How to set the tools attribute in Android?

In Android development, the tools attribute is used to assist developers in design time and will not be compiled into the final APK file. Setting the tools attribute can help developers preview and debug layout files.

Commonly used tools properties include:

1. text processing tools

<TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    tools:text="Hello World" />

1. list item: tool

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:listitem="@layout/item_list" />

1. source of tools

<ImageView
    android:id="@+id/imageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    tools:src="@drawable/sample_image" />

The method of setting the tools attribute is the same as setting regular attributes, just add the tools prefix to the corresponding control. During compilation, Android Studio will ignore these attributes and only work at design time.