Helper.java
/*
* Copyright 2021 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.wear.protolayout.material;
import static androidx.wear.protolayout.DimensionBuilders.dp;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;
import androidx.annotation.RestrictTo.Scope;
import androidx.wear.protolayout.DeviceParametersBuilders;
import androidx.wear.protolayout.DeviceParametersBuilders.DeviceParameters;
import androidx.wear.protolayout.DimensionBuilders.DpProp;
import androidx.wear.protolayout.ModifiersBuilders.ElementMetadata;
import androidx.wear.protolayout.ModifiersBuilders.Modifiers;
import androidx.wear.protolayout.TypeBuilders.StringProp;
import androidx.wear.protolayout.TypeBuilders.FloatProp;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Collection;
/**
* Helper class used for ProtoLayout Material.
*
*/
@RestrictTo(Scope.LIBRARY_GROUP)
public class Helper {
private Helper() {}
/**
* Returns given value if not null or throws {@code NullPointerException} otherwise.
*
*/
@RestrictTo(Scope.LIBRARY_GROUP)
@NonNull
public static <T> T checkNotNull(@Nullable T value) {
if (value == null) {
throw new NullPointerException();
}
return value;
}
/** Returns radius in {@link DpProp} of the given diameter. */
@NonNull
static DpProp radiusOf(DpProp diameter) {
return dp(diameter.getValue() / 2);
}
/**
* Returns true if the given DeviceParameters belong to the round screen device.
*
*/
@RestrictTo(Scope.LIBRARY_GROUP)
public static boolean isRoundDevice(@NonNull DeviceParameters deviceParameters) {
return deviceParameters.getScreenShape() == DeviceParametersBuilders.SCREEN_SHAPE_ROUND;
}
/**
* Returns String representation of tag from byte array.
*
*/
@RestrictTo(Scope.LIBRARY_GROUP)
@NonNull
public static String getTagName(@NonNull byte[] tagData) {
return new String(tagData, StandardCharsets.UTF_8);
}
/**
* Returns byte array representation of tag from String.
*
*/
@RestrictTo(Scope.LIBRARY_GROUP)
@NonNull
public static byte[] getTagBytes(@NonNull String tagName) {
return tagName.getBytes(StandardCharsets.UTF_8);
}
/** Returns the String representation of metadata tag from the given ElementMetadata. */
@NonNull
public static String getMetadataTagName(@NonNull ElementMetadata metadata) {
return getTagName(getMetadataTagBytes(metadata));
}
/** Returns the metadata tag from the given ElementMetadata. */
@NonNull
public static byte[] getMetadataTagBytes(@NonNull ElementMetadata metadata) {
return checkNotNull(metadata).getTagData();
}
/** Returns true if the given Modifiers have Metadata tag set to the given String value. */
public static boolean checkTag(@Nullable Modifiers modifiers, @NonNull String validTag) {
return modifiers != null
&& modifiers.getMetadata() != null
&& validTag.equals(getMetadataTagName(modifiers.getMetadata()));
}
/**
* Returns true if the given Modifiers have Metadata tag set to any of the value in the given
* String collection.
*/
public static boolean checkTag(
@Nullable Modifiers modifiers, @NonNull Collection<String> validTags) {
return modifiers != null
&& modifiers.getMetadata() != null
&& validTags.contains(getMetadataTagName(modifiers.getMetadata()));
}
/**
* Returns true if the given Modifiers have Metadata tag set with prefix that is equal to the
* given String and its length is of the given base array.
*/
public static boolean checkTag(
@Nullable Modifiers modifiers, @NonNull String validPrefix, @NonNull byte[] validBase) {
if (modifiers == null || modifiers.getMetadata() == null) {
return false;
}
byte[] metadataTag = getMetadataTagBytes(modifiers.getMetadata());
byte[] tag = Arrays.copyOf(metadataTag, validPrefix.length());
return metadataTag.length == validBase.length && validPrefix.equals(getTagName(tag));
}
/**
* Returns a {@link StringProp} for the given string value.
*/
@NonNull
public static StringProp staticString(@NonNull String value) {
return new StringProp.Builder(value).build();
}
/**
* Returns a {@link FloatProp} for the given float value.
*/
@NonNull
public static FloatProp staticFloat(float staticValue) {
return new FloatProp.Builder(staticValue).build();
}
}