MTK camera 4.2 app UI elements 介绍(2013/4)

前言

UI layout的结构分析在camera 4.2 UI layout 结构(2013/4)已完成。 
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

ViewManager is a abstract class 
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

由该图可见，pickerManager中有三个PickerButton,对应着界面上的闪光，镜头切换,(另外一个不清楚)。


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

setting_indicator.xml只是一个RotateImageView

ThumbnailManager

IndicatorManager

res/layout/onscreen_indicators.xml 



在Camera中，只有private
void doShowIndicator() 函数中有调用其显示mIndicatorManager.show();