的EditText preference禁用按钮？ [英] EditTextPreference Disable Buttons?

问题描述

我想有一个EditText preference将禁用确定按钮，如果有在现场的EditText没有文本。我创建了一个自定义的EditText preference类，我能够得到的EditText对象，并设置一个TextWatcher，但我不能找到一种方法来禁用该按钮。它看起来像我只是没有获得确定和取消按钮，在对话框。

I want to have an EditTextPreference that will disable the OK button if there is no text in the EditText field. I created a custom EditTextPreference class and I am able to get the EditText object and set a TextWatcher, but I can't find a way to disable the button. It looks like I just don't have access to the OK and Cancel buttons in the Dialog.

任何人都知道一个办法让这些按钮或做什么，我想干什么？

Anyone know a way to get at these buttons or to do what I am trying to do?

唯一的选择就是尽量从头创建一个自定义对话框，看起来像和模仿的EditText preference。

Only other option is to try to create from scratch a custom Dialog that looks like and mimics the EditTextPreference.

推荐答案

下面是一个code样品的启用/禁用按钮取决于 onCheckValue 函数返回真或假。

Here is a code sample that enables/disables button depending on whether onCheckValue function returns true or false.

public class ValidatedEditTextPreference extends EditTextPreference
{
    public ValidatedEditTextPreference(Context ctx, AttributeSet attrs, int defStyle)
    {
        super(ctx, attrs, defStyle);        
    }

    public ValidatedEditTextPreference(Context ctx, AttributeSet attrs)
    {
        super(ctx, attrs);                
    }

    private class EditTextWatcher implements TextWatcher
    {    
        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count){}

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

        @Override
        public void afterTextChanged(Editable s)
        {        
            onEditTextChanged();
        }
    }
    EditTextWatcher m_watcher = new EditTextWatcher();

    /**
     * Return true in order to enable positive button or false to disable it.
     */
    protected boolean onCheckValue(String value)
    {        
        return Strings.hasValue(value);
    }

    protected void onEditTextChanged()
    {
        boolean enable = onCheckValue(getEditText().getText().toString());
        Dialog dlg = getDialog();
        if(dlg instanceof AlertDialog)
        {
            AlertDialog alertDlg = (AlertDialog)dlg;
            Button btn = alertDlg.getButton(AlertDialog.BUTTON_POSITIVE);
            btn.setEnabled(enable);                
        }
    }

    @Override
    protected void showDialog(Bundle state)
    {
        super.showDialog(state);

        getEditText().removeTextChangedListener(m_watcher);
        getEditText().addTextChangedListener(m_watcher);
        onEditTextChanged();
    }    
}

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