如何使用Android的Camera2 API _android

冲天香阵透长安，满城尽带黄金甲。这篇文章主要讲述如何使用Android的Camera2 API相关的知识，希望能为你提供帮助。
[我正在尝试使用camera2 API创建可以拍照的应用程序，并将其保存到我的设备中以备后用。
我目前在拍照方面存在问题，预览效果很好，但是当我尝试拍照时却无法这样做。

package uk.ac.abertay.cmp309_courswork_1700673_keiranwait; import android.Manifest; import android.content.Context; import android.content.pm.PackageManager; import android.graphics.ImageFormat; import android.graphics.SurfaceTexture; import android.hardware.camera2.CameraAccessException; import android.hardware.camera2.CameraCaptureSession; import android.hardware.camera2.CameraCharacteristics; import android.hardware.camera2.CameraDevice; import android.hardware.camera2.CameraManager; import android.hardware.camera2.CameraMetadata; import android.hardware.camera2.CaptureRequest; import android.hardware.camera2.TotalCaptureResult; import android.hardware.camera2.params.StreamConfigurationMap; import android.media.Image; import android.media.ImageReader; import android.os.Bundle; import android.os.Environment; import android.os.Handler; import android.os.HandlerThread; import android.util.Size; import android.util.SparseIntArray; import android.view.Surface; import android.view.TextureView; import android.view.View; import android.widget.Button; import android.widget.Toast; import androidx.annotation.NonNull; import androidx.appcompat.app.AppCompatActivity; import androidx.core.app.ActivityCompat; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.nio.ByteBuffer; import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class CameraActivity extends AppCompatActivity {Button button; TextureView textureView; private static final SparseIntArray orientations = new SparseIntArray(); static { orientations.append(Surface.ROTATION_0,90); orientations.append(Surface.ROTATION_90,0); orientations.append(Surface.ROTATION_180,270); orientations.append(Surface.ROTATION_270,180); }private String cameraId; CameraDevice cameraDevice; CameraCaptureSession cameraCaptureSession; CaptureRequest captureRequest; CaptureRequest.Builder captureRequestBuilder; private Size imageDimensions; private ImageReader imageReader; private File file; Handler mBackgroundHandler; HandlerThread mBackgroundThread; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_camera); textureView = findViewById(R.id.texture); button = findViewById(R.id.btnPic); textureView.setSurfaceTextureListener(textureListener); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { try { takePicture(); } catch (CameraAccessException e) { e.printStackTrace(); } } }); }@Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (requestCode == 101){ if (grantResults[0] == PackageManager.PERMISSION_DENIED){ Toast.makeText(getApplicationContext(),"Sorry Camera Permission Denied",Toast.LENGTH_SHORT).show(); //finish(); } } }TextureView.SurfaceTextureListener textureListener = new TextureView.SurfaceTextureListener() { @Override public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) { try { openCamera(); } catch (CameraAccessException e) { e.printStackTrace(); }}@Override public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {}@Override public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) { return false; }@Override public void onSurfaceTextureUpdated(SurfaceTexture surface) {} }; private final CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() { @Override public void onOpened(CameraDevice camera) { cameraDevice = camera; try { createCameraPreview(); } catch (CameraAccessException e) { e.printStackTrace(); }}@Override public void onDisconnected(CameraDevice camera) { cameraDevice.close(); }@Override public void onError(CameraDevice camera, int error) { cameraDevice.close(); cameraDevice = null; } }; private void createCameraPreview() throws CameraAccessException { SurfaceTexture texture = textureView.getSurfaceTexture(); texture.setDefaultBufferSize(imageDimensions.getWidth(), imageDimensions.getHeight()); Surface surface = new Surface(texture); captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW); captureRequestBuilder.addTarget(surface); cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() { @Override public void onConfigured(CameraCaptureSession session) { Toast.makeText(getApplicationContext(),"On Config",Toast.LENGTH_SHORT).show(); if (cameraDevice == null) { return; }cameraCaptureSession = session; try { updatePreview(); } catch (CameraAccessException e) { e.printStackTrace(); }}@Override public void onConfigureFailed(CameraCaptureSession session) { Toast.makeText(getApplicationContext(),"Configuration Changed",Toast.LENGTH_SHORT).show(); } },null); }private void updatePreview() throws CameraAccessException { if (cameraDevice == null) { return; }captureRequestBuilder.set(captureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO); cameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(),null, mBackgroundHandler); }private void openCamera() throws CameraAccessException { CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE); cameraId = manager.getCameraIdList()[0]; CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId); StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP); imageDimensions = map.getOutputSizes(SurfaceTexture.class) [0]; if (ActivityCompat.checkSelfPermission(this,Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED & & ActivityCompat.checkSelfPermission(this,Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(CameraActivity.this,new String[]{Manifest.permission.CAMERA,Manifest.permission.WRITE_EXTERNAL_STORAGE},101); return; }manager.openCamera(cameraId,stateCallback,null); }private void takePicture() throws CameraAccessException { if (cameraDevice == null){ return; }CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE); CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId()); Size[] jpegSizes = null; jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(ImageFormat.JPEG); int width = 640; int height = 480; if (jpegSizes != null & & jpegSizes.length > 0){ width = jpegSizes[0].getWidth(); height = jpegSizes[0].getHeight(); }ImageReader reader = ImageReader.newInstance(width,height,ImageFormat.JPEG,1); List< Surface> outputSurfaces = new ArrayList< > (2); outputSurfaces.add(reader.getSurface()); outputSurfaces.add(new Surface(textureView.getSurfaceTexture())); final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(cameraDevice.TEMPLATE_STILL_CAPTURE); captureBuilder.addTarget(reader.getSurface()); captureBuilder.set(CaptureRequest.CONTROL_MODE,CameraMetadata.CONTROL_MODE_AUTO); int rotation = getWindowManager().getDefaultDisplay().getRotation(); captureBuilder.set(captureRequest.JPEG_ORIENTATION,orientations.get(rotation)); Long tsLong = System.currentTimeMillis() /1000; String ts = tsLong.toString(); file = new File(Environment.getExternalStorageDirectory() + "/" + ts+".jpg"); ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() { @Override public void onImageAvailable(ImageReader reader) { Toast.makeText(getApplicationContext(),"Image Avail",Toast.LENGTH_SHORT).show(); Image image = null; image = reader.acquireLatestImage(); ByteBuffer buffer = image.getPlanes()[0].getBuffer(); byte[] bytes = new byte[buffer.capacity()]; buffer.get(bytes); try { save(bytes); } catch (IOException e) { e.printStackTrace(); }finally { if (image != null){ image.close(); } }} }; reader.setOnImageAvailableListener(readerListener,mBackgroundHandler); final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() { @Override public void onCaptureCompleted(CameraCaptureSession session,CaptureRequest request,TotalCaptureResult result) { super.onCaptureCompleted(session, request, result); Toast.makeText(getApplicationContext(),"Saved",Toast.LENGTH_SHORT).show(); try { createCameraPreview(); } catch (CameraAccessException e) { e.printStackTrace(); }} }; cameraDevice.createCaptureSession(outputSurfaces, new CameraCaptureSession.StateCallback() { @Override public void onConfigured(CameraCaptureSession session) { Toast.makeText(getApplicationContext(),"On Config 2",Toast.LENGTH_SHORT).show(); try { session.capture(captureBuilder.build(),captureListener,mBackgroundHandler); } catch (CameraAccessException e) { e.printStackTrace(); }}@Override public void onConfigureFailed(CameraCaptureSession session) { Toast.makeText(getApplicationContext(),"Error",Toast.LENGTH_SHORT).show(); } },mBackgroundHandler); }private void save(byte[] bytes) throws IOException { OutputStream outputStream = null; outputStream = new FileOutputStream(file); outputStream.write(bytes); outputStream.close(); }@Override protected void onResume() { super.onResume(); startBackgroundThread(); if (textureView.isAvailable()){ try { openCamera(); } catch (CameraAccessException e) { e.printStackTrace(); } } else { textureView.setSurfaceTextureListener(textureListener); }}private void startBackgroundThread() { mBackgroundThread = new HandlerThread("Camera Background"); mBackgroundThread.start(); mBackgroundHandler = new Handler(mBackgroundThread.getLooper()); }@Override protected void onPause() { try { stopBackgroundThread(); } catch (InterruptedException e) { e.printStackTrace(); } super.onPause(); }protected void stopBackgroundThread() throws InterruptedException { mBackgroundThread.quitSafely(); mBackgroundThread.join(); mBackgroundThread = null; mBackgroundHandler = null; } }

当它运行时，它似乎没有输入onImageAvailable方法，我相信这是问题所在，但是由于我对如何利用此API尚不了解，所以我不确定100％是否是问题所在。
答案【如何使用Android的Camera2 API】此问题已通过使用我的真实设备而不是模拟器来解决