我试图从我的应用程序中打开画廊内置应用程序中的图像/图片。
我有一个图片的URI(图片位于SD卡上)。
你有什么建议吗?
我试图从我的应用程序中打开画廊内置应用程序中的图像/图片。
我有一个图片的URI(图片位于SD卡上)。
你有什么建议吗?
当前回答
hcpl的方法在kitkat之前工作得很好,但不能与DocumentsProvider API一起工作。为此,只需简单地遵循官方的Android文档提供者教程:https://developer.android.com/guide/topics/providers/document-provider.html ->打开一个文档,位图部分。
简单地,我使用了hcpl的代码并扩展了它:如果图像的检索路径的文件抛出异常,我调用这个函数:
private Bitmap getBitmapFromUri(Uri uri) throws IOException {
ParcelFileDescriptor parcelFileDescriptor =
getContentResolver().openFileDescriptor(uri, "r");
FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
Bitmap image = BitmapFactory.decodeFileDescriptor(fileDescriptor);
parcelFileDescriptor.close();
return image;
}
在Nexus 5上测试。
其他回答
这里有两个关于图像拾取器的有用教程,可下载源代码:
如何创建Android图像拾取器
如何在Android上选择和裁剪图像
但是,应用程序有时会被迫关闭,你可以通过添加android:configChanges属性到Manifest文件中的主活动来修复它:
<activity android:name=".MainActivity"
android:label="@string/app_name" android:configChanges="keyboardHidden|orientation" >
似乎相机API失去了对方向的控制,所以这将有助于它。:)
要显示图像和视频,请尝试以下方法:
Intent intent = new Intent();
intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, 1);
startActivityForResult(Intent.createChooser(intent,"Wybierz plik"), SELECT_FILE);
package com.ImageConvertingDemo;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.Log;
import android.widget.EditText;
import android.widget.ImageView;
public class MyActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
EditText tv = (EditText)findViewById(R.id.EditText01);
ImageView iv = (ImageView)findViewById(R.id.ImageView01);
FileInputStream in;
BufferedInputStream buf;
try
{
in = new FileInputStream("/sdcard/smooth.png");
buf = new BufferedInputStream(in,1070);
System.out.println("1.................."+buf);
byte[] bMapArray= new byte[buf.available()];
tv.setText(bMapArray.toString());
buf.read(bMapArray);
Bitmap bMap = BitmapFactory.decodeByteArray(bMapArray, 0, bMapArray.length);
/*for (int i = 0; i < bMapArray.length; i++)
{
System.out.print("bytearray"+bMapArray[i]);
}*/
iv.setImageBitmap(bMap);
//tv.setText(bMapArray.toString());
//tv.setText(buf.toString());
if (in != null)
{
in.close();
}
if (buf != null)
{
buf.close();
}
}
catch (Exception e)
{
Log.e("Error reading file", e.toString());
}
}
}
这是我对这个主题的回顾,收集了这里的所有信息,再加上其他相关的堆栈溢出问题。它从某些提供者返回图像,同时处理内存不足的情况和图像旋转。它支持画廊,picasa和文件管理器,如下拉框。用法很简单:作为输入,构造函数接收内容解析器和uri。输出是最终的位图。
/**
* Creates resized images without exploding memory. Uses the method described in android
* documentation concerning bitmap allocation, which is to subsample the image to a smaller size,
* close to some expected size. This is required because the android standard library is unable to
* create a reduced size image from an image file using memory comparable to the final size (and
* loading a full sized multi-megapixel picture for processing may exceed application memory budget).
*/
public class UserPicture {
static int MAX_WIDTH = 600;
static int MAX_HEIGHT = 800;
Uri uri;
ContentResolver resolver;
String path;
Matrix orientation;
int storedHeight;
int storedWidth;
public UserPicture(Uri uri, ContentResolver resolver) {
this.uri = uri;
this.resolver = resolver;
}
private boolean getInformation() throws IOException {
if (getInformationFromMediaDatabase())
return true;
if (getInformationFromFileSystem())
return true;
return false;
}
/* Support for gallery apps and remote ("picasa") images */
private boolean getInformationFromMediaDatabase() {
String[] fields = { Media.DATA, ImageColumns.ORIENTATION };
Cursor cursor = resolver.query(uri, fields, null, null, null);
if (cursor == null)
return false;
cursor.moveToFirst();
path = cursor.getString(cursor.getColumnIndex(Media.DATA));
int orientation = cursor.getInt(cursor.getColumnIndex(ImageColumns.ORIENTATION));
this.orientation = new Matrix();
this.orientation.setRotate(orientation);
cursor.close();
return true;
}
/* Support for file managers and dropbox */
private boolean getInformationFromFileSystem() throws IOException {
path = uri.getPath();
if (path == null)
return false;
ExifInterface exif = new ExifInterface(path);
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
this.orientation = new Matrix();
switch(orientation) {
case ExifInterface.ORIENTATION_NORMAL:
/* Identity matrix */
break;
case ExifInterface.ORIENTATION_FLIP_HORIZONTAL:
this.orientation.setScale(-1, 1);
break;
case ExifInterface.ORIENTATION_ROTATE_180:
this.orientation.setRotate(180);
break;
case ExifInterface.ORIENTATION_FLIP_VERTICAL:
this.orientation.setScale(1, -1);
break;
case ExifInterface.ORIENTATION_TRANSPOSE:
this.orientation.setRotate(90);
this.orientation.postScale(-1, 1);
break;
case ExifInterface.ORIENTATION_ROTATE_90:
this.orientation.setRotate(90);
break;
case ExifInterface.ORIENTATION_TRANSVERSE:
this.orientation.setRotate(-90);
this.orientation.postScale(-1, 1);
break;
case ExifInterface.ORIENTATION_ROTATE_270:
this.orientation.setRotate(-90);
break;
}
return true;
}
private boolean getStoredDimensions() throws IOException {
InputStream input = resolver.openInputStream(uri);
Options options = new Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(resolver.openInputStream(uri), null, options);
/* The input stream could be reset instead of closed and reopened if it were possible
to reliably wrap the input stream on a buffered stream, but it's not possible because
decodeStream() places an upper read limit of 1024 bytes for a reset to be made (it calls
mark(1024) on the stream). */
input.close();
if (options.outHeight <= 0 || options.outWidth <= 0)
return false;
storedHeight = options.outHeight;
storedWidth = options.outWidth;
return true;
}
public Bitmap getBitmap() throws IOException {
if (!getInformation())
throw new FileNotFoundException();
if (!getStoredDimensions())
throw new InvalidObjectException(null);
RectF rect = new RectF(0, 0, storedWidth, storedHeight);
orientation.mapRect(rect);
int width = (int)rect.width();
int height = (int)rect.height();
int subSample = 1;
while (width > MAX_WIDTH || height > MAX_HEIGHT) {
width /= 2;
height /= 2;
subSample *= 2;
}
if (width == 0 || height == 0)
throw new InvalidObjectException(null);
Options options = new Options();
options.inSampleSize = subSample;
Bitmap subSampled = BitmapFactory.decodeStream(resolver.openInputStream(uri), null, options);
Bitmap picture;
if (!orientation.isIdentity()) {
picture = Bitmap.createBitmap(subSampled, 0, 0, options.outWidth, options.outHeight,
orientation, false);
subSampled.recycle();
} else
picture = subSampled;
return picture;
}
}
引用:
http://developer.android.com/training/displaying-bitmaps/index.html 通过编程方式从Android内置的Gallery应用程序中获取/选择一张图像 在将图像加载到位图对象时出现奇怪的内存不足问题 使用ExifInterface设置图像方向 https://gist.github.com/9re/1990019 如何获得位图信息,然后解码位图从internet-inputStream?
在上面代码的基础上,我反映了如下代码,可能它更适合:
public String getPath(Uri uri) {
String selectedImagePath;
//1:MEDIA GALLERY --- query from MediaStore.Images.Media.DATA
String[] projection = { MediaStore.Images.Media.DATA };
Cursor cursor = managedQuery(uri, projection, null, null, null);
if(cursor != null){
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
selectedImagePath = cursor.getString(column_index);
}else{
selectedImagePath = null;
}
if(selectedImagePath == null){
//2:OI FILE Manager --- call method: uri.getPath()
selectedImagePath = uri.getPath();
}
return selectedImagePath;
}