Android:从位图裁剪位图并设置为ImageView src

Question

我正在尝试从精灵表中裁剪精灵，但是裁剪后的图像不是我指定的图像的一部分。

精灵表包含大小为 32 x 32 像素的精灵，

因此第一个精灵应位于像素 0 到 32（水平）和 0 到 32（垂直），假设左上角最上角的像素是 [0， 0]。

Bitmap spritesheet = BitmapFactory.decodeResource(getResources(), R.drawable.spritesheet_32x32);
Bitmap sprite = Bitmap.createBitmap(spritesheet, 0, 0, 32, 32);

ImageView

只是一个普通的ImageView，没有设置src，宽度或高度。

ImageView view = (ImageView)findViewById(R.id.player1);
view.setImageBitmap(sprite);

但显示的图像只是第一个精灵的一小部分。我监督什么？view.setImageBitmap(sprite);是正确的方法吗？在设置位图之前，图像视图是否需要固定宽度和高度？

编辑：也许我应该更清楚地了解我的布局。LinearLayout上排列着两个ImageView。下面是 XML：

<LinearLayout
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:baselineAligned="false">
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleX="-1"
        android:id="@+id/player1"
        android:layout_weight="1"
        android:layout_gravity="center_vertical" />
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/player2"
        android:layout_weight="1"
        android:layout_gravity="center_vertical" />
</LinearLayout>

Answer 1

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
public class ImageResizer {
public static Bitmap decodeSampledBitmapFromFile(String filename,
    int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options
        options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filename, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(filename, options);
}
public static int calculateInSampleSize(BitmapFactory.Options options,
    int reqWidth, int reqHeight) {
// BEGIN_INCLUDE (calculate_sample_size)
// 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;
    }
    // This offers some additional logic in case the image has a strange
    // aspect ratio. For example, a panorama may have a much larger
    // width than height. In these cases the total pixels might still
    // end up being too large to fit comfortably in memory, so we should
    // be more aggressive with sample down the image (=larger inSampleSize).
    long totalPixels = width * height / inSampleSize;
    // Anything more than 2x the requested pixels we'll sample down further
    final long totalReqPixelsCap = reqWidth * reqHeight * 2;
    while (totalPixels > totalReqPixelsCap) {
        inSampleSize *= 2;
        totalPixels /= 2;
    }
}
return inSampleSize;
// END_INCLUDE (calculate_sample_size)
 }
}

调用方法

Bitmap bmp = ImageResizer.decodeSampledBitmapFromFile(new  File(filePath).getAbsolutePath(), 512, 342);               

我还没有尝试过，但以下内容可能会传递方法参数，例如
imageView.getWidth（） ， imageView.getHeight（）