我在listview中添加了自定义适配器。数据是来自手机的通话记录。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listview时，我有一个很大的滞后。我的滚动不顺畅。有没有办法让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;
}
}
答案 0 :(得分：1)
你的获取是巨大的。 您的（如果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。
你需要做的是重构getview，不要太慢。你可以做的一件事就是创建一个类，它已经为你完成了所有的查找，然后将它放在转换后的视图的.tag中。更改你的onclicks以使用它，以一种你不必重新创建它们的方式（其他方法也存在）。
理想情况下，如果您已经转换了视图，那么您的代码应该只是.settexts（）。
取决于列表的大小，您可以为每个调用者创建一个视图，并避免完全回收转换后的视图，在这种情况下，您可以提前创建它们。
同样取决于列表的大小，您可以在滚动视图中创建一个简单的线性布局。如果你的名单不是很大而且不适合某些旧款手机，它的效果也不错（在你尝试使用手机之前，不要将其作为糟糕的建议，在列表视图开始变得更有意义之前可能会有多大） 。
答案 1 :(得分：1)
尝试使用ViewHolder并使用AsyncTask加载位图。 你可以这样试试。
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);
}