怎么在Android项目中实现一个重力传感器功能
怎么在Android项目中实现一个重力传感器功能?很多新手对此不是很清楚,为了帮助大家解决这个难题,下面小编将为大家详细讲解,有这方面需求的人可以来学习下,希望你能有所收获。
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首先我们创建一个传感器管理器和一个传感器监听器,管理器用来管理传感器以及创建各种各样的传感器,监听器用来监视传感器的变化并且进行相应的操作
private SensorManager sensorManager; private MySensorEventListener mySensorEventListener; mySensorEventListener= new MySensorEventListener();//这个监听器当然是我们自己定义的,在重力感应器感应到手机位置有变化的时候,我们可以采取相应的操作,这里紧紧是将x,y,z的值打印出来 private final class MySensorEventListener implements SensorEventListener{ @Override //可以得到传感器实时测量出来的变化值 public void onSensorChanged(SensorEvent event) { //重力传感器 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是界面上的一个TextView标签,不再赘述 tv_orientation.setText("Orientation:"+x+","+y+","+z); } }
我们在onResume()
方法中创建重力传感器,并向系统注册监听器
protected void onResume() { Sensor sensor_accelerometer=sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); sensorManager.registerListener(mySensorEventListener,sensor_accelerometer, SensorManager.SENSOR_DELAY_UI); super.onResume(); }
最后我们在onPause()
中注销所有传感器的监听,释放重力感应器资源!
protected void onPause() { //注销所有传感器的监听 sensorManager.unregisterListener(mySensorEventListener); super.onPause(); }
到此,有关重力传感器的介绍完毕!
接下来看一个Android用重力传感器做横竖屏切换的例子
在播放视频的时候,可能要做横竖屏的切换,但是,用户可以设置自己的手机关掉屏幕旋转,这个时候就需要想其他的办法了,比如:重力传感器。
public class ScreenSwitchUtils { private static final String TAG = ScreenSwitchUtils.class.getSimpleName(); private volatile static ScreenSwitchUtils mInstance; private Activity mActivity; // 是否是竖屏 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, 切换成横屏); mActivity.setRequestedOrientation(0); isPortrait = false; } } else if ((orientation > 315 && orientation < 360) || (orientation > 0 && orientation < 45)) { if (!isPortrait) { Log.e(test,切换成竖屏); mActivity.setRequestedOrientation(1); isPortrait = true; } } break; default: break; } }; }; /** 返回ScreenSwitchUtils单例 **/ 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.); // 注册重力感应器,监听屏幕旋转 sm = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE); sensor = sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); listener = new OrientationSensorListener(mHandler); // 根据 旋转之后/点击全屏之后 两者方向一致,激活sm. sm1 = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE); sensor1 = sm1.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); listener1 = new OrientationSensorListener1(); } /** 开始监听 */ public void start(Activity activity) { Log.d(TAG, start orientation listener.); mActivity = activity; sm.registerListener(listener, sensor, SensorManager.SENSOR_DELAY_UI); } /** 停止监听 */ public void stop() { Log.d(TAG, stop orientation listener.); sm.unregisterListener(listener); sm1.unregisterListener(listener1); } /** * 手动横竖屏切换方向 */ public void toggleScreen() { sm.unregisterListener(listener); sm1.registerListener(listener1, sensor1,SensorManager.SENSOR_DELAY_UI); if (isPortrait) { isPortrait = false; // 切换成横屏 mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); } else { isPortrait = true; // 切换成竖屏 mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); } } public boolean isPortrait(){ return this.isPortrait; } /** * 重力感应监听者 */ 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) { // 屏幕旋转时 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) { // 屏幕旋转时 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) {// 检测到当前实际是横屏 if (!isPortrait) { sm.registerListener(listener, sensor,SensorManager.SENSOR_DELAY_UI); sm1.unregisterListener(listener1); } } else if ((orientation > 315 && orientation < 360) || (orientation > 0 && orientation < 45)) {// 检测到当前实际是竖屏 if (isPortrait) { sm.registerListener(listener, sensor,SensorManager.SENSOR_DELAY_UI); sm1.unregisterListener(listener1); } } } } }
使用的时候:
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()) { // 切换成竖屏 LayoutParams params1 = new RelativeLayout.LayoutParams(screenWidth, DensityUtil.dip2px(this, 160)); videoView.setLayoutParams(params1); Toast.makeText(getApplicationContext(), 竖屏, 0).show(); Log.e(test, 竖屏); } else { // 切换成横屏 LayoutParams params1 = new RelativeLayout.LayoutParams(screenHeight, screenWidth); videoView.setLayoutParams(params1); Toast.makeText(getApplicationContext(), 横屏, 0).show(); Log.e(test, 横屏); } } @Override public void onClick(View arg0) { switch (arg0.getId()) { case R.id.iv_stretch: instance.toggleScreen(); break; } } }
调用了activity.setRequestedOrientation()
以后,会触发activity.onConfigurationChanged();
可以在这里面重新设置播放界面的大小。
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