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) {}
         });