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，
Android用重力传感器做横竖屏切换
。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 rientation = 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 rientation = 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 neEightyOverPi = 57.29577957855f; float angle = (float) Math.atan2(-Y, X) * OneEightyOverPi; rientation = 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 rientation = 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 neEightyOverPi = 57.29577957855f; float angle = (float) Math.atan2(-Y, X) * OneEightyOverPi; rientation = 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); } } } }}转载请标明出处：http://blog.csdn.net/goldenfish1919/article/details/47423131
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，