技术标签: Android基础笔记 android CameraManager TextureView 摄像头 CameraId
博主前些天发现了一个巨牛的人工智能学习网站,通俗易懂,风趣幽默,忍不住也分享一下给大家,
点击跳转到网站
前言:
实现拍照功能的主要步骤:
首先是布局页面activity_camera_demo.xml,用户点击进来后,通过设置完相应的参数后,对摄像头得到照片进行预览,通过TextureView实现
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".CameraDemoActivity">
<TextureView
android:id="@+id/textureView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<Button
android:id="@+id/btn_photo"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="50dp"
android:text="拍照" />
</RelativeLayout>
对应的CameraDemoActivity类实现拍照,并保存到本地的功能
public class CameraDemoActivity extends AppCompatActivity {
private TextureView textureView;
private HandlerThread handlerThread;
private Handler mCameraHandler;
private CameraManager cameraManager;
//最佳的预览尺寸
private Size previewSize;
//最佳的拍照尺寸
private Size mCaptureSize;
private String mCameraId;
private CameraDevice cameraDevice;
private CaptureRequest.Builder captureRequestBuilder;
private CaptureRequest captureRequest;
private CameraCaptureSession mCameraCaptureSession;
private Button btn_photo;
private ImageReader imageReader;
private static final SparseArray ORIENTATION = new SparseArray();
static {
ORIENTATION.append(Surface.ROTATION_0, 90);
ORIENTATION.append(Surface.ROTATION_90, 0);
ORIENTATION.append(Surface.ROTATION_180, 270);
ORIENTATION.append(Surface.ROTATION_270, 180);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera_demo);
textureView = findViewById(R.id.textureView);
btn_photo = findViewById(R.id.btn_photo);
btn_photo.setOnClickListener(OnClick);
}
private final View.OnClickListener OnClick = new View.OnClickListener() {
@Override
public void onClick(View v) {
//获取摄像头的请求
try {
CaptureRequest.Builder cameraDeviceCaptureRequest = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
cameraDeviceCaptureRequest.addTarget(imageReader.getSurface());
//获取摄像头的方向
int rotation = getWindowManager().getDefaultDisplay().getRotation();
CameraCaptureSession.CaptureCallback mCaptureCallback = new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
Toast.makeText(CameraDemoActivity.this, "拍照结束,相片已保存!", Toast.LENGTH_SHORT).show();
unLockFocus();
}
};
//设置拍照方向
cameraDeviceCaptureRequest.set(CaptureRequest.JPEG_ORIENTATION, (Integer) ORIENTATION.get(rotation));
mCameraCaptureSession.stopRepeating();
mCameraCaptureSession.capture(cameraDeviceCaptureRequest.build(), mCaptureCallback, mCameraHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
//获取图像的缓冲区
//获取文件的存储权限及操作
}
};
private void unLockFocus() {
captureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
try {
mCameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), null, mCameraHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
protected void onResume() {
super.onResume();
startCameraThread();
if (!textureView.isAvailable()) {
textureView.setSurfaceTextureListener(mTextureListener);
} else {
startPreview();
}
}
TextureView.SurfaceTextureListener mTextureListener = new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(@NonNull SurfaceTexture surface, int width, int height) {
//SurfaceTexture组件可用的时候,设置相机参数,并打开摄像头
//设置摄像头参数
setUpCamera(width, height);
//打开摄像头
openCamera();
}
@Override
public void onSurfaceTextureSizeChanged(@NonNull SurfaceTexture surface, int width, int height) {
//尺寸发生变化的时候
}
@Override
public boolean onSurfaceTextureDestroyed(@NonNull SurfaceTexture surface) {
//组件被销毁的时候
return false;
}
@Override
public void onSurfaceTextureUpdated(@NonNull SurfaceTexture surface) {
//组件更新的时候
}
};
private void setUpCamera(int width, int height) {
cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
//拿到摄像头的id
try {
for (String cameraId : cameraManager.getCameraIdList()) {
//得到摄像头的参数
CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId);
Integer facing = cameraCharacteristics.get(CameraCharacteristics.LENS_FACING);
if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
continue;
}
StreamConfigurationMap map = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
if (map != null) {
//找到摄像头能够输出的,最符合我们当前屏幕能显示的最小分辨率
previewSize = getOptimalSize(map.getOutputSizes(SurfaceTexture.class), width, height);
mCaptureSize = Collections.max(Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)), new Comparator<Size>() {
@Override
public int compare(Size o1, Size o2) {
return Long.signum(o1.getWidth() * o1.getHeight() - o2.getWidth() * o2.getHeight());
}
});
}
//建立ImageReader准备存储照片
setUpImageReader();
mCameraId = cameraId;
break;
}
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void setUpImageReader() {
imageReader = ImageReader.newInstance(mCaptureSize.getWidth(), mCaptureSize.getHeight(), ImageFormat.JPEG, 2);
imageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader reader) {
mCameraHandler.post(new ImageSaver(reader.acquireNextImage()));
}
}, mCameraHandler);
}
//存储图片的过程
private class ImageSaver implements Runnable {
private Image image;
public ImageSaver(Image image) {
this.image = image;
}
@Override
public void run() {
ByteBuffer byteBuffer = image.getPlanes()[0].getBuffer();
byte[] data = new byte[byteBuffer.remaining()];
byteBuffer.get(data);
// String path =getFilesDir();
String path = Environment.getExternalStorageDirectory() + "/DCIM/CameraV2/";
File file = new File(path);
//判断当前的文件目录是否存在,如果不存在就创建这个文件目录
if (!file.exists()) {
file.mkdir();
}
String timeStamp = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
String fileName = "IMG_" + timeStamp + ".jpg";
FileOutputStream fileOutputStream = null;
try {
fileOutputStream = new FileOutputStream(fileName);
fileOutputStream.write(data, 0, data.length);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (fileOutputStream != null) {
try {
fileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
//得到最佳的预览尺寸
private Size getOptimalSize(Size[] outputSizes, int width, int height) {
ArrayList<Size> arrayList = new ArrayList<>();
for (Size option : outputSizes) {
if (width > height) {
//横屏
if (option.getWidth() > width && option.getHeight() > height) {
arrayList.add(option);
}
} else {
//竖屏
if (option.getWidth() > height && option.getHeight() > width) {
arrayList.add(option);
}
}
}
if (arrayList.size() > 1) {
return Collections.min(arrayList, new Comparator<Size>() {
@Override
public int compare(Size o1, Size o2) {
return Long.signum(o1.getWidth() * o1.getHeight() - o2.getWidth() * o2.getHeight());
}
});
}
return outputSizes[0];
}
private void openCamera() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{
Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
return;
}
try {
cameraManager.openCamera(mCameraId, mStateCallback, mCameraHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
//摄像头打开
cameraDevice = camera;
startPreview();
}
@Override
public void onDisconnected(@NonNull CameraDevice camera) {
//摄像头关闭
cameraDevice.close();
cameraDevice = null;
}
@Override
public void onError(@NonNull CameraDevice camera, int error) {
//摄像头出现错误
cameraDevice.close();
cameraDevice = null;
}
};
//开始预览
private void startPreview() {
//建立图像缓冲区
SurfaceTexture surfaceTexture = textureView.getSurfaceTexture();
surfaceTexture.setDefaultBufferSize(previewSize.getWidth(), previewSize.getHeight());
//得到界面的显示对象
Surface surface = new Surface(surfaceTexture);
try {
captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
captureRequestBuilder.addTarget(surface);
//建立通道(CaptureRequest和CaptureSession会话)
cameraDevice.createCaptureSession(Arrays.asList(surface, imageReader.getSurface()), new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession session) {
captureRequest = captureRequestBuilder.build();
mCameraCaptureSession = session;
try {
mCameraCaptureSession.setRepeatingRequest(captureRequest, null, mCameraHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession session) {
}
}, mCameraHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
//开启摄像头线程
private void startCameraThread() {
handlerThread = new HandlerThread("myHandlerThread");
handlerThread.start();
mCameraHandler = new Handler(handlerThread.getLooper());
}
}
代码有点多,但是注释已经在代码中给出,大家可以体会一下,其中的用法,根据自己的需求封装该功能~
文章浏览阅读2.1k次。FX3 JLINK调试是一个有些麻烦的事情,经常有些莫名其妙的问题。 设置参见 c:\Program Files (x86)\Cypress\EZ-USB FX3 SDK\1.3\doc\firmware 下的 EzUsbSuite_UG.pdf 文档。 常见问题: 1.装了多个版本的jlink,使用了未注册或不适当的版本 选择一个正确的版本。JLinkARM_V408l,JLinkA_ezusbsuite_qsg.pdf
文章浏览阅读2.6k次。** 本文仅通过用openGL+QT简单实现二进制stl文件读取显示并通过鼠标旋转缩放, 是比较入门的级别,由于个人能力有限,新手级别,所以未能施加光影灯光等操作, 未能让显示的stl文件更加真实。****效果图:**1. main.cpp```cpp#include "widget.h"#include <QApplication>int main(int argc, char *argv[]){ QApplication a(argc, argv); _qopengl如何鼠标控制旋转
文章浏览阅读943次,点赞22次,收藏19次。以大规模预训练语言模型为基础的chatgpt成功出圈,在近几日已经给人工智能板块带来了多次涨停,这足够说明这一风口的到来。而作为曾经的风口“知识图谱”而言,如何找到其与chatgpt之间的区别,找好自身的定位显得尤为重要。形式化知识和参数化知识在表现形式上一直都是大家考虑的问题,两种技术都应该有自己的定位与价值所在。知识图谱构建往往是抽取式的,而且往往包含一系列知识冲突检测、消解过程,整个过程都能溯源。以这样的知识作为输入,能在相当程度上解决当前ChatGPT的事实谬误问题,并具有可解释性。
文章浏览阅读1.3k次。最重要的一点,一定是degbug的方式启动,不然热部署不会生效,注意,注意!_tomcat热部署
文章浏览阅读10w+次,点赞56次,收藏482次。html5 ,用css去修饰自己的个人主页代码如下:<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xh..._个人主页源码
文章浏览阅读201次。开发者(KaiFaX)面向全栈工程师的开发者专注于前端、Java/Python/Go/PHP的技术社区来源:开源最前线链接:https://github.com/svenstaro/gen..._程序员怎么上班摸鱼
文章浏览阅读1.3k次。改变Block UI界面的尺寸_ug二次开发 调整 对话框大小
文章浏览阅读1.3w次,点赞18次,收藏291次。基于深度学习的股票预测数据获取数据转换LSTM模型搭建训练模型预测结果数据获取采用tushare的数据接口(不知道tushare的筒子们自行百度一下,简而言之其免费提供各类金融数据 , 助力智能投资与创新型投资。)python可以直接使用pip安装tushare!pip install tushareCollecting tushare Downloading https://files.pythonhosted.org/packages/17/76/dc6784a1c07ec040e74_基于深度学习的股票操纵识别研究python代码
文章浏览阅读2k次。【IT168 厂商动态】 近日,北京中科网威(NETPOWER)工业级防火墙通过了中国电力工业电力设备及仪表质量检验测试中心(厂站自动化及远动)测试,并成为中国首家通过电力协议访问控制专业测评的工业级防火墙生产厂商。 北京中科网威(NETPOWER)工业级防火墙专为工业及恶劣环境下的网络安全需求而设计,它采用了非X86的高可靠嵌入式处理器并采用无风扇设计,整机功耗不到22W,具备极_电力行业防火墙有哪些
文章浏览阅读206次。/*烟台大学计算机学院 作者:董玉祥 完成日期: 2017 12 3 问题描述:二叉树排序树中查找的路径 */#include #include #define MaxSize 100typedef int KeyType; //定义关键字类型typedef char InfoType;typedef struct node
文章浏览阅读775次。当时老师一定会告诉你,这个一个"warning"的报警,可以不用管它,也确实如此。不过,这条报警信息我们至少可以知道一点,就是scanf函数调用完之后是有一个返回值的,下面我们就要对scanf返回值进行详细的讨论。并给出在编程时利用scanf的返回值可以实现的一些功能。_c语言ignoring return value
文章浏览阅读9.6k次。十四五规划下,数据安全成为国家、社会发展面临的重要议题,《数据安全法》《个人信息保护法》《关键信息基础设施安全保护条例》已陆续施行。如何做好“数据安全建设”是数字时代的必答题。_数字医疗服务保障方案