android选择相册图片另存为并在Imageview中显示的相关问题

来源：互联网发布：sql内连接和外连接编辑：程序博客网时间：2024/05/18 09:50

网上有很多选择相册图片并且裁剪的方法，今天我们这里介绍一种不裁减图片，并且使用输入输出流把图片另存为一个文件夹。

直接看代码：

public void saveImage(Uri uri) {//        LogUtil.augusLogW("one");//        LogUtil.augusLogW(String.valueOf(uri));        File readFile = getFileFromMediaUri(this, uri);        if (readFile.exists() && readFile.length() > 0) {            try {                LogUtil.augusLogW("two");                //读                FileInputStream fis = new FileInputStream(readFile);                byte[] buf = new byte[(int) readFile.length()];                fis.read(buf);                fis.close();                //写                FileOutputStream fos;                switch (type) {                    case "up":                        upImage = new File(BaseApplication.CACHE_PATH, "up.png");                        fos = new FileOutputStream(upImage);                        fos.write(buf);                        fos.close();                        if (upImage.exists() && upImage.length() > 0) {                            isUp = true;                        } else {                            Common.staticToast(baseFragActivity, "该图片不存在");                        }                        new BitmapWorkerTask(miv_upImage).execute(BaseApplication.CACHE_PATH + "up.png");                        break;                    case "down":                        downImage = new File(BaseApplication.CACHE_PATH, "down.png");                        fos = new FileOutputStream(downImage);                        fos.write(buf);                        fos.close();                        if (downImage.exists() && downImage.length() > 0) {                            isDown = true;                        } else {                            Common.staticToast(baseFragActivity, "该图片不存在");                        }                        new BitmapWorkerTask(miv_downImage).execute(BaseApplication.CACHE_PATH + "down.png");                        break;                    case "hand":                        handImage = new File(BaseApplication.CACHE_PATH, "hand.png");                        fos = new FileOutputStream(handImage);                        fos.write(buf);                        fos.close();                        if (handImage.exists() && handImage.length() > 0) {                            isHand = true;                        } else {                            Common.staticToast(baseFragActivity, "该图片不存在");                        }                        new BitmapWorkerTask(miv_handImage).execute(BaseApplication.CACHE_PATH + "hand.png");                        break;                }            } catch (IOException e) {                e.printStackTrace();            }        }    }

相关的类和几个方法：

public static File getFileFromMediaUri(Context ac, Uri uri) {    if (uri.getScheme().toString().compareTo("content") == 0) {        ContentResolver cr = ac.getContentResolver();        Cursor cursor = cr.query(uri, null, null, null, null);// 根据Uri从数据库中找        if (cursor != null) {            cursor.moveToFirst();            String filePath = cursor.getString(cursor.getColumnIndex("_data"));// 获取图片路径            cursor.close();            if (filePath != null) {                return new File(filePath);            }        }    } else if (uri.getScheme().toString().compareTo("file") == 0) {        return new File(uri.toString().replace("file://", ""));    }    return null;}public static int calculateInSampleSize(BitmapFactory.Options options,                                        int reqWidth, int reqHeight) {    // Raw height and width of image    final int height = options.outHeight;    final int width = options.outWidth;    int inSampleSize = 1;    if (height > reqHeight || width > reqWidth) {        if (width > height) {            inSampleSize = Math.round((float) height / (float) reqHeight);        } else {            inSampleSize = Math.round((float) width / (float) reqWidth);        }    }    return inSampleSize;}public static Bitmap decodeSampledBitmapFromFile(String filename,                                                 int reqWidth, int reqHeight) {    // First decode with inJustDecodeBounds=true to check dimensions    final BitmapFactory.Options options = new BitmapFactory.Options();    options.inJustDecodeBounds = true;    BitmapFactory.decodeFile(filename, options);    // Calculate inSampleSize    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);    // Decode bitmap with inSampleSize set    options.inJustDecodeBounds = false;    return BitmapFactory.decodeFile(filename, options);}

class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {    private final WeakReference<ImageView> imageViewReference;    private String data = null;    public BitmapWorkerTask(ImageView imageView) {        // Use a WeakReference to ensure the ImageView can be garbage collected        imageViewReference = new WeakReference<ImageView>(imageView);    }    // Decode image in background.    @Override    protected Bitmap doInBackground(String... params) {        data = params[0];        return decodeSampledBitmapFromFile(data, 100, 100);    }    // Once complete, see if ImageView is still around and set bitmap.    @Override    protected void onPostExecute(Bitmap bitmap) {        if (imageViewReference != null && bitmap != null) {            final ImageView imageView = imageViewReference.get();            if (imageView != null) {                imageView.setImageBitmap(bitmap);            }        }    }}

注意：其中在给imageview设置图片的时候不能直接使用bitmap，因为如果图片过大的话，是显示不出来的，因此显示时要压缩显示。

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