Android: How to compare Drawables

Answer:

  drawable1.getConstantState().equals(drawable2.getConstantState());

It doesn't compare actual data (bytes of images) so it is fast and memory efficient.

Android: How to use Android default font size example

Small:

<style name="DefaultMedium">

<item name="android:textAppearance">?android:attr/textAppearanceSmall</item>

</style>

Medium:

<style name="DefaultMedium">

<item name="android:textAppearance">?android:attr/textAppearanceMedium</item>

</style>

Large:

<style name="DefaultMedium">

<item name="android:textAppearance">?android:attr/textAppearanceLarge</item>

</style>

Reference: Android source code

Android Styles.xml
https://github.com/android/platform_frameworks_base/blob/master/core/res/res/values/styles.xml

Android Res files
https://github.com/android/platform_frameworks_base/tree/master/core/res/res

Android: Full Screen & No title/action bar example

No Action bar:

this.requestWindowFeature(Window.FEATURE_NO_TITLE);
Caution: this code has to be written BEFORE setContentView(...); or it will crash!

Full Screen:
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

this.requestWindowFeature(Window.FEATURE_NO_TITLE);

this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

setContentView(R.layout.layout_main);

}

Android: Question mark only in strings.xml resource example

Use backslash:

    <string name="quick_question">\?</string>

Android: Get screen width programmatically example

It returns number in pixel

      @SuppressLint("NewApi")

      private int getScreenWidth() {

            int iMeasuredwidth = 0;

            Point size = new Point();

            WindowManager w = getWindowManager();

            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2){

                  w.getDefaultDisplay().getSize(size);

                  iMeasuredwidth = size.x;

            }else{

                  Display d = w.getDefaultDisplay();

                  iMeasuredwidth = d.getWidth();

            }

            return iMeasuredwidth;

      }

Android: How to convert from dp to px? (example)

From dp to pixel:

 

private static int fromDp2Px(int dp, Context context) {

final Resources res = context.getResources();

float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, res.getDisplayMetrics());

return (int) px;

}

 

or

 

private static int fromDp2Px(int dp, Context context) {

final Resources res = context.getResources();

DisplayMetrics metrics = res.getDisplayMetrics();

float px = dp * (metrics.densityDpi / 160f);

return (int) px;

}

 

 

 

 

From pixel to dp:

 

private static int fromPx2Dp(int px, Context context) {

final Resources res = context.getResources();

DisplayMetrics metrics = res.getDisplayMetrics();

float dp = px / (metrics.densityDpi / 160f);

return (int) dp;

}