“Canvas: trying to draw too large bitmap” problem in Android Studio

问题

When I try to get bitmap from website, Canvas: trying to draw too large problem is occured.

So I search this problem on google and many people wrote their solutions, but that solution is about bitmap file in directory drawable.

• What should I do if the bitmap image taken from the website is too large?

This is my code.

            Thread mThread = new Thread() {
                @Override
                public void run() {
                    try {
                        URL url = new URL(postImgUrl);

                        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                        conn.setDoInput(true);
                        conn.connect();

                        InputStream inputStream = conn.getInputStream();
                        postImgBitmap = BitmapFactory.decodeStream(inputStream);
                        inputStream.close();
                        conn.disconnect();

                    } catch (MalformedURLException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            };
            mThread.start();
            mThread.join();

            if (postImgBitmap != null){
                postImg.setImageBitmap(postImgBitmap);

When a problem occurs, variable postImgUrl is "http://www.hstree.org/data/ck_tmp/202001/de3kOOtFqV6Bc2o7xCa7vg1UwFWJ.jpg" and variable postImg is ImageView.

Please advise me.

回答1:

The error means the size of Bitmap is too large for the ImageView. Before setImageBitmap() to ImageView, you can scale the large Bitmap to a smaller one with Bitmap.createScaledBitmap(). Then you can safely set the Bitmap to ImageView.

A sample code:

public class MainActivity extends AppCompatActivity {
    private static final String imageUrl
        = "http://www.hstree.org/data/ck_tmp/202001/de3kOOtFqV6Bc2o7xCa7vg1UwFWJ.jpg";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final ImageView imageView = findViewById(R.id.imageView);

        new Thread(new Runnable() {
            @Override
            public void run() {
                URL url = null;
                try {
                    url = new URL(imageUrl);
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                }

                try (BufferedInputStream bufferedInputStream
                        = new BufferedInputStream(url.openStream())) {
                    Bitmap bitmap = BitmapFactory.decodeStream(bufferedInputStream);

                    final Bitmap scaledBitmap = Bitmap.createScaledBitmap(
                        bitmap,
                        (int) (bitmap.getWidth() * 0.1),
                        (int) (bitmap.getHeight() * 0.1),
                        true
                    );

                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            imageView.setImageBitmap(scaledBitmap);
                        }
                    });
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }
}

来源：https://stackoverflow.com/questions/61134238/canvas-trying-to-draw-too-large-bitmap-problem-in-android-studio