我需要只使用文件名来显示图像，而不是使用资源id。
ImageView imgView = new ImageView(this);
imgView.setBackgroundResource(R.drawable.img1);
我在可绘制文件夹中有图像img1。我想展示文件中的图像。
我该怎么做呢?
当前回答
public static Bitmap decodeFile(String path) {
Bitmap b = null;
File f = new File(path);
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream fis = null;
try {
fis = new FileInputStream(f);
BitmapFactory.decodeStream(fis, null, o);
fis.close();
int IMAGE_MAX_SIZE = 1024; // maximum dimension limit
int scale = 1;
if (o.outHeight > IMAGE_MAX_SIZE || o.outWidth > IMAGE_MAX_SIZE) {
scale = (int) Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
}
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
fis = new FileInputStream(f);
b = BitmapFactory.decodeStream(fis, null, o2);
fis.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return b;
}
public static Bitmap showBitmapFromFile(String file_path)
{
try {
File imgFile = new File(file_path);
if(imgFile.exists()){
Bitmap pic_Bitmap = decodeFile(file_path);
return pic_Bitmap;
}
} catch (Exception e) {
MyLog.e("Exception showBitmapFromFile");
return null;
}
return null;
}
如果你在列表视图中使用图像加载，那么使用Aquery概念。
https://github.com/AshishPsaini/AqueryExample
AQuery aq= new AQuery((Activity) activity, convertView);
//load image from file, down sample to target width of 250 pixels .gi
File file=new File("//pic/path/here/aaaa.jpg");
if(aq!=null)
aq.id(holder.pic_imageview).image(file, 250);
其他回答
public static Bitmap decodeFile(String path) {
Bitmap b = null;
File f = new File(path);
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream fis = null;
try {
fis = new FileInputStream(f);
BitmapFactory.decodeStream(fis, null, o);
fis.close();
int IMAGE_MAX_SIZE = 1024; // maximum dimension limit
int scale = 1;
if (o.outHeight > IMAGE_MAX_SIZE || o.outWidth > IMAGE_MAX_SIZE) {
scale = (int) Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
}
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
fis = new FileInputStream(f);
b = BitmapFactory.decodeStream(fis, null, o2);
fis.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return b;
}
public static Bitmap showBitmapFromFile(String file_path)
{
try {
File imgFile = new File(file_path);
if(imgFile.exists()){
Bitmap pic_Bitmap = decodeFile(file_path);
return pic_Bitmap;
}
} catch (Exception e) {
MyLog.e("Exception showBitmapFromFile");
return null;
}
return null;
}
如果你在列表视图中使用图像加载，那么使用Aquery概念。
https://github.com/AshishPsaini/AqueryExample
AQuery aq= new AQuery((Activity) activity, convertView);
//load image from file, down sample to target width of 250 pixels .gi
File file=new File("//pic/path/here/aaaa.jpg");
if(aq!=null)
aq.id(holder.pic_imageview).image(file, 250);
你可以使用:
ImageView imgView = new ImageView(this);
InputStream is = getClass().getResourceAsStream("/drawable/" + fileName);
imgView.setImageDrawable(Drawable.createFromStream(is, ""));
使用位图可以很容易地做到这一点。你可以在下面找到代码:
ImageView imageView=findViewById(R.id.imageView);
Bitmap bitMapImage= BitmapFactory.decodeFile("write path of your image");
imageView.setImageBitmap(bitMapImage);
您可以使用它来访问特定的文件夹并获得特定的图像
public void Retrieve(String path, String Name)
{
File imageFile = new File(path+Name);
if(imageFile.exists()){
Bitmap myBitmap = BitmapFactory.decodeFile(path+Name);
myImage = (ImageView) findViewById(R.id.savedImage);
myImage.setImageBitmap(myBitmap);
Toast.makeText(SaveImage.this, myBitmap.toString(), Toast.LENGTH_LONG).show();
}
}
然后你就可以过来了
Retrieve(Environment.getExternalStorageDirectory().toString()+"/Aqeel/Images/","Image2.PNG");
Toast.makeText(SaveImage.this, "Saved", Toast.LENGTH_LONG).show();
来自官方网站:http://developer.android.com/training/displaying-bitmaps/load-bitmap.html
ImageView image = (ImageView) findViewById(R.id.imagePreview);
try {
image.setImageBitmap(decodeSampledBitmap(picFilename));
} catch (Exception e) {
e.printStackTrace();
}
方法如下:
private 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) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
private Bitmap decodeSampledBitmap(String pathName,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(pathName, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(pathName, options);
}
//I added this to have a good approximation of the screen size:
private Bitmap decodeSampledBitmap(String pathName) {
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;
return decodeSampledBitmap(pathName, width, height);
}
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