Android Versions

Android Architecture
https://developer.android.com/guide/platform

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https://developer.android.com/guide/components/fundamentals

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Activity Lifecycle
https://developer.android.com/reference/android/app/Activity

Log Methods
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Resources Types
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Resources Tags
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Layouts
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An Android layout is a class that handles arranging the way its children appear on the screen. Anything that is a View (or inherits from View) can be a child of a layout. All of the layouts inherit from ViewGroup (which inherits from View) so you can nest layouts. You could also create your own custom layout by making a class that inherits from ViewGroup.

View Properties
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layout_width and layout_height
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Dimension Units
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Dimension Units
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View Classes
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RelativeLayout
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RelativeLayout is a view group that displays child views in relative positions. The position of each view can be specified as relative to sibling elements (such as to the left-of or below another view) or in positions relative to the parent RelativeLayout area (such as aligned to the bottom, left or center).

RelativeLayout Properties
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android:layout_above
android:layout_below
android:layout_toLeftOf
android:layout_toRightOf
android:layout_toStartOf
android:layout_toEndOf
android:layout_alignBottom
android:layout_alignLeft
android:layout_alignRight
android:layout_alignStart
android:layout_alignEnd
android:layout_alignTop
android:layout_alignBaseline
android:layout_alignParentBottom
android:layout_alignParentRight
android:layout_alignParentLeft
android:layout_alignParentStart
android:layout_alignParentEnd
android:layout_alignParentTop
android:layout_centerInParent
android:layout_centerHorizontal
android:layout_centerVertical

LinearLayout
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LinearLayout is a ViewGroup that arranges the child View(s) in a single direction, either vertically or horizontally.

LinearLayout Properties
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android:orientation = "vertical"|"horizontal"
android:weightSum = "10“
android:layout_weight = "1"
android:layout_gravity = "top"|"bottom"|"left"|"right"|
"center_vertical"|"center_horizontal"|"center"|
"fill_vertical"|"fill_horizontal"|"fill"|
"clip_vertical"|"clip_horizontal"|
"start"|"end"

FrameLayout
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FrameLayout is a simple layout. It can contain one or more child View(s), and they can overlap each other. Therefore, the android:layout_gravity attribute is used to locate the child View(s).

android:layout_gravity
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TableLayout
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TableLayout arranges the View(s) in table format. Specifically, TableLayout is a ViewGroup containing one or more TableRow(s). Each TableRow is a row in the table containing cells. Child View(s) can be placed in one cell or in a merged cell from adjacent cells of a row. Unlike tables in HTML, you cannot merge consecutive cells in the one column.

GridLayout
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GridLayout uses a grid of infinitely-thin lines to separate its drawing area into: rows, columns, and cells. It supports both row and column spanning, this means it is possible to merge adjacent cells into a large cell (a rectangle) to contain a View.

Gravity and Layout_Gravity
https://learntodroid.com/what-is-the-difference-between-gravity-and-layout_gravity-in-android/

Padding
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Margins
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Example
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ConstraintLayout
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ConstraintLayout – Introduced in Android 7, use of this layout manager is recommended for most layout
requirements. ConstraintLayout allows the positioning and behavior of the views in a layout to be defined
by simple constraint settings assigned to each child view. The flexibility of this layout allows complex layouts
to be quickly and easily created without the necessity to nest other layout types inside each other, resulting
in improved layout performance. ConstraintLayout is also tightly integrated into the Android Studio Layout
Editor tool. Unless otherwise stated, this is the layout of choice for the majority of examples in this book.

ConstraintLayout
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ConstraintLayout Properties
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app:layout_constraintDimensionRatio="1:0.5"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintVertical_bias="0.5"
app:layout_constraintWidth_default="percent"
app:layout_constraintWidth_percent="0.5"
app:layout_constraintHeight_default="percent"
app:layout_constraintHeight_percent="0.5"
app:layout_constraintHorizontal_chainStyle = "spread"|"spread_inside"|"packed"
app:layout_constraintHorizontal_weight = "1"
app:layout_constraintVertical_chainStyle = "spread"|"spread_inside"|"packed"
app:layout_constraintVertical_weight = "1"

ConstraintLayout Properties2
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layout_constraintLeft_toLeftOf
layout_constraintLeft_toRightOf
layout_constraintRight_toLeftOf
layout_constraintRight_toRightOf
layout_constraintTop_toTopOf
layout_constraintTop_toBottomOf
layout_constraintBottom_toBottomOf
layout_constraintBottom_toTopOf
layout_constraintBaseline_toBaselineOf
layout_constraintStart_toEndOf
layout_constraintStart_toStartOf
layout_constraintEnd_toStartOf
layout_constraintEnd_toEndOf

include
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ConstraintLayout ChainStyle
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Android …
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