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

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：

<!--{cke_protected}{C}%3C!%2D%2D%3Fxml%20version%3D%221.0%22%20encoding%3D%22utf-8%22%3F%2D%2D%3E-->
<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><button android:id="@+id/startAccelerSensor" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="启动AccelerSensor" android:textallcaps="false"></button><button android:id="@+id/startMagneticSensor" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="启动MagneticSensor" android:textallcaps="false"></button></textview></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：

<!--{cke_protected}{C}%3C!%2D%2D%3Fxml%20version%3D%221.0%22%20encoding%3D%22utf-8%22%3F%2D%2D%3E-->
<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">

</textview></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：

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：

<!--{cke_protected}{C}%3C!%2D%2D%3Fxml%20version%3D%221.0%22%20encoding%3D%22utf-8%22%3F%2D%2D%3E-->
<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">

</textview></textview></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 and