Android-获取MotionSensor失败(空指针)
我目前正在尝试实现一个ScrollView,希望其中包含的ImageView可以通过RotationVectorSensor和SensorEventListener滚动 这是我目前的代码:Android-获取MotionSensor失败(空指针),android,nullpointerexception,sensors,sensormanager,Android,Nullpointerexception,Sensors,Sensormanager,我目前正在尝试实现一个ScrollView,希望其中包含的ImageView可以通过RotationVectorSensor和SensorEventListener滚动 这是我目前的代码: import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; im
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.Menu;
import android.widget.HorizontalScrollView;
import android.widget.Toast;
public class MainActivity extends Activity implements SensorEventListener {
private SensorManager sensorManager;
private Sensor sensor;
private HorizontalScrollView scrollView;
private String TAG = MainActivity.class.getSimpleName();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);
if (sensor != null) {
sensorManager.registerListener(this, sensor,
SensorManager.SENSOR_DELAY_NORMAL);
Log.d(TAG, "Sensor found.");
} else {
Log.e(TAG, "Sensor NOT found.");
Toast.makeText(this, "ROTATION_VECTOR Sensor not found",
Toast.LENGTH_LONG).show();
finish();
}
scrollView = (HorizontalScrollView) findViewById(R.id.panoramaScrollView);
Log.d(TAG, "Panorama Scroll View found.");
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub
}
@Override
public void onSensorChanged(SensorEvent event) {
Toast.makeText(this, "rotating Yippi!", Toast.LENGTH_LONG).show();
if (event.sensor.getType() == Sensor.TYPE_ROTATION_VECTOR) {
final float angle = event.values[2];
scrollView.post(new Runnable() {
public void run() {
if (scrollView != null) {
scrollView.scrollTo((int)angle, scrollView.getBottom());
Log.d(TAG, "scrollTo executed.");
}
}
});
}
}
@Override
public void onResume() {
super.onResume();
sensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL);
Log.d(TAG, "SensorListener registered");
}
@Override
public void onPause() {
super.onPause();
if (sensor != null) {
sensorManager.unregisterListener(this);
Log.d(TAG, "SensorListener unregistered");
}
}
}
传感器初始化后直接出现空指针:
sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);
因此,应用程序退出并打印:未找到传感器
有什么我忘了的吗?
提前谢谢 我找到了解决办法。android清单中缺少以下行:
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION"/>
您是否检查过您的设备是否有特定的传感器?看起来好像没有。我还没有想到这一点,但旋转传感器不仅仅是磁场传感器和加速计的组合吗?清单中可能缺少特定的权限吗?你说的对,它组合传感器,但通常也使用陀螺仪。你有陀螺吗?你在用什么设备?是的。我在三星S3上测试了它。我想它也可能使用指南针来计算旋转矢量,因此需要这些权限。