为什么在 Android 上滚动列表时内存不断增加答案

【问题标题】：Why memory keeps increasing when you scroll in a List on Android为什么在 Android 上滚动列表时内存不断增加
【发布时间】：2017-03-24 20:58:03
【问题描述】：

我正在观看 Android 上的显示器，我注意到当您向下和向上滚动时内存不断增加。我正在使用Adaper。应该是复用view，但是好像不行。

正如您在下图中所见，内存从 9.94 MB 开始，我可以通过向下和向上滚动将其增加到 25.82 MB。

你可以看到我使用的代码。

public class ListMainFragment
            extends Fragment
            implements LoaderManager.LoaderCallbacks<List<Earthquake>> {

    public ListMainFragment() {
        // Required empty public constructor
    }
    ListView listView;

    @Override
    public View onCreateView(final LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

        View viewRoot = inflater.inflate(R.layout.fragment_mainlist, container, false);

        final ArrayList<Earthquake> earthquake =
            (ArrayList<Earthquake>) new EarthquakeController(new EarthquakesJson()).getListOfEarthquakes();

        listView = (ListView)viewRoot.findViewById(R.id.list_view);
        EarthquakeAdapter noteAdapter = new EarthquakeAdapter(getActivity(), earthquake);
        listView.setAdapter(noteAdapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            //final String mensaje = notas.get(position).getMag();
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.setData(Uri.parse(earthquake.get(0).getMapURL()));
                Log.w("ListView", "Se despliega la siguente URL " + earthquake.get(0).getMapURL());
                startActivity(intent);
            }
        });

        return viewRoot;
    }
}

Adapter:

public class EarthquakeAdapter extends ArrayAdapter <Earthquake> {

    public EarthquakeAdapter(Context context, ArrayList<Earthquake> notas) {
        super(context, 0, notas);
    }

    private static final String LOCATION_SEPARATOR = " of";
    View view;

    @NonNull
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        /*if(convertView == null){
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item,parent,false);
        */
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item,parent,false);
            Log.w("AppList", "converView es null");
        }

        Earthquake note = getItem(position);

        Date dateObject = new Date(note.getTimeInMilliseconds());
        TextView locationOffset = (TextView)convertView.findViewById(R.id.listItem_tv_locationOffset);
        TextView place = (TextView)convertView.findViewById(R.id.listItem_tv_place);
        TextView date = (TextView)convertView.findViewById(R.id.lisItem_tv_date);
        TextView time = (TextView)convertView.findViewById(R.id.lisItem_tv_time);
        TextView mag = (TextView) convertView.findViewById(R.id.listItem_tv_mag);

        GradientDrawable magnitudCicle = (GradientDrawable) mag.getBackground();
        magnitudCicle.setColor(getMagnitudColor(note.getMag()));
        String str_locationOffset, str_place;

        if (note.getPlace().contains(LOCATION_SEPARATOR)) {
            String [] locations = note.getPlace().split(LOCATION_SEPARATOR);
            str_locationOffset = locations[0];
            str_place = locations[1];
        }
        else {
            str_place = note.getPlace();
            str_locationOffset = getContext().getString(R.string.near_the);
        }

        mag.setText( new DecimalFormat("0.0").format(note.getMag()));
        date.setText(formatDate(dateObject));
        place.setText(str_place);
        time.setText(formatTime(dateObject));
        locationOffset.setText(str_locationOffset);

        /* final String  mensaje = title.getText().toString();
        convertView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getContext(),mensaje,Toast.LENGTH_SHORT).show();
            }
        });*/

        return convertView;
    }
}

【问题讨论】：

你没有像你应该的那样实现 ViewHolder 方法。 findViewById 可能是一个紧张的过程，每次获取 GradientDrawable 可能会将 drawable 推送到内存中。

标签： android performance memory-leaks heap-memory

【解决方案1】：

您应该使用 Recycler View 以获得更好的性能。

发件人：https://developer.android.com/training/material/lists-cards.html

【讨论】：

这应该是一条评论。