图片比例缩放以及bitMap转BitmapDrawable

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ImageView.ScaleType;

/**
 * This example shows how to resize an image
 * @author FaYnaSoft Labs
 *
 */
public class Main extends Activity {

	@Override
	public void onCreate(Bundle icicle) {
		super.onCreate(icicle);
		LinearLayout linearLayout = new LinearLayout(this);

		Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);

		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		int newWidth = 640;
		int newHeight = 480;

		float scaleWidth = ((float) newWidth) / width;
		float scaleHeight = ((float) newHeight) / height;

		Matrix matrix = new Matrix();
		matrix.postScale(scaleWidth, scaleHeight);

		// create the new Bitmap object
		Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0, width,
				height, matrix, true);
		BitmapDrawable bmd = new BitmapDrawable(resizedBitmap);

		ImageView imageView = new ImageView(this);
		imageView.setImageDrawable(bmd);
		imageView.setScaleType(ScaleType.CENTER);

		linearLayout.addView(imageView, new LinearLayout.LayoutParams(
				LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
		setContentView(linearLayout);
	}
}