Android 当 x 轴改变时加速度计会发出蜂鸣声

Question

我是 Android 工作室的新手，我只是使用在线资源来学习 Android。我想制作一个应用程序，当加速度计的 x 轴发生变化时，它会发出哔哔声。

这是我的代码：

package com.hamzah.accelerometer;

import android.content.res.AssetFileDescriptor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.media.MediaPlayer;


public class MainActivity extends AppCompatActivity implements 
SensorEventListener {

private float mLastX, mLastY, mLastZ;
private boolean mInitialized;
private SensorManager mSensorManager;
private Sensor mAccelerometer;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mInitialized = false;
    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mSensorManager.registerListener(this, mAccelerometer , SensorManager.SENSOR_DELAY_NORMAL);
    final MediaPlayer player = MediaPlayer.create(this, R.raw.beep);
}
protected void onResume() {
    super.onResume();
    mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
}
protected void onPause() {
    super.onPause();
    mSensorManager.unregisterListener(this);
}

@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {

}

@Override
public void onSensorChanged(SensorEvent event){
    TextView tvX= (TextView)findViewById(R.id.x_axis);
    TextView tvY= (TextView)findViewById(R.id.y_axis);
    TextView tvZ= (TextView)findViewById(R.id.z_axis);
    float x = event.values[0];
    float y = event.values[1];
    float z = event.values[2];
    if (!mInitialized) {
        mLastX = x;
        mLastY = y;
        mLastZ = z;
        tvX.setText("0.0");
        tvY.setText("0.0");
        tvZ.setText("0.0");
        mInitialized = true;
    } else {
        float deltaX = Math.abs(mLastX - x);
        float deltaY = Math.abs(mLastY - y);
        float deltaZ = Math.abs(mLastZ - z);
        float NOISE = (float) 2.0;
        if (deltaX < NOISE) deltaX = (float)0.0;
        if (deltaY < NOISE) deltaY = (float)0.0;
        if (deltaZ < NOISE) deltaZ = (float)0.0;
        mLastX = x;
        mLastY = y;
        mLastZ = z;
        tvX.setText(Float.toString(deltaX));
        tvY.setText(Float.toString(deltaY));
        tvZ.setText(Float.toString(deltaZ));
        if (deltaX > deltaY) {
            player.start();
        } else {
            iv.setVisibility(View.INVISIBLE);
        }
    }
}
}

我不知道该怎么做，我所做的是，如果 x 轴的加速度大于 y 轴的加速度，那么应该发出哔哔声（我已将其上传到原始文件夹中） .

player.start()肯定有问题，我不知道这部分怎么写。

Answer 1

您正在尝试在 onSensorChanged(SensorEvent event) 的主体内转换方法 "player.start();"。您的对象播放器在 onCreate(Bundle savedInstanceState) 内部声明。所以它只能在这里使用。你必须申报

private final MediaPlayer player;

然后在onCreate中初始化

player = MediaPlayer.create(this, R.raw.beep);

Android 当 x 轴改变时加速度计会发出蜂鸣声

Android accelerometer plays a beep when x-axis changes

android

accelerometer

android-mediaplayer