Android Camera2 拍照（三）——切換攝像頭，延時拍攝和閃光模式
阿新 • • 發佈：2018-06-13
openca any The visible surface else 提示 再次 .cn 原文:Android Camera2 拍照（三）——切換攝像頭，延時拍攝和閃光模式
關閉攝像頭：
打開新的攝像頭：
如果TextureView是available的，那麽直接調用openCamera（）打開camera（openCamera()的代碼參考之前的博客）；如果|TextureView是unavailable的，那麽調用TextureView的setSurfaceTextureListener設置SurfaceTextureListener（參考上一篇博客）。
變量mDelayTime和mDelaySate的定義：
當拍攝按鈕被點擊時：
但有3s或10s延時的時候，利用CountDownTimer實現倒計時並每隔一秒更新剩余時間提示，到時候執行拍照功能。
在takePicture（）之前，需要再次設置：
一、切換攝像頭
在前後攝像頭之間切換，首先需要關閉之前打開的攝像頭，關閉preview，之後重新打開新的攝像頭，重新打開preview。
public void switchCamera() { if (mCameraId.equals(CAMERA_FRONT)) { mCameraId = CAMERA_BACK; closeCamera(); reopenCamera(); } else if (mCameraId.equals(CAMERA_BACK)) { mCameraId = CAMERA_FRONT; closeCamera(); reopenCamera(); } }
關閉攝像頭：
/** * Closes the current {@link CameraDevice}. */ private void closeCamera() { try { mCameraOpenCloseLock.acquire(); synchronized (mCameraStateLock) { // Reset state and clean up resources used by the camera. // Note: After calling this, the ImageReaders will be closed after any background // tasks saving Images from these readers have been completed. mPendingUserCaptures = 0; mState = STATE_CLOSED; if (null != mCaptureSession) { mCaptureSession.close(); mCaptureSession = null; } if (null != mCameraDevice) { mCameraDevice.close(); mCameraDevice = null; } if (null != mJpegImageReader) { mJpegImageReader.close(); mJpegImageReader = null; } if (null != mRawImageReader) { mRawImageReader.close(); mRawImageReader = null; } } } catch (InterruptedException e) { throw new RuntimeException("Interrupted while trying to lock camera closing.", e); } finally { mCameraOpenCloseLock.release(); } }
打開新的攝像頭：
public void reopenCamera() {
if (mTextureView.isAvailable()) {
openCamera();
} else {
mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
}
}如果TextureView是available的，那麽直接調用openCamera（）打開camera（openCamera()的代碼參考之前的博客）；如果|TextureView是unavailable的，那麽調用TextureView的setSurfaceTextureListener設置SurfaceTextureListener（參考上一篇博客）。
二、延時拍攝
要實現延時拍攝，核心是實現一個定時器。本例延時分為三種模式：3s延時，10s按時，無延時。可以在三種模式之中自有切換。
private void switchDelayState() {
switch (mDelayState) {
case 0:
mTimer.setImageResource(R.mipmap.ic_3s);
mDelayTime = 3 * 1000;
mDelayState = 1;
break;
case 1:
mTimer.setImageResource(R.mipmap.ic_10s);
mDelayTime = 10 * 1000;
mDelayState = 2;
break;
case 2:
mTimer.setImageResource(R.mipmap.timer);
mDelayTime = 0;
mDelayState = 0;
break;
default:
break;
}
}變量mDelayTime和mDelaySate的定義：
/*
* Delay state, 0 represents no delay, 1 represents 3s delay, while 2 represents 10s delay
*/
private short mDelayState = 0; // Timer
private short mDelayTime;當拍攝按鈕被點擊時：
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.capture: {
if (mDelayState == 0) {
takePicture();
} else {
new CountDownTimer(mDelayTime, TIME_INTERVAL) {
@Override
public void onTick(long millisUntilFinished) {
mTimeText.setVisibility(View.VISIBLE);
mTimeText.setText("" + millisUntilFinished / TIME_INTERVAL);
}
@Override
public void onFinish() {
mTimeText.setVisibility(View.GONE);
takePicture();
}
}.start();
}
break;
}但有3s或10s延時的時候，利用CountDownTimer實現倒計時並每隔一秒更新剩余時間提示，到時候執行拍照功能。
三、切換閃光模式
支持自動，強制，禁止閃光。與閃光模式有關的屬性是CaptureRequest.CONTROL_AE_MODE和CaptureRequest.FLASH_MODE。 如果要使用FLASH_MODE屬相，閃光燈必須可用，並且，CONTROL_AE_MODE必須設置為on或off，否則，自動曝光屬性的ON_AUTO_FLASH,ON_ALWAYS_FLASH, ON_AUTO_FLASH_REDEYE將會覆蓋FLASH_MODE的設置。
private void switchFlashMode() {
switch (mFlashMode) {
case 0:
mFlashMode = 1;
mFlashBtn.setImageResource(R.mipmap.flash_auto);
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
try {
mCaptureSession.setRepeatingRequest(
mPreviewRequestBuilder.build(),
mPreCaptureCallback, mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
return;
}
break;
case 1:
mFlashMode = 2;
mFlashBtn.setImageResource(R.mipmap.flash_on);
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
try {
mCaptureSession.setRepeatingRequest(
mPreviewRequestBuilder.build(),
mPreCaptureCallback, mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
return;
}
break;
case 2:
mFlashMode = 0;
mFlashBtn.setImageResource(R.mipmap.flash_off);
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
mPreviewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
try {
mCaptureSession.setRepeatingRequest(
mPreviewRequestBuilder.build(),
mPreCaptureCallback, mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
return;
}
break;
}
}在takePicture（）之前，需要再次設置：
private void setFlashMode() {
switch (mFlashMode) {
case 0:
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
mPreviewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
break;
case 1:
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
break;
case 2:
mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
break;
}
}代碼參考：https://github.com/gengqifu/361Camera，歡迎fork/star。Android Camera2 拍照（三）——切換攝像頭，延時拍攝和閃光模式