1. Linear Layout:
Horizontal Vertical
android: orirntation = "vertical" vertical, the other horizontal,
2. button on the right:
<the Button
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: the above mentioned id = "@ + the above mentioned id / bu_deng"
Android: text = "Login"
Android: layout_alignParentRight = "to true" // button is placed right
/>
3. Controls from top to bottom is marginTop = "20dp"
4. Remove our user name and password
String
Analyzing string variable str, string is not empty
method of detecting an empty string
IF ( "." The equals (name))
{
}
fritters method of
IF (TextUtils.isEmpty (name))
{
}
The cipher text operation, the password is not shown as a star
android: password = "true"
6. Examples of a the TextView
the TextView TV1 = (the TextView) the findViewById (R.id.tv_denglu);
7. File icon folder
D: \ Example_android \ layouttt \ app \ src \ main \ res \ mipmap-xxhdpi
8. toast display
Toast.makeText (MainActivity.this, "You password or account is empty", Toast.LENGTH_SHORT) .show ();
9. The interface conversion
Intent my1 = new Intent(sman.this, s208.class);
startActivity(my1);
10. The linear layout of the vertical layout
android: orientation = "vertical"
horizontal layout
android:orientation="horizontal"
11. anonymous inner classes, written in Oncreate inside
= Bb_210 the Button (the Button) the findViewById (R.id.b210);
bb_210.setOnClickListener (new new View.OnClickListener () {
@Override
public void the onClick (View V) {
the Intent MMY the Intent new new = (sman.this, s210.class) ;
startActivity (MMY);
}
});
12 is, image files referenced in the xml file
Eclipse: Android: background = "@ the drawable / Sliding"
AS: Android: background = "@ as mipmap / Sliding"
13.
Android: layout_marginStart: if in the layout pattern LTR, which is equivalent to the attribute android: layout_marginLeft. If the layout in the RTL mode, which is equivalent to the attribute android: layout_marginRight.