Question

我正在Android中开发，我尝试通过.csv将Android手机的传感器值记录到BufferedWriter文件中。

代码如下：

//recordData
private float ACCELEROMETER_Gx = 0 , ACCELEROMETER_Gy = 0 , ACCELEROMETER_Gz = 0;
private float GRAVITY_X = 0 , GRAVITY_Y = 0 , GRAVITY_Z = 0;
private float GYROSCOPE_X = 0 , GYROSCOPE_Y = 0 , GYROSCOPE_Z = 0;
private float ACCELERATION_X = 0 , ACCELERATION_Y = 0 , ACCELERATION_Z = 0;
private float MAGNETIC_FIELD_X = 0 , MAGNETIC_FIELD_Y = 0 , MAGNETIC_FIELD_Z = 0;
private float PRESSURE = 0;
private float ROTATION_VECTOR_X = 0 , ROTATION_VECTOR_Y = 0 , ROTATION_VECTOR_Z = 0;

当传感器发生变化时，它将写入.csv文件。

    @Override
        public void onSensorChanged(SensorEvent event) {
            if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {

                ACCELEROMETER_Gx = event.values[0];
                ACCELEROMETER_Gy = event.values[1];
                ACCELEROMETER_Gz = event.values[2];

            }else if (event.sensor.getType() == Sensor.TYPE_GRAVITY) {
                GRAVITY_X = event.values[0];
                GRAVITY_Y = event.values[1];
                GRAVITY_Z = event.values[2];


            }else if (event.sensor.getType() == Sensor.TYPE_GYROSCOPE) {
                GYROSCOPE_X = event.values[0];
                GYROSCOPE_Y = event.values[1];
                GYROSCOPE_Z = event.values[2];


            }else if (event.sensor.getType() == Sensor.TYPE_LINEAR_ACCELERATION) {
                ACCELERATION_X = event.values[0];
                ACCELERATION_Y = event.values[1];
                ACCELERATION_Z = event.values[2];


            }else if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {

                MAGNETIC_FIELD_X = event.values[0];
                MAGNETIC_FIELD_Y = event.values[1];
                MAGNETIC_FIELD_Z = event.values[2];

            }else if (event.sensor.getType() == Sensor.TYPE_PRESSURE) {
                PRESSURE = event.values[0];

            }else if (event.sensor.getType() == Sensor.TYPE_ROTATION_VECTOR) {

                ROTATION_VECTOR_X = event.values[0];
                ROTATION_VECTOR_Y = event.values[1];
                ROTATION_VECTOR_Z = event.values[2];
            }


            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss.SSS");
            String SensorChangeTime = sdf.format(new Date(System.currentTimeMillis()));

            String SensorValue =
                    SensorChangeTime + "," +
                    appendcomma(ACCELEROMETER_Gx) + appendcomma(ACCELEROMETER_Gy) + appendcomma(ACCELEROMETER_Gz) +
                    appendcomma(GRAVITY_X) + appendcomma(GRAVITY_Y) + appendcomma(GRAVITY_Z) +
                    appendcomma(GYROSCOPE_X) + appendcomma(GYROSCOPE_Y) + appendcomma(GYROSCOPE_Z) +
                    appendcomma(ACCELERATION_X) + appendcomma(ACCELERATION_Y) + appendcomma(ACCELERATION_Z) +
                    appendcomma(MAGNETIC_FIELD_X) + appendcomma(MAGNETIC_FIELD_Y) + appendcomma(MAGNETIC_FIELD_Z) +
                    appendcomma(PRESSURE) +
                    appendcomma(ROTATION_VECTOR_X) + appendcomma(ROTATION_VECTOR_Y) + appendcomma(ROTATION_VECTOR_Z) + '\n';

            writeData(SensorValue);
        }

        private String appendcomma(float value){
            return String.valueOf(value) + ",";
        }

        private void writeData(String Data){
            try {

                fw = new FileWriter(path+"/" + FileRecordName, true);
                BufferedWriter bw = new BufferedWriter(fw);
                bw.write(Data);
                bw.close();

            }catch (IOException e){
                Log.d(TAG,"writeData---e = " + e.toString());
            }
        }

当传感器值发生变化时，每次都会通过以下代码写入.csv文件：

            fw = new FileWriter(path+"/" + FileRecordName, true);
            BufferedWriter bw = new BufferedWriter(fw);
            bw.write(Data);
            bw.close();

每次创建new FileWriter和coles是否正确？

如何改善Android中BufferedWriter的效果？

Answer 1

是的，这是一种正确的行为，对于每次写入操作，您必须创建一个新的FileWriter并关闭它。但是，从API 19开始，为了简单起见，您可以使用try-with-resources执行此操作：

try (BufferedWriter bw = new BufferedWriter(new FileWriter(FILENAME))) {

    bw.write(data);

    // no need to close it.
    //bw.close();

} catch (IOException e) {
    e.printStackTrace();
}

如何提高Android中BufferedWriter的性能？

1 个答案: