所以我从厨房加载图像并显示到ImageView
,图像变成黑色。但不是所有的图像,只是一定的。为什么会这样?
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case RESULT_LOAD_IMAGE:
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK & null != data) {
imageUri = data.getData();
imageView.setImageURI(imageUri);
}
break;
}
}
然后我尝试了这种方法。图像显示但看起来很模糊。
imageView.setImageBitmap(decodeUri(imageUri));
private Bitmap decodeUri(Uri selectedImage) throws FileNotFoundException {
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(
getContentResolver().openInputStream(selectedImage), null, o);
final int REQUIRED_SIZE = 100;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while (true) {
if (width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE) {
break;
}
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeStream(
getContentResolver().openInputStream(selectedImage), null, o2);
}
答案 0 :(得分:2)
是的,当Bitmap
无法加载时会发生这种情况,因为图片的高度和宽度较大,为2048*2048
。通过相机拍摄的图像通常很大,因此,最好调整图像大小。
以下只是裁剪图像的示例,如果尺寸较大,并且不考虑图像比率
public class InputImageCompressor extends Activity{
public static void compressInputImage(Intent data, Context context, ImageView newIV)
{
Bitmap bitmap;
Uri inputImageData = data.getData();
try
{
Bitmap bitmapInputImage = MediaStore.Images.Media.getBitmap(context.getContentResolver(), inputImageData);
if (bitmapInputImage.getWidth() > 2048 && bitmapInputImage.getHeight() > 2048)
{
bitmap = Bitmap.createScaledBitmap(bitmapInputImage, 1024, 1280, true);
newIV.setImageBitmap(bitmap);
}
else if (bitmapInputImage.getWidth() > 2048 && bitmapInputImage.getHeight() < 2048)
{
bitmap = Bitmap.createScaledBitmap(bitmapInputImage, 1920, 1200, true);
newIV.setImageBitmap(bitmap);
}
else if (bitmapInputImage.getWidth() < 2048 && bitmapInputImage.getHeight() > 2048)
{
bitmap = Bitmap.createScaledBitmap(bitmapInputImage, 1024, 1280, true);
newIV.setImageBitmap(bitmap);
}
else if (bitmapInputImage.getWidth() < 2048 && bitmapInputImage.getHeight() < 2048)
{
bitmap = Bitmap.createScaledBitmap(bitmapInputImage, bitmapInputImage.getWidth(), bitmapInputImage.getHeight(), true);
newIV.setImageBitmap(bitmap);
}
} catch (Exception e)
{
Toast.makeText(context, e.toString(), Toast.LENGTH_LONG).show();
}
}
}
在onActivityResult
中将其用作:
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case RESULT_LOAD_IMAGE:
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK & null != data) {
InputImageCompressor.compressInputImage(data, your_activity_context.this, imageView);
}
break;
}
}
答案 1 :(得分:1)
代码看起来还不错,你看到模糊图像的事实也证实了这一点。
我认为REQUIRED_SIZE对于您正在尝试的设备来说太小了。对于初学者,请尝试将REQUIRED_SIZE设置为更大的值,例如350,看看它是否提高了图像质量。如果是,则使用REQUIRED_SIZE = SCREEN_WIDTH
要查找SCREEN_WIDTH,请在活动(或至少一个视图)中使用以下内容:
DisplayMetrics displaymetrics = new DisplayMetrics();
((Activity) getContext()).getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int SCREEN_WIDTH = displaymetrics.widthPixels;