Revealing the layout of Android and revealing the secrets of android

Revealing the layout of Android and revealing the secrets of android
Preface

Today, I will write down some understanding of the layout. The main content includes the inheritance relationship between the control attributes, the relationship between the control attributes and the container attributes, and the use of various types of attributes.

Property type of the control

Generally speaking, when assigning values to attributes of a control, there are generally some types of attributes, one starting with layout, one is an attribute that does not start with layout _. TextView is used as an example to describe it as follows:

　　

 1 <RelativeLayout 2     android:layout_width="match_parent" 3     android:layout_height="match_parent" > 4  5     <TextView 6         android:layout_width="wrap_content" 7         android:layout_height="wrap_content" 8         android:text="hello_world" /> 9         10 </RelativeLayout>

I have set three attributes layout_width, layout_height, and text for TextView. We can see that the layout_width and layout_height attributes of the three attributes start with layout _, while the text attributes do not start with Layout.

Attributes starting with layout _ are inherited from the container. In this example, they are inherited from RelativeLayout, and TextView itself does not. Text is the property of TextView.

To illustrate that the layout attribute is a container attribute, I used the following example to place the TextView in RelativeLayout and LinearLayout, and set the layout_centerInParent attribute for the TextView, this is because this attribute is RelativeLayout and LinearLayout does not. The experiment code is as follows:

　　

 1 <RelativeLayout 2     android:layout_width="wrap_content" 3     android:layout_height="wrap_content" > 4  5     <TextView 6         android:layout_width="wrap_content" 7         android:layout_height="wrap_content" 8         android:layout_centerInParent="true" 9         android:text="hello_world" />10 </RelativeLayout>11 12 <LinearLayout13     android:layout_width="wrap_content"14     android:layout_height="wrap_content" >15 16     <TextView17         android:layout_width="wrap_content"18         android:layout_height="wrap_content"19         android:layout_centerInParent="true"20         android:text="hello world2" />21 </LinearLayout>

After the preceding settings, the editor prompts "Invalid layout param in a LinearLayout: layout_centerInParent", as shown below:

　　

Through this experiment, we can draw a conclusion that the attribute starting with layout is not owned by TextView, but inherits the layout attribute in the container. Then, we can draw a conclusion, controls can be divided into their own attributes and the layout attributes in the container. Next we will analyze the attributes in detail through TextView and each layout container.

LinearLayout and TextView

This section describes the attributes of LinearLayout and TextView. First, let's take a look at the attributes of TextView and the property inheritance relationship,

The attributes of TextView are as follows:

XML Attributes
Attribute Name
Android: autoLink
Android: autoText
Android: bufferType
Android: capitalize
Android: cursorVisible
Android: digits
Android: drawableBottom
Android: drawableEnd
Android: drawableLeft
Android: drawablePadding
Android: drawableRight
Android: drawableStart
Android: drawableTop
Android: editable
Android: editorExtras
Android: ellipsize
Android: EMS
Android: fontFamily
Android: freezesText
Android: gravity
Android: height
Android: hint
Android: imeActionId
Android: imeActionLabel
Android: imeOptions
Android: includeFontPadding
Android: inputMethod
Android: inputType
Android: lineSpacingExtra
Android: lineSpacingMultiplier
Android: lines
Android: linksClickable
Android: marqueeRepeatLimit
Android: maxEms
Android: maxHeight
Android: maxLength
Android: maxLines
Android: maxWidth
Android: minEms
Android: minHeight
Android: minLines
Android: minWidth
Android: numeric
Android: password
Android: phoneNumber
Android: privateImeOptions
Android: scrollHorizontally
Android: selectAllOnFocus
Android: shadowColor
Android: shadowDx
Android: shadowDy
Android: shadowRadius
Android: singleLine
Android: text
Android: textAllCaps
Android: textAppearance
Android: textColor
Android: textColorHighlight
Android: textColorHint
Android: textColorLink
Android: textIsSelectable
Android: textScaleX
Android: textSize
Android: textStyle
Android: typeface
Android: width

　　
TextView inherited attributes

　　

Inherited XML Attributes

From class android. view. View

Attribute Name

Android: accessibilityLiveRegion

Android: alpha

Android: background

Android: clickable

Android: contentDescription

Android: drawingCacheQuality

Android: duplicateParentState

Android: fadeScrollbars

Android: fadingEdgeLength

Android: filterTouchesWhenObscured

Android: fitsSystemWindows

Android: focusable

Android: focusableInTouchMode

Android: hapticFeedbackEnabled

Android: id

Android: importantForAccessibility

Android: isScrollContainer

Android: keepScreenOn

Android: layerType

Android: layoutDirection

Android: longClickable

Android: minHeight

Android: minWidth

Android: nextFocusDown

Android: nextFocusForward

Android: nextFocusLeft

Android: nextFocusRight

Android: nextFocusUp

Android: onClick

Android: padding

Android: paddingBottom

Android: paddingEnd

Android: paddingLeft

Android: paddingRight

Android: paddingStart

Android: paddingTop

Android: requiresFadingEdge

Android: rotation

Android: rotationX

Android: rotationY

Android: saveEnabled

Android: scaleX

Android: scaleY

Android: scrollX

Android: scrollY

Android: scrollbarAlwaysDrawHorizontalTrack

Android: scrollbarAlwaysDrawVerticalTrack

Android: scrollbardefadeldelaybeforefade

Android: scrollbarFadeDuration

Android: scrollbarSize

Android: scrollbarStyle

Android: scrollpolicumbhorizontal

Android: scrollpolicumbvertical

Android: scrollbarTrackHorizontal

Android: scrollbarTrackVertical

Android: scrollbars

Android: soundEffectsEnabled

Android: tag

Android: textAlignment

Android: textDirection

Android: transformPivotX

Android: transformPivotY

Android: translationX

Android: translationY

Android: visibility

That is to say, these two parts are all attributes of TextView. However, when we edit the code in the XML editor, we will find that in addition to the above attributes, there are also many attributes starting with layout that can be set, these are the container attributes. The following uses LinearLayout as an example. The experiment scenario is as follows:

　　

 1 <LinearLayout 2     android:layout_width="wrap_content" 3     android:layout_height="wrap_content" > 4  5     <TextView 6         android:layout_width="wrap_content" 7         android:layout_height="wrap_content" 9         android:text="hello world2" />10 </LinearLayout>

Next, let's take a look at the layout attributes of LinearLayout, which are embodied in the LinearLayout. LayoutParams class.

The help document shows that its attributes are as follows:

　　

XML Attributes
Attribute Name
Android: layout_gravity
Android: layout_weight

Two types of attributes are inherited: android. view. ViewGroup. MarginLayoutParams

　　

Attribute Name

Android: layout_marginBottom

Android: layout_marginEnd

Android: layout_marginLeft

Android: layout_marginRight

Android: layout_marginStart

Android: layout_marginTop

And android. view. ViewGroup. LayoutParams

Attribute Name	Related Method	Description
Android: layout_height		Specifies the basic height of the view.
Android: layout_width		Specifies the basic width of the view.

All the preceding attributes are the layout Attributes provided by the layout control.

Therefore, the attributes that TextView can set are its own attributes and the preceding layout attributes.

Postscript

We have analyzed the attribute usage of the layout in Android through the combination of LinearLayout and TextView. Through the above analysis, we can understand the origin of the control property, in this way, you can make the interface layout as you like.

Similarly, you can analyze RelativeLayout, TableLayout, and so on.

　　

Address: http://www.cnblogs.com/luoaz/p/3947100.html

 

　　

 

Android layout selection call

Extends activityGroup
Add a ScrollView to the xml framework layout.
<ScrollView android: measureAllChildren = "true" android: id = "@ + id/aa"
Android: layout_weight = "1" android: layout_height = "fill_parent"
Android: layout_width = "fill_parent">
</ScrollView>

In the Code:
Aa. removeAllViews ();
Aa. addView (getLocalActivityManager (). startActivity (
"Module1 ",
New Intent (this, xml2.class)
. AddFlags (Intent. FLAG_ACTIVITY_CLEAR_TOP ))
. GetDecorView ());

How to Implement the layout of android

If there are no Fragments in the lower part of 3.0, after you layout the left and right sides, update the corresponding view based on the click event.