ViewGroupUtils.java
/*
* Copyright (C) 2016 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.transition;
import android.annotation.SuppressLint;
import android.os.Build;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
* Compatibility utilities for platform features of {@link ViewGroup}.
*/
class ViewGroupUtils {
/**
* False when linking of the hidden suppressLayout method has previously failed.
*/
private static boolean sTryHiddenSuppressLayout = true;
private static Method sGetChildDrawingOrderMethod;
private static boolean sGetChildDrawingOrderMethodFetched;
/**
* Backward-compatible {@link ViewGroup#getOverlay()}.
*/
static ViewGroupOverlayImpl getOverlay(@NonNull ViewGroup group) {
if (Build.VERSION.SDK_INT >= 18) {
return new ViewGroupOverlayApi18(group);
}
return ViewGroupOverlayApi14.createFrom(group);
}
/**
* Provides access to the hidden ViewGroup#suppressLayout method.
*/
static void suppressLayout(@NonNull ViewGroup group, boolean suppress) {
if (Build.VERSION.SDK_INT >= 29) {
group.suppressLayout(suppress);
} else if (Build.VERSION.SDK_INT >= 18) {
hiddenSuppressLayout(group, suppress);
} else {
ViewGroupUtilsApi14.suppressLayout(group, suppress);
}
}
@RequiresApi(18)
@SuppressLint("NewApi") // Lint doesn't know about the hidden method.
private static void hiddenSuppressLayout(@NonNull ViewGroup group, boolean suppress) {
if (sTryHiddenSuppressLayout) {
// Since this was an @hide method made public, we can link directly against it with
// a try/catch for its absence instead of doing the same through reflection.
try {
group.suppressLayout(suppress);
} catch (NoSuchMethodError e) {
sTryHiddenSuppressLayout = false;
}
}
}
/**
* Returns the index of the child to draw for this iteration.
*/
static int getChildDrawingOrder(@NonNull ViewGroup viewGroup, int i) {
if (Build.VERSION.SDK_INT >= 29) {
return viewGroup.getChildDrawingOrder(i);
} else {
if (!sGetChildDrawingOrderMethodFetched) {
try {
sGetChildDrawingOrderMethod = ViewGroup.class.getDeclaredMethod(
"getChildDrawingOrder", int.class, int.class);
sGetChildDrawingOrderMethod.setAccessible(true);
} catch (NoSuchMethodException ignore) {
}
sGetChildDrawingOrderMethodFetched = true;
}
if (sGetChildDrawingOrderMethod != null) {
try {
return (Integer) sGetChildDrawingOrderMethod.invoke(viewGroup,
viewGroup.getChildCount(), i);
} catch (IllegalAccessException ignore) {
} catch (InvocationTargetException ignore) {
}
}
// fallback implementation
return i;
}
}
private ViewGroupUtils() {
}
}