android camerax怎樣處理預(yù)覽

小樊
81
2024-11-16 20:18:01
欄目: 編程語言

Android CameraX 是一個(gè)用于簡(jiǎn)化 Android 相機(jī)功能開發(fā)的庫。要處理預(yù)覽，您需要遵循以下步驟：

  1. 添加依賴項(xiàng)

在您的 build.gradle 文件中添加 CameraX 和 CameraX LiveData 依賴項(xiàng)：

dependencies {
    implementation 'androidx.camera:camera-core:1.0.0'
    implementation 'androidx.camera:camera-camera2:1.0.0'
    implementation 'androidx.camera:camera-lifecycle:1.0.0'
    implementation 'androidx.camera:camera-view:1.0.0'
    implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.3.1'
}
  1. 配置 CameraX

在您的應(yīng)用模塊（通常是 MainActivity）中，配置 CameraX：

import android.Manifest
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import androidx.camera.core.CameraSelector
import androidx.camera.core.ImageAnalysis
import androidx.camera.core.ImageProxy
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {

    private lateinit var cameraProviderFuture: ProcessCameraProvider
    private lateinit var imageAnalyzer: ImageAnalyzer

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

        // 檢查相機(jī)權(quán)限
        if (hasCameraPermission()) {
            // 獲取 CameraProvider
            cameraProviderFuture = ProcessCameraProvider.getInstance(this)
            // 創(chuàng)建 ImageAnalyzer
            imageAnalyzer = ImageAnalyzer()
            // 設(shè)置預(yù)覽
            setupPreview()
        } else {
            requestCameraPermission()
        }
    }

    private fun hasCameraPermission(): Boolean {
        return ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED
    }

    private fun requestCameraPermission() {
        ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.CAMERA), REQUEST_CAMERA_PERMISSION)
    }

    private fun setupPreview() {
        cameraProviderFuture.addListener({
            val cameraProvider = cameraProviderFuture.get()
            bindPreview(cameraProvider)
        }, ContextCompat.getMainExecutor(this))
    }

    private fun bindPreview(cameraProvider: ProcessCameraProvider) {
        val preview = androidx.camera.core.Preview.Builder().build()
        preview.setSurfaceProvider(findViewById<androidx.camera.core.PreviewView>(R.id.previewView).surfaceProvider)

        val cameraSelector = CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()

        cameraProvider.unbindAll()
        cameraProvider.bindToLifecycle(this, cameraSelector, preview, imageAnalyzer)
    }

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
        when (requestCode) {
            REQUEST_CAMERA_PERMISSION -> {
                if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    setupPreview()
                } else {
                    // 處理權(quán)限被拒絕的情況
                }
            }
        }
    }

    companion object {
        private const val REQUEST_CAMERA_PERMISSION = 1
    }
}
  1. 創(chuàng)建預(yù)覽視圖

在您的布局文件（例如 activity_main.xml）中，添加一個(gè) PreviewView：

<androidx.camera.core.PreviewView
    android:id="@+id/previewView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
  1. 創(chuàng)建圖像分析器

創(chuàng)建一個(gè)繼承自 ImageAnalyzer 的類，并實(shí)現(xiàn) ImageProxy.Listener 接口。在這個(gè)類中，您可以處理圖像數(shù)據(jù)，例如使用機(jī)器學(xué)習(xí)模型進(jìn)行物體識(shí)別。

import android.graphics.ImageFormat
import android.os.Build
import android.renderscript.Allocation
import android.renderscript.Element
import android.renderscript.RenderScript
import android.renderscript.ScriptIntrinsicBlur
import androidx.camera.core.ImageProxy
import java.nio.ByteBuffer

class ImageAnalyzer : ImageAnalyzer() {

    private val scriptIntrinsicBlur = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs))

    override fun analyze(imageProxy: ImageProxy) {
        if (imageProxy.image == null) {
            return
        }

        val mediaImage = imageProxy.image!!
        val buffer = mediaImage.planes[0].buffer
        val byteArray = ByteArray(buffer.capacity())
        buffer.get(byteArray)

        // 將字節(jié)數(shù)組轉(zhuǎn)換為 Bitmap
        val bitmap = BitmapFactory.decodeByteArray(byteArray, 0, byteArray.size)

        // 使用 RenderScript 進(jìn)行模糊處理
        val input = Allocation.createFromBitmap(rs, bitmap)
        val output = Allocation.createFromBitmap(rs, bitmap)
        scriptIntrinsicBlur.setRadius(15f)
        scriptIntrinsicBlur.setInput(input)
        scriptIntrinsicBlur.forEach(output)
        output.copyTo(bitmap)

        // 將處理后的 Bitmap 轉(zhuǎn)換回字節(jié)數(shù)組
        val outputBuffer = output.getBuffer()
        outputBuffer.get(byteArray)

        // 處理圖像數(shù)據(jù)（例如上傳到服務(wù)器或顯示在 UI 上）
    }
}

現(xiàn)在，當(dāng)您運(yùn)行應(yīng)用時(shí)，CameraX 應(yīng)該會(huì)處理預(yù)覽并將圖像傳遞給 ImageAnalyzer 類進(jìn)行分析。

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