我更新了Kotlin语言的答案!

对于Kotlin:您应该调用窗口管理器并获取指标。在那简单的方法之后。

val displayMetrics = DisplayMetrics()
windowManager.defaultDisplay.getMetrics(displayMetrics)

var width = displayMetrics.widthPixels
var height = displayMetrics.heightPixels

如何用Kotlin语言有效地独立活动地使用它?

这里，我在一般的Kotlin类中创建了一个方法。你可以在所有活动中使用它。

private val T_GET_SCREEN_WIDTH:String = "screen_width"
private val T_GET_SCREEN_HEIGHT:String = "screen_height"

private fun getDeviceSizes(activity:Activity, whichSize:String):Int{

    val displayMetrics = DisplayMetrics()
    activity.windowManager.defaultDisplay.getMetrics(displayMetrics)

    return when (whichSize){
        T_GET_SCREEN_WIDTH -> displayMetrics.widthPixels
        T_GET_SCREEN_HEIGHT -> displayMetrics.heightPixels
        else -> 0 // Error
    }
}

Display display = ((WindowManager) this.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int mWidthScreen = display.getWidth();
int mHeightScreen = display.getHeight();

使用这段代码，你可以得到运行时显示的宽度和高度:

DisplayMetrics displayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int height = displayMetrics.heightPixels;
int width = displayMetrics.widthPixels;

在视图中，你需要这样做:

((Activity) getContext()).getWindowManager()
                         .getDefaultDisplay()
                         .getMetrics(displayMetrics);

在某些情况下，设备有一个导航栏，你必须在运行时检查:

public boolean showNavigationBar(Resources resources)
{
    int id = resources.getIdentifier("config_showNavigationBar", "bool", "android");
    return id > 0 && resources.getBoolean(id);
}

如果设备有一个导航栏，那么计算它的高度:

private int getNavigationBarHeight() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
        DisplayMetrics metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);
        int usableHeight = metrics.heightPixels;
        getWindowManager().getDefaultDisplay().getRealMetrics(metrics);
        int realHeight = metrics.heightPixels;
        if (realHeight > usableHeight)
            return realHeight - usableHeight;
        else
            return 0;
    }
    return 0;
}

所以设备的最终高度是:

int height = displayMetrics.heightPixels + getNavigationBarHeight();

    int getScreenSize() {
        int screenSize = getResources().getConfiguration().screenLayout &
                Configuration.SCREENLAYOUT_SIZE_MASK;
//        String toastMsg = "Screen size is neither large, normal or small";
        Display display = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
        int orientation = display.getRotation();

        int i = 0;
        switch (screenSize) {

            case Configuration.SCREENLAYOUT_SIZE_NORMAL:
                i = 1;
//                toastMsg = "Normal screen";
                break;
            case Configuration.SCREENLAYOUT_SIZE_SMALL:
                i = 1;
//                toastMsg = "Normal screen";
                break;
            case Configuration.SCREENLAYOUT_SIZE_LARGE:
//                toastMsg = "Large screen";
                if (orientation == Surface.ROTATION_90
                        || orientation == Surface.ROTATION_270) {
                    // TODO: add logic for landscape mode here
                    i = 2;
                } else {
                    i = 1;
                }


                break;
            case Configuration.SCREENLAYOUT_SIZE_XLARGE:
                if (orientation == Surface.ROTATION_90
                        || orientation == Surface.ROTATION_270) {
                    // TODO: add logic for landscape mode here
                    i = 4;
                } else {
                    i = 3;
                }

                break;


        }
//        customeToast(toastMsg);
        return i;
    }

这里没有一个答案适用于Chrome OS的多显示器，或即将到来的可折叠设备。

在查找当前配置时，始终使用getResources(). getconfiguration()中当前活动的配置。不要使用来自后台活动或系统资源的配置。后台活动没有大小，系统的配置可能包含多个大小和方向冲突的窗口，因此无法提取可用的数据。

所以答案是

val config = context.getResources().getConfiguration()
val (screenWidthPx, screenHeightPx) = config.screenWidthDp.dp to config.screenHeightDp.dp

只是通过parag和SpK更新答案，使其与当前SDK的向后兼容性保持一致:

int Measuredwidth = 0;  
int Measuredheight = 0;  
Point size = new Point();
WindowManager w = getWindowManager();

if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)    {
    w.getDefaultDisplay().getSize(size);
    Measuredwidth = size.x;
    Measuredheight = size.y; 
}else{
    Display d = w.getDefaultDisplay(); 
    Measuredwidth = d.getWidth(); 
    Measuredheight = d.getHeight(); 
}