BaseAdapter不填充列表

Question

因此，我有一个工作的ArrayAdapter，在我的列表中填充了一个特定的项目布局，但是我希望合并多个项目类型，所以我切换到了一个BaseAdpater。我的问题是，现在ListView不再填充列表了。知道发生了什么，或者如何调试它，即使它没有造成崩溃？

公共类SettingAdapter扩展BaseAdapter {

Context context;

private static final int LIST_ITEM_TYPE_1 = 0;
private static final int LIST_ITEM_TYPE_2 = 1;
private static final int LIST_ITEM_TYPE_3 = 2;

private static final int OPTION_ID_1 = 0;
private static final int OPTION_ID_2 = 1;
private static final int OPTION_ID_3 = 2;
private static final int OPTION_ID_4 = 3;

private static final int LIST_ITEM_TYPE_COUNT = 3;

private LayoutInflater inflater;
private List<Setting> options_list;

public SettingAdapter(Context context, List<Setting> options) {
    inflater = LayoutInflater.from(context);
    options_list = options;
}

@Override
public int getCount() {
    return options_list.size();
}

@Override
public Setting getItem(int position) {
    return options_list.get(position);
}

@Override
public long getItemId(int position) {
    return options_list.get(position).getID();
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;
    SettingHolder holder;

    Setting data = getItem(position);

    if(row == null) {
        inflater = ((Activity)context).getLayoutInflater();
        holder = new SettingHolder();
        if(data.getType() == OPTION_ID_1){
            Log.d("option1", Integer.toString(OPTION_ID_1));
            row = inflater.inflate(R.layout.item_option_1, parent, false);
            holder.s_heading = (TextView)row.findViewById(R.id.option1_heading);
            holder.s_sub_heading = (TextView)row.findViewById(R.id.option1_sub_heading);
        } else if(data.getType() == OPTION_ID_3){
            Log.d("option3", Integer.toString(OPTION_ID_3));
            row = inflater.inflate(R.layout.item_option_2, parent, false);
            holder.s_heading = (TextView)row.findViewById(R.id.option3_heading);
            holder.s_checked = (CheckBox)row.findViewById(R.id.option3_checkbox);
        } else {
            Log.d("option2", Integer.toString(OPTION_ID_2));
            row = inflater.inflate(R.layout.item_option_3, parent, false);
            holder.s_heading = (TextView)row.findViewById(R.id.option2_heading);
        }
        row.setTag(holder);
    } else {
        holder = (SettingHolder)row.getTag();
    }

    if(options_list.size() != 0 && options_list != null){
        Log.d("data", "exists");
        if(data == null){
            holder.s_heading.setText("heading");
            holder.s_sub_heading.setText("sub heading");
            holder.s_checked.setChecked(false);
        } else {
            holder.s_heading.setText(data.getName());
            if(data.getType() == OPTION_ID_1) {
                holder.s_sub_heading.setText(data.getSubHeading());
            }
            if(data.getChecked() != null && data.getType() == OPTION_ID_3){
                holder.s_checked.setChecked(data.getChecked());
            }
        }
    } else {
        Log.d("data", "none");
    }
    return row;
}

class SettingHolder {
    TextView s_heading;
    TextView s_sub_heading;
    CheckBox s_checked;
}

}

和活动类包含：

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

    // Grab references to UI elements.
    ListView option_data = (ListView) findViewById(R.id.settings_list);

    setting_db = new SettingDatabaseHandler(this);

    List<Setting> setting_list = setting_db.getAllSettings();

    if(setting_list.size() == 0){
        setting_db.addSetting(new Setting(OPTION_ID_1, "Profile Settings"));
        setting_db.addSetting(new Setting(OPTION_ID_2, "Font Size", "20sp"));
        setting_db.addSetting(new Setting(OPTION_ID_3, "Proxy", "Configure HTTP proxy for network requests"));
        setting_db.addSetting(new Setting(OPTION_ID_4, "Offline Mode", false));
        setting_db.addSetting(new Setting(OPTION_ID_5, "Location", true));
        setting_db.addSetting(new Setting(OPTION_ID_6, "About", "Help, Terms of Service and Privacy Policy"));
        setting_list = setting_db.getAllSettings();
    }

    if(setting_list != null && setting_list.size() > 0) {
        Log.d("Setting list size::", "" + Integer.toString(setting_list.size()));
    }

    SettingAdapter adapter = new SettingAdapter(this, setting_list);
    // Assign adapter to ListView
    option_data.setAdapter(adapter);

最后的列表布局：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.mapbox.aerove.settings.SettingActivity">

    <ListView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/settings_list"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:clickable="true"
        android:focusable="false"
        android:layout_alignParentTop="true">
    </ListView>
</RelativeLayout>

Answer 1

检查列表是否为空，大小大于零，然后调用适配器。

if(setting_list != null && setting_list.size() > 0){

Log.d(“列表大小：”、“+setting_list.size()>0”)；

SettingAdapter适配器=新SettingAdapter(this，setting_list)；}

在适配器getView()方法中

使用代码

设置选项=options_list.get(位置)；

而不是

设置选项=数据交换；

Answer 2

如果Adapter从BaseAdapter扩展，则必须重写getCount()方法，否则getCount()将始终返回0，而getView()将永远得不到调用。