android.widget.ImageView#getMaxHeight ( )源码实例Demo

/**
 * {@inheritDoc}
 * <br />
 * 3) Get <b>maxHeight</b>
 */
@Override
public int getHeight() {
    int height = super.getHeight();
    if (height <= 0) {
        ImageView imageView = (ImageView) viewRef.get();
        if (imageView != null) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                height = imageView.getMaxHeight();
            } else {
                height = getImageViewFieldValue(imageView, "mMaxHeight"); // Check maxHeight parameter
            }
        }
    }
    return height;
}
 

public static void updateImageView(Context context, ImageView imageView, Uri uri) {
    try {
        InputStream inputStream = context.getContentResolver().openInputStream(uri);
        // Avoid decoding the entire image if the imageView holding this image is smaller.
        BitmapFactory.Options bounds = new BitmapFactory.Options();
        bounds.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(inputStream, null, bounds);
        int streamWidth = bounds.outWidth;
        int streamHeight = bounds.outHeight;
        int maxDesiredWidth = imageView.getMaxWidth();
        int maxDesiredHeight = imageView.getMaxHeight();
        int ratio = Math.max(streamWidth / maxDesiredWidth, streamHeight / maxDesiredHeight);
        if (ratio > 1) {
            bounds.inSampleSize = ratio;
        }
        bounds.inJustDecodeBounds = false;

        inputStream = context.getContentResolver().openInputStream(uri);
        imageView.setImageBitmap(BitmapFactory.decodeStream(inputStream, null, bounds));
    } catch (FileNotFoundException e) {
        Toast.makeText(context, R.string.error_opening_image_file, Toast.LENGTH_SHORT);
    }
}
 

/**
 * 获取 ImageView 最大高度
 * @param imageView ImageView
 * @return view 最大高度
 */
@RequiresApi(Build.VERSION_CODES.JELLY_BEAN)
public static int getMaxHeight(final ImageView imageView) {
    if (imageView != null) {
        return imageView.getMaxHeight();
    }
    return -1;
}
 

private void setImageToView(){
    // Restore preferences
    SharedPreferences settings = getSharedPreferences(PREFS_FILE_NAME, 0);
    String savedPhotoPath = settings.getString(PHOTO_PATH, null);

    //Initialize the image view and display the picture if one exists
    imageView = (ImageView) findViewById(R.id.lock_imageView);
    Intent intent = getIntent();

    String passedPhotoPath = intent.getStringExtra(
            MainActivity.EXTRA_FILEPATH);
    if (passedPhotoPath != null) {
        mCurrentPhotoPath = passedPhotoPath;
    } else {
        mCurrentPhotoPath = savedPhotoPath;
    }

    if (mCurrentPhotoPath != null) {
        int targetH = imageView.getMaxHeight();
        int targetW = imageView.getMaxWidth();

        // Get the dimensions of the bitmap

        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        bmOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
        int photoH = bmOptions.outHeight;
        int photoW = bmOptions.outWidth;

        // Determine how much to scale down image
        int scaleFactor = Math.min(photoW/targetW, photoH/targetH);

        // Decode the image file into a Bitmap sized to fill the View
        bmOptions.inJustDecodeBounds = false;
        bmOptions.inSampleSize = scaleFactor;

        Bitmap imageBitmap = BitmapFactory.decodeFile(mCurrentPhotoPath,
                bmOptions);
        imageView.setImageBitmap(imageBitmap);
    }
}
 

private void setImageToView(){

        // Restore preferences
        SharedPreferences settings = getSharedPreferences(PREFS_FILE_NAME, 0);
        String savedPhotoPath = settings.getString(PHOTO_PATH, null);

        //Initialize the image view and display the picture if one exists
        imageView = (ImageView) findViewById(R.id.lock_imageView);
        Intent intent = getIntent();

        String passedPhotoPath = intent.getStringExtra(
                MainActivity.EXTRA_FILEPATH);
        if (passedPhotoPath != null) {
            mCurrentPhotoPath = passedPhotoPath;
        } else {
            mCurrentPhotoPath = savedPhotoPath;
        }

        if (mCurrentPhotoPath != null) {
            int targetH = imageView.getMaxHeight();
            int targetW = imageView.getMaxWidth();

            // Get the dimensions of the bitmap
            BitmapFactory.Options bmOptions = new BitmapFactory.Options();
            bmOptions.inJustDecodeBounds = true;
            BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
            int photoH = bmOptions.outHeight;
            int photoW = bmOptions.outWidth;

            // Determine how much to scale down image
            int scaleFactor = Math.min(photoW/targetW, photoH/targetH);


            // Decode the image file into a Bitmap sized to fill the View
            bmOptions.inJustDecodeBounds = false;
            bmOptions.inSampleSize = scaleFactor;

            Bitmap imageBitmap = BitmapFactory.decodeFile(mCurrentPhotoPath,
                    bmOptions);
            imageView.setImageBitmap(imageBitmap);
        }
    }