“ 'onSensorChanged' 不覆盖任何内容” 错误

Question

我正在尝试从 SensorManager 获取值。我从 Android API 复制了代码。但是问题出现了。请看代码。我正在研究陀螺仪传感器。我想检查陀螺仪值和结果。我在这个网站上找到了代码 " https://developer.android.com/guide/topics/sensors/sensors_motion#sensors-motion-gyro "

我在 override fun onSensorChanged（事件：SensorEvent？）它说“'onSensorChanged' 什么都不覆盖”

 class MainActivity : AppCompatActivity() {
    
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)
        }
    
    
        // Create a constant to convert nanoseconds to seconds.
        private val NS2S = 1.0f / 1000000000.0f
        private val deltaRotationVector = FloatArray(4) { 0f }
        private var timestamp: Float = 0f
    
    
    
         override fun onSensorChanged(event: SensorEvent?) {
            // This timestep's delta rotation to be multiplied by the current rotation
            // after computing it from the gyro sample data.
            if (timestamp != 0f && event != null) {
                val dT = (event.timestamp - timestamp) * NS2S
                // Axis of the rotation sample, not normalized yet.
                var axisX: Float = event.values[0]
                var axisY: Float = event.values[1]
                var axisZ: Float = event.values[2]
    
                // Calculate the angular speed of the sample
                val omegaMagnitude: Float = sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ)
    
                // Normalize the rotation vector if it's big enough to get the axis`enter code here`
                // (that is, EPSILON should represent your maximum allowable margin of error)
                if (omegaMagnitude > EPSILON) {
                    axisX /= omegaMagnitude
                    axisY /= omegaMagnitude
                    axisZ /= omegaMagnitude
                }
    
                // Integrate around this axis with the angular speed by the timestep
                // in order to get a delta rotation from this sample over the timestep
                // We will convert this axis-angle representation of the delta rotation
                // into a quaternion before turning it into the rotation matrix.
    
                val thetaOverTwo: Float = omegaMagnitude * dT / 2.0f
                val sinThetaOverTwo: Float = sin(thetaOverTwo).toFloat()
                val cosThetaOverTwo: Float = cos(thetaOverTwo).toFloat()
    
                deltaRotationVector[0] = sinThetaOverTwo * axisX
                deltaRotationVector[1] = sinThetaOverTwo * axisY
                deltaRotationVector[2] = sinThetaOverTwo * axisZ
                deltaRotationVector[3] = cosThetaOverTwo
    
                Log.d("DENEME", "onSensorChanged: " + axisX)
    
                Log.d("DENEME", "onSensorChanged: " + axisY)
    
                Log.d("DENEME", "onSensorChanged: " + axisZ)
            }
    
            timestamp = event?.timestamp?.toFloat() ?: 0f
            val deltaRotationMatrix = FloatArray(9) { 0f }
            SensorManager.getRotationMatrixFromVector(deltaRotationMatrix, deltaRotationVector);
    
            // User code should concatenate the delta rotation we computed with the current rotation
            // in order to get the updated rotation.
            // rotationCurrent = rotationCurrent * deltaRotationMatrix;
        }
    
        fun onClickDevam(view: View) // click event button to check values
        {      
            val sensorManager = getSystemService(Context.SENSOR_SERVICE) as SensorManager
            val sensor: Sensor? = sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE)
        }
    }

Answer 1

Kotlin 中的 override 关键字表明 class 是从超 class 或接口继承函数。 Android 文档似乎缺少一个非常重要的步骤，即让您的 activity class 实现 SensorEventListener 接口。

为此，请将您的 MainActivity 声明更改为如下内容：

class MainActivity : AppCompatActivity(), SensorEventListener {

SensorEventListener 包含您正在谈论的 onSensorChanged 函数。它还将要求您覆盖一个附加函数 onAccuracyChanged，因此您也需要这样做（但如果您真的不关心精度变化，您可以将函数的主体留空 - 您只需要覆盖它以满足接口）。

Android Studio 有一个方便的快捷方式，可以自动覆盖界面中的函数，您可能会发现它很有用：Ctrl+O

“ 'onSensorChanged' 不覆盖任何内容” 错误

" 'onSensorChanged' overrides nothing " Fault

android

gyroscope

android-sensors

kotlin