英文:
Unresolved reference in Kotlin using JNI-Bridge
问题
我想在Kotlin的可组合函数中调用startOsc()函数，但出现了这个错误：Unresolved reference: startOsc
这是我的Kotlin代码：
class MainActivity : ComponentActivity() {
private external fun startEngine()
private external fun stopEngine()
private external fun startOsc() // <-- 这里定义了函数
companion object {
init {
System.loadLibrary("pitch_andoid")
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
TwoNotesView()
}
startEngine()
}
override fun onDestroy() {
super.onDestroy()
stopEngine()
}
}
@Composable
fun TwoNotesView() {
Column(
modifier = Modifier
.fillMaxSize()
.background(colorResource(id = R.color.cyan))
) {
Row {
Box (
modifier = Modifier
.clickable {
startOsc() // <-- 这是错误的那一行
}
) {
AnswerButton(ImageSource = R.drawable.round_replay_24_cyan) // 这是其他可组合部分，我为简单起见省略了
}
}
}
}
CMakeLists.txt可能是正确的，因为startEngine()和stopEngine()没有未解决的引用。这是startOsc()函数的jni-bridge.cpp代码：
JNIEXPORT void JNICALL
Java_com_example_pitch_1andoid_MainActivity_startOsc(JNIEnv *env, jobject/* this */) {
audioEngine->setToneOn(true);
}
我拼写错误了项目的名称，这就是为什么所有东西都叫做"andoid"而不是"android"。抱歉。
编辑：错误应该是将函数从MainActivity传递到可组合函数中。我尝试在MainActivity中调用函数，并没有出错。
英文:
I want to call the startOsc()function inside of a Composable in Kotlin and get this error: Unresolved reference: startOsc
This is my Kotlin code:
class MainActivity : ComponentActivity() {
private external fun startEngine()
private external fun stopEngine()
private external fun startOsc() // <-- here the function is defined
companion object {
init {
System.loadLibrary("pitch_andoid")
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
TwoNotesView()
}
startEngine()
}
override fun onDestroy() {
super.onDestroy()
stopEngine()
}
}
@Composable
fun TwoNotesView() {
Column(
modifier = Modifier
.fillMaxSize()
.background(colorResource(id = R.color.cyan))
) {
Row {
Box (
modifier = Modifier
.clickable {
startOsc() // <-- this is the line of the error
}
) {
AnswerButton(ImageSource = R.drawable.round_replay_24_cyan) // this is some other composable I left out for simplicity
}
}
}
}
The CMakeLists.txt is probably correct, since there is no Unresolved Reference for startEngine() and stopEngine().
Here is the code of the jni-bridge.cpp for the startOsc()function:
JNIEXPORT void JNICALL
Java_com_example_pitch_1andoid_MainActivity_startOsc(JNIEnv *env, jobject/* this */) {
audioEngine->setToneOn(true);
}
I made a spelling mistake naming the project, that's why everything is called "andoid" instead of "android", Sorry.
edit: the error has to be passing down the function from MainActivity to the Composable. I tried calling the function inside MainActivity and got no error.
答案1
得分: 0
通过以下方式传递 startOsc() 来解决这个问题：
class MainActivity : ComponentActivity() {
private external fun startEngine()
private external fun stopEngine()
external fun startOsc() // <-- 删除 'private'
companion object {
init {
System.loadLibrary("pitch_andoid")
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
TwoNotesView(::startOsc) // <-- 作为参数传递 startOsc()
}
startEngine()
}
override fun onDestroy() {
super.onDestroy()
stopEngine()
}
}
@Composable
fun TwoNotesView(startOsc: () -> Unit) { // <-- 添加 startOsc() 作为参数
Column(
modifier = Modifier
.fillMaxSize()
.background(colorResource(id = R.color.cyan))
) {
Row {
Box (
modifier = Modifier
.clickable {
startOsc()
}
) {
AnswerButton(ImageSource = R.drawable.round_replay_24_cyan) // 这是我为简单起见略去的另一个可组合部分
}
}
}
}
英文:
Solved it by passing down startOsc() like this:
class MainActivity : ComponentActivity() {
private external fun startEngine()
private external fun stopEngine()
external fun startOsc() // <-- deleted 'private'
companion object {
init {
System.loadLibrary("pitch_andoid")
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
TwoNotesView(::startOsc) // <-- pass down startOsc() as parameter
}
startEngine()
}
override fun onDestroy() {
super.onDestroy()
stopEngine()
}
}
@Composable
fun TwoNotesView(startOsc: () -> Unit) { // <-- add startOsc() as parameter
Column(
modifier = Modifier
.fillMaxSize()
.background(colorResource(id = R.color.cyan))
) {
Row {
Box (
modifier = Modifier
.clickable {
startOsc()
}
) {
AnswerButton(ImageSource = R.drawable.round_replay_24_cyan) // this is some other composable I left out for simplicity
}
}
}
}
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