使用呼叫日志在列表视图上平滑滚动

Question

我有一个自定义适配器添加到列表视图。数据是来自电话的通话记录。我通过仅显示 3 天的记录来减少列表。问题是当我尝试从上到下滚动列表视图时，我有很大的滞后。我的 Scroll 不流畅。有什么办法让listview滚动更流畅？

这是我的自定义适配器：

    public class CallListAdapter extends ArrayAdapter<CallList> {

    Activity activity;

    public CallListAdapter(Context context, ArrayList<CallList> calls, Activity activity) {
        super(context, 0, calls);
        this.activity = activity;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        final CallList callList = getItem(position);

        int actualPosition = 0;

        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.call_list, parent, false);
        }

        final TextView call1 = convertView.findViewById(R.id.callNumber);
        final TextView call2 = convertView.findViewById(R.id.callDate);
        final TextView call3 = convertView.findViewById(R.id.conversationTime);
        final TextView call4 = convertView.findViewById(R.id.callType);
        final Button callView = convertView.findViewById(R.id.getViewName);
        final ImageView bio = convertView.findViewById(R.id.lookBio);
        final ImageView edit = convertView.findViewById(R.id.edit_call);
        final ImageView block = convertView.findViewById(R.id.blockCall);
        final ImageView call = convertView.findViewById(R.id.callUser);
        final TextView bioLabel = convertView.findViewById(R.id.BioLabelSug);
        final TextView editLabel = convertView.findViewById(R.id.NoteLabel);
        final TextView blockLabel = convertView.findViewById(R.id.BlockLabelSug);
        final TextView callLabel = convertView.findViewById(R.id.CallLabelSug);
        final ConstraintLayout callContainer = convertView.findViewById(R.id.contact_container);
        final ConstraintLayout bioContainer = convertView.findViewById(R.id.bio_container);
        final ConstraintLayout blockContainer = convertView.findViewById(R.id.ignore_container);
        final ConstraintLayout noteContainer = convertView.findViewById(R.id.note_container);
        final TextView btnMarg = convertView.findViewById(R.id.buttonMargin);
        final TextView callListNr2 = convertView.findViewById(R.id.callNumber2);

        final LayoutInflater factory = activity.getLayoutInflater();

        final View fullView = factory.inflate(R.layout.fragment_calls, null);

        final RelativeLayout loading = fullView.findViewById(R.id.loadingBar);


        String[] jsonData = new manageCalls().intentCallValues(position);

        StringBuilder builder = new StringBuilder();
        for (String s : jsonData) {
            builder.append(s + "\n");
        }
        String str = builder.toString();

        final String num = jsonData[0];
        final String dat = jsonData[1];
        final String typeCall = jsonData[2];
        final String dur = jsonData[3];
        final String authToken = SaveSharedPreferences.getPrefTokenName(getContext());

        final Animation slideUp = AnimationUtils.loadAnimation(getContext(), R.anim.slideup);
        final Animation slideDown = AnimationUtils.loadAnimation(getContext(), R.anim.slidedown);

        final Handler handler = new Handler();

        callView.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                if (bioContainer.getVisibility() == View.GONE) {

                    callListNr2.setVisibility(View.GONE);
                    bio.setVisibility(View.VISIBLE);
                    bioLabel.setVisibility(View.VISIBLE);
                    edit.setVisibility(View.VISIBLE);
                    editLabel.setVisibility(View.VISIBLE);

                } else if (bioContainer.getVisibility() == View.VISIBLE) {

                    handler.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            bio.setVisibility(View.GONE);
                            callContainer.setVisibility(View.GONE);
                            bioContainer.setVisibility(View.GONE);
                            noteContainer.setVisibility(View.GONE);
                            blockContainer.setVisibility(View.GONE);

                        }
                    }, 300);

                }
            }
        });


        if (actualPosition != position) {

            if (bioContainer.getVisibility() == View.VISIBLE) {

                bioContainer.setVisibility(View.GONE);
                callContainer.setVisibility(View.GONE);
                noteContainer.setVisibility(View.GONE);
                blockContainer.setVisibility(View.GONE);

            }

            actualPosition = position;

        }


        call.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                call.setEnabled(false);
                loading.setVisibility(View.VISIBLE);
                Intent intentCall = new Intent(view.getContext(), CallUserActivity.class);

                intentCall.putExtra("number", num);
                intentCall.putExtra("authToken", authToken);
                intentCall.putExtra("Date", dat);

                activity.startActivityForResult(intentCall, position);

                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        call.setEnabled(true);
                        loading.setVisibility(View.GONE);
                    }
                }, 1000);
            }
        });

        call2.setText(callList.callDate);
        call3.setText(callList.conversationTime);
        call4.setText(callList.callType);

        return convertView;
        }
}

Answer 1

尝试使用 ViewHolder 并使用 AsyncTask 加载位图。 你可以试试这个方法。

    private static class ViewHolder {
            public TextView call1;
            public TextView call2;
            public TextView call3;
            public TextView call4;
            public Button callView;
            public ImageView bio;
            public ImageView edit;
            public ImageView block;
            public ImageView call;
            public TextView bioLabel;
            public TextView editLabel;
            public TextView blockLabel;
            public TextView callLabel;
            public ConstraintLayout callContainer;
            public ConstraintLayout bioContainer;
            public ConstraintLayout blockContainer;
            public ConstraintLayout noteContainer;
            public TextView btnMarg;
            public TextView callListNr2;
    }
    
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
                // inflate the layout
                LayoutInflater inflater = LayoutInflater.from(getContext());
                convertView = inflater.inflate(layoutResourceId, parent, false);
                holder = new ViewHolder();
                holder.call1 = convertView.findViewById(R.id....);
                holder.call2 = convertView.findViewById(R.id....);
                //Same for all other views
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

        holder.call1.setText(....);
        //Lazy load for bitmap
        loadBitmap(yourFileName..., bio)
       
        return convertView;
    }

    static class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {
        private final WeakReference<ImageView> imageViewReference;

        BitmapWorkerTask(ImageView imageView) {
            // Use a WeakReference to ensure the ImageView can be garbage collected
            imageViewReference = new WeakReference<ImageView>(imageView);
        }

        // Decode image in background.
        @Override
        protected Bitmap doInBackground(String... params) {
            return decodeSampledBitmapFromResource(params[0], 300, 300);
        }

        // Once complete, see if ImageView is still around and set bitmap.
        @Override
        protected void onPostExecute(Bitmap bitmap) {
            if (imageViewReference != null && bitmap != null) {
                final ImageView imageView = imageViewReference.get();
                if (imageView != null) {
                    imageView.setImageBitmap(bitmap);
                }
            }
        }
    }


    public void loadBitmap(String fileName, ImageView imageView) {
        BitmapWorkerTask task = new BitmapWorkerTask(imageView);
        task.execute(fileName);
    }

  public static Bitmap decodeSampledBitmapFromResource(String fileName,
                                                     int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(fileName, options);
    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeFile(fileName, options);
}

Answer 2

你的 getview 是巨大的。 您的 (if convertview==null) 基本上几乎没有效果，因为您无论如何都要再次设置视图。

您需要做的是重构 getview 以使其不那么慢。您可以做的一件事是创建一个已经为您完成所有 findview 的类，然后将其放在转换后的视图的 .tag 中。更改您的点击以使用它，以您不必重新创建它们的方式（也存在其他方法）。

理想情况下，如果您已经转换了视图，您的代码应该只是 .settexts()。

根据列表的大小，您可以为每个调用者创建一个视图，避免一起回收转换后的视图，在这种情况下，您可以提前创建它们。

还取决于您的列表的大小，您可以在滚动视图中创建一个简单的线性布局而不是创建一个简单的线性布局。如果您的列表不是很大并且不适用于某些旧手机，那么它也可以正常工作（在您尝试使用手机之前，在列表视图开始变得更有意义之前，不要将此视为坏建议） .