java - 在用户输入时更改 TextInputLayout 的提示值

Question

这是我在 TextInputLayout 中的 TextInputEditText。您可以看到的提示是在 TextInputLayout 上设置的。

用户必须写255 个字符，否则帖子无效。

我希望数字 255 随着用户键入而减少，当达到 0 时，提示应为空白。

这是我的代码:

private int charactersLeft = 256; 在 onCreate 方法之外声明。

这段代码在 onCreate 方法中:

final TextInputLayout postTextInputBase = findViewById(R.id.post_text_input_base);

final TextInputEditText postTextInput = findViewById(R.id.post_text_input);

postTextInput.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) {

        if (charactersLeft == 0) {
            postTextInputBase.setHint(null);
        } else {
            postTextInputBase.setHint((charactersLeft - 1) + " characters left");
        }
    }

    @Override
    public void afterTextChanged(Editable s) {

    }
});

我还尝试将 charactersLeft 设置为 characterLeft -= 1 但是，java 不允许我这样做。

那么，我该怎么做呢？

Answer 1

使用 app:counterEnabled="true"

• 是否在此布局中启用了字符计数器功能。

也可以使用 app:counterMaxLength="250"

• 设置在字符计数器上显示的最大长度。

试试这个

<android.support.design.widget.TextInputLayout
    android:id="@+id/post_text_input_base"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:counterEnabled="true"
    app:counterMaxLength="250">

    <EditText
        android:id="@+id/post_text_input"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="UserName" />
</android.support.design.widget.TextInputLayout>

输出

编辑

public class RecyclerViewActivity extends AppCompatActivity {

    TextInputLayout postTextInputBase;
    EditText postTextInputEditText;

    int textLength = 9;
    int len = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_recycler_view);

        postTextInputBase = findViewById(R.id.post_text_input_base);

        postTextInputEditText = findViewById(R.id.post_text_input);

        postTextInputBase.setHint(textLength + " characters left");

        postTextInputEditText.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) {

                // first check your EditText is empty or not
                if (!TextUtils.isEmpty(postTextInputEditText.getText().toString())) {

                    int len = postTextInputEditText.getText().toString().length();
                    // than check that editText text length is less than max length or not
                    // for test case i have set max length 10
                    if (len < 9) {
                        // if length of text is less than max length than use minus one from max length and set error in your text input layout
                        textLength--;
                    } else {
                        textLength++;
                        
                    }
                    
                    postTextInputBase.setHint(textLength + " characters left");
                } else {
                    textLength = 9;
                }
            }

            @Override
            public void afterTextChanged(Editable s) {

              if(postTextInputEditText.getText().toString().isEmpty()){
                  textLength = 9;
                  postTextInputBase.setHint(textLength + " characters left");
              }
            }
        });


    }


}

输出

EDIT 2 如果你需要设置提示而不是使用这个

postTextInputBase.setHint(textLength + " characters left");

输出

NOTE Don't forgot to set android:maxLength="10" in edittext