实例介绍
【实例简介】
【实例截图】
【核心代码】
package com.zzu.zzh.camera_v2_0972;
import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
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.Build;
import android.os.Bundle;
import android.util.Log;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.widget.Toast;
import androidx.annotation.RequiresApi;
import androidx.core.app.ActivityCompat;
import java.io.File;
import java.io.FileOutputStream;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public class MainActivity extends Activity implements View.OnClickListener, PermissionManager.PermissionsResultListener {
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
private static final String TAG = "MainActivity";
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 AutoFitTextureView textureView;
// 摄像头ID（通常0代表后置摄像头，1代表前置摄像头）
private String mCameraId = "0";
// 定义代表摄像头的成员变量
private CameraDevice cameraDevice;
// 预览尺寸
private Size previewSize;
private CaptureRequest.Builder previewRequestBuilder;
// 定义用于预览照片的捕获请求
private CaptureRequest previewRequest;
// 定义CameraCaptureSession成员变量
private CameraCaptureSession captureSession;
private ImageReader imageReader;
private final TextureView.SurfaceTextureListener mSurfaceTextureListener = new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(SurfaceTexture texture, int width, int height) {
// 当TextureView可用时，打开摄像头
openCamera(width, height);
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture texture, int width, int height) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture texture) {
return true;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture texture) {
}
};
private final CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
// 摄像头被打开时激发该方法
@Override
public void onOpened(CameraDevice cameraDevice) {
MainActivity.this.cameraDevice = cameraDevice;
// 开始预览
createCameraPreviewSession();
}
// 摄像头断开连接时激发该方法
@Override
public void onDisconnected(CameraDevice cameraDevice) {
cameraDevice.close();
MainActivity.this.cameraDevice = null;
}
// 打开摄像头出现错误时激发该方法
@Override
public void onError(CameraDevice cameraDevice, int error) {
cameraDevice.close();
MainActivity.this.cameraDevice = null;
MainActivity.this.finish();
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
PermissionManager.requestPermission(this, "申请摄像头权限", 0, this, Manifest.permission.CAMERA);
textureView = findViewById(R.id.texture);
// 为该组件设置监听器
textureView.setSurfaceTextureListener(mSurfaceTextureListener);
findViewById(R.id.capture).setOnClickListener(this);
}
@Override
public void onClick(View view) {
captureStillPicture();
}
/**
* 捕获静态图像
*/
private void captureStillPicture() {
try {
if (cameraDevice == null) {
return;
}
// 创建作为拍照的CaptureRequest.Builder
final CaptureRequest.Builder captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
// 将imageReader的surface作为CaptureRequest.Builder的目标
captureRequestBuilder.addTarget(imageReader.getSurface());
// 设置自动对焦模式
captureRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
// 设置自动曝光模式
captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
// 获取设备方向
int rotation = getWindowManager().getDefaultDisplay().getRotation();
// 根据设备方向计算设置照片的方向
captureRequestBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
// 停止连续取景
captureSession.stopRepeating();
// 捕获静态图像
captureSession.capture(captureRequestBuilder.build(), new CameraCaptureSession.CaptureCallback() {
// 拍照完成时激发该方法
@Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
try {
// 重设自动对焦模式
previewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
// 设置自动曝光模式
previewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
// 打开连续取景模式
captureSession.setRepeatingRequest(previewRequest, null, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
// 打开摄像头
private void openCamera(int width, int height) {
setUpCameraOutputs(width, height);
CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
try {
manager.openCamera(mCameraId, stateCallback, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* // 摄像头被打开时开始预览
*/
private void createCameraPreviewSession() {
try {
SurfaceTexture texture = textureView.getSurfaceTexture();
texture.setDefaultBufferSize(previewSize.getWidth(), previewSize.getHeight());
Surface surface = new Surface(texture);
// 创建作为预览的CaptureRequest.Builder
previewRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
// 将textureView的surface作为CaptureRequest.Builder的目标
previewRequestBuilder.addTarget(new Surface(texture));
// 创建CameraCaptureSession，该对象负责管理处理预览请求和拍照请求
cameraDevice.createCaptureSession(Arrays.asList(surface, imageReader.getSurface()), new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(CameraCaptureSession cameraCaptureSession) {
// 如果摄像头为null，直接结束方法
if (null == cameraDevice) {
return;
}
// 当摄像头已经准备好时，开始显示预览
captureSession = cameraCaptureSession;
try {
// 设置自动对焦模式
previewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
// 设置自动曝光模式
previewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
// 开始显示相机预览
previewRequest = previewRequestBuilder.build();
// 设置预览时连续捕获图像数据
captureSession.setRepeatingRequest(previewRequest, null, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
Toast.makeText(MainActivity.this, "配置失败！", Toast.LENGTH_SHORT).show();
}
}, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
/**
* 摄像头的配置
* @param width
* @param height
*/
private void setUpCameraOutputs(int width, int height) {
CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
// 获取指定摄像头的特性
CameraCharacteristics characteristics = manager.getCameraCharacteristics(mCameraId);
// 获取摄像头支持的配置属性
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
// 获取摄像头支持的最大尺寸
Size largest = Collections.max(Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)), new CompareSizesByArea());
// 创建一个ImageReader对象，用于获取摄像头的图像数据
imageReader = ImageReader.newInstance(largest.getWidth(), largest.getHeight(), ImageFormat.JPEG, 2);
imageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
// 当照片数据可用时激发该方法
@Override
public void onImageAvailable(ImageReader reader) {
// 获取捕获的照片数据
Image image = reader.acquireNextImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.remaining()];
// 使用IO流将照片写入指定文件
File file = new File(getExternalFilesDir(null), "pic.jpg");
buffer.get(bytes);
try (FileOutputStream output = new FileOutputStream(file)) {
output.write(bytes);
Toast.makeText(MainActivity.this, "保存: " file, Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
} finally {
image.close();
}
}
}, null);
// 获取最佳的预览尺寸
previewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), width, height, largest);
// 根据选中的预览尺寸来调整预览组件（TextureView的）的长宽比
int orientation = getResources().getConfiguration().orientation;
if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
textureView.setAspectRatio(previewSize.getWidth(), previewSize.getHeight());
} else {
textureView.setAspectRatio(previewSize.getHeight(), previewSize.getWidth());
}
} catch (CameraAccessException e) {
e.printStackTrace();
} catch (NullPointerException e) {
Log.d(TAG, "出现错误");
}
}
/**
* 获取最佳的预览尺寸
* @param choices
* @param width
* @param height
* @param aspectRatio
* @return
*/
private static Size chooseOptimalSize(Size[] choices, int width, int height, Size aspectRatio) {
// 收集摄像头支持的打过预览Surface的分辨率
List<Size> bigEnough = new ArrayList<>();
int w = aspectRatio.getWidth();
int h = aspectRatio.getHeight();
for (Size option : choices) {
if (option.getHeight() == option.getWidth() * h / w && option.getWidth() >= width && option.getHeight() >= height) {
bigEnough.add(option);
}
}
// 如果找到多个预览尺寸，获取其中面积最小的。
if (bigEnough.size() > 0) {
return Collections.min(bigEnough, new CompareSizesByArea());
} else {
System.out.println("找不到合适的预览尺寸！！！");
return choices[0];
}
}
@Override
public void onPermissionGranted(int requestCode) {
}
@Override
public void onPermissionDenied(int requestCode) {
}
// 为Size定义一个比较器Comparator
static class CompareSizesByArea implements Comparator<Size> {
@Override
public int compare(Size lhs, Size rhs) {
// 强转为long保证不会发生溢出
return Long.signum((long) lhs.getWidth() * lhs.getHeight() - (long) rhs.getWidth() * rhs.getHeight());
}
}
}
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