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

试试Kotlin的这段代码

 val display = windowManager.defaultDisplay
 val size = Point()
 display.getSize(size)
 var DEVICE_WIDTH = size.x
 var DEVICE_HEIGHT = size.y

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)
}

正如android官方文档所说，默认显示使用Context#getDisplay()，因为该方法在API级别30中已弃用。

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

下面给出的代码是kotlin，是根据Android的最新版本编写的，帮助您确定宽度和高度:

fun getWidth(context: Context): Int {
    var width:Int = 0
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        val displayMetrics = DisplayMetrics()
        val display: Display? = context.getDisplay()
        display!!.getRealMetrics(displayMetrics)
        return displayMetrics.widthPixels
    }else{
        val displayMetrics = DisplayMetrics()
        this.windowManager.defaultDisplay.getMetrics(displayMetrics)
        width = displayMetrics.widthPixels
        return width
    }
}

fun getHeight(context: Context): Int {
    var height: Int = 0
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        val displayMetrics = DisplayMetrics()
        val display = context.display
        display!!.getRealMetrics(displayMetrics)
        return displayMetrics.heightPixels
    }else {
        val displayMetrics = DisplayMetrics()
        this.windowManager.defaultDisplay.getMetrics(displayMetrics)
        height = displayMetrics.heightPixels
        return height
    }
}

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;
    }
}

似乎所有这些答案都不适合我的Galaxy M51和Android 11。在做了一些研究之后，我发现了这个代码:

WindowMetrics windowmetrics = MainActivity.getWindowManager().getCurrentWindowMetrics();
Rect rect = windowmetrics.getBounds();
int width = rect.right;
int height =rect.bottom;

显示我的真实设备分辨率为1080x2400，其余只返回810x1800。