前言
这里对UI的各元素进行分析。
UI界面
在该界面能够看到的元素有：
- ShutterManager
- ModePiker
- ThumbnailManager
- SettingManager
- PickerManager
- IndicatorManager
只有ShutterManager构造函数中使用super(context, VIEW_LAYER_SHUTTER)；其余的都是调用super(context);
ViewManager默认的构造函数指定layout是VIEW_LAYER_NORMAL，所以这几个view都在同一个layout
public ViewManager(Camera context) {
this(context, VIEW_LAYER_NORMAL);
}
基本元素
TwoStateImageView
TwoStateImageView只提供了两个方法：
- setEnabled(boolean enabled)
- enableFilter(boolean enabled) 控制setAlpha 1.0f/0.4f
子类：
- PickerButton
- FlashPickerButton
- RotateAnimationImageView
- SelfRotateImageView
- ShutterButton
继承关系图：
RotateImageView
RotateImageView实现动画形式旋转ImageView。实现了setOrientation(int degree, boolean animation) 接口，提供了setBitmap(Bitmap bitmap) ,getDegree()方法。
不错的设计是， 在setBitmap()中先把bitmap转换成较小的thumbnail bitmap ，再生成TransitionDrawable或者BitmapDrawable。
生成TransitionDrawable之后通过onDraw()绘制动画过程。这个以后进一步学习
组合关系图
ViewManager
通过这个类图可以看到，每个feature对应的view都定义单独的ViewManager。(一共16个)
ViewManager中定义了abstract getView(),继承的子类中只需要实现该方法，通常是inflate() xml layout文件，并通过Camera的addView()方法加入到对应的view layer即可。（另外一篇文档有整个过程的描述）
ShutterManager
ShutterManager负责管理ShutterButton简介
shutter button负责监听click,long click事件，并通过内部自定义接口OnShutterButtonListener向外通知shutter button focus/click/long pressed 事件。
在ShutterManager中作为属性。
/**
* A button designed to be used for the on-screen shutter button.
* It's currently an {@code ImageView} that can call a delegate when the
* pressed state changes.
*/
实现
Overrides: performClick() in View 监听button click
Overrides: drawableStateChanged() in ImageView 实现button focus
implements View.OnLongClickListener
在drawableStateChanged中，有注释到写到，为了保证物理按键，轨迹球，touch event都有相同的事件时序，通过post方法调整了touch events的时序。注释及代码如下：
// When pressing the physical camera button the sequence of
// events is:
// focus pressed, optional camera pressed, focus released.
// We want to emulate this sequence of events with the shutter
// button. When clicking using a trackball button, the view
// system changes the drawable state before posting click
// notification, so the sequence of events is:
// pressed(true), optional click, pressed(false)
// When clicking using touch events, the view system changes the
// drawable state after posting click notification, so the
// sequence of events is:
// pressed(true), pressed(false), optional click
// Since we're emulating the physical camera button, we want to
// have the same order of events. So we want the optional click
// callback to be delivered before the pressed(false) callback.
//
// To do this, we delay the posting of the pressed(false) event
// slightly by pushing it on the event queue. This moves it
// after the optional click notification, so our client always
// sees events in this sequence:
// pressed(true), optional click, pressed(false)
post(new Runnable() {
@Override
public void run() {
callShutterButtonFocus(pressed);
}
});
layout文件
res/layout-land/camera_shutter_photo_video.xml
res/layout-port/camera_shutter_photo_video.xml
<style name="ShutterButton">
<item name="android:layout_height">@dimen/shutter_size</item>
<item name="android:layout_width">@dimen/shutter_size</item>
<item name="android:scaleType">center</item>
<item name="android:clickable">true</item>
<item name="android:focusable">true</item>
</style>
加载到主界面
由ShutterManager类的show()完成。
通过ViewGroup com.android.camera.Camera.getViewLayer(int layer)
case ViewManager.VIEW_LAYER_SHUTTER:
viewLayer = mViewLayerShutter;
ModePicker
ModePicker中定义了10种模式；
设置，高亮当前模式；
通过内部接口类OnModeChangedListener向外通知listener;
加载layout文件。
该类只负责View,没有任何修改preference,parameter的行为
public static final int MODE_PHOTO = 0; public static final int MODE_HDR = 1; public static final int MODE_FACE_BEAUTY = 2; public static final int MODE_PANORAMA = 3; public static final int MODE_MAV = 4; public static final int MODE_ASD = 5; public static final int MODE_SMILE_SHOT = 6; public static final int MODE_BEST = 7; public static final int MODE_EV = 8; public static final int MODE_VIDEO = 9;
layout文件
res/layout-land/mode_picker.xml
res/layout-port/mode_picker.xml
PickerManager
PickerButton onClick
PickerButton通过内部定义的Listener，通知监听者PickerManager，再通知PickerManager的监听者Camera。以下是相关的interface.
PickerButton在向listener通知click事件的同时，会更新preference.
public interface Listener {
boolean onPicked(PickerButton button, String key, String newValue);
}
public interface PickerListener {
boolean onCameraPicked(int camerId);
boolean onFlashPicked(String flashMode);
boolean onStereoPicked(boolean stereoType);
}
SettingManager
ThumbnailManager
IndicatorManager
