Quickly grasp the Android screen knowledge points _android

First, to introduce the following about PX, PT, PPI, DPI, DP knowledge

Terms	Description
Px	(pixel), pixel, the most basic point on the screen to display data
Pt	(point), Dot 1pt=1/72 inch
Ppi	(pixel per inch), number of pixels in each inch
Dpi	(dot/inch), dots per inch
Dp	i.e. dip (density-independent pixel), device independent pixel 1dp=160dpi 1px length

where PX, PT, DP for length units, PPI and dpi for density units

Density	ldpi	mdpi	hdpi	xhdpi	xxhdpi
Density value	120	160	240	320	480
Resolution	240*320	320*480	480*800	720*1280	1080*1920
Icon size	36*36	48*48	72*72	96*96	144*144

Two, the following provide several commonly used methods

1. Get screen height

public int getrealheight (activity activity) { 
 int heightpixels = 0; 
 Display display = Activity.getwindowmanager (). Getdefaultdisplay (); 
 Final int VERSION = Build.VERSION.SDK_INT; 

 if (VERSION <) { 
   display.getheight (); 
 } else if (VERSION = = 
   try { 
     heightpixels = (Integer) Display.class.getMethod ("Getrawheight"). Invoke (Display ); 
   } catch (Exception e) { 
   } 
 } else {point 
   realsize = new Point (); 
   try { 
     Display.class.getMethod ("Getrealsize", Point.class). Invoke (Display, realsize); 
     Heightpixels = realsize.y; 
   } catch (Exception e) { 
   } 
 } return 
 heightpixels 
}

2. Get screen density

/** 
* Get screen density 
* @return 
/public static float getscreendensity (activity activity) { 
 Displaymetrics displaymetrics = new Displaymetrics (); 
 Activity.getwindowmanager (). Getdefaultdisplay (). Getmetrics (displaymetrics); 
 return displaymetrics.density; 
}

3, get the screen can operate area width DP number

/** 
* Get screen operable area width DP number 
* 
* @param activity * @return/public 
Static float GETSCREENWIDTHDP (activity activity) {return 
 getscreenwidth (activity)/getscreendensity (activity); 
}

4, obtain the screen height can operate the area DP number

/** 
* Get screen height operable area DP Number 
* 
* @param activity * @return/public 
Static float GETSCREENHEIGHTDP (activity activity) {return 
 getscreenheight (activity)/getscreendensity (activity); 
}

5, get the screen true width DP number

/** 
* Get screen True width DP number 
* 
* @param activity 
* @return 
/public static float GETREALWIDTHDP ( Activity activity) {return 
 getrealwidth (activity)/getscreendensity (activity); 
}

6, get the screen true height DP number

/** 
* Get screen True height DP number 
* 
* @param activity 
* @return/public 
static float GETREALHEIGHTDP (Activity activity) {return 
 getrealheight [activity]/getscreendensity (activity); 
}

7, to determine whether the plate

public static Boolean Istablet [activity activity] {return 
 ismorethan6inch (activity) && Isscreensizelarge (activity); 
}

/** 
* Determine if greater than 6 inches 
* @param activity 
* @return 
/Public 
static Boolean ismorethan6inch ( Activity activity) {return 
 getscreeninch (activity) >= 6.0 
}

/** 
* Determine if the device is a large size screen 
* 
* @param context 
* @return 
/Public 
static Boolean Isscreensizelarge ( Context context) {return 
 (Context.getresources (). GetConfiguration (). Screenlayout & Configuration.screenlayout_size_mask) >= configuration.screenlayout_size_large; 
}

Summarize

This is all about the Android screen knowledge Point, I hope the content of this article for your Android developers can help, if you have questions you can message exchange.