Intent选择器，开系统图库选择图片，开相机拍照

 	//开启系统图库
        Intent intent1 = new Intent(Intent.ACTION_PICK);
        intent1.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "image/*");

        //开相机
        Intent intent2 = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), System.currentTimeMillis() + ".jpg");
        path = file.getAbsolutePath();
        Uri path = Uri.fromFile(file);
        intent2.putExtra(MediaStore.EXTRA_OUTPUT, path);

        //intent选择器
        Intent chooser = Intent.createChooser(intent1, "选择头像");
        chooser.putExtra(Intent.EXTRA_INITIAL_INTENTS, new Intent[]{intent2});
        startActivityForResult(chooser, 100);

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK && requestCode == 101) {
            String filePath = "";
            if (data != null) {
                //图库选图
                //对于部分手机来说，在安卓原生的拍照程序基础上做了修改
                //导致拍照的照片会随着arg2返回到这里
                Uri uri = data.getData();

                if (uri != null) {
                    if (!uri.getPath().equals(imageUri.getPath())) {
                        //图库
                        Cursor cursor = getContentResolver().query(uri, new String[]{MediaStore.Images.Media.DATA}, null, null, null);
                        cursor.moveToNext();
                        filePath = cursor.getString(0);
                        cursor.close();

                    } else {
                        //拍照
                        //拍照的路径依然是cameraPath
                        filePath = cameraPath;
                    }
                } else {
                    Bundle bundle = data.getExtras();
                    //bitmap是拍照回来的照片
                    Bitmap bitmap = (Bitmap) bundle.get("data");
                    //TODO 将bitmap存储到SD卡
                }

            } else {
                //相机拍照
                filePath = cameraPath;
            }


        }

        super.onActivityResult(requestCode, resultCode, data);
    }

调用系统的摄像头进行拍照：

第一步：声明个imageUri，以便拍照时返回用

第二步：

 //创建file对象，用于存储拍照后的图片
                File outputImage = new File(getExternalCacheDir(), "output_image.jpg");
                try {
                    if (outputImage.exists()) {
                        outputImage.delete();
                    }
                    outputImage.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (Build.VERSION.SDK_INT >= 24) {
                    //android 7.0后的特性，直接使用fromFile不安全，所以用getUriForFile
                    imageUri = FileProvider.getUriForFile(MainActivity.this, "com.example.fileprovider", outputImage);
                } else {
                    imageUri = Uri.fromFile(outputImage);
                }
                //启动拍照相机程序
                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                startActivityForResult(intent, TAKE_PHOTO);

第三部：

   @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    try {
                        Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                        imageView.setImageBitmap(bitmap);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                }
                break;
        }
    }

第四部：

因为用到了FileProvider，所以需要在manifest中注册

同时也要为了兼顾旧版本，需要加权限。

第五部：创建xml文件夹，并创建file_path文件

调用系统图库选择图片

  if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                        != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 100);
                } else {
                    openAlbum();
                }

  private void openAlbum() {
        Intent intent = new Intent("android.intent.action.GET_CONTENT");
        intent.setType("image/*");
        startActivityForResult(intent, CHOOSE_PHOTO);
    }

 @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == 100) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                openAlbum();
            } else {
                Log.i("TAG", "onRequestPermissionsResult: " + "error");
            }
        }

    }

然后在OnActivityResult里面

case CHOOSE_PHOTO:
                if (resultCode == RESULT_OK) {
                    if (Build.VERSION.SDK_INT >= 19) {
                        handlerImageOnKitKat(data);
                    } else {
                        handlerImageBeforeKitKat(data);
                    }
                }
                break;

private void handlerImageOnKitKat(Intent data) {
        String imagePath = null;
        Uri uri = data.getData();
        if (DocumentsContract.isDocumentUri(this, uri)) {
            //如果是document类型的uri
            String docId = DocumentsContract.getDocumentId(uri);
            if ("com.android.providers.media.documents".equals(uri.getAuthority())) {
                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 contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));
                imagePath = getImagePath(contentUri, null);
            }
        } else if ("content".equalsIgnoreCase(uri.getScheme())) {
            //content类型
            imagePath = getImagePath(uri, null);
        } else if ("file".equalsIgnoreCase(uri.getScheme())) {
            //file类型
            imagePath = uri.getPath();
        }
        displayImage(imagePath);
    }

    private void handlerImageBeforeKitKat(Intent data) {
        String path = getImagePath(data.getData(), null);
        displayImage(path);
    }

    private void displayImage(String path) {
        if (path != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(path);
            imageView.setImageBitmap(bitmap);
        }
    }

    private String getImagePath(Uri data, String selection) {
        String path = null;
        Cursor cursor = getContentResolver().query(data, null, selection, null, null);
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            }
            cursor.close();
        }
        return path;
    }