added in version 25.1.0
belongs to Maven artifact com.android.support:gridlayout-v7:28.0.0-alpha1
Summary: Nested Classes | Constants | Inherited Constants | Fields | Inherited Fields | Ctors | Methods | Protected Methods | Inherited Methods | [Expand All]

GridLayout

public class GridLayout
extends ViewGroup

java.lang.Object
   ↳ android.view.View
     ↳ android.view.ViewGroup
       ↳ android.support.v7.widget.GridLayout

A layout that places its children in a rectangular grid.

The grid is composed of a set of infinitely thin lines that separate the viewing area into cells. Throughout the API, grid lines are referenced by grid indices. A grid with N columns has N + 1 grid indices that run from 0 through N inclusive. Regardless of how GridLayout is configured, grid index 0 is fixed to the leading edge of the container and grid index N is fixed to its trailing edge (after padding is taken into account).

Row and Column Specs

Children occupy one or more contiguous cells, as defined by their rowSpec and columnSpec layout parameters. Each spec defines the set of rows or columns that are to be occupied; and how children should be aligned within the resulting group of cells. Although cells do not normally overlap in a GridLayout, GridLayout does not prevent children being defined to occupy the same cell or group of cells. In this case however, there is no guarantee that children will not themselves overlap after the layout operation completes.

Default Cell Assignment

If a child does not specify the row and column indices of the cell it wishes to occupy, GridLayout assigns cell locations automatically using its: orientation, rowCount and columnCount properties.

Space

Space between children may be specified either by using instances of the dedicated Space view or by setting the leftMargin, topMargin, rightMargin and bottomMargin layout parameters. When the useDefaultMargins property is set, default margins around children are automatically allocated based on the prevailing UI style guide for the platform. Each of the margins so defined may be independently overridden by an assignment to the appropriate layout parameter. Default values will generally produce a reasonable spacing between components but values may change between different releases of the platform.

Excess Space Distribution

GridLayout's distribution of excess space accommodates the principle of weight. In the event that no weights are specified, columns and rows are taken as flexible if their views specify some form of alignment within their groups.

The flexibility of a view is therefore influenced by its alignment which is, in turn, typically defined by setting the gravity property of the child's layout parameters. If either a weight or alignment were defined along a given axis then the component is taken as flexible in that direction. If no weight or alignment was set, the component is instead assumed to be inflexible.

Multiple components in the same row or column group are considered to act in parallel. Such a group is flexible only if all of the components within it are flexible. Row and column groups that sit either side of a common boundary are instead considered to act in series. The composite group made of these two elements is flexible if one of its elements is flexible.

To make a column stretch, make sure all of the components inside it define a weight or a gravity. To prevent a column from stretching, ensure that one of the components in the column does not define a weight or a gravity.

When the principle of flexibility does not provide complete disambiguation, GridLayout's algorithms favour rows and columns that are closer to its right and bottom edges. To be more precise, GridLayout treats each of its layout parameters as a constraint in the a set of variables that define the grid-lines along a given axis. During layout, GridLayout solves the constraints so as to return the unique solution to those constraints for which all variables are less-than-or-equal-to the corresponding value in any other valid solution.

Interpretation of GONE

For layout purposes, GridLayout treats views whose visibility status is GONE, as having zero width and height. This is subtly different from the policy of ignoring views that are marked as GONE outright. If, for example, a gone-marked view was alone in a column, that column would itself collapse to zero width if and only if no gravity was defined on the view. If gravity was defined, then the gone-marked view has no effect on the layout and the container should be laid out as if the view had never been added to it. GONE views are taken to have zero weight during excess space distribution.

These statements apply equally to rows as well as columns, and to groups of rows or columns.

See GridLayout.LayoutParams for a full description of the layout parameters used by GridLayout.

Summary

Nested classes

class GridLayout.Alignment

Alignments specify where a view should be placed within a cell group and what size it should be. 

class GridLayout.LayoutParams

Layout information associated with each of the children of a GridLayout. 

class GridLayout.Spec

A Spec defines the horizontal or vertical characteristics of a group of cells. 

Constants

int ALIGN_BOUNDS

This constant is an alignmentMode.

int ALIGN_MARGINS

This constant is an alignmentMode.

int HORIZONTAL

The horizontal orientation.

int UNDEFINED

The constant used to indicate that a value is undefined.

int VERTICAL

The vertical orientation.

Inherited constants

From class android.view.ViewGroup
From class android.view.View

Fields

public static final GridLayout.Alignment BASELINE

Indicates that a view should be aligned with the baselines of the other views in its cell group.

public static final GridLayout.Alignment BOTTOM

Indicates that a view should be aligned with the bottom edges of the other views in its cell group.

public static final GridLayout.Alignment CENTER

Indicates that a view should be centered with the other views in its cell group.

public static final GridLayout.Alignment END

Indicates that a view should be aligned with the end edges of the other views in its cell group.

public static final GridLayout.Alignment FILL

Indicates that a view should expanded to fit the boundaries of its cell group.

public static final GridLayout.Alignment LEFT

Indicates that a view should be aligned with the left edges of the other views in its cell group.

public static final GridLayout.Alignment RIGHT

Indicates that a view should be aligned with the right edges of the other views in its cell group.

public static final GridLayout.Alignment START

Indicates that a view should be aligned with the start edges of the other views in its cell group.

public static final GridLayout.Alignment TOP

Indicates that a view should be aligned with the top edges of the other views in its cell group.

Inherited fields

From class android.view.View

Public constructors

GridLayout(Context context, AttributeSet attrs, int defStyle)

GridLayout(Context context, AttributeSet attrs)

GridLayout(Context context)

Public methods

GridLayout.LayoutParams generateLayoutParams(AttributeSet attrs)
int getAlignmentMode()

Returns the alignment mode.

int getColumnCount()

Returns the current number of columns.

int getOrientation()

Returns the current orientation.

Printer getPrinter()

Return the printer that will log diagnostics from this layout.

int getRowCount()

Returns the current number of rows.

boolean getUseDefaultMargins()

Returns whether or not this GridLayout will allocate default margins when no corresponding layout parameters are defined.

boolean isColumnOrderPreserved()

Returns whether or not column boundaries are ordered by their grid indices.

boolean isRowOrderPreserved()

Returns whether or not row boundaries are ordered by their grid indices.

void requestLayout()
void setAlignmentMode(int alignmentMode)

Sets the alignment mode to be used for all of the alignments between the children of this container.

void setColumnCount(int columnCount)

ColumnCount is used only to generate default column/column indices when they are not specified by a component's layout parameters.

void setColumnOrderPreserved(boolean columnOrderPreserved)

When this property is true, GridLayout is forced to place the column boundaries so that their associated grid indices are in ascending order in the view.

void setOrientation(int orientation)

GridLayout uses the orientation property for two purposes:

  • To control the 'direction' in which default row/column indices are generated when they are not specified in a component's layout parameters.

void setPrinter(Printer printer)

Set the printer that will log diagnostics from this layout.

void setRowCount(int rowCount)

RowCount is used only to generate default row/column indices when they are not specified by a component's layout parameters.

void setRowOrderPreserved(boolean rowOrderPreserved)

When this property is true, GridLayout is forced to place the row boundaries so that their associated grid indices are in ascending order in the view.

void setUseDefaultMargins(boolean useDefaultMargins)

When true, GridLayout allocates default margins around children based on the child's visual characteristics.

static GridLayout.Spec spec(int start, float weight)

Equivalent to: spec(start, 1, weight).

static GridLayout.Spec spec(int start, int size, GridLayout.Alignment alignment)

Equivalent to: spec(start, size, alignment, 0f).

static GridLayout.Spec spec(int start, GridLayout.Alignment alignment)

Return a Spec, spec, where:

  • spec.span = [start, start + 1]
  • spec.alignment = alignment

To leave the start index undefined, use the value UNDEFINED.

static GridLayout.Spec spec(int start)

Return a Spec, spec, where:

  • spec.span = [start, start + 1]

To leave the start index undefined, use the value UNDEFINED.

static GridLayout.Spec spec(int start, int size, GridLayout.Alignment alignment, float weight)

Return a Spec, spec, where:

  • spec.span = [start, start + size]
  • spec.alignment = alignment
  • spec.weight = weight

To leave the start index undefined, use the value UNDEFINED.

static GridLayout.Spec spec(int start, int size, float weight)

Equivalent to: spec(start, 1, default_alignment, weight) - where default_alignment is specified in GridLayout.LayoutParams.

static GridLayout.Spec spec(int start, int size)

Return a Spec, spec, where:

  • spec.span = [start, start + size]

To leave the start index undefined, use the value UNDEFINED.

static GridLayout.Spec spec(int start, GridLayout.Alignment alignment, float weight)

Equivalent to: spec(start, 1, alignment, weight).

Protected methods

boolean checkLayoutParams(ViewGroup.LayoutParams p)
GridLayout.LayoutParams generateDefaultLayoutParams()
GridLayout.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp)
void onLayout(boolean changed, int left, int top, int right, int bottom)

void onMeasure(int widthSpec, int heightSpec)

Inherited methods

From class android.view.ViewGroup
From class android.view.View
From class java.lang.Object
From interface android.view.ViewParent
From interface android.view.ViewManager
From interface android.graphics.drawable.Drawable.Callback
From interface android.view.KeyEvent.Callback
From interface android.view.accessibility.AccessibilityEventSource

Constants

ALIGN_BOUNDS

added in version 25.1.0 
int ALIGN_BOUNDS

This constant is an alignmentMode. When the alignmentMode is set to ALIGN_BOUNDS, alignment is made between the edges of each component's raw view boundary: i.e. the area delimited by the component's: top, left, bottom and right properties.

For example, when GridLayout is in ALIGN_BOUNDS mode, children that belong to a row group that uses TOP alignment will all return the same value when their getTop() method is called.

Constant Value: 0 (0x00000000)

ALIGN_MARGINS

added in version 25.1.0 
int ALIGN_MARGINS

This constant is an alignmentMode. When the alignmentMode is set to ALIGN_MARGINS, the bounds of each view are extended outwards, according to their margins, before the edges of the resulting rectangle are aligned.

For example, when GridLayout is in ALIGN_MARGINS mode, the quantity top - layoutParams.topMargin is the same for all children that belong to a row group that uses TOP alignment.

Constant Value: 1 (0x00000001)

HORIZONTAL

added in version 25.1.0 
int HORIZONTAL

The horizontal orientation.

Constant Value: 0 (0x00000000)

UNDEFINED

added in version 25.1.0 
int UNDEFINED

The constant used to indicate that a value is undefined. Fields can use this value to indicate that their values have not yet been set. Similarly, methods can return this value to indicate that there is no suitable value that the implementation can return. The value used for the constant (currently MIN_VALUE) is intended to avoid confusion between valid values whose sign may not be known.

Constant Value: -2147483648 (0x80000000)

VERTICAL

added in version 25.1.0 
int VERTICAL

The vertical orientation.

Constant Value: 1 (0x00000001)

Fields

BASELINE

added in version 25.1.0 
GridLayout.Alignment BASELINE

Indicates that a view should be aligned with the baselines of the other views in its cell group. This constant may only be used as an alignment in rowSpecs.

See also:

BOTTOM

added in version 25.1.0 
GridLayout.Alignment BOTTOM

Indicates that a view should be aligned with the bottom edges of the other views in its cell group.

CENTER

added in version 25.1.0 
GridLayout.Alignment CENTER

Indicates that a view should be centered with the other views in its cell group. This constant may be used in both rowSpecs and columnSpecs.

END

added in version 25.1.0 
GridLayout.Alignment END

Indicates that a view should be aligned with the end edges of the other views in its cell group.

FILL

added in version 25.1.0 
GridLayout.Alignment FILL

Indicates that a view should expanded to fit the boundaries of its cell group. This constant may be used in both rowSpecs and columnSpecs.

LEFT

added in version 25.1.0 
GridLayout.Alignment LEFT

Indicates that a view should be aligned with the left edges of the other views in its cell group.

added in version 25.1.0 
GridLayout.Alignment RIGHT

Indicates that a view should be aligned with the right edges of the other views in its cell group.

START

added in version 25.1.0 
GridLayout.Alignment START

Indicates that a view should be aligned with the start edges of the other views in its cell group.

TOP

added in version 25.1.0 
GridLayout.Alignment TOP

Indicates that a view should be aligned with the top edges of the other views in its cell group.

Public constructors

GridLayout

added in version 25.1.0
GridLayout (Context context, 
                AttributeSet attrs, 
                int defStyle)

Parameters
context Context

attrs AttributeSet

defStyle int

GridLayout

added in version 25.1.0
GridLayout (Context context, 
                AttributeSet attrs)

Parameters
context Context

attrs AttributeSet

GridLayout

added in version 25.1.0
GridLayout (Context context)

Parameters
context Context

Public methods

generateLayoutParams

added in version 26.1.0
GridLayout.LayoutParams generateLayoutParams (AttributeSet attrs)

Parameters
attrs AttributeSet

Returns
GridLayout.LayoutParams

getAlignmentMode

added in version 25.1.0
int getAlignmentMode ()

Returns the alignment mode.

Returns
int the alignment mode; either ALIGN_BOUNDS or ALIGN_MARGINS

getColumnCount

added in version 25.1.0
int getColumnCount ()

Returns the current number of columns. This is either the last value that was set with setColumnCount(int) or, if no such value was set, the maximum value of each the upper bounds defined in columnSpec.

Returns
int the current number of columns

getOrientation

added in version 25.1.0
int getOrientation ()

Returns the current orientation.

Returns
int either HORIZONTAL or VERTICAL

getPrinter

added in version 25.1.0
Printer getPrinter ()

Return the printer that will log diagnostics from this layout.

Returns
Printer the printer associated with this view

getRowCount

added in version 25.1.0
int getRowCount ()

Returns the current number of rows. This is either the last value that was set with setRowCount(int) or, if no such value was set, the maximum value of each the upper bounds defined in rowSpec.

Returns
int the current number of rows

getUseDefaultMargins

added in version 25.1.0
boolean getUseDefaultMargins ()

Returns whether or not this GridLayout will allocate default margins when no corresponding layout parameters are defined.

Returns
boolean true if default margins should be allocated

isColumnOrderPreserved

added in version 25.1.0
boolean isColumnOrderPreserved ()

Returns whether or not column boundaries are ordered by their grid indices.

Returns
boolean true if column boundaries must appear in the order of their indices, false otherwise

isRowOrderPreserved

added in version 25.1.0
boolean isRowOrderPreserved ()

Returns whether or not row boundaries are ordered by their grid indices.

Returns
boolean true if row boundaries must appear in the order of their indices, false otherwise

requestLayout

void requestLayout ()

setAlignmentMode

added in version 25.1.0
void setAlignmentMode (int alignmentMode)

Sets the alignment mode to be used for all of the alignments between the children of this container.

The default value of this property is ALIGN_MARGINS.

Parameters
alignmentMode int: either ALIGN_BOUNDS or ALIGN_MARGINS

setColumnCount

added in version 25.1.0
void setColumnCount (int columnCount)

ColumnCount is used only to generate default column/column indices when they are not specified by a component's layout parameters.

Parameters
columnCount int: the number of columns.

setColumnOrderPreserved

added in version 25.1.0
void setColumnOrderPreserved (boolean columnOrderPreserved)

When this property is true, GridLayout is forced to place the column boundaries so that their associated grid indices are in ascending order in the view.

When this property is false GridLayout is at liberty to place the horizontal column boundaries in whatever order best fits the given constraints.

The default value of this property is true.

Parameters
columnOrderPreserved boolean: use true to force GridLayout to respect the order of column boundaries.

setOrientation

added in version 25.1.0
void setOrientation (int orientation)

GridLayout uses the orientation property for two purposes:

  • To control the 'direction' in which default row/column indices are generated when they are not specified in a component's layout parameters.
  • To control which axis should be processed first during the layout operation: when orientation is HORIZONTAL the horizontal axis is laid out first.
The order in which axes are laid out is important if, for example, the height of one of GridLayout's children is dependent on its width - and its width is, in turn, dependent on the widths of other components.

If your layout contains a TextView (or derivative: Button, EditText, CheckBox, etc.) which is in multi-line mode (the default) it is normally best to leave GridLayout's orientation as HORIZONTAL - because TextView is capable of deriving its height for a given width, but not the other way around.

Other than the effects above, orientation does not affect the actual layout operation of GridLayout, so it's fine to leave GridLayout in HORIZONTAL mode even if the height of the intended layout greatly exceeds its width.

The default value of this property is HORIZONTAL.

Parameters
orientation int: either HORIZONTAL or VERTICAL

See also:

setPrinter

added in version 25.1.0
void setPrinter (Printer printer)

Set the printer that will log diagnostics from this layout. The default value is created by LogPrinter.

Parameters
printer Printer: the printer associated with this layout

See also:

setRowCount

added in version 25.1.0
void setRowCount (int rowCount)

RowCount is used only to generate default row/column indices when they are not specified by a component's layout parameters.

Parameters
rowCount int: the number of rows

setRowOrderPreserved

added in version 25.1.0
void setRowOrderPreserved (boolean rowOrderPreserved)

When this property is true, GridLayout is forced to place the row boundaries so that their associated grid indices are in ascending order in the view.

When this property is false GridLayout is at liberty to place the vertical row boundaries in whatever order best fits the given constraints.

The default value of this property is true.

Parameters
rowOrderPreserved boolean: true to force GridLayout to respect the order of row boundaries

setUseDefaultMargins

added in version 25.1.0
void setUseDefaultMargins (boolean useDefaultMargins)

When true, GridLayout allocates default margins around children based on the child's visual characteristics. Each of the margins so defined may be independently overridden by an assignment to the appropriate layout parameter.

When false, the default value of all margins is zero.

When setting to true, consider setting the value of the alignmentMode property to ALIGN_BOUNDS.

The default value of this property is false.

Parameters
useDefaultMargins boolean: use true to make GridLayout allocate default margins

spec

added in version 25.1.0
GridLayout.Spec spec (int start, 
                float weight)

Equivalent to: spec(start, 1, weight).

Parameters
start int: the start
weight float: the weight

Returns
GridLayout.Spec

spec

added in version 25.1.0
GridLayout.Spec spec (int start, 
                int size, 
                GridLayout.Alignment alignment)

Equivalent to: spec(start, size, alignment, 0f).

Parameters
start int: the start
size int: the size
alignment GridLayout.Alignment: the alignment

Returns
GridLayout.Spec

spec

added in version 25.1.0
GridLayout.Spec spec (int start, 
                GridLayout.Alignment alignment)

Return a Spec, spec, where:

  • spec.span = [start, start + 1]
  • spec.alignment = alignment

To leave the start index undefined, use the value UNDEFINED.

Parameters
start int: the start index
alignment GridLayout.Alignment: the alignment
Returns
GridLayout.Spec

spec

added in version 25.1.0
GridLayout.Spec spec (int start)

Return a Spec, spec, where:

  • spec.span = [start, start + 1]

To leave the start index undefined, use the value UNDEFINED.

Parameters
start int: the start index
Returns
GridLayout.Spec

See also:

spec

added in version 25.1.0
GridLayout.Spec spec (int start, 
                int size, 
                GridLayout.Alignment alignment, 
                float weight)

Return a Spec, spec, where:

  • spec.span = [start, start + size]
  • spec.alignment = alignment
  • spec.weight = weight

To leave the start index undefined, use the value UNDEFINED.

Parameters
start int: the start
size int: the size
alignment GridLayout.Alignment: the alignment
weight float: the weight

Returns
GridLayout.Spec

spec

added in version 25.1.0
GridLayout.Spec spec (int start, 
                int size, 
                float weight)

Equivalent to: spec(start, 1, default_alignment, weight) - where default_alignment is specified in GridLayout.LayoutParams.

Parameters
start int: the start
size int: the size
weight float: the weight

Returns
GridLayout.Spec

spec

added in version 25.1.0
GridLayout.Spec spec (int start, 
                int size)

Return a Spec, spec, where:

  • spec.span = [start, start + size]

To leave the start index undefined, use the value UNDEFINED.

Parameters
start int: the start
size int: the size
Returns
GridLayout.Spec

spec

added in version 25.1.0
GridLayout.Spec spec (int start, 
                GridLayout.Alignment alignment, 
                float weight)

Equivalent to: spec(start, 1, alignment, weight).

Parameters
start int: the start
alignment GridLayout.Alignment: the alignment
weight float: the weight

Returns
GridLayout.Spec

Protected methods

checkLayoutParams

boolean checkLayoutParams (ViewGroup.LayoutParams p)

Parameters
p ViewGroup.LayoutParams

Returns
boolean

generateDefaultLayoutParams

added in version 26.1.0
GridLayout.LayoutParams generateDefaultLayoutParams ()

Returns
GridLayout.LayoutParams

generateLayoutParams

added in version 26.1.0
GridLayout.LayoutParams generateLayoutParams (ViewGroup.LayoutParams lp)

Parameters
lp ViewGroup.LayoutParams

Returns
GridLayout.LayoutParams

onLayout

added in version 25.1.0
void onLayout (boolean changed, 
                int left, 
                int top, 
                int right, 
                int bottom)

Parameters
changed boolean

left int

top int

right int

bottom int

onMeasure

void onMeasure (int widthSpec, 
                int heightSpec)

Parameters
widthSpec int

heightSpec int