通过从相机拍照使 onActivityResult 为空

Question

我在我的应用程序中创建了一个从相机拍照的类。 此类将使用相机拍照并将其存储在具有唯一名称的文件夹中。 但是当我想在onActivityResult方法中获取图片路径时，总是data的Iget null！

这是我的班级相机：

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();
      }
    }
  }
}

我在使用相机的 Activity 中设置 onActivityResult() 方法。像这样：

 @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");
    }
  }

这工作正常，拍摄的照片可在 SD_Card 上使用，但是当我想获取图片路径时，我不能，因为 onActivityResult 中的“数据”一直为空！ 这段代码哪里出了问题？

谢谢。

Answer 1

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

如您所见，您已将文件 Uri 传递给意图，即相机应用程序会将拍摄的图像写入此路径，并且不会返回位图。 只需将此路径保存为类中的全局路径并在 onActivityResult() 中使用它。 您还需要添加它，因为相机应用程序依赖于设备。

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

Answer 2

当我想获取图片路径时

你已经有了图片的路径。它是outFile。将其保存在一个字段中并在配置更改时保留它。此外，由于 Uri.fromFile() 在 Android 7.0+ 上无法运行得特别好，请考虑切换到 FileProvider，就像我在来自 this sample project 的以下活动中所做的那样：

/***
 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();
      }
    }
  }
}