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问题:

I created a class to take picture from camera in my application. This class will take a picture with camera and store it in a folder with an unique name. But when I want to get picture path in onActivityResult method Iget null of data all the time!

this is my class Camera:

public class Camera{

  private Activity activity;
  private SystemTools systemTools;


  public Camera(Context context) {

    this.activity = (Activity) context;
    systemTools = new SystemTools();
  }

  /**
   * This Method will take a picture with camera for us
   */

  public void takePicture() {

    boolean cameraAvailable = systemTools.device_isHardwareFeatureAvailable(activity, PackageManager.FEATURE_CAMERA);

    if (cameraAvailable &&
      systemTools.system_isIntentAvailable(activity, MediaStore.ACTION_IMAGE_CAPTURE)) {

      Intent takePicIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

      //We prepare the intent to store the taken picture
      try {

        File outputDir = systemTools.storage_getExternalPublicFolder("ReportsAttachments", true);
        File outFile = systemTools.storage_createUniqueFileName("cameraPic", ".jpg", outputDir);

        takePicIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(outFile));

      } catch (Exception e) {
        Toast.makeText(activity, "در دریافت تصویر اشکالی رخ داده است ، لطفا دوباره تلاش کنید.", Toast.LENGTH_SHORT).show();
      }

      activity.startActivityForResult(takePicIntent, App.REQUEST_IMAGE_CAPTURE);


    } else {
      if (cameraAvailable) {
        Toast.makeText(activity, "برنامه ی دوربین دستگاه خراب است.", Toast.LENGTH_SHORT).show();

      } else {
        Toast.makeText(activity, "دسترسی به دوربین سیستم امکان پذیر نمی باشد.", Toast.LENGTH_SHORT).show();
      }
    }
  }
}

An i Set onActivityResult() method in Activity that i used camera. like this:

 @Override
  public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    try {
      if (requestCode == App.REQUEST_IMAGE_CAPTURE) {
        if (resultCode == Activity.RESULT_OK && data != null) {
          Log.i("ATTACH", "In Result");

          Bitmap bmp = (Bitmap) data.getExtras().get("data");
          ByteArrayOutputStream stream = new ByteArrayOutputStream();

          // CALL THIS METHOD TO GET THE URI FROM THE BITMAP
          Uri selectedImage = getImageUri(this, bmp);
          String realPath = getRealPathFromURI(selectedImage);
          selectedImage = Uri.parse(realPath);
          presenter.onNewAttachmentRequest(selectedImage.getPath());


        }
      }
    } catch (Exception e) {
      Log.i("ATTACH", e + "  Something went wrong");
    }
  }

this works fine and taked pictre is avaliable on SD_Card but when I want to get path of picture I cant't because 'data' in onActivityResult is null all the time! Where is the problem with this code?

Thank you.

回答1:

takePicIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(outFile));

As you see you have pass the File Uri to the intent i.e the Camera app will write the taken image at this path and will not return the Bitmap. Just save this path as global in your class and use it in onActivityResult(). You need to add this also cause camera apps are device dependent.

takePicIntent.putExtra("return-data", false);

回答2:

when I want to get path of picture

You already have the path of the picture. It is outFile. Save it in a field and hold onto it across configuration changes. Also, since Uri.fromFile() will not work on Android 7.0+ especially well, consider switching to FileProvider, as I do in the following activity from this sample project:

/***
 Copyright (c) 2008-2017 CommonsWare, LLC
 Licensed under the Apache License, Version 2.0 (the "License"); you may not
 use this file except in compliance with the License. You may obtain a copy
 of the License at http://www.apache.org/licenses/LICENSE-2.0. Unless required
 by applicable law or agreed to in writing, software distributed under the
 License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
 OF ANY KIND, either express or implied. See the License for the specific
 language governing permissions and limitations under the License.

 Covered in detail in the book _The Busy Coder's Guide to Android Development_
 https://commonsware.com/Android
 */

package com.commonsware.android.camcon;

import android.Manifest;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.ClipData;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.MediaStore;
import android.support.v4.content.FileProvider;
import android.widget.Toast;
import java.io.File;
import java.util.List;

public class MainActivity extends Activity {
  private static final String EXTRA_FILENAME=
    "com.commonsware.android.camcon.EXTRA_FILENAME";
  private static final String FILENAME="CameraContentDemo.jpeg";
  private static final int CONTENT_REQUEST=1337;
  private static final String AUTHORITY=
    BuildConfig.APPLICATION_ID+".provider";
  private static final String PHOTOS="photos";
  private File output=null;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (savedInstanceState==null) {
      output=new File(new File(getFilesDir(), PHOTOS), FILENAME);

      if (output.exists()) {
        output.delete();
      }
      else {
        output.getParentFile().mkdirs();
      }

      Intent i=new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
      Uri outputUri=FileProvider.getUriForFile(this, AUTHORITY, output);

      i.putExtra(MediaStore.EXTRA_OUTPUT, outputUri);

      if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.LOLLIPOP) {
        i.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
      }
      else if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.JELLY_BEAN) {
        ClipData clip=
          ClipData.newUri(getContentResolver(), "A photo", outputUri);

        i.setClipData(clip);
        i.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
      }
      else {
        List<ResolveInfo> resInfoList=
          getPackageManager()
            .queryIntentActivities(i, PackageManager.MATCH_DEFAULT_ONLY);

        for (ResolveInfo resolveInfo : resInfoList) {
          String packageName = resolveInfo.activityInfo.packageName;
          grantUriPermission(packageName, outputUri,
            Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        }
      }

      try {
        startActivityForResult(i, CONTENT_REQUEST);
      }
      catch (ActivityNotFoundException e) {
        Toast.makeText(this, R.string.msg_no_camera, Toast.LENGTH_LONG).show();
        finish();
      }
    }
    else {
      output=(File)savedInstanceState.getSerializable(EXTRA_FILENAME);
    }
  }

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);

    outState.putSerializable(EXTRA_FILENAME, output);
  }

  @Override
  protected void onActivityResult(int requestCode, int resultCode,
                                  Intent data) {
    if (requestCode == CONTENT_REQUEST) {
      if (resultCode == RESULT_OK) {
        Intent i=new Intent(Intent.ACTION_VIEW);
        Uri outputUri=FileProvider.getUriForFile(this, AUTHORITY, output);

        i.setDataAndType(outputUri, "image/jpeg");
        i.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

        try {
          startActivity(i);
        }
        catch (ActivityNotFoundException e) {
          Toast.makeText(this, R.string.msg_no_viewer, Toast.LENGTH_LONG).show();
        }

        finish();
      }
    }
  }
}