MarginLayoutParamsCompat.java
/*
* Copyright 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.core.view;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
/**
* Helper for accessing API features in
* {@link ViewGroup.MarginLayoutParams MarginLayoutParams} in a backwards compatible
* way.
*/
public final class MarginLayoutParamsCompat {
/**
* Get the relative starting margin that was set.
*
* <p>On platform versions supporting bidirectional text and layouts
* this value will be resolved into the LayoutParams object's left or right
* margin as appropriate when the associated View is attached to a window
* or when the layout direction of that view changes.</p>
*
* @param lp LayoutParams to query
* @return the margin along the starting edge in pixels
*/
public static int getMarginStart(@NonNull ViewGroup.MarginLayoutParams lp) {
return lp.getMarginStart();
}
/**
* Get the relative ending margin that was set.
*
* <p>On platform versions supporting bidirectional text and layouts
* this value will be resolved into the LayoutParams object's left or right
* margin as appropriate when the associated View is attached to a window
* or when the layout direction of that view changes.</p>
*
* @param lp LayoutParams to query
* @return the margin along the ending edge in pixels
*/
public static int getMarginEnd(@NonNull ViewGroup.MarginLayoutParams lp) {
return lp.getMarginEnd();
}
/**
* Set the relative start margin.
*
* <p>On platform versions supporting bidirectional text and layouts
* this value will be resolved into the LayoutParams object's left or right
* margin as appropriate when the associated View is attached to a window
* or when the layout direction of that view changes.</p>
*
* @param lp LayoutParams to query
* @param marginStart the desired start margin in pixels
*/
public static void setMarginStart(@NonNull ViewGroup.MarginLayoutParams lp, int marginStart) {
lp.setMarginStart(marginStart);
}
/**
* Set the relative end margin.
*
* <p>On platform versions supporting bidirectional text and layouts
* this value will be resolved into the LayoutParams object's left or right
* margin as appropriate when the associated View is attached to a window
* or when the layout direction of that view changes.</p>
*
* @param lp LayoutParams to query
* @param marginEnd the desired end margin in pixels
*/
public static void setMarginEnd(@NonNull ViewGroup.MarginLayoutParams lp, int marginEnd) {
lp.setMarginEnd(marginEnd);
}
/**
* Check if margins are relative.
*
* @return true if either marginStart or marginEnd has been set.
*/
public static boolean isMarginRelative(@NonNull ViewGroup.MarginLayoutParams lp) {
return lp.isMarginRelative();
}
/**
* Returns the layout direction. Can be either {@link ViewCompat#LAYOUT_DIRECTION_LTR} or
* {@link ViewCompat#LAYOUT_DIRECTION_RTL}.
*
* @return the layout direction.
*/
public static int getLayoutDirection(@NonNull ViewGroup.MarginLayoutParams lp) {
int result;
result = lp.getLayoutDirection();
if ((result != View.LAYOUT_DIRECTION_LTR)
&& (result != View.LAYOUT_DIRECTION_RTL)) {
// This can happen on older platform releases where the default (unset) layout direction
// is -1
result = View.LAYOUT_DIRECTION_LTR;
}
return result;
}
/**
* Set the layout direction.
*
* @param lp LayoutParameters for which to set the layout direction.
* @param layoutDirection the layout direction.
* Should be either {@link ViewCompat#LAYOUT_DIRECTION_LTR}
* or {@link ViewCompat#LAYOUT_DIRECTION_RTL}.
*/
public static void setLayoutDirection(@NonNull ViewGroup.MarginLayoutParams lp,
int layoutDirection) {
lp.setLayoutDirection(layoutDirection);
}
/**
* This will be called by {@link View#requestLayout()}. Left and Right margins
* may be overridden depending on layout direction.
*/
public static void resolveLayoutDirection(@NonNull ViewGroup.MarginLayoutParams lp,
int layoutDirection) {
lp.resolveLayoutDirection(layoutDirection);
}
private MarginLayoutParamsCompat() {
}
}