android - 拍照后获取gps位置

Question

我在拍照时试图获取 gps 位置。当 LocationChanged 方法在变量中运行时，我保存了位置监听器的位置，并希望在拍照时显示它。这是正确的方法吗？我使用安卓 2.3.6。这是我的代码:

    package com.exercise;



import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.content.pm.ActivityInfo;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore.Images.Media;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;

public class AndroidCamera extends Activity implements SurfaceHolder.Callback{

    Camera camera;
    SurfaceView surfaceView;
    SurfaceHolder surfaceHolder;
    boolean previewing = false;
    LayoutInflater controlInflater = null;

    Button buttonTakePicture;

    final int RESULT_SAVEIMAGE = 0;

    public Location test;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

        LocationManager mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        LocationListener mlocListener = new MyLocationListener();
        mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener);

        getWindow().setFormat(PixelFormat.UNKNOWN);
        surfaceView = (SurfaceView)findViewById(R.id.camerapreview);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        controlInflater = LayoutInflater.from(getBaseContext());
        View viewControl = controlInflater.inflate(R.layout.control, null);
        LayoutParams layoutParamsControl 
            = new LayoutParams(LayoutParams.FILL_PARENT, 
            LayoutParams.FILL_PARENT);
        this.addContentView(viewControl, layoutParamsControl);

        buttonTakePicture = (Button)findViewById(R.id.takepicture);
        buttonTakePicture.setOnClickListener(new Button.OnClickListener(){

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                camera.takePicture(myShutterCallback, 
                        myPictureCallback_RAW, myPictureCallback_JPG);
            }});

        LinearLayout layoutBackground = (LinearLayout)findViewById(R.id.background);
        layoutBackground.setOnClickListener(new LinearLayout.OnClickListener(){

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub

                buttonTakePicture.setEnabled(false);
                camera.autoFocus(myAutoFocusCallback);
            }});
    }

    public class MyLocationListener implements LocationListener{

        @Override

        public void onLocationChanged(Location loc){
            loc.getLatitude();
            loc.getLongitude();
            String Text = "Lat = " + loc.getLatitude() + "|Long = " + loc.getLongitude();
            Toast.makeText( getApplicationContext(), Text, Toast.LENGTH_SHORT).show();
          //  final TextView tv = (TextView) findViewById(R.id.text);
          //  tv.setText(tv.getText()+ "||" + Text);
            test = loc;
        }

        @Override

        public void onProviderDisabled(String provider){
            Toast.makeText( getApplicationContext(),"Gps Disabled", Toast.LENGTH_SHORT ).show();
        }

        @Override

        public void onProviderEnabled(String provider){
            Toast.makeText( getApplicationContext(),"Gps Enabled",Toast.LENGTH_SHORT).show();
        }

        @Override

        public void onStatusChanged(String provider, int status, Bundle extras){
        }

    }

    AutoFocusCallback myAutoFocusCallback = new AutoFocusCallback(){

        @Override
        public void onAutoFocus(boolean arg0, Camera arg1) {
            // TODO Auto-generated method stub
            buttonTakePicture.setEnabled(true);
        }};

    ShutterCallback myShutterCallback = new ShutterCallback(){

        @Override
        public void onShutter() {
            // TODO Auto-generated method stub

        }};

    PictureCallback myPictureCallback_RAW = new PictureCallback(){

        @Override
        public void onPictureTaken(byte[] arg0, Camera arg1) {
            // TODO Auto-generated method stub

        }};

    PictureCallback myPictureCallback_JPG = new PictureCallback(){

        @Override
        public void onPictureTaken(byte[] arg0, Camera arg1) {
            // TODO Auto-generated method stub
            /*Bitmap bitmapPicture 
                = BitmapFactory.decodeByteArray(arg0, 0, arg0.length);  */

            Uri uriTarget = getContentResolver().insert(Media.EXTERNAL_CONTENT_URI, new ContentValues());

            OutputStream imageFileOS;
            try {
                imageFileOS = getContentResolver().openOutputStream(uriTarget);
                imageFileOS.write(arg0);
                imageFileOS.flush();
                imageFileOS.close();

//              Toast.makeText(AndroidCamera.this, 
//                      "Image saved: " + uriTarget.toString(), 
//                      Toast.LENGTH_LONG).show();
//              test.getLatitude();
//              test.getLongitude();
//              String Text = "Lat = " + test.getLatitude() + "|Long = " + test.getLongitude();
//              Toast.makeText( getApplicationContext(), Text, Toast.LENGTH_SHORT).show();
                if (test==null){
                    Toast.makeText(AndroidCamera.this, "null", Toast.LENGTH_SHORT).show();
                }
                else{
                    test.getLatitude();
                    String ausgabe = String.valueOf(test.getLatitude());
                    Toast.makeText(AndroidCamera.this, ausgabe, Toast.LENGTH_SHORT).show();
                }

            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            camera.startPreview();
        }};

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        // TODO Auto-generated method stub
        if(previewing){
            camera.stopPreview();
            previewing = false;
        }

        if (camera != null){
            try {
                camera.setPreviewDisplay(surfaceHolder);
                camera.startPreview();
                previewing = true;
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        camera = Camera.open();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        camera.stopPreview();
        camera.release();
        camera = null;
        previewing = false;
    }
}

Answer 1

是的，这是一种公平的方式。顺便说一下，您可以改用 .requestSingleUpdate()，因为您只需要一次更新。您可能也不应该等到 GPS 信息到达(并且，您还可以指定不同于 gps 提供商的内容，例如任何提供商，它可能会更快地响应——而不是从 GPS 可能冷启动)。如果这些都不起作用，您可以随时查询最后已知的位置。由于更新可能暂时不会到达，您可能应该懒惰地将图像数据保存在某个地方(没有位置信息)，然后在位置可用时更新信息。