问题描述
我是用viewpager做的滑动查看大图的功能
static class SamplePagerAdapter extends PagerAdapter {WeakReference<PreviewImgFragment> mActivity;PreviewImgFragment theActivity;AlertDialog.Builder saveBuilder;AlertDialog.Builder warningBuilder;Bitmap bitmap;public SamplePagerAdapter(PreviewImgFragment activity) { mActivity = new WeakReference<>(activity); theActivity = mActivity.get(); saveBuilder = new AlertDialog.Builder(theActivity.activity); saveBuilder.setMessage('保存图片'); saveBuilder.setPositiveButton('确定', new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) { dialog.dismiss(); AppUtils.saveImageToGallery(bitmap); ToastUtil.showToast('保存成功');} }); warningBuilder = new AlertDialog.Builder(theActivity.activity); warningBuilder.setMessage('图片还没有准备好！'); warningBuilder.setPositiveButton('确定', new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) { dialog.dismiss();} }); saveBuilder.setOnDismissListener(onDismissListener); warningBuilder.setOnDismissListener(onDismissListener);}private DialogInterface.OnDismissListener onDismissListener = new DialogInterface.OnDismissListener() { @Override public void onDismiss(DialogInterface dialog) {if (null != cacheView) { cacheView.setEnabled(true);} }};@Overrideprotected void finalize() throws Throwable { super.finalize(); onLongClickListener = null;}private View cacheView = null;View.OnLongClickListener onLongClickListener = new View.OnLongClickListener() { @Override public boolean onLongClick(View v) {cacheView = v;v.setEnabled(false);Uri uri = (Uri) v.getTag();bitmap = AppUtils.returnBitmap(uri);if (null != bitmap) { Log.i('bitmap', bitmap.getHeight() + '*********' + bitmap.getWidth() + ''); saveBuilder.show();} else { warningBuilder.show();}return true; }};@Overridepublic int getCount() { return theActivity.list == null ? 1 : theActivity.list.size();}@Overridepublic View instantiateItem(ViewGroup container, int position) { Log.e('instantiateItem','instantiateItem'); View convertView = View.inflate(SmartApplication.application, R.layout.loading_layout, null); PhotoDraweeView photo = (PhotoDraweeView) convertView.findViewById(R.id.each_photo); Uri uri = null; if (theActivity.list != null) {String url = AppUtils.getImg(theActivity.list.get(position) instanceof ImageInfo ? ((ImageInfo) theActivity.list.get(position)).getBigImageUrl() : (String) theActivity.list.get(position));if (url.startsWith('http')) { uri = Uri.parse(url);} else { uri = (new Uri.Builder()) .scheme('file') .path(url) .build();} } else {if (theActivity.img.startsWith('http')) { uri = Uri.parse(theActivity.img);} else { uri = (new Uri.Builder()) .scheme('file') .path(AppUtils.getImg(theActivity.img)) .build();} } GenericDraweeHierarchy hierarchy = photo.getHierarchy(); if (null == photo.getTag()) {hierarchy.setProgressBarImage(new CustomProgressBar(photo)); } else {//Log.e('previewLLL', photo.getTag().toString());hierarchy = null; } photo.setPhotoUri(uri); photo.setOnLongClickListener(onLongClickListener); photo.setOnPhotoTapListener(new OnPhotoTapListener() {@Overridepublic void onPhotoTap(View view, float x, float y) { theActivity.back.callOnClick();} }); container.addView(convertView); return convertView;}@Overridepublic void destroyItem(ViewGroup container, int position, Object object) { Log.e('destroyItem','destroyItem'); View contentView = (View) object; container.removeView(contentView);}@Overridepublic boolean isViewFromObject(View view, Object object) { return view == object;} }
现在发现滑动的时候卡顿这是什么原因的大大们 ，求帮忙。谢谢！
问题解答
回答1：大图要压缩，比如图片是2000X2000以上的图片，但是整个手机屏幕都没那么大，就导致bitmap很大了，在需要放大的时候才局部加载。另外viewpager还得考虑缓存，就是加载多少页缓存，viewpager的PagerAdapter有多种，而且可以设置，如果不当，你设置个100页，可能都一次加载了，就可能很卡了。
根据你得代码滑动的时候加载的是网络图片，不知道你这边怎么处理的，推荐使用Picasso,或者glide来处理。
回答2：没有看出哪里卡顿, 建议加个BlockCanary检查一下, 针对性解决
