如何验证特定int范围的EditTextPreference值 [英] How to validate an EditTextPreference value for a specific int range

问题描述

我想验证一个 EditTextPreference 值是否在特定的 int 范围内（比如说1到22） 。我可以验证的唯一部分是 inputType （仅限数字），在prefs.xml文件中包含以下xml声明。

I want to validate an EditTextPreference value to be inside a specific int range (lets say 1 to 22). The only part that I could validate was the inputType (number only) with the following xml declaration in the prefs.xml file.

android：inputType =number

android:inputType="number"

我做的第二件事就是写 ListSettings 活动中的以下代码。

The second thing that I did is to write the following code in the ListSettings activity.

public class ListSettings extends PreferenceActivity implements OnSharedPreferenceChangeListener{

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.prefs);
    SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
    sp.registerOnSharedPreferenceChangeListener(this);
}
 public void onSharedPreferenceChanged(SharedPreferences sp, String key) {
        String value = sp.getString(key, null);
        int intZoomValue = Integer.parseInt(value);
        if (intZoomValue < 1 || intZoomValue > 22) {
            Intent intent = new Intent().setClass(this, dialog.class);
            // I want to call the dialog activity here...
        }

  }

并且dialog.class如下：

and the dialog.class is the following:

public class dialog extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);

  AlertDialog.Builder builder = new AlertDialog.Builder(this);
  builder.setMessage("Please enter a value between 1-22!");
  builder.setCancelable(true);

  AlertDialog alert = builder.create();
  alert.show();
  }
}

我想要实现的是调用<$每当用户输入的值不在1-22范围内时，c $ c> dialog.class （警告对话框）。

What I want to achieve is to call the dialog.class (the alert dialog box) whenever the user enters a value not in the range 1-22.

I无法真正理解如何以正确的方式进行验证。

I can't really understand how to validate with the proper way.

推荐答案

仅仅钳位值可能更加用户友好如果输入的值无效，则在允许的范围内，并通过Toast通知用户您已经这样做。

It might be more user-friendly to just clamp the value to the permitted range if an invalid value is entered, and notify the user with a Toast that you have done so.

如果您的范围很小，例如1-22 ，那么您甚至可以考虑使用 Spinner 而不是 EditText ，这样用户就无法输入无效值首先。

If your range is small, such as 1-22, then you may even consider using a Spinner instead of an EditText so that the user can't enter an invalid value in the first place.

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