Android -- Camera源码简析,启动流程
catch (InterruptedException ex) {
// ignore
}
mCameraPreviewThread = null;
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2、surfaceCreated
啥都没做
3、surfaceChanged
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// 确保在holder中有surface
if (holder.getSurface() == null) {
Log.d(TAG, holder.getSurface() == null);
return;
}
// We need to save the holder for later use, even when the mCameraDevice
// is null. This could happen if onResume() is invoked after this
// function.
mSurfaceHolder = holder;
if (mCameraDevice == null) return;
if (mPausing || isFinishing()) return;
// Set preview display if the surface is being created. Preview was
// already started. Also restart the preview if display rotation has
// changed. Sometimes this happens when the device is held in portrait
// and camera app is opened. Rotation animation takes some time and
// display rotation in onCreate may not be what we want.
if (mCameraState == PREVIEW_STOPPED) {
startPreview();
startFaceDetection();
} else {
if (Util.getDisplayRotation(this) != mDisplayRotation) {
setDisplayOrientation();
}
if (holder.isCreating()) {
// Set preview display if the surface is being created and preview
// was already started. That means preview display was set to null
// and we need to set it now.
setPreviewDisplay(holder);
}
}
// If first time initialization is not finished, send a message to do
// it later. We want to finish surfaceChanged as soon as possible to let
// user see preview first.
if (!mFirstTimeInitialized) {
mHandler.sendEmptyMessage(FIRST_TIME_INIT);
} else {
initializeSecondTime();
}
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如果是第一次加载,则执行mHandler.sendEmptyMessage(FIRST_TIME_INIT); 对应处理的是initializeFirstTime();
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/**
* 初始化,第一次初始化
* // Snapshots can only be taken after this is called. It should be called
* // once only. We could have done these things in onCreate() but we want to
* // make preview screen appear as soon as possible.
*/
private void initializeFirstTime() {
if (mFirstTimeInitialized) return;
// Create orientation listenter. This should be done first because it
// takes some time to get first orientation.
mOrientationListener = new MyOrientationEventListener(Camera.this);
mOrientationListener.enable();
// Initialize location sevice.
boolean recordLocation = RecordLocationPreference.get(
mPreferences, getContentResolver());
// 初始化屏幕最上方的标志,比如开启了曝光值啊,什么的
initOnScreenIndicator();
// 位置服务
mLocationManager.recordLocation(recordLocation);
keepMediaProviderInstance();
// 检查存储空间和初始化储存目录
checkStorage();
// Initialize last picture button.
mContentResolver = getContentResolver();
if (!mIsImageCaptureIntent) { // no thumbnail in image capture intent
// 初始化缩略图
initThumbnailButton();
}
// Initialize shutter button.
// 初始化拍照按钮并设置监听事件
mShutterButton = (ShutterButton) findViewById(R.id.shutter_button);
mShutterButton.setOnShutterButtonListener(this);
mShutterButton.setVisibility(View.VISIBLE);
// Initialize focus UI.
mPreviewFrame = findViewById(R.id.camera_preview);
mPreviewFrame.setOnTouchListener(this);
// 聚焦框
mFocusAreaIndicator = (RotateLayout) findViewById(R.id.focus_indicator_rotate_layout);
CameraInfo info = CameraHolder.instance().getCameraInfo()[mCameraId];
boolean mirror = (info.facing == CameraInfo.CAMERA_FACING_FRONT);
mFocusManager.initialize(mFocusAreaIndicator, mPreviewFrame, mFaceView, this,
mirror, mDisplayOrientation);
// 初始化一个图片的保存线程
mImageSaver = new ImageSaver();
// 设置屏幕亮度
Util.initializeScreenBrightness(getWindow(), getContentResolver());
// 注册SD卡相关的广播,比如拔出存储卡什么的
installIntentFilter();
// 初始化缩放UI
initializeZoom();
// 更新屏幕上的闪光灯什么的标记
updateOnScreenIndicators();
// 开始面
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