Question

我有一个简单的布局，我想要一个背景图片。首先，我尝试将背景图像放在xml中，但是有很多滞后。

所以我跟着Set image through AsyncTask但仍然没有运气。

图像分辨率为1131 X 1800，大小为369kb。

I/Choreographer: Skipped 33 frames!  The application may be doing too much work on its main thread.
I/Choreographer: Skipped 37 frames!  The application may be doing too much work on its main thread.
I/Choreographer: Skipped 34 frames!  The application may be doing too much work on its main thread.
I/Choreographer: Skipped 34 frames!  The application may be doing too much work on its main thread.
I/Choreographer: Skipped 34 frames!  The application may be doing too much work on its main thread.

Java文件

public class MainActivity extends flights{
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    new LoadDrawable().execute();
}

private class LoadDrawable extends AsyncTask<Drawable, Void, Drawable> {
    @Override
    protected Drawable doInBackground(Drawable... params) {
        //Loading the drawable in the background
        final Drawable image = getResources().getDrawable(R.drawable.as);
        //After the drawable is loaded, onPostExecute is called
        return image;
    }

    @Override
    protected void onPostExecute(Drawable loaded) {
        //Hide the progress bar
        //ProgressBar progress = (ProgressBar) findViewById(R.id.progress_bar);
        //progress.setVisibility(View.GONE);
        //Set the layout background with your loaded drawable
        RelativeLayout layout = (RelativeLayout) findViewById(R.id.root);
        layout.setBackgroundDrawable(loaded);
    }

    @Override
    protected void onPreExecute() {}

    @Override
    protected void onProgressUpdate(Void... values) {}
}

}

Answer 1

您的图片尺寸很大。将图像设置为背景的问题是图像的大小而不适合分辨率。我有同样的问题。经过搜索和测试很多方法，我发现滑行是一个很好的库来设置图像。使用此库，您的设备大小并不重要。滑行会设置它。

来自drawable的set image，你可以像这样编码：

 Glide.with(this).load(R.drawable.backtwo).asBitmap().into(new SimpleTarget<Bitmap>(size.x, size.y) {
            @Override
            public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
                Drawable drawable = new BitmapDrawable(resource);
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                    iv_background.setBackground(drawable);
                }
            }
        });

另一种方法是针对不同的设备屏幕使用不同的图像分辨率。这种方法的弱点是增加apk大小

Answer 2

重要的是要理解onPostExecute（）发生在主线程上，因此可能导致你所看到的（但你没有解决方法）。

至于你的问题，图像不是那么大，所以好像它不应该引起这种问题;然而，如果将它替换为较小的图像，可能值得测试会发生什么（顺便说一句，最好是拥有均匀分辨率的图像 - 1131这里的数字很差）。

另一种选择是在异步任务中解码位图（这很费时） -

private class LoadDrawable extends AsyncTask<Drawable, Void, Drawable> {
    @Override
    protected Drawable doInBackground(Drawable... params) {
        return new BitmapDrawable(BitmapFactory.decodeResource(getResources(), R.drawable.as)); 
    }
    ...
}

导致滞后和框架跳的背景图象

2 个答案: