public class Guideline extends View


Utility class representing a Guideline helper object for ConstraintLayout. Helper objects are not displayed on device (they are marked as View.GONE) and are only used for layout purposes. They only work within a ConstraintLayout.

A Guideline can be either horizontal or vertical:

  • Vertical Guidelines have a width of zero and the height of their ConstraintLayout parent
  • Horizontal Guidelines have a height of zero and the width of their ConstraintLayout parent

Positioning a Guideline is possible in three different ways:

  • specifying a fixed distance from the left or the top of a layout (layout_constraintGuide_begin)
  • specifying a fixed distance from the right or the bottom of a layout (layout_constraintGuide_end)
  • specifying a percentage of the width or the height of a layout (layout_constraintGuide_percent)

Widgets can then be constrained to a Guideline, allowing multiple widgets to be positioned easily from one Guideline, or allowing reactive layout behavior by using percent positioning.

See the list of attributes in androidx.constraintlayout.widget.ConstraintLayout.LayoutParams to set a Guideline in XML, as well as the corresponding setGuidelineBegin, setGuidelineEnd and setGuidelinePercent functions in ConstraintSet.

Example of a Button constrained to a vertical Guideline:

         <androidx.constraintlayout.widget.ConstraintLayout
             xmlns:android="http://schemas.android.com/apk/res/android"
             xmlns:app="http://schemas.android.com/apk/res-auto"
             xmlns:tools="http://schemas.android.com/tools"
             android:layout_width="match_parent"
             android:layout_height="match_parent">

             <androidx.constraintlayout.widget.Guideline
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:id="@+id/guideline"
                 app:layout_constraintGuide_begin="100dp"
                 android:orientation="vertical"/>
             <Button
                 android:text="Button"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:id="@+id/button"
                 app:layout_constraintLeft_toLeftOf="@+id/guideline"
                 android:layout_marginTop="16dp"
                 app:layout_constraintTop_toTopOf="parent" />
         </androidx.constraintlayout.widget.ConstraintLayout>
       

Summary

Public constructors

Guideline(Context context)
Guideline(Context context, AttributeSet attrs)
Guideline(Context context, AttributeSet attrs, int defStyleAttr)
Guideline(
    Context context,
    AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Public methods

void
draw(@NonNull Canvas canvas)

We are overriding draw and not calling super.draw() here because Helper objects are not displayed on device.

void
setFilterRedundantCalls(boolean filter)

filter redundant calls to setGuidelineBegin, setGuidelineEnd &setGuidelinePercent.

void
setGuidelineBegin(int margin)

Set the guideline's distance from the top or left edge.

void
setGuidelineEnd(int margin)

Set a guideline's distance to end.

void
setGuidelinePercent(float ratio)

Set a Guideline's percent.

void
setVisibility(int visibility)

Protected methods

void
onMeasure(int widthMeasureSpec, int heightMeasureSpec)

Inherited Constants

From android.view.View
static final int
static final int
static final int
static final int
static final int
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static final Property<ViewFloat>
static final int
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DATE = "creditCardExpirationDate"
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_DAY = "creditCardExpirationDay"
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_MONTH = "creditCardExpirationMonth"
static final String
AUTOFILL_HINT_CREDIT_CARD_EXPIRATION_YEAR = "creditCardExpirationYear"
static final String
static final String
AUTOFILL_HINT_CREDIT_CARD_SECURITY_CODE = "creditCardSecurityCode"
static final String
static final String
static final String
static final String
static final String
static final String
static final String
static final int
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static final int
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static final int[]
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static final int
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static final int[]
static final int
static final int
static final int
static final int
static final int
static final int
static final int
GONE = 8
static final int
static final int
static final int
static final int
static final int
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static final int
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static final int
static final int
static final int
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static final int
static final int
KEEP_SCREEN_ON = 67108864
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
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static final int
NO_ID = -1
static final int
static final int
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static final int[]
static final int[]
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static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final int[]
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
static final int
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static final int
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static final int
static final int
static final int
static final int
static final int
static final int
static final int[]
static final int[]
static final int
static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int

This field is deprecated.

static final int
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static final int
static final int
static final int
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static final int
static final int
static final int
static final int
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>
static final String
VIEW_LOG_TAG = "View"
static final int
static final int[]
static final Property<ViewFloat>
static final Property<ViewFloat>
static final Property<ViewFloat>

Inherited methods

From android.view.View
void
void
addExtraDataToAccessibilityNodeInfo(
    AccessibilityNodeInfo info,
    String extraDataKey,
    Bundle arguments
)
void
addFocusables(ArrayList<View> views, int direction)
void
void
void
void
void
ViewPropertyAnimator
void
void
boolean
void
void

This method is deprecated.

void
boolean
boolean
boolean
boolean
boolean
canScrollHorizontally(int direction)
boolean
canScrollVertically(int direction)
final void
void
final void
boolean
void
void
void
static int
combineMeasuredStates(int curState, int newState)
int
int
int
void
WindowInsets
int
int
int
AccessibilityNodeInfo
void
void

This method is deprecated.

WindowInsets
boolean
void
void
dispatchCreateViewTranslationRequest(
    Map<AutofillId, long[]> viewIds,
    int[] supportedFormats,
    TranslationCapability capability,
    List<ViewTranslationRequest> requests
)
void
boolean
void
void
dispatchDrawableHotspotChanged(float x, float y)
void
boolean
boolean
boolean
boolean
boolean
boolean
boolean
boolean
dispatchNestedFling(float velocityX, float velocityY, boolean consumed)
boolean
dispatchNestedPreFling(float velocityX, float velocityY)
boolean
dispatchNestedPrePerformAccessibilityAction(
    int action,
    Bundle arguments
)
boolean
dispatchNestedPreScroll(
    int dx,
    int dy,
    int[] consumed,
    int[] offsetInWindow
)
boolean
dispatchNestedScroll(
    int dxConsumed,
    int dyConsumed,
    int dxUnconsumed,
    int dyUnconsumed,
    int[] offsetInWindow
)
void
dispatchPointerCaptureChanged(boolean hasCapture)
boolean
void
void
void
void
void
dispatchScrollCaptureSearch(
    Rect localVisibleRect,
    Point windowOffset,
    Consumer<ScrollCaptureTarget> targets
)
void
dispatchSetActivated(boolean activated)
void
dispatchSetPressed(boolean pressed)
void
dispatchSetSelected(boolean selected)
void
void

This method is deprecated.

boolean
boolean
boolean
dispatchUnhandledMove(View focused, int direction)
void
dispatchVisibilityChanged(View changedView, int visibility)
void
dispatchWindowFocusChanged(boolean hasFocus)
void
void
WindowInsets
WindowInsetsAnimation.Bounds
void

This method is deprecated.

void
void
drawableHotspotChanged(float x, float y)
void
View
final OnBackInvokedDispatcher
final T
<T extends View> findViewById(int id)
final T
<T extends View> findViewWithTag(Object tag)
void
findViewsWithText(
    ArrayList<View> outViews,
    CharSequence searched,
    int flags
)
boolean

This method is deprecated.

View
focusSearch(int direction)
void
forceHasOverlappingRendering(boolean hasOverlappingRendering)
void
boolean
void
generateDisplayHash(
    String hashAlgorithm,
    Rect bounds,
    Executor executor,
    DisplayHashResultCallback callback
)
static int
CharSequence
View.AccessibilityDelegate
int
AccessibilityNodeProvider
CharSequence
int
int
String
String
float
Animation
Matrix
IBinder
int[]
Map<IntegerInteger>
String[]
final AutofillId
int
AutofillValue
Drawable
BlendMode
ColorStateList
PorterDuff.Mode
int
final int
float
int
float
Rect
boolean
final boolean
final ContentCaptureSession
CharSequence
final Context
ContextMenu.ContextMenuInfo
final boolean
static int
getDefaultSize(int size, int measureSpec)
Display
final int[]
Bitmap

This method is deprecated.

int

This method is deprecated.

int

This method is deprecated.

void
long
float
int
boolean
boolean
int
ArrayList<View>
getFocusables(int direction)
void
Drawable
int
BlendMode
ColorStateList
PorterDuff.Mode
boolean
getGlobalVisibleRect(Rect r, Point globalOffset)
Handler
float
float
float
float
Runnable
final boolean
final int
void
getHitRect(Rect outRect)
int
int
Drawable
Drawable
int
int
int
int
boolean
KeyEvent.DispatcherState
int
int
int