android studio for android learning (十五) Camera2界面定制与保存到外部存储

时间：2016-07-15 11:15:54 阅读：729 评论：0 收藏：0 [点我收藏+]

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1.使用android 5.0的Camera V2来控制手机拍照，5.0以后对拍照的API进行了全新的设计，这些API不仅大幅度提高了android的拍照功能，还支持RAW照片输出，还可以程序调整相机的对焦模式，曝光模式，快门等。

2.关键API简介

CameraManager:摄像头管理器
CameraCharacteristics:摄像头特性
CameraDevice:代表系统摄像头
CameraCaptureSession:创建会话的API，是一个非常重要的API，当程序不管是拍照还是预览都需要通过该API来创建会话，其中控制预览的方法为setRepeatingRequest();控制拍照的方法为capture()
为了监听cameraCaptureSession的创建过程和CameraCaptureSession的拍照过程API为CameraCaptureSession提供了stateCallback,CaptureCallback等内部类
CameraRequest代表一次捕获请求，CameraRequest.Builder则负责后成CameraRequest对象。

3.本示例演示打开摄像头通过camera2的API，将拍好的照片保存到外部存储器SD中，其中控制拍照的大致步骤如下：

调用CameraManager的openCamera()方法，该方法有三个参数，第一个是代表要打开的摄像头，第二个参数用于监听摄像头的状态，第三个参数代表要执行的callback的Hander,如果在当前执行，可以设置为NULL
当调用上面的openCamera后，就可以获取指定的系统摄像头CameraDevice,然后调用指定的CameraDevice的createCaptureSession()来创建CameraCaptureSession,该方法有三个参数，第一个是一个LIST集合，封装了所有需要从该摄像头获取图片的surface,第二个参数用来监听CameraCaptureSession的创建过程。第三个参数代表执行callback的handler.设置为null就是在本线程中执行。
调用cameraDevice中的createCaptureRequest()方法，该方法支持的请求参数包括预览，拍摄视频，拍照等
根据上面的方式来设置各种参数，这里是设置各种拍照参数
调用captureRequest.Builder的build方法，即可得打为CaptureRequest对象，接下来可通过CameraCaptureSession的setRepeatingRuest()方法来开始预览和拍照。

4示例代码和相关文件

androidMainfest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.dragon.camera"
    android:versionCode="1"
    android:versionName="1.0"
    >

    <user-sdk
        android:minSdkVersion="21"
        android:targetSdkVersion="21"/>

    <!--添加必要的用户权限-->
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera2.full" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />


    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".Main">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

strings.xml

<resources>
    <string name="app_name">Camera</string>
    <string name="take_picture">take picture</string>
</resources>

布局文件main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.dragon.camera.Main">
    <TextureView
        android:id="@+id/texture"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentEnd="true"
        android:layout_above="@+id/btn_takepicture" />
    <Button
        android:id="@+id/btn_takepicture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="16dp"
        android:layout_marginTop="16dp"
        android:text="@string/take_picture" />
</RelativeLayout>

代码文件Main.java，核心代码文件，以加注释，大家可以慢慢看

package com.dragon.camera;

import android.Manifest;
import android.app.Activity;
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.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
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.Button;
import android.widget.Toast;
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 Main extends Activity {
    private static final String TAG = " dragon camera test";
//    两个组件
    private Button takePictureButton;
    private TextureView textureView;
//用SparseIntArray来代替hashMap,进行性能优化
    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);
    }
//    摄像头ID，一般0是后视，1是前视
    private String cameraId;
//定义代表摄像头的成员变量，代表系统摄像头，该类的功能类似早期的Camera类。
    protected CameraDevice cameraDevice;
//    定义CameraCaptureSession成员变量，是一个拍摄绘话的类，用来从摄像头拍摄图像或是重新拍摄图像,这是一个重要的API.
    protected CameraCaptureSession cameraCaptureSessions;
//    当程序调用setRepeatingRequest()方法进行预览时，或调用capture()进行拍照时，都需要传入CaptureRequest参数时
//    captureRequest代表一次捕获请求，用于描述捕获图片的各种参数设置。比如对焦模式，曝光模式...等，程序对照片所做的各种控制，都通过CaptureRequest参数来进行设置
//    CaptureRequest.Builder 负责生成captureRequest对象
    protected CaptureRequest.Builder captureRequestBuilder;
//预览尺寸
    private Size imageDimension;
//   ImageReader allow direct application access to image data rendered into a Surface.
    private ImageReader imageReader;
//请求码常量，可以自定义
    private static final int REQUEST_CAMERA_PERMISSION = 300;
    private Handler mBackgroundHandler;
    private HandlerThread mBackgroundThread;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        textureView = (TextureView) findViewById(R.id.texture);
        assert textureView != null;
//        设置监听
        textureView.setSurfaceTextureListener(textureListener);
        takePictureButton = (Button) findViewById(R.id.btn_takepicture);
//        为空时抛出异常
        assert takePictureButton != null;
        class takePictureBtn implements View.OnClickListener{
            public void onClick(View v) {
                takePicture();
            }
        }
        takePictureButton.setOnClickListener(new takePictureBtn());
    }

//    定义了一个独立的监听类
    TextureView.SurfaceTextureListener textureListener = new TextureView.SurfaceTextureListener() {
        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
            //open your camera here
            openCamera();
        }
        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
            // Transform you image captured size according to the surface width and height
        }
        @Override
        public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
            return true;
        }
        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture surface) {
        }
    };

    private final CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
        @Override
//        摄像头打开激发该方法
        public void onOpened(CameraDevice camera) {

            Log.e(TAG, "onOpened");
            cameraDevice = camera;
//            开始预览
            createCameraPreview();
        }
//        摄像头断开连接时的方法
        @Override
        public void onDisconnected(CameraDevice camera) {
            cameraDevice.close();
            Main.this.cameraDevice = null;
        }
//        打开摄像头出现错误时激发方法
        @Override
        public void onError(CameraDevice camera, int error) {
            cameraDevice.close();
            Main.this.cameraDevice = null;
        }
    };

    protected void startBackgroundThread() {
        mBackgroundThread = new HandlerThread("Camera Background");
        mBackgroundThread.start();
        mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
    }
    protected void stopBackgroundThread() {
        mBackgroundThread.quitSafely();
        try {
            mBackgroundThread.join();
            mBackgroundThread = null;
            mBackgroundHandler = null;
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    protected void takePicture() {
        if(null == cameraDevice) {
            Log.e(TAG, "cameraDevice is null");
//            如果没打开则返回
            return;
        }
//        摄像头管理器，专门用于检测、打开系统摄像头，并连接CameraDevices.
        CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
        try {
            Log.e(TAG,"cameraDevice.getId "+cameraDevice.getId());//查看选中的摄像头ID
//            获取指定摄像头的相关特性（此处摄像头已经打开）
            CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());

//            定义图像尺寸
            Size[] jpegSizes = null;
            if (characteristics != null) {
//                获取摄像头支持的最大尺寸
                jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(ImageFormat.JPEG);
            }
            int width = 640;
            int height = 480;
            if (jpegSizes != null && 0 < jpegSizes.length) {
                width = jpegSizes[0].getWidth();
                height = jpegSizes[0].getHeight();
            }
//            创建一个ImageReader对象，用于获得摄像头的图像数据
            ImageReader reader = ImageReader.newInstance(width, height, ImageFormat.JPEG, 1);
//动态数组
            List<Surface> outputSurfaces = new ArrayList<Surface>(2);

            outputSurfaces.add(reader.getSurface());
            outputSurfaces.add(new Surface(textureView.getSurfaceTexture()));
//生成请求对象（TEMPLATE_STILL_CAPTURE此处请求是拍照）
            final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
//            将ImageReader的surface作为captureBuilder的输出目标
            captureBuilder.addTarget(reader.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);
            captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);//推荐采用这种最简单的设置请求模式
            // 获取设备方向
            int rotation = getWindowManager().getDefaultDisplay().getRotation();
//            根据设置方向设置照片显示的方向
            captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
//            设置图片的存储位置
            final File file = new File(Environment.getExternalStorageDirectory()+"/pic.jpg");
//ImageReader监听函数
            ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
                @Override
                public void onImageAvailable(ImageReader reader) {
                    Image image = null;
//                    读取图像并保存
                    try {
                        image = reader.acquireLatestImage();
                        ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                        byte[] bytes = new byte[buffer.capacity()];
                        buffer.get(bytes);
                        save(bytes);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } finally {
                        if (image != null) {
                            image.close();
                        }
                    }
                }
                private void save(byte[] bytes) throws IOException {
                    OutputStream output = null;
                    try {
                        output = new FileOutputStream(file);
                        output.write(bytes);
                    } finally {
                        if (null != output) {
                            output.close();
                        }
                    }
                }
            };

            reader.setOnImageAvailableListener(readerListener, mBackgroundHandler);
            //拍照开始或是完成时调用，用来监听CameraCaptureSession的创建过程
            final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
                @Override
//                拍照完成后提示图片的保存位置
                public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
                    super.onCaptureCompleted(session, request, result);
                    Toast.makeText(Main.this, "Saved:" + file, Toast.LENGTH_SHORT).show();
                    createCameraPreview();
                }
            };

            cameraDevice.createCaptureSession(outputSurfaces, new CameraCaptureSession.StateCallback() {
                @Override
                public void onConfigured(CameraCaptureSession session) {
                    try {
                        session.capture(captureBuilder.build(), captureListener, mBackgroundHandler);
                    } catch (CameraAccessException e) {
                        e.printStackTrace();
                    }
                }
                @Override
                public void onConfigureFailed(CameraCaptureSession session) {
                }
            }, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }


    protected void createCameraPreview() {
        try {
            SurfaceTexture texture = textureView.getSurfaceTexture();
            assert texture != null;
//            设置默认的预览大小
            texture.setDefaultBufferSize(imageDimension.getWidth(), imageDimension.getHeight());
            Surface surface = new Surface(texture);
//            请求预览
            captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);

            captureRequestBuilder.addTarget(surface);
//            创建cameraCaptureSession,第一个参数是图片集合，封装了所有图片surface,第二个参数用来监听这处创建过程
            cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback(){
                @Override
                public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                    //The camera is already closed
                    if (null == cameraDevice) {
                        return;
                    }
                    // When the session is ready, we start displaying the preview.
                    cameraCaptureSessions = cameraCaptureSession;
                    updatePreview();
                }
                @Override
                public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                    Toast.makeText(Main.this, "Configuration change", Toast.LENGTH_SHORT).show();
                }
            }, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }
    private void openCamera() {
//        实例化摄像头
        CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
        Log.e(TAG, "is camera open");
        try {
//            指定要打开的摄像头
            cameraId = manager.getCameraIdList()[0];
//            获取打开摄像头的属性
            CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
//The available stream configurations that this camera device supports; also includes the minimum frame durations and the stall durations for each format/size combination.
            StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
            assert map != null;
            imageDimension = map.getOutputSizes(SurfaceTexture.class)[0];
            // Add permission for camera and let user grant the permission
//            权限检查
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(Main.this, new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_CAMERA_PERMISSION);
                return;
            }
//            打开摄像头，第一个参数代表要打开的摄像头，第二个参数用于监测打开摄像头的当前状态，第三个参数表示执行callback的Handler,
//            如果程序希望在当前线程中执行callback，像下面的设置为null即可。
            manager.openCamera(cameraId, stateCallback, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
        Log.e(TAG, "openCamera 1");
    }
    protected void updatePreview() {
        if(null == cameraDevice) {
            Log.e(TAG, "updatePreview error, return");
        }
//        设置模式为自动
        captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
        try {

            cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(), null, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }
    private void closeCamera() {
        if (null != cameraDevice) {
            cameraDevice.close();
            cameraDevice = null;
        }
        if (null != imageReader) {
            imageReader.close();
            imageReader = null;
        }
    }
//    如果没有相应的权限测关闭APP
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == REQUEST_CAMERA_PERMISSION) {
            if (grantResults[0] == PackageManager.PERMISSION_DENIED) {
                // close the app
                Toast.makeText(Main.this, "Sorry!!!, you can‘t use this app without granting permission", Toast.LENGTH_LONG).show();
                finish();
            }
        }
    }
    @Override
    protected void onResume() {
        super.onResume();
        Log.e(TAG, "onResume");
        startBackgroundThread();
        if (textureView.isAvailable()) {
            Log.e(TAG, "textureViewAvailable");
//            openCamera();
            takePicture();
        } else {
            textureView.setSurfaceTextureListener(textureListener);
        }
    }
    @Override
    protected void onPause() {
        Log.e(TAG, "onPause");
        closeCamera();
        stopBackgroundThread();
        super.onPause();
    }
}




//        takePictureButton.setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View v) {
//                takePicture();
//            }
//        });

整个工程或是项目源码下载地址：githubCamera2

另欢迎大家加入AR/VR交流群，后面将会有基于手机摄像头增强现实的实现讨论和实例：

技术分享

Reference:

1.http://blog.csdn.net/torvalbill/article/details/40376145
2.http://wiki.jikexueyuan.com/project/android-actual-combat-skills/android-hardware-camera2-operating-guide.html
3.https://developer.android.com/samples/Camera2Basic/src/com.example.android.camera2basic/Camera2BasicFragment.html
4.https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html

android studio for android learning (十五) Camera2界面定制与保存到外部存储

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原文地址：http://blog.csdn.net/yywan1314520/article/details/51911869

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