要解决Android Studio的decodeStream方法返回的图像以横向方向显示的问题,可以使用Matrix类来对图像进行旋转操作。下面是一个包含代码示例的解决方法:
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
private ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageView = findViewById(R.id.imageView);
// 加载图片资源
Bitmap bitmap = decodeSampledBitmapFromResource(getResources(), R.drawable.image, 100, 100);
// 检查图片是否需要旋转
if (bitmap.getWidth() > bitmap.getHeight()) {
Matrix matrix = new Matrix();
matrix.postRotate(90); // 顺时针旋转90度
// 旋转图片
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
}
// 显示图片
imageView.setImageBitmap(bitmap);
}
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, int reqWidth, int reqHeight) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
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;
while ((halfHeight / inSampleSize) >= reqHeight && (halfWidth / inSampleSize) >= reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
}
上述代码中,首先使用decodeSampledBitmapFromResource方法来加载图片资源并进行适当缩放。然后,使用Matrix类对图像进行旋转操作,将宽度大于高度的图片顺时针旋转90度。最后,将旋转后的图片显示在ImageView中。