android - 如何创建仅接受预定义范围值的 EditTextPreference？

Question

我希望 EditTextPreference 只接受 6000 到 65536 之间的值，我该怎么做？谢谢!

顺便说一句，代码 A 不起作用，我无法在 EditTextPreference 的编辑框中输入任何数字，其中键是“WebServerPort”

<EditTextPreference
    android:key="WebServerPort"
    android:defaultValue="6000"
    android:title="Port"
    android:summary="Set port for web server, it should be greater than 6000 and less than 65536"
    android:inputType="number"
    android:layout="@layout/layout_customize_preference_item"
/>

代码A

public class UIPreference extends PreferenceActivity {
    private AdView adView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.mypreference);
        setContentView(R.layout.layout_preference);


        EditTextPreference edit_Pref = (EditTextPreference) getPreferenceScreen().findPreference("WebServerPort");
        edit_Pref.getEditText().setFilters(new InputFilter[]{ new InputFilterMinMax("6000", "65536")});
    }
}


class InputFilterMinMax implements InputFilter {

    private int min, max;

    public InputFilterMinMax(int min, int max) {
        this.min = min;
        this.max = max;
    }

    public InputFilterMinMax(String min, String max) {
        this.min = Integer.parseInt(min);
        this.max = Integer.parseInt(max);
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
        try {
            int input = Integer.parseInt(dest.toString() + source.toString());
            if (isInRange(min, max, input))
                return null;
        } catch (NumberFormatException nfe) { }
        return "";
    }

    private boolean isInRange(int a, int b, int c) {
        return b > a ? c >= a && c <= b : c >= b && c <= a;
    }
}

Answer 1

您可以为您的 EditText 分配一个 TextWatcher 并在那里监听文本更改，例如:

editTextPreference.getEditText().addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {
            try {
                long val = Long.parseLong(s.toString());
                if(val > 65536) {
                     s.replace(0, s.length(), "65536", 0, 5);
                } else if(val < 6000) {
                     s.replace(0, s.length(), "6000", 0, 4);
                }
            } catch (NumberFormatException ex) {
                 // Do something
            }
      }
});