Question

我是java的新手，我想如何返回并显示多个值。

这是我的代码。

MainActivity.java

private void updatePressureValue(BluetoothGattCharacteristic characteristic) {

    if (mPressureCals == null) 
        return;
     double pressure = SensorTagData.extractBarometer(characteristic, mPressureCals);
     double temp = SensorTagData.extractBarTemperature(characteristic, mPressureCals);

    mTemperature.setText(String.format("%.1f\u00B0C", temp));
    mPressure.setText(String.format("%.2f", pressure));
}

private void updateAccelerometerValue(BluetoothGattCharacteristic characteristic ){

    double accelerometerx = SensorTagData.extractAccelerometer(characteristic, mAccelerometerx);
    double accelerometery = SensorTagData.extractAccelerometer(characteristic, mAccelerometery);
    double accelerometerz = SensorTagData.extractAccelerometer(characteristic, mAccelerometerz);

    mAccelerometerx.setText(String.format("%.4f", accelerometerx));
    mAccelerometery.setText(String.format("%.4f", accelerometery));
    mAccelerometerz.setText(String.format("%.4f", accelerometerz));
}
}

SensorData.java

public class SensorData {

public static double extractHumAmbientTemperature(BluetoothGattCharacteristic c) {
    int rawT = shortSignedAtOffset(c, 0);

    return -46.85 + 175.72/65536 *(double)rawT;
}

public static double extractAccelerometer(BluetoothGattCharacteristic c) {

    Integer x = c.getIntValue(FORMAT_SINT8, 0);
    Integer y = c.getIntValue(FORMAT_SINT8, 1);
    Integer z = c.getIntValue(FORMAT_SINT8, 2) * -1;

    double scaledX = x / 64.0;
    double scaledY = y / 64.0;
    double scaledZ = z / 64.0;

    return scaledX; scaledY; scaledZ ;
}

我从互联网上获取了代码，只显示了传感器的值，我想添加加速度计，但是鼻子如何。有人能帮助我吗？

感谢。

Answer 1

Java中没有元组表面上容易让你这么做。与此相伴，函数参数没有参考传递。

在Java中执行此操作的常规方法是创建一个包含与返回值相关的字段的类，并返回该类的实例。这是一种深思熟虑的语言设计选择：返回类实例往往会产生良好的可维护代码。

Answer 2

你可以返回一个数组......

public static double[] extractAccelerometer(BluetoothGattCharacteristic c) {

    Integer x = c.getIntValue(FORMAT_SINT8, 0);
    Integer y = c.getIntValue(FORMAT_SINT8, 1);
    Integer z = c.getIntValue(FORMAT_SINT8, 2) * -1;

    double scaledX = x / 64.0;
    double scaledY = y / 64.0;
    double scaledZ = z / 64.0;

    return new double[] {scaledX, scaledY, scaledZ};
}

Answer 3

列出双打并将其返回

    public class SensorData {

    public static double extractHumAmbientTemperature(BluetoothGattCharacteristic c) {
     int rawT = shortSignedAtOffset(c, 0);

     return -46.85 + 175.72/65536 *(double)rawT;
    }

   public static List<Double> extractAccelerometer(BluetoothGattCharacteristic c) {

       Integer x = c.getIntValue(FORMAT_SINT8, 0);
       Integer y = c.getIntValue(FORMAT_SINT8, 1);
       Integer z = c.getIntValue(FORMAT_SINT8, 2) * -1;

       double scaledX = x / 64.0;
       double scaledY = y / 64.0;
       double scaledZ = z / 64.0;
       List<Double> list=new ArrayList<Double>();
       list.add(scaledX);
       list.add(scaledY);
       list.add(scaledZ);
       return list ;
     }

Answer 4

创建一个您想要返回的类：

public class myScaleData {
    public double scaledX,scaledY,scaledZ;
}

Answer 5

使用您需要的参数创建一个Object：

toutorial

Answer 6

尝试javatuples它比每次返回多个值时更容易上课，例如：

public static Triplet<Double,Double,Double> extractAccelerometer(BluetoothGattCharacteristic c) {
    ...
    return new Triplet<Double,Double,Double>(scaledX,scaledY,scaledZ);
}

visit javatuples website for more info

返回并显示多个参数

6 个答案: