PIXELS AND SCREEN COMPATIBILITY

================================

dp to pixels

• float scale = getResources().getDisplayMetrics().density;
• numPixels = (int) (dp * scale + 0.5f);

ViewConfiguration

• .get(myContext).getScaledTouchSlop()
  • returns int of the distance in pixels a touch
  • can wander before we think the user is scrolling

android.util package

=====================

Log

• log stuff to console
• .i
  • information
• .e
  • error
• .d
  • debug

USER INPUT

=======

Button

• android:onClick- the function to call when button is clicked

• alternative\/\/\/

    .setOnClickListener(new View.onClickListener() {
        @Override
        public void onClick(View v) {
            //do something
        }
    }
  

ImageButton

• a button that can have an image on it
• see Button

CheckBox

• yes/no input
• checkBoxElem.isChecked()
  • to get yes/no

Spinner

• dropdown menu but in popup form
• selection choices are strings in an array in strings.xml
  • see string arrays in strings.xml below
• spinnerElem.getSelectedItem().toString()
  • to get selected item

EditText

• collect text input
• lines- number of lines the textbox will have
• editTextElem.getText().toString()
  • to get entered text

LAYOUT

=======

ScrollView

<ScrollView></ScrollView>

• things inside are scrollable

LinearLayout

• one thing after another

    <LinearLayout>
        <Element/>
        <Element/>
    </LinearLayout>
  

strings.xml

===========

• stores app-wide string values/names

    <string-array name="name">
        <item>@string/stringName</item>
  

  • accessed with @array/name

<color name="white">#FFFFFF</color>

• add color
• can be accessed in code w/ @color/white

METHODS

========

findViewById(int id)

• get an element from the UI
• ex: final EditText nameField = (EditText)findViewById(R.id.EditText’sId);
  • where EditText’sId is found in id=”@+id/EditText’sId”

getBaseContext()

• returns base context (replaces this)

finish()

• sends activity to the background