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
    }
}

public class DisplayInfo {
    int screen_height=0, screen_width=0;
    WindowManager wm;
    DisplayMetrics displaymetrics;

    DisplayInfo(Context context) {
        getdisplayheightWidth(context);
    }

    void getdisplayheightWidth(Context context) {
        wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        displaymetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(displaymetrics);
        screen_height = displaymetrics.heightPixels;
        screen_width = displaymetrics.widthPixels;
    }

    public int getScreen_height() {
        return screen_height;
    }

    public int getScreen_width() {
        return screen_width;
    }
}

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(); 
}

我发现weigan的答案最好的一个在这一页，这里是如何在Xamarin使用它。Android:

public int GetScreenWidth()
{
    return Resources.System.DisplayMetrics.WidthPixels;
}

public int GetScreenHeight()
{
    return Resources.System.DisplayMetrics.HeightPixels;
}

完整的方法是使用“getRealSize”来返回真实的分辨率(包括当用户改变分辨率时)。

我注意到所有其他可用的函数，包括文档中说要用的代替this的函数，在某些情况下结果会更小。

下面是代码:

            WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
            Point size = new Point();
            wm.getDefaultDisplay().getRealSize(size);
            final int width = size.x, height = size.y;

因为这可以在不同的方向上改变，这里有一个解决方案(在Kotlin中)，无论朝向如何，都能得到正确的结果:

/**
 * returns the natural orientation of the device: Configuration.ORIENTATION_LANDSCAPE or Configuration.ORIENTATION_PORTRAIT .<br></br>
 * The result should be consistent no matter the orientation of the device
 */
@JvmStatic
fun getScreenNaturalOrientation(context: Context): Int {
    //based on : http://stackoverflow.com/a/9888357/878126
    val windowManager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
    val config = context.resources.configuration
    val rotation = windowManager.defaultDisplay.rotation
    return if ((rotation == Surface.ROTATION_0 || rotation == Surface.ROTATION_180) && config.orientation == Configuration.ORIENTATION_LANDSCAPE || (rotation == Surface.ROTATION_90 || rotation == Surface.ROTATION_270) && config.orientation == Configuration.ORIENTATION_PORTRAIT)
        Configuration.ORIENTATION_LANDSCAPE
    else
        Configuration.ORIENTATION_PORTRAIT
}

/**
 * returns the natural screen size (in pixels). The result should be consistent no matter the orientation of the device
 */
@JvmStatic
fun getScreenNaturalSize(context: Context): Point {
    val screenNaturalOrientation = getScreenNaturalOrientation(context)
    val wm = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
    val point = Point()
    wm.defaultDisplay.getRealSize(point)
    val currentOrientation = context.resources.configuration.orientation
    if (currentOrientation == screenNaturalOrientation)
        return point
    else return Point(point.y, point.x)
}

只需使用下面的函数，它以整数数组的形式返回屏幕大小的宽度和高度

private int[] getScreenSIze(){
        DisplayMetrics displaymetrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
        int h = displaymetrics.heightPixels;
        int w = displaymetrics.widthPixels;

        int[] size={w,h};
        return size;

    }

在onCreate函数或按钮上单击添加以下代码以输出屏幕大小，如下所示

 int[] screenSize= getScreenSIze();
        int width=screenSize[0];
        int height=screenSize[1];
        screenSizes.setText("Phone Screen sizes \n\n  width = "+width+" \n Height = "+height);