問(wèn)題描述

我有一些代碼，如果 editText 字段中的字符少于 3 個(gè)，我需要禁用創(chuàng)建帳戶"按鈕.如果用戶輸入 3 個(gè)字符，則該按鈕應(yīng)啟用自身以便可以使用.

I have some code where I need a "Create Account" button to be disabled if an editText field has less than 3 char in it. If the User enters 3 chars, then the button should enable itself so that it can be used.

我已經(jīng)構(gòu)建了 if else 語(yǔ)句，如果 editText 字段中的字符少于 3 個(gè)，則禁用按鈕，但是在輸入時(shí)，當(dāng)用戶插入 3 個(gè)字符時(shí)，它不會(huì)重新評(píng)估該語(yǔ)句是否為真所以按鈕當(dāng)然會(huì)保持禁用狀態(tài).

I have constructed the if else statement that disables the button if there are less than 3 char in the editText field, BUT on input, when the user inserts 3 char, it does not re-evaluate to see if the statement is true so the button of course stays disabled.

一旦用戶在編輯文本字段中輸入 3 個(gè)字符，按鈕應(yīng)該會(huì)自行啟用.

Once the user enters 3 char into the edit text field, the button should enable itself.

    Button buttonGenerate = (Button) findViewById(R.id.btnOpenAccountCreate);
    userInitials = (EditText) findViewById(R.id.etUserChar);
    if (userInitials.getText().toString().length() > 3) {
                // Account Generator Button
                            buttonGenerate.setEnabled(true); // enable button;
                            buttonGenerate.setOnClickListener(new OnClickListener() { 
//Do cool stuff here
                                @Override
                                public void onClick(View v) {

                                }
                            });// END BUTTON
            } else {

                // If UserInitials is empty, disable button
                            Toast.makeText(this, "Please enter three(3) characters in the Initials Field ", Toast.LENGTH_LONG)
                                    .show();
                            buttonGenerate.setEnabled(false); // disable button;
            }// END IF ELSE

推薦答案

你想使用一個(gè) TextWatcher

每當(dāng)您的 EditText 中具有此 listener 的文本發(fā)生更改時(shí)，都會(huì)觸發(fā)此事件.您只需像其他任何 listener 一樣將 listener 附加到您的 EditText 然后覆蓋其方法，并從下面的鏈接示例中檢查長(zhǎng)度

This will be triggered each time the text in your EditText which has this listener on it has changed. You just attach the listener to your EditText like you would any other listener then override its methods and , from the linked example below, check the length

 @Override
public void onTextChanged(CharSequence s, int start, int before, int count) 
{   
     if (s.length() > 2) 
     {
         buttonGenerate.setEnabled(true);
     }
     else
    {
         buttonGenerate.setEnabled(true);
    }
}

您不需要簽入您的 onClick() 然后，只需默認(rèn)禁用 Button 并在您的 onTextChanged() 如果滿足條件.

You don't need to check in your onClick() then, just disable the Button by default and enable in your onTextChanged() if the condition is met.

重寫(xiě)

上面可以清理為

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {   
     buttonGenerate.setEnabled((s.length() > 2));
}

我也改成了>2 因?yàn)槲艺J(rèn)為這實(shí)際上是你想要的，但你擁有它的方式有點(diǎn)令人困惑.您說(shuō)輸入三(3)"，這聽(tīng)起來(lái)正好是 3，但您的代碼看起來(lái)不同.無(wú)論如何，這對(duì)你來(lái)說(shuō)很容易改變.

I also have changed it to > 2 because I think that's actually what you want but the way you have it is a little confusing. You say "enter three(3)" which sounds like exactly 3 but your code looks different. Anyway, that's easy enough for you to change.

查看這個(gè)答案的例子

這篇關(guān)于Android - 在用戶輸入之前和之后檢查editText是否> 3的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！