如何重新缩放位图图像大小？

Question

大家好，我正在尝试从 url 加载图像，加载后我试图重新缩放它，使其适合整个屏幕，然后下面提供了文本和按钮使用滚动视图环绕的图像

这是我的片段

public class FirstFragment extends Fragment {

    ImageView im;
    Bitmap bitmap;
    Drawable dr;
    Bitmap bitap;
    Bitmap newBitmap;
    RelativeLayout rel;
    View v;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         v = inflater.inflate(R.layout.first_frag, container, false);

        rel = (RelativeLayout) v.findViewById(R.id.relativla);
        rel.setVisibility(View.INVISIBLE);


        new LoadImage().execute("http://opinions.esy.es/bg.jpg");

        Button b = (Button) v.findViewById(R.id.navi);
         im = (ImageView) v.findViewById(R.id.imageView);




        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(getContext(), Navi.class);
                startActivity(i);
            }
        });


        return v;
    }

    public static FirstFragment newInstance(String text) {

        FirstFragment f = new FirstFragment();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }
    private class LoadImage extends AsyncTask<String, String, Bitmap> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();


        }
        protected Bitmap doInBackground(String... args) {
            try {
                bitmap = BitmapFactory.decodeStream((InputStream) new URL(args[0]).getContent());

            } catch (Exception e) {
                e.printStackTrace();
            }
            return bitmap;
        }


        protected void onPostExecute(Bitmap image) {

            if(image != null){
                dr = new BitmapDrawable(getResources(),image);
                bitap = ((BitmapDrawable) dr).getBitmap();
                float scalingFactor = getBitmapScalingFactor(bitap);
                Bitmap newBitmap = Util.ScaleBitmap(bitmap, scalingFactor);

               im.setImageBitmap(newBitmap);





            }else{


                Toast.makeText(getContext(), "Image Does Not exist or Network Error", Toast.LENGTH_SHORT).show();

            }

        }
    }
    private float getBitmapScalingFactor(Bitmap bm) {
        Toast.makeText(getContext(),"entered here",Toast.LENGTH_LONG).show();
        // Get display width from device
        int displayWidth = getActivity().getWindowManager().getDefaultDisplay().getWidth();

        // Get margin to use it for calculating to max width of the ImageView
        RelativeLayout.LayoutParams layoutParams =
                (RelativeLayout.LayoutParams)this.im.getLayoutParams();
        int leftMargin = layoutParams.leftMargin;
        int rightMargin = layoutParams.rightMargin;

        // Calculate the max width of the imageView
        int imageViewWidth = displayWidth - (leftMargin + rightMargin);
        rel.setVisibility(View.VISIBLE);
        // Calculate scaling factor and return it
        return ( (float) imageViewWidth / (float) bm.getWidth() );

    }
}

我的工具class

public class Util {
    public static Bitmap ScaleBitmap(Bitmap bm, float scalingFactor) {
        int scaleHeight = (int) (bm.getHeight() * scalingFactor);
        int scaleWidth = (int) (bm.getWidth() * scalingFactor);

        return Bitmap.createScaledBitmap(bm, scaleWidth, scaleHeight, true);
    }

}

XML 文件

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/scrollView"
    android:fillViewport="true"

    >

    <RelativeLayout

        android:id="@+id/relativla"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"

        >
        <Button
            android:layout_width="30dp"
            android:layout_height="30dp"

            android:background="@drawable/hamburger"
            android:id="@+id/navi"
            android:padding="10dp"
            android:layout_alignParentTop="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:adjustViewBounds="true"
            android:id="@+id/imageView"

            android:scaleType="fitCenter"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Diet Plans"

            android:padding="10dp"
            android:layout_marginTop="10dp"
            android:textColor="@android:color/black"
            android:textSize="25sp"
            android:id="@+id/textView5"
            android:layout_below="@+id/imageView"
            />

        <TextView
            android:layout_width="wrap_content"

            android:layout_height="wrap_content"
            android:text="@string/descrpitiondietplan"
            android:textColor="#000000"
            android:gravity="center"
            android:layout_gravity="center_vertical"
            android:textSize="15sp"
            android:padding="10dp"
            android:id="@+id/textView6"
            android:layout_below="@+id/textView5"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Our Diet Plans"
            android:textColor="@android:color/black"
            android:padding="10dp"
            android:textSize="25sp"
            android:id="@+id/textView7"
            android:layout_below="@+id/textView6"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true" />

        <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@+id/textView7"
            android:layout_centerHorizontal="true"
            android:padding="10dp">

            <Button

                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Basic Diet Plan"
                android:textColor="@android:color/white"
                android:id="@+id/normmal"
                android:background="@color/btn_login"
                android:layout_marginBottom="10dp"
                android:layout_gravity="center_horizontal" />

        </LinearLayout>


    </RelativeLayout>

</ScrollView>

查看相对布局后调用 getBitmapScaling 因子的 toast 内幕

希望大家能帮我解决问题

Answer 1

尝试添加这些

WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics dm = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(dm);
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(dm.widthPixels, dm.heightPixels);
im.setLayoutParams(params);

低于im.setImageBitmap(newBitmap)； onPostExecute

如何重新缩放位图图像大小？

How to re-scale Bitmap image size?

android

bitmapfactory

android-bitmap