Question

我尝试更改ImageView的背景，但由于OutOfMemoryError而导致错误。

我已使用Bitmap搜索更改背景，但我不知道如何使用它。

当我点击按钮时，背景将变为另一张图片。

代码如下：

public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        View view = inflater.inflate(R.layout.user_guide, container, false) ;
        last = (Button) view.findViewById(R.id.last);
        user = (ImageView) view.findViewById(R.id.image);
        last.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                                user.setBackgroundResource(R.drawable.test1);
            }
        });

我搜索了以下代码，但我不知道如何使用它来更改background的{{1}}。有人可以教我如何使用它吗？

Imageview

有人可以教我如何使用它来更改public static Bitmap readBitMap(Context context, int resId){ BitmapFactory.Options opt = new BitmapFactory.Options(); opt.inPreferredConfig = Bitmap.Config.RGB_565; opt.inPurgeable = true; opt.inInputShareable = true; InputStream is = context.getResources().openRawResource(resId); return BitmapFactory.decodeStream(is,null,opt); }和ImageView的背景吗？

提前致谢。

Answer 1

尝试以下代码：

last.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                 Bitmap bitmap=readBitmap(this, R.drawable.test1);
                 image.setImageBitmap(bitmap);
                 bitmap.recycle();
                 bitmap=null;
            }
        });

使用您的方法：

public static Bitmap readBitMap(Context context, int resId){
         BitmapFactory.Options opt = new BitmapFactory.Options();
        opt.inPreferredConfig = Bitmap.Config.RGB_565;
         opt.inPurgeable = true;
         opt.inInputShareable = true;
         InputStream is = context.getResources().openRawResource(resId);
         return BitmapFactory.decodeStream(is,null,opt);
         }

Answer 2

使用这两种方法有效地加载位图..... for efficient large bitmap loading

last.setOnClickListener(new OnClickListener() {


        @Override
        public void onClick(View v) {
            WeakReference bitmapWeakReference=new  WeakReference(decodeSampledBitmapFromResource(getApplicationContext().getRssource(),drawableId,reqWidth,reqHeight));
            user.setImageBitmap(bitmapWeakReference.get());
        }
    });

public static int calculateInSampleSize(
            BitmapFactory.Options options, int reqWidth, int reqHeight) {
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;
    if (height > reqHeight || width > reqWidth) {
        final int halfHeight = height / 2;
        final int halfWidth = width / 2;
        while ((halfHeight / inSampleSize) > reqHeight
                && (halfWidth / inSampleSize) > reqWidth) {
            inSampleSize *= 2;
        }
    }
    return inSampleSize;
}
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight) {

    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

如何在Android中设置imageView的背景以避免OutOfMemoryError？

2 个答案: