android选择相册图片另存为并在Imageview中显示的相关问题

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。