Android Multimedia框架总结（十四）Camera框架初识及自定义相机案例

转载请把头部出处链接和尾部二维码一起转载，本文出自逆流的鱼yuiop：http://blog.csdn.net/hejjunlin/article/details/52738492

前言：国庆节告一段落，又是新一月，上月主要是围绕MediaPlayer相关展开，从今天开始，开始分析多媒体框架中的Camera模块，看下今天的Agenda:

Camera拍照

Camera录像

新API android.hardware.camera2

新旧API特点对比

Camera自定义相机

新API android.hardware.camera2自定义相机

Camera类被用于获取图片设置，start/stop 预览，快照图片，恢复视频编码的帧，Camera是一个client对于Camera Service来说，将管理Camera 硬件相关，

为了使用设备的camera, 须要在Manifest中加上相应的权限，如你须要自动聚焦功能，在Manifest.xml须加入

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />

Camera拍照

用Camera去拍照，将遵循以下几个步骤：

获得一个Camera的实例，通过open方法

如果必要的话，可以修改一些默认参数

通过初始化SurfaceHolder去setPreviewDisplay(SurfaceHolder),没有Surface, camera不能开始预览

调用startPreview方法开始更新预览的surface，在拍照前，预览（preview）必须被开启。

当你想开始拍照时，使用takePicture(Camera.ShutterCallback,

Camera.PictureCallback, Camera.PictureCallback, Camera.PictureCallback), 等待回调提供真实的图像数据

当拍完一张照片时，预览（preview）将会停止，当你想要拍更多的照片时，须要再一次调用startPreview方法

当调用stopPreview方法时，将停止更新预览的surface

当调用release方法时，将马上释放camera

Camera录像

以上是拍照过程，当如果切换成视频录制模式时，将遵循以下步骤：

获取一个初始化Camera,且开始预览

调用unlock方法允许media进程去访问camera

通过camera去setCamera(Camera)，了解更多，可看MediaRecorder

当完成录制时，调用reconnect方法重新获取且重新lock camera

调用stopPreview()方法且release方法时，作为以上描述

这个类是一个非线程安全类，意味着在被使用任何工作线程中，大多数长运行操作（preview,focus,photo capture 等）发生，异步调用回调是必要的。回调被调用在事件线程，Camera方法决不能一次被多个线程调用

不同的安卓设备可能有不同的硬件规格，如像素的评级和自动对焦功能。

新API android.hardware.camera2

从API-21(5.0)开始，新增一个android.hardware.camera2包，取代原来Camera.java。

Android平台支持拍照及录制视频，通过android.hardware.camera2相关API或camera Intent,下面是一些相关联的类

android.hardware.camera2

主要的API控制相机设备，被用于拍照及拍视频当build一个camera应用时

Camera

Android 5.0之前控制相机设备的class

SurfaceView

呈现实时预览给用户

MediaRecorder

用户录制视频

Intent

Intent action类型：MediaStore.ACTION_IMAGE_CAPTURE/MediaStore.ACTION_VIDEO_CAPTURE,拍照或录视频，不用直接用Camera（可通过调起第三方定义的Camera）

本文出自逆流的鱼yuiop：http://blog.csdn.net/hejjunlin/article/details/52738492

新旧API特点对比

android.hardware.camera2与原来的camera API相比，不同之处在于：

原生支持RAW照片输出突发拍摄模式

制约拍照速度的不再是软件而是硬件。以Nexus 5为例，分辨率全开下Andorid L的连拍速度可达到30fps。

全自动控制快门、感光度、对焦、测光、硬件视频防抖等多种参数都被整合到了新的API内。

新的API中添加的手动控制功能列表：感光度手动对焦/AF开关AE/AF/AWB模式AE/AWB锁硬件视频防抖连续帧

可以用单个手指进行缩放

支持QR码识别

实例

使用Camera有两种方式：通过Intent使用已有的app和通过Camera构建自己的app。通过Camera API的方式拍照。

通过Camera API方式拍照需要引入几个关键的类：

Camera类：最主要的类，用于管理Camera设备，本文中主要用到以下方法：

open()：通过open方法获取Camera实例。

setPreviewDisplay(SurfaceHolder)：设置预览拍照

startPreview()：开始预览

stopPreview()：停止预览

release():释放Camera实例

takePicture(Camera.ShutterCallback shutter, Camera.PictureCallback raw, Camera.PictureCallback jpeg)：这个是拍照要执行的方法，包含了三个回调参数。Shutter是快门按下时的回调，raw是获取拍照原始数据的回调，jpeg是获取经过压缩成jpg格式的图像数据。在本文中需要实现最后一个回调，参见下面。

Camera.PictureCallback接口：该回调接口包含了一个onPictureTaken(byte[]data, Camera camera)方法。在这个方法中可以保存图像数据。

SurfaceView类：用于控制预览界面

SurfaceHolder.Callback接口：用于处理预览的事件，需实现如下三个方法：

surfaceCreated(SurfaceHolderholder)：预览界面创建时调用，每次界面改变后都会重新创建，需要获取相机资源并设置SurfaceHolder。

surfaceChanged(SurfaceHolderholder, int format, int width, int height):预览界面发生变化时调用，每次界面发生变化之后需要重新启动预览。

surfaceDestroyed(SurfaceHolderholder)：预览销毁时调用，停止预览，释放相应资源。

通过Camera方式来实现拍照

通过Camera方式 会比通过Intent方式获得更为丰富的功能。通常创建一个定制化的Camera需要如下步骤：

(1) 通过Camera.open()来获取Camera实例。

(2) 创建Preview类，需要继承SurfaceView类并实现SurfaceHolder.Callback接口。

(3) 为相机设置Preview

(4) 构建一个Preview的Layout来预览相机；

(5) 为拍照建立Listener以获取拍照后的回调;

(6) 拍照并保存文件;

(7) 释放Camera。

本文出自逆流的鱼yuiop：http://blog.csdn.net/hejjunlin/article/details/52738492

Camera自定义相机

CameraSample代码如下：

MainActivity.java





SurfacePreview.java







activity_main.xml



效果图：



本文出自逆流的鱼yuiop：http://blog.csdn.net/hejjunlin/article/details/52738492

新API android.hardware.camera2自定义相机

接下来看来用新API自定义相机:

MainActivity.java

package com.hejunlin.camerasample2;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (null == savedInstanceState) {
getFragmentManager().beginTransaction()
.replace(R.id.container, Camera2Fragment.newInstance())
.commit();
}
}
}

Camera2Fragment.java

package com.hejunlin.camerasample2;

import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.app.Fragment;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.graphics.ImageFormat;
import android.graphics.Matrix;
import android.graphics.Point;
import android.graphics.RectF;
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.CaptureResult;
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.v13.app.FragmentCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.LayoutInflater;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

public class Camera2Fragment extends Fragment
implements View.OnClickListener, FragmentCompat.OnRequestPermissionsResultCallback {

/**
* Conversion from screen rotation to JPEG orientation.
*/
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
private static final int REQUEST_CAMERA_PERMISSION = 1;
private static final String FRAGMENT_DIALOG = "dialog";

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);
}

/**
* Tag for the {@link Log}.
*/
private static final String TAG = "Camera2Fragment";

/**
* Camera state: Showing camera preview.
*/
private static final int STATE_PREVIEW = 0;

/**
* Camera state: Waiting for the focus to be locked.
*/
private static final int STATE_WAITING_LOCK = 1;

/**
* Camera state: Waiting for the exposure to be precapture state.
*/
private static final int STATE_WAITING_PRECAPTURE = 2;

/**
* Camera state: Waiting for the exposure state to be something other than precapture.
*/
private static final int STATE_WAITING_NON_PRECAPTURE = 3;

/**
* Camera state: Picture was taken.
*/
private static final int STATE_PICTURE_TAKEN = 4;

/**
* Max preview width that is guaranteed by Camera2 API
*/
private static final int MAX_PREVIEW_WIDTH = 1920;

/**
* Max preview height that is guaranteed by Camera2 API
*/
private static final int MAX_PREVIEW_HEIGHT = 1080;

/**
* {@link TextureView.SurfaceTextureListener} handles several lifecycle events on a
* {@link TextureView}.
*/
private final TextureView.SurfaceTextureListener mSurfaceTextureListener
= new TextureView.SurfaceTextureListener() {

@Override
public void onSurfaceTextureAvailable(SurfaceTexture texture, int width, int height) {
openCamera(width, height);
}

@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture texture, int width, int height) {
configureTransform(width, height);
}

@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture texture) {
return true;
}

@Override
public void onSurfaceTextureUpdated(SurfaceTexture texture) {
}

};

/**
* ID of the current {@link CameraDevice}.
*/
private String mCameraId;

/**
* An {@link SuperTextureView} for camera preview.
*/
private SuperTextureView mTextureView;

/**
* A {@link CameraCaptureSession } for camera preview.
*/
private CameraCaptureSession mCaptureSession;

/**
* A reference to the opened {@link CameraDevice}.
*/
private CameraDevice mCameraDevice;

/**
* The {@link Size} of camera preview.
*/
private Size mPreviewSize;

/**
* {@link CameraDevice.StateCallback} is called when {@link CameraDevice} changes its state.
*/
private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {

@Override
public void onOpened(@NonNull CameraDevice cameraDevice) {
// This method is called when the camera is opened.  We start camera preview here.
mCameraOpenCloseLock.release();
mCameraDevice = cameraDevice;
createCameraPreviewSession();
}

@Override
public void onDisconnected(@NonNull CameraDevice cameraDevice) {
mCameraOpenCloseLock.release();
cameraDevice.close();
mCameraDevice = null;
}

@Override
public void onError(@NonNull CameraDevice cameraDevice, int error) {
mCameraOpenCloseLock.release();
cameraDevice.close();
mCameraDevice = null;
Activity activity = getActivity();
if (null != activity) {
activity.finish();
}
}

};

/**
* An additional thread for running tasks that shouldn't block the UI.
*/
private HandlerThread mBackgroundThread;

/**
* A {@link Handler} for running tasks in the background.
*/
private Handler mBackgroundHandler;

/**
* An {@link ImageReader} that handles still image capture.
*/
private ImageReader mImageReader;

/**
* This is the output file for our picture.
*/
private File mFile;

/**
* This a callback object for the {@link ImageReader}. "onImageAvailable" will be called when a
* still image is ready to be saved.
*/
private final ImageReader.OnImageAvailableListener mOnImageAvailableListener
= new ImageReader.OnImageAvailableListener() {

@Override
public void onImageAvailable(ImageReader reader) {
mBackgroundHandler.post(new ImageSaver(reader.acquireNextImage(), mFile));
}

};

/**
* {@link CaptureRequest.Builder} for the camera preview
*/
private CaptureRequest.Builder mPreviewRequestBuilder;

/**
* {@link CaptureRequest} generated by {@link #mPreviewRequestBuilder}
*/
private CaptureRequest mPreviewRequest;

/**
* The current state of camera state for taking pictures.
*
* @see #mCaptureCallback
*/
private int mState = STATE_PREVIEW;

/**
* A {@link Semaphore} to prevent the app from exiting before closing the camera.
*/
private Semaphore mCameraOpenCloseLock = new Semaphore(1);

/**
* Whether the current camera device supports Flash or not.
*/
private boolean mFlashSupported;

/**
* Orientation of the camera sensor
*/
private int mSensorOrientation;

/**
* A {@link CameraCaptureSession.CaptureCallback} that handles events related to JPEG capture.
*/
private CameraCaptureSession.CaptureCallback mCaptureCallback
= new CameraCaptureSession.CaptureCallback() {

private void process(CaptureResult result) {
switch (mState) {
case STATE_PREVIEW: {
// We have nothing to do when the camera preview is working normally.
break;
}
case STATE_WAITING_LOCK: {
Integer afState = result.get(CaptureResult.CONTROL_AF_STATE);
if (afState == null) {
captureStillPicture();
} else if (CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED == afState ||
CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED == afState) {
// CONTROL_AE_STATE can be null on some devices
Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
if (aeState == null ||
aeState == CaptureResult.CONTROL_AE_STATE_CONVERGED) {
mState = STATE_PICTURE_TAKEN;
captureStillPicture();
} else {
runPrecaptureSequence();
}
}
break;
}
case STATE_WAITING_PRECAPTURE: {
// CONTROL_AE_STATE can be null on some devices
Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
if (aeState == null ||
aeState == CaptureResult.CONTROL_AE_STATE_PRECAPTURE ||
aeState == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED) {
mState = STATE_WAITING_NON_PRECAPTURE;
}
break;
}
case STATE_WAITING_NON_PRECAPTURE: {
// CONTROL_AE_STATE can be null on some devices
Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
if (aeState == null || aeState != CaptureResult.CONTROL_AE_STATE_PRECAPTURE) {
mState = STATE_PICTURE_TAKEN;
captureStillPicture();
}
break;
}
}
}

@Override
public void onCaptureProgressed(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request,
@NonNull CaptureResult partialResult) {
process(partialResult);
}

@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request,
@NonNull TotalCaptureResult result) {
process(result);
}

};

/**
* Shows a {@link Toast} on the UI thread.
*
* @param text The message to show
*/
private void showToast(final String text) {
final Activity activity = getActivity();
if (activity != null) {
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(activity, text, Toast.LENGTH_SHORT).show();
}
});
}
}

/**
* Given {@code choices} of {@code Size}s supported by a camera, choose the smallest one that
* is at least as large as the respective texture view size, and that is at most as large as the
* respective max size, and whose aspect ratio matches with the specified value. If such size
* doesn't exist, choose the largest one that is at most as large as the respective max size,
* and whose aspect ratio matches with the specified value.
*
* @param choices           The list of sizes that the camera supports for the intended output
*                          class
* @param textureViewWidth  The width of the texture view relative to sensor coordinate
* @param textureViewHeight The height of the texture view relative to sensor coordinate
* @param maxWidth          The maximum width that can be chosen
* @param maxHeight         The maximum height that can be chosen
* @param aspectRatio       The aspect ratio
* @return The optimal {@code Size}, or an arbitrary one if none were big enough
*/
private static Size chooseOptimalSize(Size[] choices, int textureViewWidth,
int textureViewHeight, int maxWidth, int maxHeight, Size aspectRatio) {

// Collect the supported resolutions that are at least as big as the preview Surface
List<Size> bigEnough = new ArrayList<>();
// Collect the supported resolutions that are smaller than the preview Surface
List<Size> notBigEnough = new ArrayList<>();
int w = aspectRatio.getWidth();
int h = aspectRatio.getHeight();
for (Size option : choices) {
if (option.getWidth() <= maxWidth && option.getHeight() <= maxHeight &&
option.getHeight() == option.getWidth() * h / w) {
if (option.getWidth() >= textureViewWidth &&
option.getHeight() >= textureViewHeight) {
bigEnough.add(option);
} else {
notBigEnough.add(option);
}
}
}

// Pick the smallest of those big enough. If there is no one big enough, pick the
// largest of those not big enough.
if (bigEnough.size() > 0) {
return Collections.min(bigEnough, new CompareSizesByArea());
} else if (notBigEnough.size() > 0) {
return Collections.max(notBigEnough, new CompareSizesByArea());
} else {
Log.e(TAG, "Couldn't find any suitable preview size");
return choices[0];
}
}

public static Camera2Fragment newInstance() {
return new Camera2Fragment();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_camera2, container, false);
}

@Override
public void onViewCreated(final View view, Bundle savedInstanceState) {
view.findViewById(R.id.picture).setOnClickListener(this);
//        view.findViewById(R.id.info).setOnClickListener(this);
mTextureView = (SuperTextureView) view.findViewById(R.id.texture);
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mFile = getOutputMediaFile();
}

private File getOutputMediaFile(){
//get the mobile Pictures directory
File picDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
//get the current time
String timeStamp = new SimpleDateFormat("yyyy-MMdd-HHmmss").format(new Date());
return new File(picDir.getPath() + File.separator + "hejunlin_camera2_"+ timeStamp + ".jpg");
}

@Override
public void onResume() {
super.onResume();
startBackgroundThread();

// When the screen is turned off and turned back on, the SurfaceTexture is already
// available, and "onSurfaceTextureAvailable" will not be called. In that case, we can open
// a camera and start preview from here (otherwise, we wait until the surface is ready in
// the SurfaceTextureListener).
if (mTextureView.isAvailable()) {
openCamera(mTextureView.getWidth(), mTextureView.getHeight());
} else {
mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
}
}

@Override
public void onPause() {
closeCamera();
stopBackgroundThread();
super.onPause();
}

private void requestCameraPermission() {
if (FragmentCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
new ConfirmationDialog().show(getChildFragmentManager(), FRAGMENT_DIALOG);
} else {
FragmentCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA},
REQUEST_CAMERA_PERMISSION);
}
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
if (requestCode == REQUEST_CAMERA_PERMISSION) {
if (grantResults.length != 1 || grantResults[0] != PackageManager.PERMISSION_GRANTED) {
ErrorDialog.newInstance("需要申请摄像头权限")
.show(getChildFragmentManager(), FRAGMENT_DIALOG);
}
} else {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
}

/**
* Sets up member variables related to camera.
*
* @param width  The width of available size for camera preview
* @param height The height of available size for camera preview
*/
private void setUpCameraOutputs(int width, int height) {
Activity activity = getActivity();
CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
try {
for (String cameraId : manager.getCameraIdList()) {
CameraCharacteristics characteristics
= manager.getCameraCharacteristics(cameraId);

// We don't use a front facing camera in this sample.
Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
continue;
}

StreamConfigurationMap map = characteristics.get(
CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
if (map == null) {
continue;
}

// For still image captures, we use the largest available size.
Size largest = Collections.max(
Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)),
new CompareSizesByArea());
mImageReader = ImageReader.newInstance(largest.getWidth(), largest.getHeight(),
ImageFormat.JPEG, /*maxImages*/2);
mImageReader.setOnImageAvailableListener(
mOnImageAvailableListener, mBackgroundHandler);

// Find out if we need to swap dimension to get the preview size relative to sensor
// coordinate.
int displayRotation = activity.getWindowManager().getDefaultDisplay().getRotation();
//noinspection ConstantConditions
mSensorOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
boolean swappedDimensions = false;
switch (displayRotation) {
case Surface.ROTATION_0:
case Surface.ROTATION_180:
if (mSensorOrientation == 90 || mSensorOrientation == 270) {
swappedDimensions = true;
}
break;
case Surface.ROTATION_90:
case Surface.ROTATION_270:
if (mSensorOrientation == 0 || mSensorOrientation == 180) {
swappedDimensions = true;
}
break;
default:
Log.e(TAG, "Display rotation is invalid: " + displayRotation);
}

Point displaySize = new Point();
activity.getWindowManager().getDefaultDisplay().getSize(displaySize);
int rotatedPreviewWidth = width;
int rotatedPreviewHeight = height;
int maxPreviewWidth = displaySize.x;
int maxPreviewHeight = displaySize.y;

if (swappedDimensions) {
rotatedPreviewWidth = height;
rotatedPreviewHeight = width;
maxPreviewWidth = displaySize.y;
maxPreviewHeight = displaySize.x;
}

if (maxPreviewWidth > MAX_PREVIEW_WIDTH) {
maxPreviewWidth = MAX_PREVIEW_WIDTH;
}

if (maxPreviewHeight > MAX_PREVIEW_HEIGHT) {
maxPreviewHeight = MAX_PREVIEW_HEIGHT;
}

// Danger, W.R.! Attempting to use too large a preview size could  exceed the camera
// bus' bandwidth limitation, resulting in gorgeous previews but the storage of
// garbage capture data.
mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class),
rotatedPreviewWidth, rotatedPreviewHeight, maxPreviewWidth,
maxPreviewHeight, largest);

// We fit the aspect ratio of TextureView to the size of preview we picked.
int orientation = getResources().getConfiguration().orientation;
if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
//                    mTextureView.setAspectRatio(
//                            mPreviewSize.getWidth(), mPreviewSize.getHeight());
} else {
//                    mTextureView.setAspectRatio(
//                            mPreviewSize.getHeight(), mPreviewSize.getWidth());
}

// Check if the flash is supported.
Boolean available = characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
mFlashSupported = available == null ? false : available;

mCameraId = cameraId;
return;
}
} catch (CameraAccessException e) {
e.printStackTrace();
} catch (NullPointerException e) {
// Currently an NPE is thrown when the Camera2API is used but not supported on the
// device this code runs.
ErrorDialog.newInstance("该设备不支持Camera2API")
.show(getChildFragmentManager(), FRAGMENT_DIALOG);
}
}

/**
* Opens the camera specified by {@link Camera2Fragment#mCameraId}.
*/
private void openCamera(int width, int height) {
if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED) {
requestCameraPermission();
return;
}
setUpCameraOutputs(width, height);
configureTransform(width, height);
Activity activity = getActivity();
CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
try {
if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {
throw new RuntimeException("Time out waiting to lock camera opening.");
}
manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
} catch (InterruptedException e) {
throw new RuntimeException("Interrupted while trying to lock camera opening.", e);
}
}

/**
* Closes the current {@link CameraDevice}.
*/
private void closeCamera() {
try {
mCameraOpenCloseLock.acquire();
if (null != mCaptureSession) {
mCaptureSession.close();
mCaptureSession = null;
}
if (null != mCameraDevice) {
mCameraDevice.close();
mCameraDevice = null;
}
if (null != mImageReader) {
mImageReader.close();
mImageReader = null;
}
} catch (InterruptedException e) {
throw new RuntimeException("Interrupted while trying to lock camera closing.", e);
} finally {
mCameraOpenCloseLock.release();
}
}

/**
* Starts a background thread and its {@link Handler}.
*/
private void startBackgroundThread() {
mBackgroundThread = new HandlerThread("CameraBackground");
mBackgroundThread.start();
mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
}

/**
* Stops the background thread and its {@link Handler}.
*/
private void stopBackgroundThread() {
mBackgroundThread.quitSafely();
try {
mBackgroundThread.join();
mBackgroundThread = null;
mBackgroundHandler = null;
} catch (InterruptedException e) {
e.printStackTrace();
}
}

/**
* Creates a new {@link CameraCaptureSession} for camera preview.
*/
private void createCameraPreviewSession() {
try {
SurfaceTexture texture = mTextureView.getSurfaceTexture();
assert texture != null;

// We configure the size of default buffer to be the size of camera preview we want.
texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());

// This is the output Surface we need to start preview.
Surface surface = new Surface(texture);

// We set up a CaptureRequest.Builder with the output Surface.
mPreviewRequestBuilder
= mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
mPreviewRequestBuilder.addTarget(surface);

// Here, we create a CameraCaptureSession for camera preview.
mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()),
new CameraCaptureSession.StateCallback() {

@Override
public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
// The camera is already closed
if (null == mCameraDevice) {
return;
}

// When the session is ready, we start displaying the preview.
mCaptureSession = cameraCaptureSession;
try {
// Auto focus should be continuous for camera preview.
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,
CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
// Flash is automatically enabled when necessary.
setAutoFlash(mPreviewRequestBuilder);

// Finally, we start displaying the camera preview.
mPreviewRequest = mPreviewRequestBuilder.build();
mCaptureSession.setRepeatingRequest(mPreviewRequest,
mCaptureCallback, mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

@Override
public void onConfigureFailed(
@NonNull CameraCaptureSession cameraCaptureSession) {
showToast("Failed");
}
}, null
);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

/**
* Configures the necessary {@link Matrix} transformation to `mTextureView`.
* This method should be called after the camera preview size is determined in
* setUpCameraOutputs and also the size of `mTextureView` is fixed.
*
* @param viewWidth  The width of `mTextureView`
* @param viewHeight The height of `mTextureView`
*/
private void configureTransform(int viewWidth, int viewHeight) {
Activity activity = getActivity();
if (null == mTextureView || null == mPreviewSize || null == activity) {
return;
}
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
Matrix matrix = new Matrix();
RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
RectF bufferRect = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth());
float centerX = viewRect.centerX();
float centerY = viewRect.centerY();
if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
float scale = Math.max(
(float) viewHeight / mPreviewSize.getHeight(),
(float) viewWidth / mPreviewSize.getWidth());
matrix.postScale(scale, scale, centerX, centerY);
matrix.postRotate(90 * (rotation - 2), centerX, centerY);
} else if (Surface.ROTATION_180 == rotation) {
matrix.postRotate(180, centerX, centerY);
}
mTextureView.setTransform(matrix);
}

/**
* Initiate a still image capture.
*/
private void takePicture() {
lockFocus();
}

/**
* Lock the focus as the first step for a still image capture.
*/
private void lockFocus() {
try {
// This is how to tell the camera to lock focus.
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
CameraMetadata.CONTROL_AF_TRIGGER_START);
// Tell #mCaptureCallback to wait for the lock.
mState = STATE_WAITING_LOCK;
mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

/**
* Run the precapture sequence for capturing a still image. This method should be called when
* we get a response in {@link #mCaptureCallback} from {@link #lockFocus()}.
*/
private void runPrecaptureSequence() {
try {
// This is how to tell the camera to trigger.
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_START);
// Tell #mCaptureCallback to wait for the precapture sequence to be set.
mState = STATE_WAITING_PRECAPTURE;
mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

/**
* Capture a still picture. This method should be called when we get a response in
* {@link #mCaptureCallback} from both {@link #lockFocus()}.
*/
private void captureStillPicture() {
try {
final Activity activity = getActivity();
if (null == activity || null == mCameraDevice) {
return;
}
// This is the CaptureRequest.Builder that we use to take a picture.
final CaptureRequest.Builder captureBuilder =
mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureBuilder.addTarget(mImageReader.getSurface());

// Use the same AE and AF modes as the preview.
captureBuilder.set(CaptureRequest.CONTROL_AF_MODE,
CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
setAutoFlash(captureBuilder);

// Orientation
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, getOrientation(rotation));

CameraCaptureSession.CaptureCallback CaptureCallback
= new CameraCaptureSession.CaptureCallback() {

@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session,
@NonNull CaptureRequest request,
@NonNull TotalCaptureResult result) {
showToast("拍照成功，图片保存为: " + mFile);
Log.d(TAG, mFile.toString());
unlockFocus();
}
};

mCaptureSession.stopRepeating();
mCaptureSession.capture(captureBuilder.build(), CaptureCallback, null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

/**
* Retrieves the JPEG orientation from the specified screen rotation.
*
* @param rotation The screen rotation.
* @return The JPEG orientation (one of 0, 90, 270, and 360)
*/
private int getOrientation(int rotation) {
// Sensor orientation is 90 for most devices, or 270 for some devices (eg. Nexus 5X)
// We have to take that into account and rotate JPEG properly.
// For devices with orientation of 90, we simply return our mapping from ORIENTATIONS.
// For devices with orientation of 270, we need to rotate the JPEG 180 degrees.
return (ORIENTATIONS.get(rotation) + mSensorOrientation + 270) % 360;
}

/**
* Unlock the focus. This method should be called when still image capture sequence is
* finished.
*/
private void unlockFocus() {
try {
// Reset the auto-focus trigger
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
setAutoFlash(mPreviewRequestBuilder);
mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
mBackgroundHandler);
// After this, the camera will go back to the normal state of preview.
mState = STATE_PREVIEW;
mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback,
mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.picture: {
takePicture();
break;
}
}
}

private void setAutoFlash(CaptureRequest.Builder requestBuilder) {
if (mFlashSupported) {
requestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
}
}

/**
* Saves a JPEG {@link Image} into the specified {@link File}.
*/
private static class ImageSaver implements Runnable {

/**
* The JPEG image
*/
private final Image mImage;
/**
* The file we save the image into.
*/
private final File mFile;

public ImageSaver(Image image, File file) {
mImage = image;
mFile = file;
}

@Override
public void run() {
ByteBuffer buffer = mImage.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.remaining()];
buffer.get(bytes);
FileOutputStream output = null;
try {
output = new FileOutputStream(mFile);
output.write(bytes);
} catch (IOException e) {
e.printStackTrace();
} finally {
mImage.close();
if (null != output) {
try {
output.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

}

/**
* Compares two {@code Size}s based on their areas.
*/
static class CompareSizesByArea implements Comparator<Size> {

@Override
public int compare(Size lhs, Size rhs) {
// We cast here to ensure the multiplications won't overflow
return Long.signum((long) lhs.getWidth() * lhs.getHeight() -
(long) rhs.getWidth() * rhs.getHeight());
}

}

/**
* Shows an error message dialog.
*/
public static class ErrorDialog extends DialogFragment {

private static final String ARG_MESSAGE = "message";

public static ErrorDialog newInstance(String message) {
ErrorDialog dialog = new ErrorDialog();
Bundle args = new Bundle();
args.putString(ARG_MESSAGE, message);
dialog.setArguments(args);
return dialog;
}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final Activity activity = getActivity();
return new AlertDialog.Builder(activity)
.setMessage(getArguments().getString(ARG_MESSAGE))
.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
activity.finish();
}
})
.create();
}

}

/**
* Shows OK/Cancel confirmation dialog about camera permission.
*/
public static class ConfirmationDialog extends DialogFragment {

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final Fragment parent = getParentFragment();
return new AlertDialog.Builder(getActivity())
.setMessage("需要申请摄像头权限")
.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
FragmentCompat.requestPermissions(parent,
new String[]{Manifest.permission.CAMERA},
REQUEST_CAMERA_PERMISSION);
}
})
.setNegativeButton(android.R.string.cancel,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Activity activity = parent.getActivity();
if (activity != null) {
activity.finish();
}
}
})
.create();
}
}

}

布局文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<com.hejunlin.camerasample2.SuperTextureView
android:id="@+id/texture"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

<FrameLayout
android:id="@+id/control"
android:layout_width="match_parent"
android:layout_height="112dp"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:background="#000000">

<ImageView
android:id="@+id/picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:src="@mipmap/capture" />

</FrameLayout>

</RelativeLayout>

效果图：



从效果图上看出，新API功能更强大，拍照效果更好。

以上两个自定义相机案例完整下载地址：

https://github.com/hejunlin2013/MultiMediaSample

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