JSONConstraintSet.kt
/*
* Copyright (C) 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.constraintlayout.compose
import androidx.compose.ui.layout.Measurable
import androidx.constraintlayout.core.parser.CLKey
import androidx.constraintlayout.core.parser.CLParser
import androidx.constraintlayout.core.parser.CLParsingException
import androidx.constraintlayout.core.state.ConstraintSetParser
import androidx.constraintlayout.core.state.Transition
import org.intellij.lang.annotations.Language
internal class JSONConstraintSet(
@Language("json5") content: String,
@Language("json5") overrideVariables: String? = null,
override val extendFrom: ConstraintSet? = null
) : EditableJSONLayout(content), DerivedConstraintSet {
private val overridedVariables = HashMap<String, Float>()
private val overrideVariables = overrideVariables
private var _isDirty = true
init {
initialization()
}
override fun equals(other: Any?): Boolean {
if (other is JSONConstraintSet) {
return this.getCurrentContent() == other.getCurrentContent()
}
return false
}
override fun isDirty(measurables: List<Measurable>): Boolean {
return _isDirty
}
// Only called by MotionLayout in MotionMeasurer
override fun applyTo(transition: Transition, type: Int) {
val layoutVariables = ConstraintSetParser.LayoutVariables()
applyLayoutVariables(layoutVariables)
ConstraintSetParser.parseJSON(getCurrentContent(), transition, type)
}
fun emitDesignElements(designElements: ArrayList<ConstraintSetParser.DesignElement>) {
try {
designElements.clear()
ConstraintSetParser.parseDesignElementsJSON(getCurrentContent(), designElements)
} catch (e: Exception) {
// nothing (content might be invalid, sent by live edit)
}
}
// Called by both MotionLayout & ConstraintLayout measurers
override fun applyToState(state: State) {
val layoutVariables = ConstraintSetParser.LayoutVariables()
applyLayoutVariables(layoutVariables)
// TODO: Need to better handle half parsed JSON and/or incorrect states.
try {
ConstraintSetParser.parseJSON(getCurrentContent(), state, layoutVariables)
_isDirty = false
} catch (e: Exception) {
// nothing (content might be invalid, sent by live edit)
_isDirty = true
}
}
override fun onNewContent(content: String) {
super.onNewContent(content)
_isDirty = true
}
override fun override(name: String, value: Float): ConstraintSet {
overridedVariables[name] = value
return this
}
private fun applyLayoutVariables(layoutVariables: ConstraintSetParser.LayoutVariables) {
if (overrideVariables != null) {
try {
val variables = CLParser.parse(overrideVariables)
for (i in 0 until variables.size()) {
val key = variables[i] as CLKey
val variable = key.value.float
// TODO: allow arbitrary override, not just float values
layoutVariables.putOverride(key.content(), variable)
}
} catch (e: CLParsingException) {
System.err.println("exception: " + e)
}
}
for (name in overridedVariables.keys) {
layoutVariables.putOverride(name, overridedVariables[name]!!)
}
}
}