touchImageView只有在捏一下手势后才显示图像

我正在使用自定义视图 TouchImageView . 但是,当我设置位图时,它不会显示图像,除非我在上面做了一个捏手势。

public class PhotoOverlayActivity extends AppCompatActivity {

    public static final String CURRENT_MESSAGE_KEY = "message";

    private static final int IMAGE_REQUEST_CODE = 0;

    String currentMessage;
    private Bitmap bitmap;
    private TouchImageView mImageView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_photo_overlay);

        setupToolbar();
        setupImageView();

        currentMessage = getIntent().getStringExtra(CURRENT_MESSAGE_KEY);
        chooseImage();
    }

    private void setupToolbar() {
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.setDisplayHomeAsUpEnabled(true);
            actionBar.setDisplayShowHomeEnabled(true);
            actionBar.setTitle("");
        }
    }

    private void setupImageView() {
        mImageView = findViewById(R.id.imageView);

    }

    private void chooseImage() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        startActivityForResult(intent, IMAGE_REQUEST_CODE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == IMAGE_REQUEST_CODE && resultCode == Activity.RESULT_OK)
            try {
                if (bitmap != null) {
                    bitmap.recycle();
                }
                InputStream stream = getContentResolver().openInputStream(data.getData());
                bitmap = BitmapFactory.decodeStream(stream);
                stream.close();
                int nh = (int) (bitmap.getHeight() * (512.0 / bitmap.getWidth()));
                Bitmap scaled = Bitmap.createScaledBitmap(bitmap, 512, nh, true);
                mImageView.setImageBitmap(scaled);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        super.onActivityResult(requestCode, resultCode, data);
    }

}

我终于找到了隐藏的解决方案 here ,所以我把我的答案贴在下面。