Android 中的地理编码器自动完成

Question

我一直在谷歌上搜索试图找到与我有同样问题的人，但没有运气。所以这是我的问题：

当用户使用 Android 中的地理编码器键入地点名称时，我试图实现地址的自动完成建议。我希望它的行为与使用组合框的 javascript 版本大致相同。

我使用带有 AutoCompleteTextView 的布局和数组适配器来根据用户类型动态更新建议列表。我在使用处理程序调用 geocoder.getFromLocationName 之前添加了从收到 onTextChanged() 事件起的 500 毫秒延迟。如果用户在 500 毫秒内输入更多字母，则最后一个事件将被取消。我遇到的问题是，建议几乎从不作为下拉菜单中的可选选项显示在用户界面中。我得到了地址建议，但是当我将它们添加到附加到 autocomplatetextview 的适配器时，它们根本不会显示。

我正在使用 API 级别 7 的模拟器上运行它，其中包含 google api。

现在一些源代码可以帮助您： 布局：

<LinearLayout android:id="@+id/searchInputLayout"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="6dip"
    android:orientation="vertical">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/searchMessage" />
    <EditText android:id="@+id/freetextInput" 
        android:hint="@string/searchFreetextLabel"
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:background="@android:drawable/editbox_background" />
    <CheckBox android:id="@+id/includeVincinityCheckbox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/includeVincinityLabel"
        android:checked="true"
        android:onClick="includeVincinityClick" />
    <AutoCompleteTextView android:id="@+id/locationInput" 
        android:hint="@string/locationInputHint"
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" />
    <Button android:id="@+id/searchButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/searchBtnLabel" 
        android:onClick="searchBtnClicked" />
    </LinearLayout>

我的活动的源代码（我省略了不相关的代码）：

public class SearchLocationTabActivity extends Activity implements TextWatcher, OnItemSelectedListener {

private static final int MESSAGE_TEXT_CHANGED = 0;
private static final int AUTOCOMPLETE_DELAY = 500;
private static final int THRESHOLD = 3;
private String latitude, longitude;
private List<Address> autoCompleteSuggestionAddresses;
private ArrayAdapter<String> autoCompleteAdapter;
private Handler messageHandler;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.search);
    setDefaultKeyMode(DEFAULT_KEYS_SEARCH_LOCAL);

    messageHandler = new MyMessageHandler(this, this);
    autoCompleteAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, new ArrayList<String>());
    autoCompleteAdapter.setNotifyOnChange(false);
    AutoCompleteTextView locationinput = (AutoCompleteTextView) findViewById(R.id.locationInput);
    locationinput.addTextChangedListener(this);
    locationinput.setOnItemSelectedListener(this);
    locationinput.setThreshold(THRESHOLD);
    locationinput.setAdapter(autoCompleteAdapter);
}

@Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
    messageHandler.removeMessages(MESSAGE_TEXT_CHANGED);
}

@Override
public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
String value = arg0.toString();
if (!"".equals(value) && value.length() >= THRESHOLD) {
    Message msg = Message.obtain(messageHandler, MESSAGE_TEXT_CHANGED, arg0.toString());
    messageHandler.sendMessageDelayed(msg, AUTOCOMPLETE_DELAY);
} else {
    autoCompleteAdapter.clear();
}
}

@Override
public void afterTextChanged(Editable arg0) {
}

@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
    if (arg2 < autoCompleteSuggestionAddresses.size()) {
        Address selected = autoCompleteSuggestionAddresses.get(arg2);
        latitude = Double.toString(selected.getLatitude());
        longitude = Double.toString(selected.getLongitude());
    }
}

private void notifyResult(List<Address> suggestions) {
    latitude = longitude = null;
    autoCompleteAdapter.clear();
    for (Address a : autoCompleteSuggestionAddresses) {
        autoCompleteAdapter.add(a.toString());//TODO: figure out a nice way to display this address in list
    }
    autoCompleteAdapter.notifyDataSetChanged();
}

@Override
public void onNothingSelected(AdapterView<?> arg0) {
    latitude = longitude = null;
}

private class MyMessageHandler extends Handler {

    private Context context;
    private AsyncTaskSubscriber subscriber;

    public MyMessageHandler(Context context, AsyncTaskSubscriber subscriber) {
        this.context = context;
        this.subscriber = subscriber;
    }

    @Override
    public void handleMessage(Message msg) {
        if (msg.what == MESSAGE_TEXT_CHANGED) {
            String enteredText = (String) msg.obj;

            try {
                autoCompleteSuggestionAddresses = new Geocoder(context).getFromLocationName(enteredText, 10);

                notifyResult(response);
            } catch (IOException ex) {
                Log.e(GeoCoderAsyncTask.class.getName(), "Failed to get autocomplete suggestions", ex);
            }
        }
    }
}
}

非常感谢任何帮助！

Answer 1

对于那些未能删除过滤的人，这就是我所做的（以及其他小的修改，但我认为它们不会对过滤部分产生影响）。另请注意，要检测要检测的某个项目的点击，您需要添加一个 OnItemClickListener。

autoCompleteAdapter = new ArrayAdapterNoFilter(this, android.R.layout.simple_dropdown_item_1line);

ArrayAdapterNoFilter 的灵感来自另一个答案：

public class ArrayAdapterNoFilter extends ArrayAdapter<String> {

    public ArrayAdapterNoFilter(Context context, int textViewResourceId) {
        super(context, textViewResourceId);
    }

    private static final NoFilter NO_FILTER = new NoFilter();

    /**
     * Override ArrayAdapter.getFilter() to return our own filtering.
     */
    @Override
    public Filter getFilter() {
        return NO_FILTER;
    }

    /**
     * Class which does not perform any filtering. Filtering is already done by
     * the web service when asking for the list, so there is no need to do any
     * more as well. This way, ArrayAdapter.mOriginalValues is not used when
     * calling e.g. ArrayAdapter.add(), but instead ArrayAdapter.mObjects is
     * updated directly and methods like getCount() return the expected result.
     */
    private static class NoFilter extends Filter {
        protected FilterResults performFiltering(CharSequence prefix) {
            return new FilterResults();
        }

        protected void publishResults(CharSequence constraint, FilterResults results) {
            // Do nothing
        }
    }
}

Answer 2

好的，这个有一个非常简单的解决方案。由于 AutoCompleteTExtView 组件中的过滤机制，结果并不总是显示出来。由于地理编码器的所有结果不一定包含输入的字符串，因此它不会显示这些结果。