Android displaymetrics Get screen-related information

Android source code in this way to describe the displaymetrics.

/** * A structure describing general information on a display, such as its * size, density, and font scaling. * <p>to access the Displaymetrics members, initialize a object like this:</p> * <pre> displaymetrics Me Trics = new Displaymetrics (); * Getwindowmanager (). Getdefaultdisplay (). Getmetrics (metrics);</pre> * *

As you can see in the displaymetrics note, we just write an example to test everything. I'm using Xiaomi 3:

Displaymetrics metrics =NewDisplaymetrics ();        Getactivity (). Getwindowmanager (). Getdefaultdisplay (). Getmetrics (metrics); /*** The logical density of the display. This was a scaling factor for the * Density independent Pixel Unit, where one DIP was one Pixel on an * appr oximately dpi screen (for example a 240x320, 1.5 "x2" screen), * Providing the baseline of the system ' s display . Thus on a 160dpi screens * This density value would be 1; On a-DPI screen it would is. 75;         etc. * * <p>this value does not exactly follow the real screen size (as given by * {@link#xdpi} and {@link#ydpi}, but rather was used to scale the size of * The overall UI in steps based on gross changes in the DISPL  Ay dpi. For * example, a 240x320 screens would have a density of 1 even if their width is * 1.8 ", 1.3", etc. However, if the screen resolution are increased to * 320x480 but the screens size remained 1.5 "x2" then the density         Would is * increased (probably to 1.5).         * * Density is a logical screen density, agreed on a 160dpi device, 1px=1dip. * Density = densitydpi/160 * *@see#DENSITY_DEFAULT*/        floatDensity =metrics.density; /*** The screen density expressed as dots-per-inch. May is either * {@link#DENSITY_LOW}, {@link#DENSITY_MEDIUM}, or {@link#DENSITY_HIGH}. * DENSITYDPI indicates the number of dots per inch (not the number of pixels)*/        intDENSITYDPI =metrics.densitydpi; /*** The absolute height of the display in pixels.         * The absolute height of the screen, in pixels. */        intHeightpixels =Metrics.heightpixels; /*** The absolute width of the display in pixels.         * Again, this is the absolute width of the screen, in pixels. */        intWidthpixels =Metrics.widthpixels; /*** The exact physical pixels per inch of the screen in the X dimension.         * Horizontally every inch of the exact physical pixel, we can try to calculate the width of the screen by this value and Widthpixels. */        floatXDPI =metrics.xdpi; /*** The exact physical pixels per inch of the screen in the Y dimension.         * Horizontally every inch of the exact physical pixel, we can try to calculate the height of the screen by this value and Heightpixels. */        floatYDPI =metrics.ydpi; /*** A scaling factor for fonts displayed on the display. this is the same * as {@link#density}, except that it is adjusted in smaller * increments at runtime based on a user preference for T         He font size. * Scaleddensity This value from the above comment, is the font-related factor, usually this value and density are equal, but if the user manually adjusted the * system font size, then this value is likely to change (in the case of Millet 3, the standard font, this value         =3, maximum font this value =3.25).         * So now in many cases, we write the font units as DP, although the fonts suggested by Google are written to sp. */        floatScaleddensity =metrics.scaleddensity; LOGUTIL.LOGD (TAG,"Metrics.density =" +density); LOGUTIL.LOGD (TAG,"METRICS.DENSITYDPI =" +densitydpi); LOGUTIL.LOGD (TAG,"Metrics.heightpixels =" +heightpixels); LOGUTIL.LOGD (TAG,"Metrics.widthpixels =" +widthpixels); LOGUTIL.LOGD (TAG,"METRICS.XDPI =" +xdpi); LOGUTIL.LOGD (TAG,"METRICS.YDPI =" +ydpi); LOGUTIL.LOGD (TAG,"Metrics.scaleddensity =" +scaleddensity); //to calculate how many inches the phone is.        floatPixelstodipwidth = widthpixels/xdpi; floatPixelstodipheight = heightpixels/ydpi; LOGUTIL.LOGD (TAG,"Pixelstodipwidth =" +pixelstodipwidth); LOGUTIL.LOGD (TAG,"Pixelstodipheight =" +pixelstodipheight); DoubleMobileinch = math.sqrt (pixelstodipheight * pixelstodipheight + pixelstodipwidth *pixelstodipwidth); //I use the millet 3, get the value is 4.917646062686045LOGUTIL.LOGD (TAG, "mobileinch =" + Mobileinch);

With this example, we understand what the dip and px represent, and we can write a way to convert the dip and PX to each other. (Dip = px/density)

    /*** Switch from DP unit to PX (pixel) According to the resolution of the phone*/     Public Static intDIP2PX (Context context,floatdpvalue) {        Final floatScale =context.getresources (). Getdisplaymetrics (). density; return(int) (Dpvalue * scale + 0.5f); }    /*** According to the resolution of the phone from PX (pixel) to the unit to become DP*/     Public Static intPx2dip (Context context,floatpxvalue) {        Final floatScale =context.getresources (). Getdisplaymetrics (). density; return(int) (Pxvalue/scale + 0.5f); }

The above added to this 0.5f reason, Google official documents in fact there are:

Then add 0.5f to round the number of the nearest whole number, when converting to an integer.

To be rounded up ...

For example, I have the above examples:

Mobileinch = 4.917646062686045, I +0.5f (=5.417646062686045), and then after rounding, I get 5.

Android displaymetrics Get screen-related information