需求描述：
在很多时候，我们需要在APP中调用摄像头拍摄相片或者选取本地相册中的图片进行裁剪，然后将裁剪后的图片上传至后台服务器。这方面有很多种实现方法，所以不再罗列，我只将我在这方面遇到的一些细节优化的地方总结一下。
关于裁剪
用的是https://github.com/jdamcd/android-crop， above API-14。这个开源代码将Itent封装的比较好。
工具入口是：
public class Crop {
public static final int REQUEST_CAPTURE = 1216;
public static final int REQUEST_CROP = 6709;
public static final int REQUEST_PICK = 9162;
public static final int RESULT_ERROR = 404;
static interface Extra {
String ASPECT_X = "aspect_x";
String ASPECT_Y = "aspect_y";
String MAX_X = "max_x";
String MAX_Y = "max_y";
String ERROR = "error";
}
private Intent cropIntent;
/**
* Create a crop Intent builder with source and destination image Uris
*
* @param source Uri for image to crop
* @param destination Uri for saving the cropped image
*/
public static Crop of(Uri source, Uri destination) {
return new Crop(source, destination);
}
private Crop(Uri source, Uri destination) {
cropIntent = new Intent();
cropIntent.setData(source);
cropIntent.putExtra(MediaStore.EXTRA_OUTPUT, destination);
}
/**
* Set fixed aspect ratio for crop area
* 自定义宽高比
* @param x Aspect X
* @param y Aspect Y
*/
public Crop withAspect(int x, int y) {
cropIntent.putExtra(Extra.ASPECT_X, x);
cropIntent.putExtra(Extra.ASPECT_Y, y);
return this;
}
/**
* Crop area with fixed 1:1 aspect ratio
* 默认一比一宽高比
*/
public Crop asSquare() {
cropIntent.putExtra(Extra.ASPECT_X, 1);
cropIntent.putExtra(Extra.ASPECT_Y, 1);
return this;
}
/**
* Set maximum crop size
*
* @param width Max width
* @param height Max height
*/
public Crop withMaxSize(int width, int height) {
cropIntent.putExtra(Extra.MAX_X, width);
cropIntent.putExtra(Extra.MAX_Y, height);
return this;
}
/**
* Send the crop Intent from an Activity
*
* @param activity Activity to receive result
*/
public void start(Activity activity) {
start(activity, REQUEST_CROP);
}
/**
* Send the crop Intent from an Activity with a custom requestCode
*
* @param activity Activity to receive result
* @param requestCode requestCode for result
*/
public void start(Activity activity, int requestCode) {
activity.startActivityForResult(getIntent(activity), requestCode);
}
/**
* Send the crop Intent from a Fragment
*
* @param context Context
* @param fragment Fragment to receive result
*/
public void start(Context context, Fragment fragment) {
start(context, fragment, REQUEST_CROP);
}
/**
* Send the crop Intent from a support library Fragment
*
* @param context Context
* @param fragment Fragment to receive result
*/
public void start(Context context, android.support.v4.app.Fragment fragment) {
start(context, fragment, REQUEST_CROP);
}
/**
* Send the crop Intent with a custom requestCode
*
* @param context Context
* @param fragment Fragment to receive result
* @param requestCode requestCode for result
*/
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public void start(Context context, Fragment fragment, int requestCode) {
fragment.startActivityForResult(getIntent(context), requestCode);
}
/**
* Send the crop Intent with a custom requestCode
*
* @param context Context
* @param fragment Fragment to receive result
* @param requestCode requestCode for result
*/
public void start(Context context, android.support.v4.app.Fragment fragment, int requestCode) {
fragment.startActivityForResult(getIntent(context), requestCode);
}
/**
* Get Intent to start crop Activity
*
* @param context Context
* @return Intent for CropImageActivity
*/
public Intent getIntent(Context context) {
cropIntent.setClass(context, CropImageActivity.class);
return cropIntent;
}
/**
* Retrieve URI for cropped image, as set in the Intent builder
*
* @param result Output Image URI
*/
public static Uri getOutput(Intent result) {
return result.getParcelableExtra(MediaStore.EXTRA_OUTPUT);
}
/**
* Retrieve error that caused crop to fail
*
* @param result Result Intent
* @return Throwable handled in CropImageActivity
*/
public static Throwable getError(Intent result) {
return (Throwable) result.getSerializableExtra(Extra.ERROR);
}
/**
* Utility to start an image picker
*
* @param activity Activity that will receive result
*/
public static void pickImage(Activity activity) {
pickImage(activity, REQUEST_PICK);
}
/**
* Utility to start an image picker with request code
*
* @param activity Activity that will receive result
* @param requestCode requestCode for result
*/
public static void pickImage(Activity activity, int requestCode) {
Intent intent = new Intent(Intent.ACTION_GET_CONTENT).setType("image/*");
try {
activity.startActivityForResult(intent, requestCode);
} catch (ActivityNotFoundException e) {
Toast.makeText(activity, R.string.crop__pick_error, Toast.LENGTH_SHORT).show();
}
}
/**
* 拍照获取
* @param activity
* 需要在Intent中加入保存的SD卡路径，否则onActivityResult中的得到的data图片会压缩很小
*/
public static void pickCAPTURE(Activity activity, Uri path) {
pickCAPTURE(activity, path, REQUEST_CAPTURE);
}
public static void pickCAPTURE(Activity activity, Uri path, int requestCode){
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, path);
try {
activity.startActivityForResult(intent, requestCode);
} catch (ActivityNotFoundException e) {
Toast.makeText(activity, R.string.crop__pick_error, Toast.LENGTH_SHORT).show();
}
}
}
当然你也可以不用这个，用SDK本身的裁剪功能就可以了，同样可以在onActivityResult中返回得到裁剪的图片，而且可以自定义裁剪尺寸：
private void startImageZoom(Uri uri) {
Intent intent = new Intent("com.android.camera.action.CROP");
intent.setDataAndType(uri, "image/*");
intent.putExtra("crop", "true");
intent.putExtra("aspectX", 1);
intent.putExtra("aspectY", 0.7);
intent.putExtra("outputX", 1080);
intent.putExtra("outputY", 756);
intent.putExtra("return-data", true);
getActivity().startActivityForResult(intent, 3);
}
关于Uri、Bitmap、以及保存路径的转换
提供一个工具类：
public class UtilsImageProcess {
/**
* 将得到的一个Bitmap保存到SD卡上，得到一个URI地址
*/
public static Uri saveBitmap(Bitmap bm) {
//在SD卡上创建目录
File tmpDir = new File(Environment.getExternalStorageDirectory() + "/org.chenlijian.test");
if (!tmpDir.exists()) {
tmpDir.mkdir();
}
File img = new File(tmpDir.getAbsolutePath() + "test.png");
try {
FileOutputStream fos = new FileOutputStream(img);
bm.compress(Bitmap.CompressFormat.PNG, 85, fos);
fos.flush();
fos.close();
return Uri.fromFile(img);
} catch (FileNotFoundException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* 将得到的一个Bitmap保存到SD卡上，得到一个绝对路径
*/
public static String getPath(Bitmap bm) {
//在SD卡上创建目录
File tmpDir = new File(Environment.getExternalStorageDirectory() + "/org.chenlijian.test");
if (!tmpDir.exists()) {
tmpDir.mkdir();
}
File img = new File(tmpDir.getAbsolutePath() + "/test.png");
try {
FileOutputStream fos = new FileOutputStream(img);
bm.compress(Bitmap.CompressFormat.PNG, 85, fos);
fos.flush();
fos.close();
return img.getCanonicalPath();
} catch (FileNotFoundException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* 将图库中选取的图片的URI转化为URI
*/
public static Uri convertUri(Uri uri, Context context) {
InputStream is;
try {
is = context.getContentResolver().openInputStream(uri);
Bitmap bitmap = BitmapFactory.decodeStream(is);
is.close();
return saveBitmap(bitmap);
} catch (FileNotFoundException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* 在拍摄照片之前生成一个文件路径Uri，保证拍出来的照片没有被压缩太小,用日期作为文件名，确保唯一性
*/
public static String getSavePath(){
String saveDir = Environment.getExternalStorageDirectory() + "/org.chenlijian.test";
File dir = new File(saveDir);
if (!dir.exists()) {
dir.mkdir();
}
Date date = new Date();
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss");
String fileName = saveDir + "/" + formatter.format(date) + ".png";
return fileName;
}
/**
* 计算图片的缩放值
*/
public static int calculateInSampleSize(BitmapFactory.Options options,int reqWidth, int reqHeight) {
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int heightRatio = Math.round((float) height/ (float) reqHeight);
final int widthRatio = Math.round((float) width / (float) reqWidth);
inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
}
return inSampleSize;
}
/**
* 根据路径获得图片并压缩，返回bitmap用于显示
*/
public static Bitmap getSmallBitmap(String filePath) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, 480, 800);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
// 设置为true，画质更好一点，加载时间略长
options.inPreferQualityOverSpeed = true;
return BitmapFactory.decodeFile(filePath, options);
}
}
关于拍照
通过拍照Intent，然后onActivityResult得到图片样张，再对其进行裁剪。一般得到的图片都很小，是因为经过了压缩，所以为了不让其压缩，需要在拍照Intent中加入保存的SD卡路径，然后在onActivityResult中得到的data为null，我们直接获取之前设置的SD卡路径的图片对其进行裁剪即可。当然不进行压缩图片肯定很大，之后我们可以根据自己的需求进行压缩。代码上面已经贴出来了。
示例
选择获取图片方式：
case R.id.btn_dialog_one_select_img:
imgDialog.dismiss();
path_name = UtilsImageProcess.getSavePath();
Crop.pickCAPTURE(getActivity(), Uri.fromFile(new File(path_name)));
break;
case R.id.btn_dialog_two_select_img:
imgDialog.dismiss();
Crop.pickImage(getActivity());
break;
返回处理结果：
public void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
if (requestCode == Crop.REQUEST_CAPTURE) { //拍照得到URI
Bitmap bitmap = UtilsImageProcess.getSmallBitmap(path_name);
Uri source = UtilsImageProcess.saveBitmap(bitmap);
beginCrop(source);
} else if (requestCode == Crop.REQUEST_PICK && data != null) { //从相册中选取得到得到图片
Uri source = UtilsImageProcess.convertUri(data.getData(), getActivity());
beginCrop(source);
} else if (requestCode == Crop.REQUEST_CROP && data != null) { //得到裁剪后的图片
handleCrop(data);
}else {
((ActivityMain) getActivity()).dialogDismiss();
}
}
}
//启动裁剪Activity
private void beginCrop(Uri source) {
Uri destination1 = Uri.fromFile(new File(Environment.getExternalStorageDirectory() + "/org.chenlijian.test", "test_crop.png"));
Crop.of(source, destination1).asSquare().start(getActivity());
}
//处理裁剪得到的图片，通过Volley上传到服务器
private void handleCrop(Intent data) {
Uri uri = Crop.getOutput(data);
try {
Bitmap bitmap = MediaStore.Images.Media.getBitmap(getActivity().getContentResolver(), uri);
String imagePath = UtilsImageProcess.getPath(bitmap);
uploadTask = networkModule.arrangeUploadImg("arrangeUploadImg", imagePath);
uploadTask.setId(0);
uploadTask.setReceiver(this);
uploadTask.pullTrigger();
} catch (IOException e) {
e.printStackTrace();
}
}
关于自定义封装Volley接口，上传图片或者文件，我会在下一篇文章中进行分析。
