Common UI controls:
- TextView:
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hello World!" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" />
mathch_parent: it means that the current control size can contain exactly the content in it, that is, the space content determines the current space size
android:layout_width: Specifies the width of the control
android:layout_height: Specifies the height of the control
Three optional values:
match_parent,fill_parent: the same size as the parent layout, match is recommended_ parent
warp_content: just the contents of the package
You can also specify a fixed value
The problem is: sometimes there are adaptation problems on different mobile screens
You can use android: gravity to specify how text is aligned
<TextView android:id="@+id/text_view" android:text="tViews" android:gravity="center" android:layout_width="match_parent" android:layout_height="wrap_content" />
Great Xia and color of the revised text
android:textSize : change the size of text in sp
android:textColor : set text size
- Button
It is an important button component to interact with users
<Button android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/button_first" android:text="to first"/> <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/button_second" android:text="to second"/>
android:textAllCaps="false" to set it
<Button android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/button_first" android:textAllCaps="false" android:text="to first"/>
You can also set up a listener:
public class FirstActivity extends AppCompatActivity { @Override protected void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.first_layout); Button first = (Button) findViewById(R.id.button_first); first.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(FirstActivity.this,SecondActivity.class); startActivity(intent); } }); } }
Each click event executes the onClick() method in the listener
You just need to implement your own logic in the listener
At the same time, the interface method can also be implemented to open and register
- EditText
Used to interact with users and allow users to enter and edit content into the control
And can be processed in the program
<EditText android:id="@+id/edit_text" android:hint="Please enter account" android:layout_width="match_parent" android:layout_height="wrap_content" />
android:hint : is the content of the prompt. Click to input the content, and the hi disappears
There is a restriction on the text content you enter
use android:maxLines : value
Limit its maximum row
- ImageView
Mainly used to display pictures on the interface
Can make the program page more colorful
Note: pictures are usually placed in the directory at the beginning of drawable
android:src: to ImageView Specify a picture <ImageView android:id="@+id/image_view" android:src="@drawable/image" android:layout_width="wrap_content" android:layout_height="wrap_content" />
ProgressBar
Used to display a progress bar on the interface
Indicates that the program loads some data