Android开发学习之路--传感器之初体验

说到传感器,还是有很多的,有加速度啊,光照啊,磁传感器等等。当然android手机之所以称为智能手机,少不了这几款传感器的功劳了。下面就学习下了,这里主要学习光照,加速度和磁。

新建工程emSensorStudy,布局如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_margin="5dp"
tools:context="com.jared.emsensorsstudy.MainActivity"> <TextView
android:text="Hello Sensors"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="22dp"/> <Button
android:id="@+id/startLightSensor"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="启动LightSensor"
android:textAllCaps="false"/> <Button
android:id="@+id/startAccelerSensor"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="启动AccelerSensor"
android:textAllCaps="false"/> <Button
android:id="@+id/startMagneticSensor"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="启动MagneticSensor"
android:textAllCaps="false"/>
</LinearLayout>

添加LightSensor,AccelerSensor,MagnetiSensor的Activity,修改MainActivity代码如下:

package com.jared.emsensorsstudy;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button; public class MainActivity extends AppCompatActivity { private Button startLightSensorBtn;
private Button startAccelerSensorBtn;
private Button startMagneticSensorBtn; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); startLightSensorBtn = (Button)findViewById(R.id.startLightSensor);
startAccelerSensorBtn = (Button)findViewById(R.id.startAccelerSensor);
startMagneticSensorBtn = (Button)findViewById(R.id.startMagneticSensor); startLightSensorBtn.setOnClickListener(new myOnClickListener());
startAccelerSensorBtn.setOnClickListener(new myOnClickListener());
startMagneticSensorBtn.setOnClickListener(new myOnClickListener());
} private class myOnClickListener implements View.OnClickListener {
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.startAccelerSensor:
Intent intent1 = new Intent(getApplicationContext(), AccelerSensor.class);
startActivity(intent1);
break;
case R.id.startLightSensor:
Intent intent2 = new Intent(getApplicationContext(), LightSensor.class);
startActivity(intent2);
break;
case R.id.startMagneticSensor:
Intent intent3 = new Intent(getApplicationContext(), MagneticSensor.class);
startActivity(intent3);
break;
default:
break;
}
}
} }

先要实现Light的功能,先修改布局如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="10dp"
tools:context="com.jared.emsensorsstudy.LightSensor"> <TextView
android:id="@+id/light_level"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="22dp"/> </LinearLayout>

简单地实现了一个textview用来显示光照强度。接着修改LightSensor代码如下:

package com.jared.emsensorsstudy;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView; public class LightSensor extends AppCompatActivity { private SensorManager sensorManager;
private TextView lightLevel; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_light_sensor); lightLevel = (TextView)findViewById(R.id.light_level); initWithLight();
} @Override
protected void onDestroy() {
super.onDestroy();
if(sensorManager != null) {
sensorManager.unregisterListener(listener);
}
} public void initWithLight() {
sensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
Sensor sensor = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
sensorManager.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_NORMAL);
} private SensorEventListener listener = new SensorEventListener() {
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
float value = sensorEvent.values[0];
lightLevel.setText("Currrent light level is "+value+"lx");
} @Override
public void onAccuracyChanged(Sensor sensor, int i) { }
};
}

这里先通过getSystemService获取sensor,然后通过注册一个listener来监听传感器的变化,当值有变化的时候会调用onSensorChanged方法,具体运行后,用手遮挡听筒附近的传感器,显示如下:

Android开发学习之路--传感器之初体验 
   Android开发学习之路--传感器之初体验

从上可见光照的效果很明显了。接着我们来试下加速度传感器。这里实现微信摇一摇功能,并且成功了震动。

修改布局如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_margin="10dp"
tools:context="com.jared.emsensorsstudy.AccelerSensor"> <TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="摇一摇获取更多哦!"
android:layout_gravity=""
android:textSize="22dp"/> <TextView
android:id="@+id/shack"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textSize="22dp"/> </LinearLayout>

接着添加代码如下:

package com.jared.emsensorsstudy;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView; public class AccelerSensor extends AppCompatActivity { private SensorManager sensorManager;
private TextView shackPhone;
private Vibrator vibrator; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_acceler_sensor);
shackPhone = (TextView)findViewById(R.id.shack); initWithAcceler();
} @Override
protected void onDestroy() {
super.onDestroy();
if(sensorManager != null) {
sensorManager.unregisterListener(listener);
}
} private void initWithAcceler() {
sensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
Sensor sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorManager.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_NORMAL);
vibrator = (Vibrator)getSystemService(Context.VIBRATOR_SERVICE);
} private SensorEventListener listener = new SensorEventListener() {
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
float xValue = Math.abs(sensorEvent.values[0]);
float yValue = Math.abs(sensorEvent.values[1]);
float zValue = Math.abs(sensorEvent.values[2]);
int medumValue = 19;
if(xValue > medumValue || yValue > medumValue || zValue > medumValue) {
vibrator.vibrate(200);
shackPhone.setText("恭喜你摇一摇成功,新年快乐!");
} else {
//Toast.makeText(getApplicationContext(), "请使劲摇哦!", Toast.LENGTH_SHORT).show();
}
} @Override
public void onAccuracyChanged(Sensor sensor, int i) { }
};
}

这里的代码和LightSensor的代码差不多,主要是当三个方向的加速度大于19的时候就表示在摇动了,然后震动下手机就ok了。效果如下:

Android开发学习之路--传感器之初体验 
  Android开发学习之路--传感器之初体验

最后来学习下magneticSensor了。这里实现个compass。首先就是提供一张图片了,修改布局如下:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="10dp"
tools:context="com.jared.emsensorsstudy.MagneticSensor"> <ImageView
android:id="@+id/compass_img"
android:layout_width="250dp"
android:layout_height="250dp"
android:layout_centerInParent="true"
android:src="@drawable/compass" /> </RelativeLayout>

接着就是修改MagneticSensor的代码了:

package com.jared.emsensorsstudy;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.ImageView; public class MagneticSensor extends AppCompatActivity { private SensorManager sensorManager;
private ImageView compassImage; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_magnetic_sensor); compassImage = (ImageView)findViewById(R.id.compass_img); initWithCompass();
} @Override
protected void onDestroy() {
super.onDestroy();
sensorManager.unregisterListener(listener);
} private void initWithCompass() {
sensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
Sensor magneticSensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
Sensor acclerSensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorManager.registerListener(listener, magneticSensor, SensorManager.SENSOR_DELAY_GAME);
sensorManager.registerListener(listener, acclerSensor, SensorManager.SENSOR_DELAY_GAME); } private SensorEventListener listener = new SensorEventListener() { float[] acclerValues = new float[3];
float[] magneticValues = new float[3];
private float lastRotateDegree; @Override
public void onSensorChanged(SensorEvent sensorEvent) {
switch (sensorEvent.sensor.getType()) {
case Sensor.TYPE_ACCELEROMETER:
acclerValues = sensorEvent.values.clone();
break;
case Sensor.TYPE_MAGNETIC_FIELD:
magneticValues = sensorEvent.values.clone();
break;
default:
break;
}
float[] values = new float[3];
float[] R = new float[9];
//调用getRotaionMatrix获得变换矩阵R[]
SensorManager.getRotationMatrix(R, null, acclerValues, magneticValues);
SensorManager.getOrientation(R, values);
//经过SensorManager.getOrientation(R, values);得到的values值为弧度
//转换为角度 float rotateDegree = -(float)Math.toDegrees(values[0]);
if(Math.abs(rotateDegree - lastRotateDegree) > 2) {
RotateAnimation animation = new RotateAnimation(
lastRotateDegree, rotateDegree, Animation.RELATIVE_TO_SELF, 0.5f,
Animation.RELATIVE_TO_SELF, 0.5f);
animation.setFillAfter(true);
compassImage.startAnimation(animation);
lastRotateDegree = rotateDegree;
}
} @Override
public void onAccuracyChanged(Sensor sensor, int i) { }
};
}

这里通过加速度和磁传感器来实现一个方向,因为方向传感器官方已经不提倡使用了。运行效果如下:

Android开发学习之路--传感器之初体验

传感器就先学习这些了。

附:参考《第一行代码》

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