Canvas.rotate和Canvas.drawBitmap坏了吗?或者我的代码有问题吗

Question

我正试图使用Canvas.rotate和/或Canvas.drawBimtap绘制图像，尽管每次使用它时，图像都会出现在随机位置，无论我将其设置为X和Y坐标。这是我的代码，让我知道这是我应该报告的问题，还是我的代码中有错误：

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ImageFormat;
import android.graphics.Paint;
import android.graphics.SurfaceTexture;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.TotalCaptureResult;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.media.Image;
import android.media.ImageReader;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Log;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.UUID;

public class Photo_Page extends AppCompatActivity implements SensorEventListener {
@Override
protected void onStart()
{
super.onStart();
GlobalClass application=(GlobalClass) getApplication();
TextView projectnameheader = (TextView) findViewById(R.id.projectnameheader2);
projectnameheader.setText(application.projectnameheader);
TextView projectnameoverlay = (TextView) findViewById(R.id.projectnameoverlay);
projectnameoverlay.setText(application.projectnameheader);
String currentDateTimeString = java.text.DateFormat.getDateTimeInstance().format(new Date());
Button addcodeandnote = (Button) findViewById(R.id.addcodebutton);
EditText entercode2 = (EditText) findViewById(R.id.entercode);
EditText enternote2 = (EditText) findViewById(R.id.enternote);
TextView codedisplay = (TextView) findViewById(R.id.code);
TextView notedisplay = (TextView) findViewById(R.id.note);
Button savecodebutton = (Button) findViewById(R.id.codesavebutton);
TextView dateandtime = (TextView) findViewById(R.id.dateandtime);
dateandtime.setText(currentDateTimeString);
addcodeandnote.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
if (addcodebuttonpressedtimes>=1) {
addcodebuttonpressedtimes=0;
entercode2.setVisibility(View.INVISIBLE);
enternote2.setVisibility(View.INVISIBLE);
savecodebutton.setVisibility(View.INVISIBLE);
}
else{
addcodebuttonpressedtimes +=1;
entercode2.setVisibility(View.VISIBLE);
enternote2.setVisibility(View.VISIBLE);
savecodebutton.setVisibility(View.VISIBLE);
savecodebutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
code=entercode2.getText().toString();
note=enternote2.getText().toString();
codedisplay.setText(code);
notedisplay.setText(note);
Toast.makeText(Photo_Page.this, "Code and Note were saved successfully!", Toast.LENGTH_LONG).show();
entercode2.setVisibility(View.INVISIBLE);
enternote2.setVisibility(View.INVISIBLE);
savecodebutton.setVisibility(View.INVISIBLE);
addcodebuttonpressedtimes=0;
if (code==null) {
codedisplay.setVisibility(View.INVISIBLE);
}
else{
codedisplay.setVisibility(View.VISIBLE);
}
if (note==null) {
notedisplay.setVisibility(View.INVISIBLE);
}
else{
notedisplay.setVisibility(View.VISIBLE);
}
}
});
}
}
});
}
String m_path = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DCIM).getAbsolutePath();
public String directionNESW;
public List gpslist = new ArrayList();
private final static String TAG = MainActivity.class.getSimpleName();
public Calendar c = Calendar.getInstance();
public SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
public SimpleDateFormat sdftime = new SimpleDateFormat("HHmmss");
public String time;
public String date;
boolean laton = false;
boolean longon = false;
boolean alton = false;
public String names = "Address (GPS signal not found)";
public double latitude;
public double longitude;
public double altitude;
public boolean photowithcode = false;
private Button btnCapture;
private TextureView textureView2;
public String addcodebuttonpressed = "false";
public int addcodebuttonpressedtimes = 0;
public String code = "Code (Empty)";
public String note = "Note (Empty)";
public TextView degrees;
public TextView direction;
public ImageView compass;
public SensorManager sensorManager;
public Sensor accelerometerSensor, magnetometerSensor;
public float[] lastAccelerometer = new float[3];
public float[] lastMagnetometer = new float[3];
public float[] rotationMatrix = new float[9];
public float[] orientation = new float[3];
boolean isLastAccelerometerArrayCopied = false;
boolean isLastMagnetometerArrayCopied = false;
long lastUpdatedTime = 0;
float currentDegrees = 0f;
private ImageView compass2;
private float[] mGravity = new float[3];
private float[] mGeomagnetic = new float[3];
private float azimuth = 0f;
private float currectAzimuth = 0f;
private SensorManager mSensorManager;
//Check state orientation of output image
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
static{
ORIENTATIONS.append(Surface.ROTATION_0,90);
ORIENTATIONS.append(Surface.ROTATION_90,0);
ORIENTATIONS.append(Surface.ROTATION_180,270);
ORIENTATIONS.append(Surface.ROTATION_270,180);
}
private String cameraId;
private CameraDevice cameraDevice;
private CameraCaptureSession cameraCaptureSessions;
private CaptureRequest.Builder captureRequestBuilder;
private Size imageDimension;
private ImageReader imageReader;
//Save to FILE
private File file;
private static final int REQUEST_CAMERA_PERMISSION = 200;
private boolean mFlashSupported;
private Handler mBackgroundHandler;
private HandlerThread mBackgroundThread;
CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
@Override
public void onOpened(@NonNull CameraDevice camera) {
cameraDevice = camera;
createCameraPreview();
}
@Override
public void onDisconnected(@NonNull CameraDevice cameraDevice) {
cameraDevice.close();
}
@Override
public void onError(@NonNull CameraDevice cameraDevice, int i) {
cameraDevice.close();
cameraDevice=null;
}
};
private TextView gpsdisplay;
public TextView altitudetext;
private LocationManager locationManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_photo_page);
compass2 = (ImageView)findViewById(R.id.compass);
degrees = (TextView)findViewById(R.id.degree);
direction = (TextView)findViewById(R.id.direction);
mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
accelerometerSensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
magnetometerSensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
TextView address = (TextView) findViewById(R.id.address);
gpsdisplay = findViewById(R.id.gpscoords);
altitudetext = findViewById(R.id.altitude);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
if(ContextCompat.checkSelfPermission(Photo_Page.this, Manifest.permission.ACCESS_COARSE_LOCATION)!= PackageManager.PERMISSION_GRANTED &&
ContextCompat.checkSelfPermission(Photo_Page.this,Manifest.permission.ACCESS_FINE_LOCATION)!=PackageManager.PERMISSION_GRANTED);
{
ActivityCompat.requestPermissions(Photo_Page.this,new String[]{Manifest.permission.ACCESS_COARSE_LOCATION,Manifest.permission.ACCESS_FINE_LOCATION},69);
}
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 10, 1, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
latitude = location.getLatitude();
longitude = location.getLongitude();
altitude = location.getAltitude();
if ((alton && laton && longon) == false) {
gpsdisplay.setText(String.format("%.5f", latitude) + ", " + String.format("%.5f", longitude));
laton = true;
longon = true;
altitudetext.setText(String.format("%.2f", altitude) + " Meters");
alton = true;
}
Geocoder geocoder = new Geocoder(Photo_Page.this, Locale.getDefault());
try {
List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1);
setUpdata(addresses);

} catch (IOException e) {
e.printStackTrace();
}
}
private void setUpdata(List<Address> addresses) {
String add = addresses.get(0).getAddressLine(0);
String city = addresses.get(0).getLocality();
String state = addresses.get(0).getAdminArea();
String zip = addresses.get(0).getPostalCode();
names = add;
address.setText(names);
}
});
textureView2 = (TextureView)findViewById(R.id.textureView);
//From Java 1.4 , you can use keyword 'assert' to check expression true or false
assert textureView2 != null;
textureView2.setSurfaceTextureListener(textureListener);
btnCapture = (Button)findViewById(R.id.btnCapture);
Button btnCapturewithcode = (Button)findViewById(R.id.btnCapturewithcode);
btnCapture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
takePicture();
}
});
btnCapturewithcode.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
photowithcode = true;
Toast.makeText(Photo_Page.this, time, Toast.LENGTH_SHORT).show();
takePicture();
}
});
}
private void takePicture() {
c = Calendar.getInstance();
time = sdftime.format(c.getTime());
date = sdf.format(c.getTime());
GlobalClass application = (GlobalClass) getApplication();
final File projectfile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM), application.projectnameheader);
if (!projectfile.exists()) {
Log.d(TAG, "Folder doesn't exist, creating it...");
boolean rv = projectfile.mkdir();
}
String currentDateTimeString = java.text.DateFormat.getDateTimeInstance().format(new Date());
TextView dateandtime = (TextView) findViewById(R.id.dateandtime);
dateandtime.setText(currentDateTimeString);
gpsdisplay.setText(String.format("%.5f", latitude) + ", " + String.format("%.5f", longitude));
altitudetext.setText(String.format("%.2f", altitude) + " Meters");
if(cameraDevice == null)
return;
CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
try{
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
Size[] jpegSizes = null;
if(characteristics != null)
jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP)
.getOutputSizes(ImageFormat.JPEG);
//Capture image with custom size
int width = 480;
int height = 640;
if(jpegSizes != null && jpegSizes.length > 0)
{
width = jpegSizes[0].getWidth();
height = jpegSizes[0].getHeight();
}
final ImageReader reader = ImageReader.newInstance(width,height,ImageFormat.JPEG,2);
List<Surface> outputSurface = new ArrayList<>(2);
outputSurface.add(reader.getSurface());
outputSurface.add(new Surface(textureView2.getSurfaceTexture()));
final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
captureBuilder.addTarget(reader.getSurface());
captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
//Check orientation base on device
time = sdftime.format(c.getTime());
date = sdf.format(c.getTime());
int rotation = getWindowManager().getDefaultDisplay().getRotation();
captureBuilder.set(CaptureRequest.JPEG_ORIENTATION,ORIENTATIONS.get(rotation));
file = new File(projectfile+"/"+(application.projectnameheader+"_"+date+"_"+time)+".jpg");
ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
@Override
public void onImageAvailable(ImageReader imageReader) {
Image image = null;
try{
image = reader.acquireLatestImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] bytes = new byte[buffer.capacity()];
buffer.get(bytes);
save(bytes);
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
finally {
{
if(image != null)
image.close();
}
}
}
private void save(byte[] bytes) throws IOException {
OutputStream outputStream = null;
try{
outputStream = new FileOutputStream(file);
outputStream.write(bytes);
}finally {
if(outputStream != null)
outputStream.close();
}
}
};
reader.setOnImageAvailableListener(readerListener,mBackgroundHandler);
final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
@Override
public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
GlobalClass application = (GlobalClass) getApplication();
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());
Bitmap dest = Bitmap.createBitmap(bitmap.getHeight(), bitmap.getWidth(), Bitmap.Config.ARGB_8888);
Canvas cs = new Canvas(dest);
cs.rotate(90,720 ,720);
Paint tPaint = new Paint();
tPaint.setTextSize(bitmap.getHeight()/25);
tPaint.setColor(Color.WHITE);
tPaint.setStyle(Paint.Style.FILL);
cs.drawBitmap(bitmap, 0f, 0f, null);
float height = tPaint.measureText("yY");
cs.rotate(270,720 ,720);
cs.drawText(application.projectnameheader, 25, bitmap.getHeight()+545+bitmap.getHeight()/25, tPaint);
cs.drawText(currentDateTimeString, 25, bitmap.getHeight()+615+bitmap.getHeight()/25, tPaint);
cs.drawText(String.format("%.0f",currectAzimuth) + "°", 1225, bitmap.getHeight()+690+bitmap.getHeight()/25, tPaint);
cs.drawText(directionNESW, 1235, bitmap.getHeight()+615+bitmap.getHeight()/25, tPaint);
cs.drawText(String.format("%.5f", latitude) + ", " + String.format("%.5f", longitude), 25, bitmap.getHeight()+690+bitmap.getHeight()/25, tPaint);
cs.drawText(String.format("%.2f", altitude) + " Meters", 25, bitmap.getHeight()+755+bitmap.getHeight()/25, tPaint);
cs.drawText(names, 25,bitmap.getHeight()+825+bitmap.getHeight()/25, tPaint);
Bitmap compassbitmap = BitmapFactory.decodeResource(getResources(), R.drawable.compass2);
cs.rotate(azimuth*-1,-190,2500);
cs.scale(0.25f,0.25f,-190,2500);
cs.drawBitmap(compassbitmap, 0, 0, null);
if (photowithcode==true) {
cs.drawText(code, 25, bitmap.getHeight()+895+bitmap.getHeight()/25, tPaint);
cs.drawText(note, 25, bitmap.getHeight()+970+bitmap.getHeight()/25, tPaint);
photowithcode=false;
}
try {
dest.compress(Bitmap.CompressFormat.JPEG, 100, new FileOutputStream(new File(projectfile+"/"+(application.projectnameheader+"_"+date+"_"+time)+"___WITHTEXT.jpg")));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
gpslist.add(latitude + longitude);
Toast.makeText(Photo_Page.this, "Saved "+file, Toast.LENGTH_SHORT).show();
createCameraPreview();
}
};
cameraDevice.createCaptureSession(outputSurface, new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
try{
cameraCaptureSession.capture(captureBuilder.build(),captureListener,mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
}
},mBackgroundHandler);

} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void createCameraPreview() {
try{
SurfaceTexture texture = textureView2.getSurfaceTexture();
assert  texture != null;
texture.setDefaultBufferSize(imageDimension.getWidth(),imageDimension.getHeight());
Surface surface = new Surface(texture);
captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
captureRequestBuilder.addTarget(surface);
cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
@Override
public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
if(cameraDevice == null)
return;
cameraCaptureSessions = cameraCaptureSession;
updatePreview();
}
@Override
public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
Toast.makeText(Photo_Page.this, "Changed", Toast.LENGTH_SHORT).show();
}
},null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
private void updatePreview() {
if(cameraDevice == null)
Toast.makeText(this, "Error", Toast.LENGTH_SHORT).show();
captureRequestBuilder.set(CaptureRequest.CONTROL_MODE,CaptureRequest.CONTROL_MODE_AUTO);
try{
cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(),null,mBackgroundHandler);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}

private void openCamera() {
CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
try{
cameraId = manager.getCameraIdList()[0];
CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
assert map != null;
imageDimension = map.getOutputSizes(SurfaceTexture.class)[0];
//Check realtime permission if run higher API 23
if(ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
{
ActivityCompat.requestPermissions(this,new String[]{
Manifest.permission.CAMERA,
Manifest.permission.WRITE_EXTERNAL_STORAGE
},REQUEST_CAMERA_PERMISSION);
return;
}
manager.openCamera(cameraId,stateCallback,null);
} catch (CameraAccessException e) {
e.printStackTrace();
}
}
TextureView.SurfaceTextureListener textureListener = new TextureView.SurfaceTextureListener() {
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
openCamera();
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i1) {
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
return false;
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
}
};
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == REQUEST_CAMERA_PERMISSION) {
if (grantResults[0] != PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "You can't use camera without permission", Toast.LENGTH_SHORT).show();
finish();
}
}
}
@Override
protected void onResume() {
super.onResume();
mSensorManager.registerListener(this,mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
SensorManager.SENSOR_DELAY_GAME);
mSensorManager.registerListener(this,mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
SensorManager.SENSOR_DELAY_GAME);
startBackgroundThread();
if(textureView2.isAvailable())
openCamera();
else
textureView2.setSurfaceTextureListener(textureListener);
}
@Override
protected void onPause() {
stopBackgroundThread();
super.onPause();
mSensorManager.unregisterListener(this);
}
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
final float alpha= 0.97f;
synchronized (this) {
if(sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
mGravity[0] = alpha*mGravity[0]+(1-alpha)*sensorEvent.values[0];
mGravity[1] = alpha*mGravity[1]+(1-alpha)*sensorEvent.values[1];
mGravity[2] = alpha*mGravity[2]+(1-alpha)*sensorEvent.values[2];
}
if(sensorEvent.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {
mGeomagnetic[0] = alpha*mGeomagnetic[0]+(1-alpha)*sensorEvent.values[0];
mGeomagnetic[1] = alpha*mGeomagnetic[1]+(1-alpha)*sensorEvent.values[1];
mGeomagnetic[2] = alpha*mGeomagnetic[2]+(1-alpha)*sensorEvent.values[2];
}
float R[] = new float[9];
float I[] = new float[9];
boolean success = SensorManager.getRotationMatrix(R,I,mGravity,mGeomagnetic);
if (success){
float orientation[] = new float[3];
SensorManager.getOrientation(R,orientation);
azimuth = (float)Math.toDegrees(orientation[0]);
azimuth = (azimuth+360)%360;
//
Animation anim = new RotateAnimation(-currectAzimuth,-azimuth, Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF,0.5f);
currectAzimuth = azimuth;
degrees.setText(String.format("%.0f",currectAzimuth) + "°");
anim.setDuration(500);
anim.setRepeatCount(0);
anim.setFillAfter(true);
compass2.startAnimation(anim);
}
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
private void stopBackgroundThread() {
mBackgroundThread.quitSafely();
try{
mBackgroundThread.join();
mBackgroundThread= null;
mBackgroundHandler = null;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
private void startBackgroundThread() {
mBackgroundThread = new HandlerThread("Camera Background");
mBackgroundThread.start();
mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
}
}

我使用此代码的目标是在保存到设备上的特殊文件的图片上绘制指南针的图像。我通过拍照测试了这一点，但我注意到，即使我的代码中没有任何更改，指南针也会移动到一个随机的位置，有时甚至不会出现。

Answer 1

旋转中心和其他项目似乎有很多硬编码的位置，这些位置可能不适合位图背景画布的实际大小。

旋转中心最好是位图的中心，即bitmap.getHeight()/2f和bitmap.getWidth()/2f，并使所有内容都与位图的大小有关。

例如

cs.rotate(90,bitmap.getWidth()/2f ,bitmap.getHeight()/2f);

你似乎也会围绕一个值旋转，这个值会随着你拿手机的方式和磁场的波动而发生很大变化。磁传感器的读数不那么准确，azimuth旋转的中心也是一个奇怪的硬编码位置(0.25f的刻度也是如此(