相机 相册

从拍照，相册中获取图片

直接上代码吧

示例代码

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申请权限
AndroidManifest.xml

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activity_camera.xml

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CameraActivity.java

public class CameraActivity extends AppCompatActivity {

    private static final int TAKE_PHOTO = 1;
    private static final int CHOOSE_PHOTO = 2;
    private ImageView iv_c_image;
    private Uri imageUri;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera);

        iv_c_image = findViewById(R.id.iv_c_image);

        // 使用相机拍照
        Button btn_c_use_camera = findViewById(R.id.btn_c_use_camera);
        btn_c_use_camera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 创建一个文件去接收图片
                File outputImage = new File(getExternalCacheDir(), "output_image.jpg");
                try {
                    // 存在该文件删除
                    if (outputImage.exists()) {
                        outputImage.delete();
                    }
                    outputImage.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                // 获取该文件的uri
                if (Build.VERSION.SDK_INT >= 24) {
                    imageUri = FileProvider.getUriForFile(CameraActivity.this,
                            "com.bl.blandroidpro.fileprovider", outputImage);
                } else {
                    imageUri = Uri.fromFile(outputImage);
                }
                // 创建打开相机意图
                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                // 用此文件接收拍照后的图片
                intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                // 打开相机
                startActivityForResult(intent, TAKE_PHOTO);
            }
        });

        // 从相册选取
        Button btn_c_use_lib = findViewById(R.id.btn_c_use_lib);
        btn_c_use_lib.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 请求权限
                if (ContextCompat.checkSelfPermission(CameraActivity.this,
                        Manifest.permission.WRITE_EXTERNAL_STORAGE)
                        != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(CameraActivity.this,
                            new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}
                            , 1);
                } else {
                    openAlbum();
                }
            }
        });
    }

    public void openAlbum() {
        // 创建打开相册意图
        Intent intent = new Intent("android.intent.action.GET_CONTENT");
        // 设置获取类型
        intent.setType("image/*");
        // 打开相册
        startActivityForResult(intent, CHOOSE_PHOTO);
    }

    /**
     * 请求权限回调
     * @param requestCode
     * @param permissions
     * @param grantResults
     */
    @Override
    public void onRequestPermissionsResult(
            int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 1:
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    openAlbum();
                } else {
                    Toast.makeText(this,
                            "You denied the permission", Toast.LENGTH_LONG).show();
                }
                break;
            default:
                break;
        }
    }

    /**
     * 关闭相机或相册回调
     * @param requestCode
     * @param resultCode
     * @param data
     */
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        switch (requestCode) {
            case TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    try {
                        // 获取刚拍好图片
                        Bitmap bitmap = BitmapFactory.decodeStream(
                                getContentResolver().openInputStream(imageUri));
                        iv_c_image.setImageBitmap(bitmap);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                }
                break;
            case CHOOSE_PHOTO:
                if (resultCode == RESULT_OK) {
                    // Android 4.4以上 使用这个方法处理图片
                    if (Build.VERSION.SDK_INT >= 19) {
                        handleImageOnKitKat(data);

                    // Android 4.4以下 使用这个方法处理图片
                    } else {
                        handleImageBeforeKitKat(data);
                    }
                }
                break;
            default:
                break;
        }
    }

    /**
     * Android 4.4+
     * @param data
     */
    @TargetApi(19)
    private void handleImageOnKitKat(Intent data) {
        String imagePath = null;
        Uri uri = data.getData();

        // 如果是 document 类型的 Uri，则通过 document id 处理
        if (DocumentsContract.isDocumentUri(this, uri)) {
            String docId = DocumentsContract.getDocumentId(uri);
            if ("com.android.providers.media.documents".equals(uri.getAuthority())) {
                // 解析出数字格式的id
                String id = docId.split(":")[1];
                String selection = MediaStore.Images.Media._ID + "=" + id;
                imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
            } else if ("com.android.providers.downloads.documents".equals(uri.getAuthority())) {
                Uri contetnUri = ContentUris.withAppendedId(
                        Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));
                imagePath = getImagePath(contetnUri, null);
            }

            // 如果是 content 类型的Uri，则使用普通方式处理
        } else if ("content".equalsIgnoreCase(uri.getScheme())) {
            imagePath = getImagePath(uri, null);

            // 如果是 file 类型的 Uri，直接截取图片路径
        } else if ("file".equalsIgnoreCase(uri.getScheme())) {
            imagePath = uri.getPath();
        }
        // 根据图片路径显示
        displayImage(imagePath);
    }

    /**
     * Android 4.4-
     * @param data
     */
    private void handleImageBeforeKitKat(Intent data) {
        Uri uri = data.getData();
        String imagePath = getImagePath(uri,null);
        displayImage(imagePath);
    }

    private String getImagePath(Uri uri, String selection) {
        String path = null;
        // 通过 Uri 和 Selection 来获取真是的图片路径
        Cursor cursor = getContentResolver().query(uri,
                null, selection, null, null);
        if (cursor != null) {
            if (cursor.moveToNext()) {
                path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            }
            cursor.close();
        }
        return path;
    }

    private void displayImage(String imagePath) {
        if (imagePath != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
            iv_c_image.setImageBitmap(bitmap);
        } else {
            Toast.makeText(this,
                    "failed to get image", Toast.LENGTH_LONG).show();
        }
    }
}

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