Android調用攝像頭和相冊

一、UI界面

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    
    <Button android:id="@+id/take_photo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Take photo"/>
    
    <Button android:id="@+id/choose_from_album"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Choose From Album"/>
    
    <ImageView android:id="@+id/picture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"/>

</LinearLayout>

二、邏輯代碼

public class MainActivity extends Activity {
	
	public static final int TAKE_PHOTO = 1;
	
	public static final int CROP_PHOTO = 2;
	
	public static final int CHOOSE_PHOTO = 3;
	
	private Button takePhoto;
	
	private ImageView picture;
	
	private Uri imageUri;
	
	private Button chooseFromAlbum;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		takePhoto = (Button) findViewById(R.id.take_photo);
		picture = (ImageView) findViewById(R.id.picture);
		
		chooseFromAlbum = (Button) findViewById(R.id.choose_from_album);
		
		takePhoto.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				//創建File對象，用於存儲拍照後的照片
				File outputImage = new File(Environment.getExternalStorageDirectory(), "output_image.jpg");
				try {
					if (outputImage.exists()) {
						outputImage.delete();
					}
					outputImage.createNewFile();
				} catch (Exception e) {
					e.printStackTrace();
				}
				imageUri = Uri.fromFile(outputImage);
				Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
				intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
				startActivityForResult(intent, TAKE_PHOTO);
			}
		});
		
		chooseFromAlbum.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				Intent intent = new Intent("android.intent.action.GET_CONTENT");
				intent.setType("image/*");
				startActivityForResult(intent, CHOOSE_PHOTO);
			}
		});
		
	}
	
	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		switch (requestCode) {
		case TAKE_PHOTO:
			if (resultCode == RESULT_OK) {
				Intent intent = new Intent("com.android.camera.action.CROP");
				intent.setDataAndType(imageUri, "image/*");
				intent.putExtra("scale", true);
				intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
				startActivityForResult(intent, CROP_PHOTO);	//啓動裁剪程序
			}
			break;
		case CROP_PHOTO:
			if (resultCode == RESULT_OK) {
				try {
					Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
					picture.setImageBitmap(bitmap);
				} catch (FileNotFoundException e) {
					e.printStackTrace();
				}
			}
			break;
		case CHOOSE_PHOTO:
			if (resultCode == RESULT_OK) {
				//判斷手機系統版本號
				if (Build.VERSION.SDK_INT >= 19) {
					//4.4及以上系統使用這個方法處理圖片
					handleImageOnKitKat(data);
				} else {
					//4.4以下系統使用這個方法處理圖片
					handleImageBeforeKitKat(data);
				}
			}
			break;

		default:
			break;
		}
	}

	@TargetApi(19)
	private void handleImageOnKitKat(Intent data) {
		String imagePath = null;
		Uri uri = data.getData();
		if (DocumentsContract.isDocumentUri(this, uri)) {
			//如果是document類型的Uri，則通過document id處理
			String docId = DocumentsContract.getDocumentId(uri);
			if ("com.android.providers.media.documents".equals(uri.getAuthority())) {
				String id = docId.split(":")[1];	//解析出數字格式的id
				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())) {
			//如果不是document類型的Uri，則使用普通方式處理
			imagePath = getImagePath(uri, null);
		}
		displayImage(imagePath);//根據圖片路徑顯示圖片
	}
	
	private void handleImageBeforeKitKat(Intent data) {
		Uri uri = data.getData();
		String imagePath = getImagePath(uri, null);
		displayImage(imagePath);
	}

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

	private String getImagePath(Uri uri, String selection) {
		String path = null;
		//通過Uri和selection來獲取真實的圖片路徑
		Cursor cursor = getContentResolver().query(uri, null, selection, null, null);
		if (cursor != null) {
			if (cursor.moveToFirst()) {
				path = cursor.getString(cursor.getColumnIndex(Media.DATA));
			}
			cursor.close();
		}
		return path;
	}
}