Android 에서 카메라 와 앨범 을 어떻게 사용 하 는 지 간단히 말씀 드 리 겠 습 니 다.

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
  <!--      Uri -->
  <!--name：  （  ）-->
  <!--path：     ，         SD  -->
  <external-path name="img" path=""/>
</PreferenceScreen>

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

<!--        -->
<Button
  android:id="@+id/choose_photo"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:text="    "
  />

/**
 *        
 */
public static final int CHOOSE_PHOTO_REQUEST_CODE = 2;
...
@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  ...
  //    
  findViewById(R.id.choose_photo).setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
      if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
            CHOOSE_PHOTO_REQUEST_CODE);
      } else {
        openAlbum();
      }
    }
});
/**
 *     
 */
private void openAlbum() {
  Intent intent = new Intent("android.intent.action.GET_CONTENT");
  intent.setType("image/*");
  startActivityForResult(intent, CHOOSE_PHOTO_REQUEST_CODE);
}

/**
 *    WRITE_EXTERNAL_STORAGE   
 *
 *              SD    ，    SD             
 *
 * WRITE_EXTERNAL_STORAGE      SD       
 * @param requestCode
 * @param permissions
 * @param grantResults
 */
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
  switch (requestCode) {
    case CHOOSE_PHOTO_REQUEST_CODE:
      if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        openAlbum();
      } else {
        Toast.makeText(this, "    ", Toast.LENGTH_SHORT).show();
      }
      break;
    default:
      break;
  }
  super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  Log.d(TAG, "requestCode: " + requestCode);
  Log.d(TAG, "imgUrl: " + imgUrl);
  switch (requestCode) {
    case OPEN_PHOTO_REQUEST_CODE:
      if (resultCode == RESULT_OK) {
        try {//       
          Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imgUrl));
          imageView.setImageBitmap(bitmap);
        } catch (FileNotFoundException e) {
          e.printStackTrace();
        }
      }
      break;
    case CHOOSE_PHOTO_REQUEST_CODE:
      if (Build.VERSION.SDK_INT >= 19) {//4.4      
        handleFor4_4(data);
      } else {
        handleForBefore4_4(data);
      }
      break;
    default:
      break;
  }
}

/**
 *     
 * android 4.4-
 *
 * @param data
 */
private void handleForBefore4_4(Intent data) {
  display(getImagePath(data.getData(),null));
}

/**
 *     
 * android 4.4+
 *
 * @param data
 */
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
private void handleFor4_4(Intent data) {
  String imagePath = null;
  Uri uri = data.getData();//    
  if (DocumentsContract.isDocumentUri(this, uri)) {//  Document   ，   document id    
    String documentId = DocumentsContract.getDocumentId(uri);
    String mediaDocumentAuthority = "com.android.providers.media.documents";
    String downloadDocumentAuthority = "com.android.providers.downloads.documents";
    if (mediaDocumentAuthority.equals(uri.getAuthority())) {//media   
      String id = documentId.split(":")[1];//      ID
      String selection = MediaStore.Images.Media._ID + "=" + id;
      imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
    } else if (downloadDocumentAuthority.equals(uri.getAuthority())) {
      Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(documentId));
      imagePath = getImagePath(contentUri, null);
    }
  } else if ("content".equalsIgnoreCase(uri.getScheme())) {//content    uri
    imagePath = getImagePath(uri, null);
  } else if ("file".equalsIgnoreCase(uri.getScheme())) {//file   ，       
    imagePath = uri.getPath();
  }
  display(imagePath);
}

/**
 *   
 * @param path
 */
private void display(String path) {
  if(path==null){
    Toast.makeText(this, "      ", Toast.LENGTH_SHORT).show();
  }else{
    imageView.setImageBitmap(BitmapFactory.decodeFile(path));
  }


}

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