有两种方法可以做到这一点:
先找到显示的高宽,调用这个方法
private void scaleImage(int displayWidth) {
// Get the ImageView and its bitmap
width=displayWidth;
Drawable drawing = holder.imagepost.getDrawable();
{
Bitmap bitmap = ((BitmapDrawable) drawing).getBitmap();
int bounding = dpToPx(width);
// Determine how much to scale: the dimension requiring less
// scaling is
// closer to the its side. This way the image always stays
// inside your
// bounding box AND either x/y axis touches it.
float xScale = ((float) bounding) / width;
float yScale = ((float) bounding) / height;
float scale = (xScale <= yScale) ? xScale : yScale;
// Create a matrix for the scaling and add the scaling data
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
// Create a new bitmap and convert it to a format understood by
// the ImageView
Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width,
height, matrix, true);
width = scaledBitmap.getWidth(); // re-use
height = scaledBitmap.getHeight(); // re-use
BitmapDrawable result = new BitmapDrawable(scaledBitmap);
// Apply the scaled bitmap
holder.imagepost.setImageDrawable(result);
// Now change ImageView's dimensions to match the scaled image
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) holder.imagepost
.getLayoutParams();
params.width = width;
params.height = height;
holder.imagepost.setLayoutParams(params);
}
}
private int dpToPx(int dp) {
float density = context.getResources().getDisplayMetrics().density;
return Math.round((float) dp * density);
}
或者我知道的最好的方法是使用 Android Query
这里是链接http://code.google.com/p/android-query/,您可以从那里自行下载。下面是保持纵横比的代码
aq.id(R.id.imageView)
.image(imageString, true, true,
displaywidth, 0, null, AQuery.FADE_IN, AQuery.RATIO_PRESERVE);