Question

当我调试下面发布的代码时，我决定在Toast语句的正文和if语句的正文中放置else，所以我可以看到错误来自哪里。当我运行应用程序时，我发现两个Toasts都已执行。最初显示Toast语句中的if，并且在几秒钟后，显示切换到Toast语句中的else，并且它们保持交替。我不知道条件如何被评估为真和假同时。请提供解决此问题的合理解释和建议。

JavaCode：

public void onSensorChanged(SensorEvent event) {
    // TODO Auto-generated method stub
    switch (event.sensor.getType()) {
    case Sensor.TYPE_ACCELEROMETER:
        accelerometerValues = event.values.clone();
        tvAcc_XReading.setText(Float.toString(accelerometerValues[0]));
        tvAcc_YReading.setText(Float.toString(accelerometerValues[1]));
        tvAcc_ZReading.setText(Float.toString(accelerometerValues[2]));
    case Sensor.TYPE_MAGNETIC_FIELD:
        magnetometerValues = event.values.clone();
        tvMagneto_XReading.setText(Float.toString(magnetometerValues[0]));
        tvMagneto_YReading.setText(Float.toString(magnetometerValues[1]));
        tvMagneto_ZReading.setText(Float.toString(magnetometerValues[2]));
    }
    if (accelerometerValues != null && magnetometerValues != null) {
        float [] matrixR = new float[9];
        float [] matrixI = new float[9];
        boolean success = SensorManager.getRotationMatrix(matrixR, matrixI, accelerometerValues, 
                magnetometerValues);
        if (success) {
            Toast.makeText(getApplicationContext(), "SUCCESS", Toast.LENGTH_LONG).show();
            float [] orientationMatrix = new float[3];
            SensorManager.getOrientation(matrixR, orientationMatrix);
            tvAzimuthReading.setText(Float.toString(orientationMatrix[0]));
            tvPitchReading.setText(Float.toString(orientationMatrix[1]));
            tvRollReading.setText(Float.toString(orientationMatrix[2]));
        } else {
            Toast.makeText(getApplicationContext(), "No Rmatrix", Toast.LENGTH_LONG).show();
        }
    }

Answer 1

尝试为您的案例添加一个break语句，否则它会失败。

switch (event.sensor.getType()) {
    case Sensor.TYPE_ACCELEROMETER:
        accelerometerValues = event.values.clone();
        tvAcc_XReading.setText(Float.toString(accelerometerValues[0]));
        tvAcc_YReading.setText(Float.toString(accelerometerValues[1]));
        tvAcc_ZReading.setText(Float.toString(accelerometerValues[2]));
        break;
    case Sensor.TYPE_MAGNETIC_FIELD:
        magnetometerValues = event.values.clone();
        tvMagneto_XReading.setText(Float.toString(magnetometerValues[0]));
        tvMagneto_YReading.setText(Float.toString(magnetometerValues[1]));
        tvMagneto_ZReading.setText(Float.toString(magnetometerValues[2]));
        break;
    }

SensorManager，同一条件的if和else同时执行

1 个答案: