我正在浏览BitmapFactory，发现我们可以减小图像的大小，如果它高于我们想要的大小，以避免内存异常。但是增加高度+宽度的方法是什么。目前我正在使用Bitmap.createScaledBitmap ..
以下是代码：
package sudipta.deb.imagedisplayer;
import sudipta.deb.image.ImageSources;
import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.Toast;
public class MainActivity extends Activity implements OnClickListener {
private static final String IMAGE_TAG = "Image Tag";
private final int PREFERRED_HEIGHT = 400;
private final int PREFERRED_WIDTH = 533;
private static int imageIndex;
private int totalImages;
private Bitmap bitmap;
private ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initialize();
}
private void initialize() {
ImageSources.configureImages();
imageIndex = 0;
totalImages = ImageSources.totalImages();
imageView = ((ImageView) findViewById(R.id.imageView1));
imageView.setOnClickListener(this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private Bitmap checkBitmapDetails(int index) {
Bitmap bitmap;
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(),
ImageSources.getImageId(index), options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
Log.i(IMAGE_TAG, "Image: " + index);
Log.i(IMAGE_TAG, "Image Height: " + imageHeight);
Log.i(IMAGE_TAG, "Image width: " + imageWidth);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, PREFERRED_WIDTH,
PREFERRED_HEIGHT);
options.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeResource(getResources(),
ImageSources.getImageId(index), options);
bitmap = Bitmap.createScaledBitmap(bitmap, PREFERRED_WIDTH,
PREFERRED_HEIGHT, false);
return bitmap;
}
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) {
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;
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.imageView1:
imageIndex++;
if (imageIndex >= totalImages) {
imageIndex = 0;
}
Log.i(IMAGE_TAG, "Loading Image: " + imageIndex);
bitmap = checkBitmapDetails(imageIndex);
imageView.setImageBitmap(bitmap);
break;
default:
break;
}
}
}
您是否有更好的信息以更好的方式执行此操作？感谢。
答案 0 :(得分：0)
您可以使用ImageView和scaleType等adjustViewBounds参数对其进行拉伸，但在屏幕上显示时会有效。但是如果你想在这里调整bmp的大小，你可以去：
/**
* Returns given @Bitmap resized the to given size.
*
* @param bm : Bitmap to resize.
* @param newHeight : Height to resize.
* @param newWidth : Width to resize.
* @return Resized Bitmap.
*/
public static Bitmap getResizedBitmap(Bitmap bitmap, int newHeight, int newWidth) {
if (bitmap == null || newHeight<0 || newWidth<0 || newHeight+newWidth==0)
return null;
Bitmap resizedBitmap = null;
final int height = bitmap.getHeight();
final int width = bitmap.getWidth();
if (newHeight==0)
newHeight = (int)((float)newWidth * (float)height / (float)width);
if (newWidth==0)
newWidth = (int)((float)newHeight * (float)width / (float)height);
float scaleHeight = ((float) newHeight) / height;
float scaleWidth = ((float) newWidth) / width;
// create a matrix for the manipulation
final Matrix matrix = new Matrix();
// resize the bit map
matrix.postScale(scaleWidth, scaleHeight);
try {
// recreate the new Bitmap
resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
// resizedBitmap = Bitmap.createScaledBitmap(bm, newWidth, // newHeight, true);
} catch (Exception e) {
android.util.Log.e(TAG, e.getMessage());
resizedBitmap = null;
} catch (Throwable e) {
android.util.Log.e(TAG, e.getMessage());
resizedBitmap = null;
}
return resizedBitmap;
}
答案 1 :(得分：0)
最后，我找到了处理这种情况的解决方案。 我所做的是，如果图像大小大于首选大小，那么首先缩小大小，然后使用createScaledBitmap将图像缩放到精确大小。
private Bitmap checkBitmapDetails(int index) {
Bitmap bitmap;
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
bitmap = BitmapFactory.decodeResource(getResources(),
ImageSources.getImageId(index), options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, PREFERRED_WIDTH,
PREFERRED_HEIGHT);
options.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeResource(getResources(),
ImageSources.getImageId(index), options);
bitmap = Bitmap.createScaledBitmap(bitmap, PREFERRED_WIDTH, PREFERRED_HEIGHT, true);
return bitmap;
}
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) {
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;
}
答案 2 :(得分：0)