CanvasUtils.java
/*
* Copyright 2019 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.graphics.Canvas;
import android.os.Build;
import androidx.annotation.NonNull;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
class CanvasUtils {
private static Method sReorderBarrierMethod;
private static Method sInorderBarrierMethod;
private static boolean sOrderMethodsFetched;
/**
* Enables Z support for the Canvas.
*
* IMPORTANT: This method doesn't work on Pie! It will thrown an exception instead
*/
@SuppressLint("SoonBlockedPrivateApi")
static void enableZ(@NonNull Canvas canvas, boolean enable) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
// no shadows yet added into a platform
} else if (Build.VERSION.SDK_INT >= 29) {
if (enable) {
canvas.enableZ();
} else {
canvas.disableZ();
}
} else if (Build.VERSION.SDK_INT == Build.VERSION_CODES.P) {
// not on P's greylist, can't use reflection
throw new IllegalStateException("This method doesn't work on Pie!");
} else {
if (!sOrderMethodsFetched) {
try {
sReorderBarrierMethod = Canvas.class.getDeclaredMethod(
"insertReorderBarrier");
sReorderBarrierMethod.setAccessible(true);
sInorderBarrierMethod = Canvas.class.getDeclaredMethod(
"insertInorderBarrier");
sInorderBarrierMethod.setAccessible(true);
} catch (NoSuchMethodException ignore) {
// Do nothing
}
sOrderMethodsFetched = true;
}
try {
if (enable && sReorderBarrierMethod != null) {
sReorderBarrierMethod.invoke(canvas);
}
if (!enable && sInorderBarrierMethod != null) {
sInorderBarrierMethod.invoke(canvas);
}
} catch (IllegalAccessException ignore) {
// Do nothing
} catch (InvocationTargetException e) {
throw new RuntimeException(e.getCause());
}
}
}
private CanvasUtils() {
}
}