Java-android Study (sixth day)

Today, the main thing is to record some trivial things, and will be added in succession to new encounters.

①, Android:gravity and android:layout_gravity Introduction and differences :

Gravity has the following properties: Center (center), Bottom (bottom), Top (top), right (starboard), left. can also be used in combination, for example: left| Bottom, indicating the lower left;

The Android:gravity property is the qualification for the content in the view. For example, a button above the text. You can set the text to the left, right, and so on, relative to the view;

android:layout_gravity is used to set the location of the view relative to the parent view. For example, a button in the LinearLayout, you want to put the button in the LinearLayout left, on the right and so on can be set by this property. That is, android:gravity is used to set the alignment of content in view relative to the view component, while android:layout_gravity is used to set the view component

The alignment relative to the container.

Explicit concealment of ② and controls

There are three types of attribute values:

Invisible: does not display, but retains the occupied space

Visible: Normal display

Gone: does not display, and does not preserve the occupied space

In XML:

android:visibility= "Visible"

In the code, such as button

Btn.setvisibility (view.visible);

Java-android Study (sixth day)