59、常规控件（2）TextInputLayout-让EditText提示更加人性化

提示语用在显示。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="20dp"
    android:orientation="vertical">
    <android.support.design.widget.TextInputLayout
        android:id="@+id/textInput"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </android.support.design.widget.TextInputLayout>
</LinearLayout>

TextInputLayout textInput = (TextInputLayout) this.findViewById(R.id.textInput);
textInput.setHint("请输入用户名");

        final TextInputLayout textInput = (TextInputLayout) this.findViewById(R.id.textInput);
        textInput.setHint("请输入用户名");

        EditText editText = textInput.getEditText();
        editText.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 (s.length() > 10) {
                    textInput.setError("用户名不能超过10位");
                    textInput.setErrorEnabled(true);
                } else {
                    textInput.setErrorEnabled(false);
                }
            }
            @Override
            public void afterTextChanged(Editable s) {}
        });