快速掌握Android屏幕的知识点

public int getRealHeight(Activity activity) { 
 int heightPixels = 0; 
 Display display = activity.getWindowManager().getDefaultDisplay(); 
 final int VERSION = Build.VERSION.SDK_INT; 

 if(VERSION <13) { 
   display.getHeight(); 
 }else if (VERSION == 13) { 
   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; 
}

/** 
* 获取屏幕密度 
* @return 
*/ 
public static float getScreenDensity(Activity activity) { 
 DisplayMetrics displayMetrics = new DisplayMetrics(); 
 activity.getWindowManager().getDefaultDisplay().getMetrics(displayMetrics); 
 return displayMetrics.density; 
}

/** 
* 获取屏幕可操作区域宽度dp数目 
* 
* @param activity 
* @return 
*/ 
public static float getScreenWidthDp(Activity activity) { 
 return getScreenWidth(activity) / getScreenDensity(activity); 
}

/** 
* 获取屏幕高度可操作区域dp数目 
* 
* @param activity 
* @return 
*/ 
public static float getScreenHeightDp(Activity activity) { 
 return getScreenHeight(activity) / getScreenDensity(activity); 
}

/** 
* 获取屏幕真实宽度dp数目 
* 
* @param activity 
* @return 
*/ 
public static float getRealWidthDp(Activity activity) { 
 return getRealWidth(activity) / getScreenDensity(activity); 
}

/** 
* 获取屏幕真实高度dp数目 
* 
* @param activity 
* @return 
*/ 
public static float getRealHeightDp(Activity activity) { 
 return getRealHeight(activity) / getScreenDensity(activity); 
}

public static boolean isTablet(Activity activity) { 
 return isMoreThan6Inch(activity) && isScreenSizeLarge(activity); 
}

/** 
* 判断是否大于6英寸 
* @param activity 
* @return 
*/ 
public static boolean isMoreThan6Inch(Activity activity) { 
 return getScreenInch(activity) >= 6.0; 
}

/** 
* 判断设备是否为大尺寸屏幕 
* 
* @param context 
* @return 
*/ 
public static boolean isScreenSizeLarge(Context context) { 
 return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_LARGE; 
}