android - 如何解决 ListView 滚动缓慢的问题？

Question

需要您的帮助来解决 ListView 中缓慢滚动的问题。当我运行我的应用程序并滚动 ListView 时，它的运行速度非常慢且有间断。

这是我的logcat:

07-07 14:27:17.682  30190-30190/com.nadolskiy.sergey.githubreader I/Choreographer﹕ Skipped 75 frames!  The application may be doing too much work on its main thread.
07-07 14:27:22.550  30190-30190/com.nadolskiy.sergey.githubreader I/Choreographer﹕ Skipped 92 frames!  The application may be doing too much work on its main thread.
07-07 14:27:30.116  30190-30190/com.nadolskiy.sergey.githubreader I/Choreographer﹕ Skipped 104 frames!  The application may be doing too much work on its main thread.
07-07 14:27:32.023  30190-30190/com.nadolskiy.sergey.githubreader I/Choreographer﹕ Skipped 111 frames!  The application may be doing too much work on its main thread.
07-07 14:27:33.828  30190-30190/com.nadolskiy.sergey.githubreader I/Choreographer﹕ Skipped 100 frames!  The application may be doing too much work on its main thread.

custom_listview.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="match_parent"
        android:layout_weight="0.2"
        android:orientation="vertical">

        <TextView
            android:id="@+id/custom_listview_tv_repositoryName"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Github-Reader"
            android:textSize="20dp" />

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/custom_listview_tv_languageLabel"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Language: "
                android:textSize="14dp" />

            <TextView
                android:id="@+id/custom_listview_tv_language"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Java"
                android:textSize="14dp" />
        </LinearLayout>

    </LinearLayout>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="match_parent"
        android:layout_weight="0.4"
        android:orientation="horizontal"
        android:gravity="center">

        <TextView
            android:id="@+id/custom_listview_tv_branchCount"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="15"
            android:textSize="20dp"
            android:layout_weight="0.5"
            android:gravity="right" />

        <ImageView
            android:id="@+id/custom_listview_iv_branch"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_branch"
            android:layout_weight="0.5" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="match_parent"
        android:layout_weight="0.4"
        android:orientation="horizontal"
        android:gravity="center">

        <TextView
            android:id="@+id/custom_listview_tv_inFavoriteCount"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="31"
            android:textSize="20dp"
            android:layout_weight="0.5"
            android:gravity="right" />

        <ImageView
            android:id="@+id/custom_listview_iv_favorite"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_star"
            android:layout_weight="0.5" />
    </LinearLayout>

</LinearLayout>

CustomAdapter.java

public class CustomAdapter extends BaseAdapter implements DialogInterface.OnClickListener {

private Activity activity;
private ArrayList data;
private static LayoutInflater inflater = null;
public Resources res;
ListModel tempValues = null;
int i = 0;
Typeface textFont;

public CustomAdapter(Activity a, ArrayList d, Resources resLocal) {
    activity = a;
    data = d;
    res = resLocal;
    textFont = Typeface.createFromAsset(activity.getAssets(), "fonts/DiamondGirl.ttf");

    inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public int getCount() {
    if (data.size() <= 0)
        return 1;
    return data.size();
}

@Override
public Object getItem(int position) {
    return position;
}

@Override
public long getItemId(int position) {
    return position;
}

public static class ViewHolder {
    public TextView repositoryName;
    public TextView language;
    public TextView branchCount;
    public TextView inFavoriteCount;
}

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

    View vi = convertView;
    ViewHolder holder;

    if (convertView == null) {
        vi = inflater.inflate(R.layout.custom_listview, null);

        holder = new ViewHolder();
        holder.repositoryName  = (TextView) vi.findViewById(
                R.id.custom_listview_tv_repositoryName);
        holder.language        = (TextView) vi.findViewById(
                R.id.custom_listview_tv_language);
        holder.branchCount     = (TextView) vi.findViewById(
                R.id.custom_listview_tv_branchCount);
        holder.inFavoriteCount = (TextView) vi.findViewById(
                R.id.custom_listview_tv_inFavoriteCount);

        vi.setTag(holder);
    } else {
        holder = (ViewHolder) vi.getTag();
    }
        ;
    if (data.size() <= 0) {
        holder.repositoryName.setText("No Data");
    } else {
        tempValues = null;
        tempValues = (ListModel) data.get(position);

        holder.repositoryName.setText(tempValues.getRepositoryName());
        holder.language.setText(tempValues.getLanguage());
        holder.branchCount.setText(tempValues.getBranchCount());
        holder.inFavoriteCount.setText(tempValues.getInFavoriteCount());

        vi.setOnClickListener(new OnItemClickListener(position));
    }

    holder.repositoryName.setTypeface(textFont);
    holder.language.setTypeface(textFont);
    holder.branchCount.setTypeface(textFont);
    holder.inFavoriteCount.setTypeface(textFont);

    return vi;
}

@Override
public void onClick(DialogInterface dialog, int which) {
    Log.v("Custom Adapter", "Button Clicked");
}

private class OnItemClickListener implements View.OnClickListener {

    private int mPosition;

    OnItemClickListener(int position) {
        mPosition = position;
    }

    @Override
    public void onClick(View v) {
        UserActivity ua = (UserActivity) activity;
        ua.onItemClick(mPosition);
    }
}

ListModel.java

public class ListModel {

private String repositoryName  = "";
private String language        = "";
private String branchCount     = "";
private String inFavoriteCount = "";

public void setRepositoryName(String repositoryName) {
    this.repositoryName = repositoryName;
}

public void setLanguage(String language) {
    this.language = language;
}

public void setBranchCount(String branchCount) {
    this.branchCount = branchCount;
}

public void setInFavoriteCount(String inFavoriteCount) {
    this.inFavoriteCount = inFavoriteCount;
}

public String getRepositoryName() {
    return repositoryName;
}

public String getLanguage() {
    return language;
}

public String getBranchCount() {
    return branchCount;
}

public String getInFavoriteCount() {
    return inFavoriteCount;
}
}

UserActivity.java

public class UserActivity extends AppCompatActivity {
    ListView list;
    CustomAdapter adapter;
    public UserActivity userActivity = null;
    public ArrayList<ListModel> customListViewValuesArr = new ArrayList<ListModel>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user);

    userActivity = this;

    setListData();

    Resources res = getResources();
    list = (ListView) findViewById(R.id.activitu_user_lv_repositoriesList);

    adapter = new CustomAdapter(userActivity, customListViewValuesArr, res);
    list.setAdapter(adapter);
}

    private void setListData() {
        for (int i = 0; i < 11; i++) {
            final ListModel sched = new ListModel();

            sched.setRepositoryName("Repository №" + i);
            sched.setLanguage("Java");
            sched.setBranchCount("" + (i+5));
            sched.setInFavoriteCount("" + (i*12));

            customListViewValuesArr.add(sched);
        }
    }

public void onItemClick(int mPosition) {
        ListModel tempValues = (ListModel) customListViewValuesArr.get(mPosition);

        Toast.makeText(userActivity, "" + tempValues.getRepositoryName(), Toast.LENGTH_LONG).show();
    }
}

谢谢，=)

Answer 1

我在这段代码中找不到问题，这很可悲，但我在 tutorial 中找到了解决方案.我重写了我的代码，这很有帮助。那么，现在看起来如何:

CustomAdapter.java 重命名为 RepositoryAdapter.java 并重写一些代码:

public class RepositoryAdapter extends BaseAdapter {

Context context;
Typeface textFont;
protected List<Repository> listRepository;
LayoutInflater inflater;

public RepositoryAdapter(Context context, List<Repository> listRepository){
    this.listRepository = listRepository;
    this.inflater = LayoutInflater.from(context);
    this.context = context;

    textFont = Typeface.createFromAsset(context.getAssets(), "fonts/DiamondGirl.ttf");
}

public int getCount(){
    return listRepository.size();
}

@Override
public Repository getItem(int position) {
    return listRepository.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}

public View getView(int position, View convertView, ViewGroup parent){
    ViewHolder holder;

    if (convertView == null) {
        holder = new ViewHolder();
        convertView = this.inflater.inflate(R.layout.custom_listview, parent, false);

        holder.tvRepositoryName =
                (TextView) convertView.findViewById(R.id.custom_listview_tv_repositoryName);
        holder.tvLanguage =
                (TextView) convertView.findViewById(R.id.custom_listview_tv_language);
        holder.tvBranchCount =
                (TextView) convertView.findViewById(R.id.custom_listview_tv_branchCount);
        holder.tvInFavoriteCount =
                (TextView) convertView.findViewById(R.id.custom_listview_tv_inFavoriteCount);

        holder.tvRepositoryName.setTypeface(textFont);
        holder.tvLanguage.setTypeface(textFont);
        holder.tvBranchCount.setTypeface(textFont);
        holder.tvInFavoriteCount.setTypeface(textFont);

        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

    Repository repository = listRepository.get(position);
    holder.tvRepositoryName.setText(repository.getRepositoryName());
    holder.tvLanguage.setText(repository.getLanguage());
    holder.tvBranchCount.setText(repository.getBranchCount());
    holder.tvInFavoriteCount.setText(repository.getInFavoriteCount());

    return convertView;
}

private class ViewHolder {
    TextView tvRepositoryName;
    TextView tvLanguage;
    TextView tvBranchCount;
    TextView tvInFavoriteCount;
}

}

ListModel.java 现在Repository.java:

public class Repository {

private String repositoryName  = "";
private String language        = "";
private String branchCount     = "";
private String inFavoriteCount = "";

public Repository(String repositoryName, String language, String branchCount, String inFavoriteCount) {
    super();

    this.repositoryName  = repositoryName;
    this.language        = language;
    this.branchCount     = branchCount;
    this.inFavoriteCount = inFavoriteCount;
}

public void setRepositoryName(String repositoryName) {
    this.repositoryName = repositoryName;
}

public void setLanguage(String language) {
    this.language = language;
}

public void setBranchCount(String branchCount) {
    this.branchCount = branchCount;
}

public void setInFavoriteCount(String inFavoriteCount) {
    this.inFavoriteCount = inFavoriteCount;
}

public String getRepositoryName() {
    return repositoryName;
}

public String getLanguage() {
    return language;
}

public String getBranchCount() {
    return branchCount;
}

public String getInFavoriteCount() {
    return inFavoriteCount;
}
}

UserActivity.java:

public class UserActivity extends AppCompatActivity implements AdapterView.OnItemClickListener {
ArrayList<Repository> arrayRepositories;
ListView listViewRepositories;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_user);

    arrayRepositories = new ArrayList<Repository>();

    fillList();

    listViewRepositories = (ListView) findViewById(R.id.activitu_user_lv_repositoriesList);
    RepositoryAdapter adapter = new RepositoryAdapter(this, arrayRepositories);
    listViewRepositories.setAdapter(adapter);
    listViewRepositories.setOnItemClickListener(this);

}

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id){
    Repository selectedRepository = arrayRepositories.get(position);
    Toast.makeText(this, selectedRepository.getRepositoryName(), Toast.LENGTH_SHORT).show();
}

private void fillList() {
    for (int i = 0; i < 12; i++) {
        Repository repository = new Repository("Repository #"+i,"Java",""+ (i*5),"" + (i*12));
        arrayRepositories.add(repository);
    }
}

}

现在可以用了，而且速度很快。感谢大家的帮助 =)