在TextInputLayout中的TextInputEditText上设置提示

<com.google.android.material.textfield.TextInputLayout
    android:id="@+id/textInputLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <com.google.android.material.textfield.TextInputEditText
        android:id="@+id/textInputEditText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</com.google.android.material.textfield.TextInputLayout>

TextInputLayout textInputLayout = findViewById(R.id.textInputLayout);
TextInputEditText textInputEditText = findViewById(R.id.textInputEditText);

textInputLayout.setHint("请输入用户名");