我已经通过很多链接寻找解决方案，但这是我在Android中的第一个官方应用。我已经制作了像计算器这样的其他小类，但没有像这样，所以即使我阅读它们，我也无法理解建议和解决方案。
该应用程序基本上执行以下操作： -
第一个类适用于曲面视图。第二个是拍摄照片和计算传感器读数
我已经制定了前两部分。但第三部分是问题。 每次拍摄图像时，应用程序都会挂起，表面视图会停止工作。没有任何反应。当我再旋转10度时，应用程序崩溃了。
有人可以告诉我我做错了什么。提前谢谢。
package com.example.mehta.accelerometerin;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.hardware.Camera;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorManager;
import android.net.Uri;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.hardware.SensorEventListener;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import static android.content.ContentValues.TAG;
import static android.provider.MediaStore.Files.FileColumns.MEDIA_TYPE_IMAGE;
import static java.lang.Math.sqrt;
class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null) {
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e) {
// ignore: tried to stop a non-existent preview
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.setDisplayOrientation(90);
mCamera.startPreview();
} catch (Exception e) {
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
}
class MainActivity extends AppCompatActivity implements SensorEventListener {
private Camera mCamera;
private CameraPreview mPreview;
private SensorManager senSensorManager;
private Sensor senAccelerometer;
private Sensor senGyroscope;
private long lastUpdate = 0;
private float last_x, last_y, last_z;
private static final int SHAKE_THRESHOLD = 600;
TextView tv1, tv2, tv3, tv4, tv5;
int j = 0;
int i = 1;
int l = 10;
int m = 0;
private float xg, yg, zg, xa, ya, za;
private float x1, y1;
float x2, y2;
private float xang, yang, zang;
private float zacc;
private float xacc;
private float yacc;
private int greset;
public static Camera getCameraInstance() {
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
} catch (Exception e) {
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create an instance of Camera
mCamera = getCameraInstance();
// Create our Preview view and set it as the content of our activity.
mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
greset = 0;
senSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
senAccelerometer = senSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
senGyroscope = senSensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
senSensorManager.registerListener(this,senAccelerometer,SensorManager.SENSOR_DELAY_NORMAL);
senSensorManager.registerListener(this,senGyroscope,SensorManager.SENSOR_DELAY_NORMAL);
}
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
/** Create a file Uri for saving an image or video */
private static Uri getOutputMediaFileUri(int type){
return Uri.fromFile(getOutputMediaFile(type));
}
/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MyCameraApp");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()){
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
} else if(type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"VID_"+ timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
Toast.makeText(getApplicationContext(), "on Picture Taken", Toast.LENGTH_SHORT).show();
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions: " );
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}
};
protected void onPause() {
super.onPause();
senSensorManager.unregisterListener(this);
}
protected void onResume() {
super.onResume();
senSensorManager.registerListener(this,senAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
senSensorManager.registerListener(this,senGyroscope,SensorManager.SENSOR_DELAY_NORMAL);
}
public void onSensorChanged(SensorEvent sensorEvent) {
Sensor mySensor = sensorEvent.sensor;
if (mySensor.getType() == Sensor.TYPE_GYROSCOPE) {
greset ++;
zg += sensorEvent.values[1];
xg +=sensorEvent.values[0];
yg +=sensorEvent.values[2];
if(zg>30)
{
zg=0;
}
if(xg>30)
{
xg=0;
}
if(yg>30)
{
yg=0;
}
xang = xg*12;
yang = yg*12;
zang = zg*12;
if(zang>=l) {
Toast.makeText(getApplicationContext(), "click="+i, Toast.LENGTH_SHORT).show();
mCamera.stopPreview();
mCamera.takePicture(null,null,mPicture);
mCamera.startPreview();
l += 10;
i++;}
if (greset >10)
{
xg +=0.1;
greset = 0;
}
}
if(mySensor.getType()==Sensor.TYPE_ACCELEROMETER)
{
xa = sensorEvent.values[0];
za = sensorEvent.values[1];
ya = sensorEvent.values[2];
zacc = (float)(za - (((90 - xang)/ 90) * 9.8));
}
if (l > 360) {
l = 10;
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
public int returnvalue(){
return(i);
}
}
答案 0 :(得分：0)
在致电stopPreview()之前不要立即致电takePicture()：This method is only valid when preview is active (after startPreview()). Preview will be stopped after the image is taken。
您应该从startPreview()致电onPictureTaken()，而不是在致电takePicture()后立即致电。
在单独的处理程序线程上打开相机，而不是在主（UI）线程上打开。
您的代码可能存在其他问题，但让我们从修复这三个直接问题开始。