在空对象引用上的Bitmap.getWidth()' [英] Bitmap.getWidth()' on a null object reference

问题描述

我刚刚在CreateScaledBitmap行上遇到了这个问题，我试图将此图像设置为设备的墙纸，并且需要将该图像缩放到设备上，这就是为什么我要使用此方法，但是不幸的是我无法修复此Bitmap宽度()错误

I just got into this problem on the line CreateScaledBitmap, I am trying to set this image as device's wallpaper and I need to scale this image to the device, thats why I am doing this method but unfortunately I cant fix this Bitmap width() error

            setWall.setOnClickListener(new View.OnClickListener() {
        @RequiresApi(api = Build.VERSION_CODES.KITKAT)
        @Override
        public void onClick(View view) {

            Picasso.with(getApplicationContext()).load(imageBrought).into(new Target() {
                @Override
                public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {

                    DisplayMetrics metrics = new DisplayMetrics();
                    getWindowManager().getDefaultDisplay().getMetrics(metrics);

                    int height = metrics.heightPixels;
                    int width = metrics.widthPixels;


                    bitmap = Bitmap.createScaledBitmap(bitmap, width, height, true);

                    WallpaperManager wallpaperManager = WallpaperManager.getInstance(AppMomentSelected.this);
                    wallpaperManager.setWallpaperOffsetSteps(1, 1);
                    wallpaperManager.suggestDesiredDimensions(width, height);


                    try {

                        wallpaperManager.setBitmap(bitmap);

                    } catch (IOException e) {

                        e.printStackTrace();
                    }

                }

                @Override
                public void onBitmapFailed(Drawable errorDrawable) {

                }

                @Override
                public void onPrepareLoad(Drawable placeHolderDrawable) {

                }
            });

推荐答案

您从Firebase中获取了图像的Url，但是用于从Url中获取Bitmap的方法效率不高，并且可能无法实现.您需要做的简单事情是使用一些自定义library来下载图像，例如毕加索 http://square.github.io/picasso/

You have Url of an image from your Firebase but approach you use to get Bitmap from Url is not efficient and probably not possible. Simple thing you need to do is to use some custom library for downloading images for example Picasso http://square.github.io/picasso/

添加到您的app gradle:compile 'com.squareup.picasso:picasso:2.5.2'

现在您可以使用Picasso从Url下载图像并转换为Bitmap:

And now you can use Picasso to download image from Url and convert to Bitmap:

                DisplayMetrics metrics = new DisplayMetrics();
                getWindowManager().getDefaultDisplay().getMetrics(metrics);

                int height = metrics.heightPixels;
                int width = metrics.widthPixels;
                WallpaperManager wallpaperManager = WallpaperManager.getInstance(AppMomentSelected.this);
                wallpaperManager.setWallpaperOffsetSteps(1, 1);
                wallpaperManager.suggestDesiredDimensions(width, height);

                Picasso.with(this)
                .load(imageBrought)
                .resize(width, height)
                .into(new Target() {
                 @Override
                  public void onBitmapLoaded (final Bitmap bitmap, Picasso.LoadedFrom from) {
                 /* Save the bitmap or do something with it here */
                 wallpaperManager.setBitmap(bitmap);
         }
    });

这篇关于在空对象引用上的Bitmap.getWidth()'的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！