android之图片截取

本文主要记录一些零碎的东西

android上的相机是经常需要用到的好东西，比如用户头像啦这些，一开始我没有截取部分，而是直接上传，后来获取图片时给我报了这样一个错：

java.lang.OutOfMemoryError: Failed to allocate a 14745612 byte allocation with 12949099free bytes and 12MB until OOM

内存不足呀，看来需要在上传图片时就截取部分上传控制图片的大小。

主要思路就是打开系统相册，截取图片，显示，这里都是在activity里调用startActivityForResult完成

先打开相册：

private static final int PHOTO_REQUEST_GALLERY = 2;// 从相册中选择private static final int PHOTO_REQUEST_CUT = 3;// 结果Intent intent = new Intent(Intent.ACTION_PICK);intent.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "image/*");startActivityForResult(intent, PHOTO_REQUEST_GALLERY);

再看看回调函数，使用系统的com.android.camera.action.CROP进行图片截取

@Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        super.onActivityResult(requestCode, resultCode, data);        if ( resultCode == Activity.RESULT_OK) {            switch (requestCode){                case PHOTO_REQUEST_GALLERY://从相册中选择                    //截取图片                    startPhotoZoom(data.getData(), 150);                    break;                case PHOTO_REQUEST_CUT://截取的结果                    Bitmap photo = null;                    //这里只会在图片没有截取时执行，默认是需要截取图片的                    Uri photoUri = data.getData();//                    Log.i("slack","photoUri:"+photoUri);                    if (photoUri != null) {                        photo = BitmapFactory.decodeFile(photoUri.getPath());                    }                    // end                    if (photo == null) {                        Bundle extra = data.getExtras();                        if (extra != null) {                            photo = (Bitmap)extra.get("data");                            ByteArrayOutputStream stream = new ByteArrayOutputStream();                            photo.compress(Bitmap.CompressFormat.JPEG, 100, stream);                        }                    }                    showPhoto(photo);                    break;                }}private void startPhotoZoom(Uri uri, int size) {        Intent intent = new Intent("com.android.camera.action.CROP");        intent.setDataAndType(uri, "image/*");        // crop为true是设置在开启的intent中设置显示的view可以剪裁        intent.putExtra("crop", "true");        // aspectX aspectY 是宽高的比例        intent.putExtra("aspectX", 1);        intent.putExtra("aspectY", 1);        // outputX,outputY 是剪裁图片的宽高        intent.putExtra("outputX", size);        intent.putExtra("outputY", size);        intent.putExtra("outputFormat", "JPEG");        intent.putExtra("noFaceDetection", true);        intent.putExtra("return-data", true);        startActivityForResult(intent, PHOTO_REQUEST_CUT);    }    private void showPhoto(Bitmap bitmap) {        userPic.setImageBitmap(bitmap);    }

关键是下面这段代码：

Bundle extra = data.getExtras();                        if (extra != null) {                            photo = (Bitmap)extra.get("data");                            ByteArrayOutputStream stream = new ByteArrayOutputStream();                            photo.compress(Bitmap.CompressFormat.JPEG, 100, stream);                        }

上面就可以实现图片截取了，在小米和魅族上亲测有效

现在的图片格式是Bitmap的，上传时可以转成文件，或者直接转成byte字节数字

/** * Bitmap transfer to bytes * 位图转移到字节 * @param byteArray * @return */public static byte[] bitmapToBytes(Bitmap bm) {byte[] bytes = null;if (bm != null) {ByteArrayOutputStream baos = new ByteArrayOutputStream();bm.compress(Bitmap.CompressFormat.PNG, 100, baos);bytes = baos.toByteArray();}return bytes;}

转文件，上传完载删除，听着都觉麻烦

/** * Check the SD card  * @return * 检查SD卡 */public static boolean checkSDCardAvailable(){return android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);}/** * Save image to the SD card 将图像保存到SD卡 * @param photoBitmap * @param photoName * @param path */public static void savePhotoToSDCard(Bitmap photoBitmap,String path,String photoName){if (checkSDCardAvailable()) {File dir = new File(path);if (!dir.exists()){dir.mkdirs();}File photoFile = new File(path , photoName + ".png");FileOutputStream fileOutputStream = null;try {fileOutputStream = new FileOutputStream(photoFile);if (photoBitmap != null) {if (photoBitmap.compress(Bitmap.CompressFormat.PNG, 100, fileOutputStream)) {fileOutputStream.flush();//fileOutputStream.close();}}} catch (FileNotFoundException e) {photoFile.delete();e.printStackTrace();} catch (IOException e) {photoFile.delete();e.printStackTrace();} finally{try {fileOutputStream.close();} catch (IOException e) {e.printStackTrace();}}} }/** * Delete the image from SD   card从SD卡删除的图像 * @param context * @param path * file:///sdcard/temp.jpg */public static void deleteAllPhoto(String path){if (checkSDCardAvailable()) {File folder = new File(path);File[] files = folder.listFiles();for (int i = 0; i < files.length; i++) {files[i].delete();}}}public static void deletePhotoAtPathAndName(String path,String fileName){if (checkSDCardAvailable()) {File folder = new File(path);File[] files = folder.listFiles();for (int i = 0; i < files.length; i++) {System.out.println(files[i].getName());if (files[i].getName().equals(fileName)) {files[i].delete();}}}}

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