下面是一个示例活动，它将启动相机应用程序，然后检索图像并显示它。

package edu.gvsu.cis.masl.camerademo;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class MyCameraActivity extends Activity
{
    private static final int CAMERA_REQUEST = 1888; 
    private ImageView imageView;
    private static final int MY_CAMERA_PERMISSION_CODE = 100;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        this.imageView = (ImageView)this.findViewById(R.id.imageView1);
        Button photoButton = (Button) this.findViewById(R.id.button1);
        photoButton.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
                {
                    requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_PERMISSION_CODE);
                }
                else
                {
                    Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
                    startActivityForResult(cameraIntent, CAMERA_REQUEST);
                } 
            }
        });
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
    {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == MY_CAMERA_PERMISSION_CODE)
        {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
            {
                Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
                Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); 
                startActivityForResult(cameraIntent, CAMERA_REQUEST);
            }
            else
            {
                Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {  
        if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK)
        {  
            Bitmap photo = (Bitmap) data.getExtras().get("data"); 
            imageView.setImageBitmap(photo);
        }  
    } 
}

请注意，相机应用程序本身提供了查看/重拍图像的功能，一旦图像被接受，活动就会显示它。

下面是上面的活动使用的布局。它只是一个包含id为button1的Button和id为imageview1的ImageView的LinearLayout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/photo"></Button>
    <ImageView android:id="@+id/imageView1" android:layout_height="wrap_content" android:src="@drawable/icon" android:layout_width="wrap_content"></ImageView>

</LinearLayout>

最后一个细节，一定要加上:

<uses-feature android:name="android.hardware.camera"></uses-feature> 

如果摄像头是你应用功能的可选选项。请确保在权限中将require设置为false。像这样

<uses-feature android:name="android.hardware.camera" android:required="false"></uses-feature>

到你的manifest.xml。

更新(2020)

谷歌已经添加了一个新的ActivityResultRegistry API，“让你处理startActivityForResult() + onActivityResult()以及requestPermissions() + onRequestPermissionsResult()流，而无需覆盖你的活动或片段中的方法，通过ActivityResultContract带来了增加的类型安全性，并为测试这些流提供了钩子”。

该API是在androidx中添加的。和androidx.fragment 1.3.0-alpha02。

所以你现在可以这样做:

val takePicture = registerForActivityResult(ActivityResultContracts.TakePicture()) { success: Boolean ->
    if (success) {
        // The image was saved into the given Uri -> do something with it
    }
}

val imageUri: Uri = ...
button.setOnClickListener {
    takePicture.launch(imageUri)
}

查看文档了解如何使用新的Activity结果API: https://developer.android.com/training/basics/intents/result#kotlin

有许多内置的activityresultcontract，允许您做不同的事情，如选择联系人，请求权限，拍照或拍摄视频。您可能对ActivityResultContracts感兴趣。拍摄上图。

注意androidx.fragment 1.3.0-alpha04弃用了Fragment上的startActivityForResult() + onActivityResult()和requestPermissions() + onRequestPermissionsResult() api。因此，从现在开始ActivityResultContracts似乎是一种新的做事方式。

原答案(2015)

我花了好几个小时才把它修好。代码几乎是从developer.android.com复制粘贴而来的，只有细微的区别。

在AndroidManifest.xml上请求此权限:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

在你的Activity中，首先定义这个:

static final int REQUEST_IMAGE_CAPTURE = 1;
private Bitmap mImageBitmap;
private String mCurrentPhotoPath;
private ImageView mImageView;

然后在onClick中触发这个Intent:

Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (cameraIntent.resolveActivity(getPackageManager()) != null) {
    // Create the File where the photo should go
    File photoFile = null;
    try {
        photoFile = createImageFile();
    } catch (IOException ex) {
        // Error occurred while creating the File
        Log.i(TAG, "IOException");
    }
    // Continue only if the File was successfully created
    if (photoFile != null) {
        cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
        startActivityForResult(cameraIntent, REQUEST_IMAGE_CAPTURE);
    }
}

添加以下支持方法:

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  // prefix
            ".jpg",         // suffix
            storageDir      // directory
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    return image;
}

然后接收结果:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        try {
            mImageBitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), Uri.parse(mCurrentPhotoPath));
            mImageView.setImageBitmap(mImageBitmap);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

使它工作的是MediaStore.Images.Media.getBitmap(this.getContentResolver()， Uri.parse(mCurrentPhotoPath))，这与developer.android.com的代码不同。原始代码给了我一个FileNotFoundException。

我创建了一个对话框，可以从图库或相机中选择图像。 回调函数为

Uri，如果图像来自图库 字符串作为文件路径，如果图像是从相机捕获。 从相机中选择的图像需要作为多部分文件数据上传到互联网上

首先，我们要在AndroidManifest中定义权限，因为我们需要在创建文件和从画廊读取图像时写入外部存储

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

中创建file_paths xml文件 应用程序/ src / main / res / xml / file_paths.xml

与路径

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="external_files" path="."/>
</paths>

然后我们需要定义文件提供者来生成Content uri来访问存储在外部存储器中的文件

<provider
    android:name="androidx.core.content.FileProvider"
    android:authorities="${applicationId}.provider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths" />
</provider>

河流布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <androidx.constraintlayout.widget.Guideline
        android:id="@+id/guideline2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintGuide_percent="0.50" />

    <ImageView
        android:id="@+id/gallery"
        android:layout_width="48dp"
        android:layout_height="48dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="32dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="@+id/guideline2"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_menu_gallery" />

    <ImageView
        android:id="@+id/camera"
        android:layout_width="48dp"
        android:layout_height="0dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="32dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/guideline2"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/ic_menu_camera" />
</androidx.constraintlayout.widget.ConstraintLayout>

ImagePicker Dailog

public class ImagePicker extends BottomSheetDialogFragment {
ImagePicker.GetImage getImage;
public ImagePicker(ImagePicker.GetImage getImage, boolean allowMultiple) {
    this.getImage = getImage;
}
File cameraImage;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.bottom_sheet_imagepicker, container, false);
    view.findViewById(R.id.camera).setOnClickListener(new View.OnClickListener() {@
        Override
        public void onClick(View view) {
            if(ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(new String[] {
                    Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE
                }, 2000);
            } else {
                captureFromCamera();
            }
        }
    });
    view.findViewById(R.id.gallery).setOnClickListener(new View.OnClickListener() {@
        Override
        public void onClick(View view) {
            if(ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(new String[] {
                    Manifest.permission.READ_EXTERNAL_STORAGE
                }, 2000);
            } else {
                startGallery();
            }
        }
    });
    return view;
}
public interface GetImage {
    void setGalleryImage(Uri imageUri);
    void setCameraImage(String filePath);
    void setImageFile(File file);
}@
Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(resultCode == Activity.RESULT_OK) {
        if(requestCode == 1000) {
            Uri returnUri = data.getData();
            getImage.setGalleryImage(returnUri);
            Bitmap bitmapImage = null;
        }
        if(requestCode == 1002) {
            if(cameraImage != null) {
                getImage.setImageFile(cameraImage);
            }
            getImage.setCameraImage(cameraFilePath);
        }
    }
}
private void startGallery() {
    Intent cameraIntent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    cameraIntent.setType("image/*");
    if(cameraIntent.resolveActivity(getActivity().getPackageManager()) != null) {
        startActivityForResult(cameraIntent, 1000);
    }
}
private String cameraFilePath;
private File createImageFile() throws IOException {
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM), "Camera");
    File image = File.createTempFile(imageFileName, /* prefix */ ".jpg", /* suffix */ storageDir /* directory */ );
    cameraFilePath = "file://" + image.getAbsolutePath();
    cameraImage = image;
    return image;
}
private void captureFromCamera() {
    try {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        intent.putExtra(MediaStore.EXTRA_OUTPUT, FileProvider.getUriForFile(getContext(), BuildConfig.APPLICATION_ID + ".provider", createImageFile()));
        startActivityForResult(intent, 1002);
    } catch(IOException ex) {
        ex.printStackTrace();
    }
}

}

像这样调用Activity或fragment 在Fragment/Activity中定义ImagePicker

ImagePicker imagePicker;

然后在点击按钮时调用dailog

      imagePicker = new ImagePicker(new ImagePicker.GetImage() {
            @Override
            public void setGalleryImage(Uri imageUri) {

                Log.i("ImageURI", imageUri + "");

                String[] filePathColumn = {MediaStore.Images.Media.DATA};

                Cursor cursor = getContext().getContentResolver().query(imageUri, filePathColumn, null, null, null);
                assert cursor != null;
                cursor.moveToFirst();

                int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
                mediaPath = cursor.getString(columnIndex);
                // Set the Image in ImageView for Previewing the Media
                imagePreview.setImageBitmap(BitmapFactory.decodeFile(mediaPath));
                cursor.close();

            }

            @Override
            public void setCameraImage(String filePath) {

                mediaPath =filePath;
                Glide.with(getContext()).load(filePath).into(imagePreview);

            }

            @Override
            public void setImageFile(File file) {

                cameraImage = file;

            }
        }, true);
        imagePicker.show(getActivity().getSupportFragmentManager(), imagePicker.getTag());

请使用Kotlin和Andoirdx支持来实现这个例子:

button1.setOnClickListener{
        file = getPhotoFile()
        val uri: Uri = FileProvider.getUriForFile(applicationContext, "com.example.foto_2.filrprovider", file!!)
        captureImage.putExtra(MediaStore.EXTRA_OUTPUT, uri)

        val camaraActivities: List<ResolveInfo> = applicationContext.getPackageManager().queryIntentActivities(captureImage, PackageManager.MATCH_DEFAULT_ONLY)

        for (activity in camaraActivities) {
            applicationContext.grantUriPermission(activity.activityInfo.packageName, uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
        }

        startActivityForResult(captureImage, REQUEST_PHOTO)
    }

活动结果:

if (requestCode == REQUEST_PHOTO) {
        val uri = FileProvider.getUriForFile(applicationContext, "com.example.foto_2.filrprovider", file!!)
        applicationContext.revokeUriPermission(uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
        imageView1.viewTreeObserver.addOnGlobalLayoutListener {
            width = imageView1.width
            height = imageView1.height
            imageView1.setImageBitmap(getScaleBitmap(file!!.path , width , height))
        }
        if(width!=0&&height!=0){
            imageView1.setImageBitmap(getScaleBitmap(file!!.path , width , height))
        }else{
            val size = Point()
            this.windowManager.defaultDisplay.getSize(size)
            imageView1.setImageBitmap(getScaleBitmap(file!!.path , size.x , size.y))
        }

    }

您可以在https://github.com/joelmmx/take_photo_kotlin.git上获得更多详细信息

我希望它能帮助你!

我知道这是一个相当老的线程，但所有这些解决方案都没有完成，当用户旋转相机时，不工作在一些设备上，因为onActivityResult中的数据是空的。这是我在很多设备上测试过的解决方案，到目前为止还没有遇到任何问题。

首先在activity中声明Uri变量:

private Uri uriFilePath;

然后创建临时文件夹，用于存储捕获的图像，并通过相机捕获图像:

PackageManager packageManager = getActivity().getPackageManager();
if (packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
    File mainDirectory = new File(Environment.getExternalStorageDirectory(), "MyFolder/tmp");
         if (!mainDirectory.exists())
             mainDirectory.mkdirs();

          Calendar calendar = Calendar.getInstance();

          uriFilePath = Uri.fromFile(new File(mainDirectory, "IMG_" + calendar.getTimeInMillis()));
          intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
          intent.putExtra(MediaStore.EXTRA_OUTPUT, uriFilePath);
          startActivityForResult(intent, 1);
}

这里有一个最重要的事情，你必须保存你的uriFilePath在onSaveInstanceState中，因为如果你不这样做，用户在使用camera时旋转他的设备，你的uri将为null。

@Override
protected void onSaveInstanceState(Bundle outState) {
     if (uriFilePath != null)
         outState.putString("uri_file_path", uriFilePath.toString());
     super.onSaveInstanceState(outState);
}

之后，你应该在onCreate方法中恢复你的uri:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
         if (uriFilePath == null && savedInstanceState.getString("uri_file_path") != null) {
             uriFilePath = Uri.parse(savedInstanceState.getString("uri_file_path"));
         }
    } 
}

这里是最后一部分，获得你的Uri在onActivityResult:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {    
    if (resultCode == RESULT_OK) {
         if (requestCode == 1) {
            String filePath = uriFilePath.getPath(); // Here is path of your captured image, so you can create bitmap from it, etc.
         }
    }
 }

附注:别忘了在你的Manifest中添加Camera和Ext. storage的写入权限。

坏的质量

根据我的经验，如果我们使用

Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, RESULT_ADD_PHOTO);

和处理onActivityResult()

Bitmap thumbnail= (Bitmap) data.getExtras().get("data");

它只会给你一个缩略图，当然有一个坏的质量。

不错的质量

您可以显示相机和保存您的图像文件在公共目录，例如在文档目录

在onClick()中使用这个

String imagePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) +
                File.separator + "your_image_name.jpeg";
Intent i =new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
imageFile = new File(imagePath );
i.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(imageFile));
startActivityForResult(i, RESULT_ADD_PHOTO);

在onActivityResult()中

Bitmap imageBitmap1 = BitmapFactory.decodeFile(imageFile.getAbsolutePath());
Matrix matrix = new Matrix();
matrix.postRotate(90);
Bitmap imageBitmap = Bitmap.createBitmap(imageBitmap1, 0, 0, imageBitmap1.getWidth(), imageBitmap1.getHeight(), matrix, true);
binding.imageView.setImageBitmap(imageBitmap);

我使用postRotate()，因为在我的代码中，图像结果向左旋转，所以我需要将其旋转90