[Android] Android G-sensor

Android G-sensor

  

小試身手前的小知識

1. 宣告一個SensorManager，SensorManager管理、調度、處理sensor的工
2. getSystemService(SENSOR_SERVICE)取得感測器服務
3. 設定取得的感測器類型 getDefaultSensor(Sensor.TYPE_ACCELEROMETER)
4. 需要與感測器互動時，必須先注冊藉此監視與感測器相關的活動，方法為SensorManger類別中的registerListener
5.  利用SensorEventListener監聽Sensor之兩件事， (a) onSensorChanged(SensorEvent event)當感測器的值有所改變。 (b)onAccuracyChanged(Sensor sensor, int accuracy)感測器精準度改變時。
6.  Sensor更新速度如下表，控制方式為程式碼淺藍色標記部分

Sensor.manager.SENSOR_DELAY_FASTEST	0ms
Sensor.manager.SENSOR_DELAY_GAME	20ms
Sensor.manager.SENSOR_DELAY_UI	60ms
Sensor.manager.SENSOR_DELAY_NORMAL	200ms

小試身手小範例

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java檔

package www.gsensor;

import android.support.v7.app.ActionBarActivity;

import android.support.v4.app.Fragment;

import android.hardware.Sensor;

import android.hardware.SensorEvent;

import android.hardware.SensorEventListener;

import android.hardware.SensorManager;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.ViewGroup;

import android.widget.TextView;

import android.view.Window;

import android.view.WindowManager;

import android.widget.Toast;

public class MainActivity extends ActionBarActivity implements SensorEventListener {

        private TextView text_x;

        private TextView text_y;

        private TextView text_z;

        private SensorManager aSensorManager;

        private Sensor aSensor;

        private float gravity[] = new float[3];

        /** Called when the activity is first created. */

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);

        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,

        WindowManager.LayoutParams.FLAG_FULLSCREEN);

        setContentView(R.layout.fragment_main);

        text_x = (TextView)findViewById(R.id.TextView01);

        text_y = (TextView)findViewById(R.id.TextView02);

        text_z = (TextView)findViewById(R.id.TextView03);

        aSensorManager=(SensorManager) getSystemService(SENSOR_SERVICE);

        aSensor = aSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);

        aSensorManager.registerListener(this, aSensor, SensorManager.SENSOR_DELAY_NORMAL);

        /*

        if (savedInstanceState == null) {

            getSupportFragmentManager().beginTransaction()

                    .add(R.id.container, new PlaceholderFragment())

                    .commit();

        }

        */

    }

    @Override

        public void onAccuracyChanged(Sensor sensor, int accuracy) {

                // TODO Auto-generated method stub

               

        }

    @Override

    public void onSensorChanged(SensorEvent event) {

    // TODO Auto-generated method stub

    gravity[0] = event.values[0];

    gravity[1] = event.values[1];

    gravity[2] = event.values[2];

    text_x.setText("X = "+gravity[0]);

    text_y.setText("Y = "+gravity[1]);

    text_z.setText("Z = "+gravity[2]);

    }

    @Override

    protected void onPause()

    {

    // TODO Auto-generated method stub

    /* 取消註冊SensorEventListener */

    aSensorManager.unregisterListener(this);

    Toast.makeText(this, "Unregister accelerometerListener", Toast.LENGTH_LONG).show();

    super.onPause();

   

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

       

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.main, menu);

        return true;

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        // Handle action bar item clicks here. The action bar will

        // automatically handle clicks on the Home/Up button, so long

        // as you specify a parent activity in AndroidManifest.xml.

        int id = item.getItemId();

        if (id == R.id.action_settings) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

    /**

     * A placeholder fragment containing a simple view.

     */

    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {

        }

        @Override

        public View onCreateView(LayoutInflater inflater, ViewGroup container,

                Bundle savedInstanceState) {

            View rootView = inflater.inflate(R.layout.fragment_main, container, false);

            return rootView;

        }

    }

}

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xml檔

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="三軸加速度 - 資料擷取"
android:textSize="25sp"
android:layout_margin="15sp"
android:layout_marginBottom="10sp"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="X"
android:id="@+id/TextView01"
android:textSize="25sp"
android:layout_margin="15sp"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Y"
android:id="@+id/TextView02"
android:textSize="25sp"
android:layout_margin="15sp"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Z"
android:id="@+id/TextView03"
android:textSize="25sp"
android:layout_margin="15sp"
/>
</LinearLayout>

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資料來源