How can I crop a bitmap for ImageView?

问题

I know this should be simple , but android:scaleType=\"centerCrop\" doesn\'t crop Image

I got image 1950 pixels wide and need it to be cropped by parent\'s width. But android:scaleType=\"centerCrop\" doesn\'t crop Image. What do I need to do in layout to show only first 400 pixels, for instance or whatever screen/parent width is

Sorry for simple question - tried to Google it - only complicated questions there. And I\'m new, so don\'t downvote please)

<RelativeLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"
    xmlns:tools=\"http://schemas.android.com/tools\"
    android:id=\"@+id/rl1\"
    android:layout_width=\"match_parent\"
    android:layout_height=\"match_parent\"
    android:background=\"@color/background_color\">

    <ImageView
            android:id=\"@+id/ver_bottompanelprayer\"
            android:layout_width=\"match_parent\"
            android:layout_height=\"227px\"
            android:layout_alignParentBottom=\"true\"
            android:layout_alignParentLeft=\"true\"
            android:scaleType=\"matrix\"

            android:background=\"@drawable/ver_bottom_panel_tiled_long\" />

</RelativeLayout>

if there\'s only way is to programmaticaly crop it - please give me an advice with a method

回答1:

Alright, I will paste the comment as answer :) ->

RelativeLayout rl = (RelativeLayout) findViewById(R.id.rl1);

final Options bitmapOptions=new Options();
DisplayMetrics metrics = getResources().getDisplayMetrics();
bitmapOptions.inDensity = metrics.densityDpi;
bitmapOptions.inTargetDensity=1;

/*`final` modifier might be necessary for the Bitmap*/
Bitmap bmp= BitmapFactory.decodeResource(getResources(), R.drawable.ver_bottom_panel_tiled_long, bitmapOptions);
bmp.setDensity(Bitmap.DENSITY_NONE);
bmp = Bitmap.createBitmap(bmp, 0, 0, rl.getWidth(), bmp.getHeight());

Then in the code:

ImageView iv = (ImageView)v.findViewById(R.id.ver_bottompanelprayer);
if (iv != null){
  iv.setImageBitmap(bmp);
}

Cheers :)

回答2:

You can also crop image by programmatically using createBitmap.

Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
bm = Bitmap.createBitmap(bm, 0, 0, 400, 400);
your_imageview.setImageBitmap(bm);

Here 400 is your width & height you can change as per your requirement.

回答3:

Make it android:scaleType="fitStart" and for android:layout_height="400px"

回答4:

You can do this programmatically (this ensures you get the right height/width):

ImageView image = (ImageView) findVieById(R.id.ver_bottompanelprayer);
DisplayMetrics dm = getResources().getDisplayMetrics();
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(1950, dm.heightPixels);
params.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
params.addRule(RelativeLayout.ALIGN_PARENT_TOP);
image.setLayoutParams(params);
image.setScaleType(ScaleType.FIT_XY);

来源：https://stackoverflow.com/questions/18232034/how-can-i-crop-a-bitmap-for-imageview

标签

java

android

imageview

crop