Android 任何可扩展文本区域（SMS消息）的就绪实现

我想知道是否有一个textarea视图可以随着用户输入更多文本而扩展。就像android内置的短信文本区

我得到了部分答案：）-我还需要一个短信风格的文本字段，所以我自己做了一个，包括一个跟踪剩余字符数的文本观察程序

这就是它的样子：

Textwatcher实现

public class SMSTextWatcher implements TextWatcher {

    private final int maxLength;
    private final int stringId;
    private final TextView textView;


    /**
     * @param maxLength  maximum number of characters that are allowed
     * @param stringId   must have at least one %s in it, for the updated character count.
     * @param targetView target text view that displays the number of characters left.
     */
    public SMSTextWatcher(int maxLength, int stringId, TextView targetView) {
        this.maxLength = maxLength;
        this.textView = targetView;
        this.stringId = stringId;

        updateTextView(maxLength);
    }

    @Override
    public void beforeTextChanged(CharSequence charSequence, int start, int count, int after) {

    }

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

    }

    @Override
    public void afterTextChanged(Editable editable) {
        //Update textview (the limit is handled by the maxLength attribute)
        updateTextView(maxLength - editable.length());
    }

    public void updateTextView(int charactersLeft) {
        textView.setText(String.format(textView.getContext().getString(stringId), charactersLeft));
    }
}

布局XML——我们称之为widget\u sms\u field.XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <EditText
        android:id="@+id/sms_field_text"
        style="@style/TextAppearance.AppCompat.Large"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:hint="@string/short_text"
        android:imeOptions="actionSend|flagNoEnterAction"
        android:inputType="textShortMessage|textAutoCorrect|textCapSentences|textMultiLine"
        android:maxLength="@integer/sms_text_max_length"
        android:paddingRight="10dp"
        android:singleLine="false" />

    <TextView
        android:id="@+id/sms_field_remaining_characters"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="right"
        android:text="@string/remaining_characters"
        android:textColor="@color/secondary_text" />
</LinearLayout>

完成：）！如果您有问题或建议，请告诉我

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <item name="sms_text_max_length" type="integer">160</item>
</resources>

<string name="remaining_characters">%s remaining Characters</string>

   @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        EditText textField = (EditText) view.findViewById(R.id.sms_field_text);
        textField.addTextChangedListener(new SMSTextWatcher(
                getResources().getInteger(R.integer.sms_text_max_length),
                R.string.remaining_characters,
                (TextView) view.findViewById(R.id.sms_field_remaining_characters)));
    }