Android手機(jī)系統(tǒng)中的重力傳感器又稱加速度傳感器,Android手機(jī)可以根據(jù)這個(gè)傳感器的度數(shù)來(lái)反轉(zhuǎn)手機(jī),感興趣的話就隨武林技術(shù)頻道小編一起來(lái)詳解Android開發(fā)中的重力傳感器用法實(shí)例吧!
重力傳感器與方向傳感器的開發(fā)步驟類似,只要理清了期中的x,y,z的值之后就可以根據(jù)他們的變化來(lái)進(jìn)行編程了,首先來(lái)看一副圖

假設(shè)當(dāng)?shù)氐闹亓铀俣戎禐間
當(dāng)手機(jī)正面朝上的時(shí)候,z的值為q,反面朝上的時(shí)候,z的值為-g
當(dāng)手機(jī)右側(cè)面朝上的時(shí)候,x的值為g,右側(cè)面朝上的時(shí)候,x的值為-g
當(dāng)手機(jī)上側(cè)面朝上的時(shí)候,y的值為g,右側(cè)面朝上的時(shí)候,y的值為-g
了解了重力傳感器中X,Y,Z的含義之后下面我們就開始學(xué)習(xí)如何使用
首先我們創(chuàng)建一個(gè)傳感器管理器和一個(gè)傳感器監(jiān)聽(tīng)器,管理器用來(lái)管理傳感器以及創(chuàng)建各種各樣的傳感器,監(jiān)聽(tīng)器用來(lái)監(jiān)視傳感器的變化并且進(jìn)行相應(yīng)的操作
private SensorManager sensorManager;private MySensorEventListener mySensorEventListener;mySensorEventListener= new MySensorEventListener();//這個(gè)監(jiān)聽(tīng)器當(dāng)然是我們自己定義的,在重力感應(yīng)器感應(yīng)到手機(jī)位置有變化的時(shí)候,我們可以采取相應(yīng)的操作,這里緊緊是將x,y,z的值打印出來(lái)private final class MySensorEventListener implements SensorEventListener{@Override//可以得到傳感器實(shí)時(shí)測(cè)量出來(lái)的變化值public void onSensorChanged(SensorEvent event) {//重力傳感器if(event.sensor.getType()==Sensor.TYPE_ACCELEROMETER){float x = event.values[SensorManager.DATA_X];float y = event.values[SensorManager.DATA_Y];float z = event.values[SensorManager.DATA_Z];//tv_accelerometer是界面上的一個(gè)TextView標(biāo)簽,不再贅述tv_orientation.setText("Orientation:"+x+","+y+","+z);}}我們?cè)?code>onResume()方法中創(chuàng)建重力傳感器,并向系統(tǒng)注冊(cè)監(jiān)聽(tīng)器
protected void onResume() { Sensor sensor_accelerometer=sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); sensorManager.registerListener(mySensorEventListener,sensor_accelerometer, SensorManager.SENSOR_DELAY_UI);super.onResume();}最后我們?cè)?code>onPause()中注銷所有傳感器的監(jiān)聽(tīng),釋放重力感應(yīng)器資源!
protected void onPause() {//注銷所有傳感器的監(jiān)聽(tīng)sensorManager.unregisterListener(mySensorEventListener);super.onPause();}到此,有關(guān)重力傳感器的介紹完畢!
接下來(lái)看一個(gè)Android用重力傳感器做橫豎屏切換的例子
在播放視頻的時(shí)候,可能要做橫豎屏的切換,但是,用戶可以設(shè)置自己的手機(jī)關(guān)掉屏幕旋轉(zhuǎn),這個(gè)時(shí)候就需要想其他的辦法了,比如:重力傳感器。
public class ScreenSwitchUtils { private static final String TAG = ScreenSwitchUtils.class.getSimpleName(); private volatile static ScreenSwitchUtils mInstance; private Activity mActivity; // 是否是豎屏 private boolean isPortrait = true; private SensorManager sm; private OrientationSensorListener listener; private Sensor sensor; private SensorManager sm1; private Sensor sensor1; private OrientationSensorListener1 listener1; private Handler mHandler = new Handler() { public void handleMessage(Message msg) { switch (msg.what) { case 888: int orientation = msg.arg1; if (orientation > 45 && orientation < 135) { } else if (orientation > 135 && orientation < 225) { } else if (orientation > 225 && orientation < 315) { if (isPortrait) { Log.e(test, 切換成橫屏); mActivity.setRequestedOrientation(0); isPortrait = false; } } else if ((orientation > 315 && orientation < 360) || (orientation > 0 && orientation < 45)) { if (!isPortrait) { Log.e(test,切換成豎屏); mActivity.setRequestedOrientation(1); isPortrait = true; } } break; default: break; } }; }; /** 返回ScreenSwitchUtils單例 **/ public static ScreenSwitchUtils init(Context context) { if (mInstance == null) { synchronized (ScreenSwitchUtils.class) { if (mInstance == null) { mInstance = new ScreenSwitchUtils(context); } } } return mInstance; } private ScreenSwitchUtils(Context context) { Log.d(TAG, init orientation listener.); // 注冊(cè)重力感應(yīng)器,監(jiān)聽(tīng)屏幕旋轉(zhuǎn) sm = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE); sensor = sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); listener = new OrientationSensorListener(mHandler); // 根據(jù) 旋轉(zhuǎn)之后/點(diǎn)擊全屏之后 兩者方向一致,激活sm. sm1 = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE); sensor1 = sm1.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); listener1 = new OrientationSensorListener1(); } /** 開始監(jiān)聽(tīng) */ public void start(Activity activity) { Log.d(TAG, start orientation listener.); mActivity = activity; sm.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_UI); } /** 停止監(jiān)聽(tīng) */ public void stop() { Log.d(TAG, stop orientation listener.); sm.unregisterListener(listener); sm1.unregisterListener(listener1); } /** * 手動(dòng)橫豎屏切換方向 */ public void toggleScreen() { sm.unregisterListener(listener); sm1.registerListener(listener1, sensor1,SensorManager.SENSOR_DELAY_UI); if (isPortrait) { isPortrait = false; // 切換成橫屏 mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); } else { isPortrait = true; // 切換成豎屏 mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); } } public boolean isPortrait(){ return this.isPortrait; } /** * 重力感應(yīng)監(jiān)聽(tīng)者 */ public class OrientationSensorListener implements SensorEventListener { private static final int _DATA_X = 0; private static final int _DATA_Y = 1; private static final int _DATA_Z = 2; public static final int ORIENTATION_UNKNOWN = -1; private Handler rotateHandler; public OrientationSensorListener(Handler handler) { rotateHandler = handler; } public void onAccuracyChanged(Sensor arg0, int arg1) { } public void onSensorChanged(SensorEvent event) { float[] values = event.values; int orientation = ORIENTATION_UNKNOWN; float X = -values[_DATA_X]; float Y = -values[_DATA_Y]; float Z = -values[_DATA_Z]; float magnitude = X * X + Y * Y; // Don't trust the angle if the magnitude is small compared to the y // value if (magnitude * 4 >= Z * Z) { // 屏幕旋轉(zhuǎn)時(shí) float OneEightyOverPi = 57.29577957855f; float angle = (float) Math.atan2(-Y, X) * OneEightyOverPi; orientation = 90 - (int) Math.round(angle); // normalize to 0 - 359 range while (orientation >= 360) { orientation -= 360; } while (orientation < 0) { orientation += 360; } } if (rotateHandler != null) { rotateHandler.obtainMessage(888, orientation, 0).sendToTarget(); } } } public class OrientationSensorListener1 implements SensorEventListener { private static final int _DATA_X = 0; private static final int _DATA_Y = 1; private static final int _DATA_Z = 2; public static final int ORIENTATION_UNKNOWN = -1; public OrientationSensorListener1() { } public void onAccuracyChanged(Sensor arg0, int arg1) { } public void onSensorChanged(SensorEvent event) { float[] values = event.values; int orientation = ORIENTATION_UNKNOWN; float X = -values[_DATA_X]; float Y = -values[_DATA_Y]; float Z = -values[_DATA_Z]; float magnitude = X * X + Y * Y; // Don't trust the angle if the magnitude is small compared to the y // value if (magnitude * 4 >= Z * Z) { // 屏幕旋轉(zhuǎn)時(shí) float OneEightyOverPi = 57.29577957855f; float angle = (float) Math.atan2(-Y, X) * OneEightyOverPi; orientation = 90 - (int) Math.round(angle); // normalize to 0 - 359 range while (orientation >= 360) { orientation -= 360; } while (orientation < 0) { orientation += 360; } } if (orientation > 225 && orientation < 315) {// 檢測(cè)到當(dāng)前實(shí)際是橫屏 if (!isPortrait) { sm.registerListener(listener, sensor,SensorManager.SENSOR_DELAY_UI); sm1.unregisterListener(listener1); } } else if ((orientation > 315 && orientation < 360) || (orientation > 0 && orientation < 45)) {// 檢測(cè)到當(dāng)前實(shí)際是豎屏 if (isPortrait) { sm.registerListener(listener, sensor,SensorManager.SENSOR_DELAY_UI); sm1.unregisterListener(listener1); } } } }}使用的時(shí)候:
public class MainActivity extends Activity implements OnClickListener { private ScreenSwitchUtils instance; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); instance = ScreenSwitchUtils.init(this.getApplicationContext()); } @Override protected void onStart() { super.onStart(); instance.start(this); } @Override protected void onStop() { super.onStop(); instance.stop(); } @SuppressLint(NewApi) @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); Log.e(test, onConfigurationChanged); if (instance.isPortrait()) { // 切換成豎屏 LayoutParams params1 = new RelativeLayout.LayoutParams(screenWidth, DensityUtil.dip2px(this, 160)); videoView.setLayoutParams(params1); Toast.makeText(getApplicationContext(), 豎屏, 0).show(); Log.e(test, 豎屏); } else { // 切換成橫屏 LayoutParams params1 = new RelativeLayout.LayoutParams(screenHeight, screenWidth); videoView.setLayoutParams(params1); Toast.makeText(getApplicationContext(), 橫屏, 0).show(); Log.e(test, 橫屏); } } @Override public void onClick(View arg0) { switch (arg0.getId()) { case R.id.iv_stretch: instance.toggleScreen(); break; } }}調(diào)用了activity.setRequestedOrientation()以后,會(huì)觸發(fā)activity.onConfigurationChanged();可以在這里面重新設(shè)置播放界面的大小。
以上就是詳解Android開發(fā)中的重力傳感器用法實(shí)例,如果你們的技術(shù)比較厲害,我們可以選擇進(jìn)行操作。
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