发生什么事。

标签： androidkotlinandroidx

解决方案

如果条件是因为它需要构建版本 26。低于版本将无法工作

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
    val bm = BitmapFactory.decodeFile("/path/to/image.jpg")
    val stream = ByteArrayOutputStream()
    bm.compress(CompressFormat.JPEG, 70, stream)
    val byteFormat = stream.toByteArray()
    val imgString = Base64.getEncoder().encodeToString(byteFormat)
}

检索路径/到/图像：

val uri = data!!.data
val picturePath = getPath(applicationContext, uri) // Write this line under the uri.
Log.d("Picture Path", picturePath)

这是获取图像路径的函数。

private fun getPath(applicationContext: Context, uri: Uri?): String? {
    var result: String? = null
    val proj = arrayOf(MediaStore.Images.Media.DATA)
    val cursor = applicationContext.getContentResolver().query(uri, proj, null, null, null)
    if (cursor != null) {
        if (cursor!!.moveToFirst()) {
            val column_index = cursor!!.getColumnIndexOrThrow(proj[0])
            result = cursor!!.getString(column_index)
        }
        cursor!!.close()
    }
    if (result == null) {
        result = "Not found"
    }
    return result
}

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