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。

拍摄照片+从图库中选择:

        a = (ImageButton)findViewById(R.id.imageButton1);

        a.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                selectImage();

            }

        });
    }
    private File savebitmap(Bitmap bmp) {
      String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
      OutputStream outStream = null;
     // String temp = null;
        File file = new File(extStorageDirectory, "temp.png");
      if (file.exists()) {
       file.delete();
       file = new File(extStorageDirectory, "temp.png");

      }

      try {
       outStream = new FileOutputStream(file);
       bmp.compress(Bitmap.CompressFormat.PNG, 100, outStream);
       outStream.flush();
       outStream.close();

      } catch (Exception e) {
       e.printStackTrace();
       return null;
      }
      return file;
     }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
     private void selectImage() {



            final CharSequence[] options = { "Take Photo", "Choose from Gallery","Cancel" };



            AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

            builder.setTitle("Add Photo!");

            builder.setItems(options, new DialogInterface.OnClickListener() {

                @Override

                public void onClick(DialogInterface dialog, int item) {

                    if (options[item].equals("Take Photo"))

                    {

                        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

                        File f = new File(android.os.Environment.getExternalStorageDirectory(), "temp.jpg");

                        intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(f));
                        //pic = f;

                        startActivityForResult(intent, 1);


                    }

                    else if (options[item].equals("Choose from Gallery"))

                    {

                        Intent intent = new   Intent(Intent.ACTION_PICK,android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

                        startActivityForResult(intent, 2);



                    }

                    else if (options[item].equals("Cancel")) {

                        dialog.dismiss();

                    }

                }

            });

            builder.show();

        }



        @Override

        protected void onActivityResult(int requestCode, int resultCode, Intent data) {

            super.onActivityResult(requestCode, resultCode, data);

            if (resultCode == RESULT_OK) {

                if (requestCode == 1) {
                    //h=0;
                    File f = new File(Environment.getExternalStorageDirectory().toString());

                    for (File temp : f.listFiles()) {

                        if (temp.getName().equals("temp.jpg")) {

                            f = temp;
                            File photo = new File(Environment.getExternalStorageDirectory(), "temp.jpg");
                           //pic = photo;
                            break;

                        }

                    }

                    try {

                        Bitmap bitmap;

                        BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();



                        bitmap = BitmapFactory.decodeFile(f.getAbsolutePath(),

                                bitmapOptions); 



                        a.setImageBitmap(bitmap);




                        String path = android.os.Environment

                                .getExternalStorageDirectory()

                                + File.separator

                                + "Phoenix" + File.separator + "default";
                        //p = path;

                        f.delete();

                        OutputStream outFile = null;

                        File file = new File(path, String.valueOf(System.currentTimeMillis()) + ".jpg");

                        try {

                            outFile = new FileOutputStream(file);

                            bitmap.compress(Bitmap.CompressFormat.JPEG, 85, outFile);
    //pic=file;
                            outFile.flush();

                            outFile.close();


                        } catch (FileNotFoundException e) {

                            e.printStackTrace();

                        } catch (IOException e) {

                            e.printStackTrace();

                        } catch (Exception e) {

                            e.printStackTrace();

                        }

                    } catch (Exception e) {

                        e.printStackTrace();

                    }

                } else if (requestCode == 2) {



                    Uri selectedImage = data.getData();
                   // h=1;
    //imgui = selectedImage;
                    String[] filePath = { MediaStore.Images.Media.DATA };

                    Cursor c = getContentResolver().query(selectedImage,filePath, null, null, null);

                    c.moveToFirst();

                    int columnIndex = c.getColumnIndex(filePath[0]);

                    String picturePath = c.getString(columnIndex);

                    c.close();

                    Bitmap thumbnail = (BitmapFactory.decodeFile(picturePath));


                    Log.w("path of image from gallery......******************.........", picturePath+"");


                    a.setImageBitmap(thumbnail);

                }

            }

在活动:

@Override
    protected void onCreate(Bundle savedInstanceState) {
                 image = (ImageView) findViewById(R.id.imageButton);
        image.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                try {
                SimpleDateFormat sdfPic = new SimpleDateFormat(DATE_FORMAT);
                currentDateandTime = sdfPic.format(new Date()).replace(" ", "");
                File imagesFolder = new File(IMAGE_PATH, currentDateandTime);
                imagesFolder.mkdirs();
                Random generator = new Random();
                int n = 10000;
                n = generator.nextInt(n);
                String fname = IMAGE_NAME + n + IMAGE_FORMAT;
                File file = new File(imagesFolder, fname);
                outputFileUri = Uri.fromFile(file);
                cameraIntent= new Intent(
                        android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
                cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
                                startActivityForResult(cameraIntent, CAMERA_DATA);
                }catch(Exception e) {
                    e.printStackTrace();
                }

            }
        });
           @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch(requestCode) {
        case CAMERA_DATA :
                final int IMAGE_MAX_SIZE = 300;
                try {
                    // Bitmap bitmap;
                    File file = null;
                    FileInputStream fis;
                    BitmapFactory.Options opts;
                    int resizeScale;
                    Bitmap bmp;
                    file = new File(outputFileUri.getPath());
                    // This bit determines only the width/height of the
                    // bitmap
                    // without loading the contents
                    opts = new BitmapFactory.Options();
                    opts.inJustDecodeBounds = true;
                    fis = new FileInputStream(file);
                    BitmapFactory.decodeStream(fis, null, opts);
                    fis.close();

                    // Find the correct scale value. It should be a power of
                    // 2
                    resizeScale = 1;

                    if (opts.outHeight > IMAGE_MAX_SIZE
                            || opts.outWidth > IMAGE_MAX_SIZE) {
                        resizeScale = (int) Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE/ (double) Math.max(opts.outHeight, opts.outWidth)) / Math.log(0.5)));
                    }

                    // Load pre-scaled bitmap
                    opts = new BitmapFactory.Options();
                    opts.inSampleSize = resizeScale;
                    fis = new FileInputStream(file);
                    bmp = BitmapFactory.decodeStream(fis, null, opts);
                    Bitmap getBitmapSize = BitmapFactory.decodeResource(
                            getResources(), R.drawable.male);
                    image.setLayoutParams(new RelativeLayout.LayoutParams(
                            200,200));//(width,height);
                    image.setImageBitmap(bmp);
                    image.setRotation(90);
                    fis.close();

                    ByteArrayOutputStream baos = new ByteArrayOutputStream();
                    bmp.compress(Bitmap.CompressFormat.JPEG, 70, baos);
                    imageByte = baos.toByteArray();
                    break;
                } catch (FileNotFoundException e) {

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

在layout.xml:

enter code here
<RelativeLayout
        android:id="@+id/relativeLayout2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">


        <ImageView
            android:id="@+id/imageButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"

                            android:src="@drawable/XXXXXXX"
            android:textAppearance="?android:attr/textAppearanceSmall" />

在manifest.xml:

< uses-permission android: name = " android.permission。CAMERA" /> <uses-feature android:name="android.硬件。相机" / >

你得好好研究一下相机。(我认为要做到你想要的，你必须保存当前的图像到你的应用程序，在那里做选择/删除，然后召回相机再试一次，而不是直接在相机内部重试。)

正如其他人所讨论的，使用data. getextras ().get("data")只会得到低质量的缩略图。

解决方案是通过ACTION_IMAGE_CAPTURE意图传递一个位置，告诉相机在哪里存储全质量图像。

代码是Kotlin，不需要任何权限。

val f = File("${getExternalFilesDir(null)}/imgShot")
val photoURI = FileProvider.getUriForFile(this, "${packageName}.fileprovider", f)
val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
        .apply { putExtra(MediaStore.EXTRA_OUTPUT, photoURI) }
startActivityForResult(intent, 1234)

然后对拍摄后的结果进行处理:

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    if (requestCode == 1234 && resultCode == Activity.RESULT_OK) {
        val bitmap = BitmapFactory.decodeFile(
                File("${getExternalFilesDir(null)}/imgShot").toString()
        )
        // use imageView.setImageBitmap(bitmap) or whatever
    }
}

您还需要像这里描述的那样添加一个外部FileProvider。AndroidManifest.xml:

<manifest>
    <application>

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

    </application>
</manifest>

添加一个新文件app/src/main/res/xml/provide_paths.xml:

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path name="external_files" path="." />
</paths>

最后，你应该用你自己的逻辑替换1234来跟踪请求代码(通常是一个包含RequestCode.CAPTURE_IMAGE等成员的枚举)

在这里你可以打开相机或图库，并设置选定的图像到imageview

private static final String IMAGE_DIRECTORY = "/YourDirectName";
private Context mContext;
private CircleImageView circleImageView;  // imageview
private int GALLERY = 1, CAMERA = 2;

在清单中添加权限

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

在onCreate ()

    requestMultiplePermissions(); // check permission 

    circleImageView = findViewById(R.id.profile_image);
    circleImageView.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            showPictureDialog();
        }
    });

显示选项对话框(用于从相机或图库中选择图像)

private void showPictureDialog() {
    AlertDialog.Builder pictureDialog = new AlertDialog.Builder(this);
    pictureDialog.setTitle("Select Action");
    String[] pictureDialogItems = {"Select photo from gallery", "Capture photo from camera"};
    pictureDialog.setItems(pictureDialogItems,
            new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    switch (which) {
                        case 0:
                            choosePhotoFromGallary();
                            break;
                        case 1:
                            takePhotoFromCamera();
                            break;
                    }
                }
            });
    pictureDialog.show();
}

从图库获取照片

public void choosePhotoFromGallary() {
    Intent galleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    startActivityForResult(galleryIntent, GALLERY);
}

从相机中获取照片

private void takePhotoFromCamera() {
    Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    startActivityForResult(intent, CAMERA);
}

一旦图像被选中或捕获，

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == this.RESULT_CANCELED) {
        return;
    }
    if (requestCode == GALLERY) {
        if (data != null) {
            Uri contentURI = data.getData();
            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), contentURI);
                String path = saveImage(bitmap);
                Toast.makeText(getApplicationContext(), "Image Saved!", Toast.LENGTH_SHORT).show();
                circleImageView.setImageBitmap(bitmap);

            } catch (IOException e) {
                e.printStackTrace();
                Toast.makeText(getApplicationContext(), "Failed!", Toast.LENGTH_SHORT).show();
            }
        }

    } else if (requestCode == CAMERA) {
        Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
        circleImageView.setImageBitmap(thumbnail);
        saveImage(thumbnail);
        Toast.makeText(getApplicationContext(), "Image Saved!", Toast.LENGTH_SHORT).show();
    }
}

现在是存储图片的时候了

public String saveImage(Bitmap myBitmap) {
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    myBitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
    File wallpaperDirectory = new File(Environment.getExternalStorageDirectory() + IMAGE_DIRECTORY);
    if (!wallpaperDirectory.exists()) {  // have the object build the directory structure, if needed.
        wallpaperDirectory.mkdirs();
    }

    try {
        File f = new File(wallpaperDirectory, Calendar.getInstance().getTimeInMillis() + ".jpg");
        f.createNewFile();
        FileOutputStream fo = new FileOutputStream(f);
        fo.write(bytes.toByteArray());
        MediaScannerConnection.scanFile(this,
                new String[]{f.getPath()},
                new String[]{"image/jpeg"}, null);
        fo.close();
        Log.d("TAG", "File Saved::--->" + f.getAbsolutePath());

        return f.getAbsolutePath();
    } catch (IOException e1) {
        e1.printStackTrace();
    }
    return "";
}

请求许可

    private void requestMultiplePermissions() {
    Dexter.withActivity(this)
            .withPermissions(
                    Manifest.permission.CAMERA,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE,
                    Manifest.permission.READ_EXTERNAL_STORAGE)
            .withListener(new MultiplePermissionsListener() {
                @Override
                public void onPermissionsChecked(MultiplePermissionsReport report) {
                    if (report.areAllPermissionsGranted()) {  // check if all permissions are granted
                        Toast.makeText(getApplicationContext(), "All permissions are granted by user!", Toast.LENGTH_SHORT).show();
                    }

                    if (report.isAnyPermissionPermanentlyDenied()) { // check for permanent denial of any permission
                        // show alert dialog navigating to Settings
                        //openSettingsDialog();
                    }
                }

                @Override
                public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
                    token.continuePermissionRequest();
                }
            }).
            withErrorListener(new PermissionRequestErrorListener() {
                @Override
                public void onError(DexterError error) {
                    Toast.makeText(getApplicationContext(), "Some Error! ", Toast.LENGTH_SHORT).show();
                }
            })
            .onSameThread()
            .check();
}