Android-用重力传感器做横竖屏切换

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);
				}
			}
		}
	}
}

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。

参考：http://download.csdn.net/download/liubo080852/8446445

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