为什么不

DisplayMetrics displaymetrics = getResources().getDisplayMetrics();

然后使用

displayMetrics.widthPixels

and

displayMetrics.heightPixels

DisplayMetrics lDisplayMetrics = getResources().getDisplayMetrics();
int widthPixels = lDisplayMetrics.widthPixels;
int heightPixels = lDisplayMetrics.heightPixels;

对于kotlin用户

fun Activity.displayMetrics(): DisplayMetrics {
   val displayMetrics = DisplayMetrics()
   windowManager.defaultDisplay.getMetrics(displayMetrics)
   return displayMetrics
}

在Activity中，你可以使用它

     resources.displayMetrics.let { displayMetrics ->
        val height = displayMetrics.heightPixels
        val width = displayMetrics.widthPixels
    }

或者碎片化

    activity?.displayMetrics()?.run {
        val height = heightPixels
        val width = widthPixels
    }

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;
    }
}

•Kotlin版本通过扩展属性

如果你想知道屏幕的像素大小以及dp，使用这些扩展属性真的很有帮助:

DimensionUtils.kt

import android.content.Context
import android.content.res.Resources
import android.graphics.Rect
import android.graphics.RectF
import android.os.Build
import android.util.DisplayMetrics
import android.view.WindowManager
import kotlin.math.roundToInt

/**
 * @author aminography
 */

private val displayMetrics: DisplayMetrics by lazy { Resources.getSystem().displayMetrics }

/**
 * Returns boundary of the screen in pixels (px).
 */
val screenRectPx: Rect
    get() = displayMetrics.run { Rect(0, 0, widthPixels, heightPixels) }

/**
 * Returns boundary of the screen in density independent pixels (dp).
 */
val screenRectDp: RectF
    get() = screenRectPx.run { RectF(0f, 0f, right.px2dp, bottom.px2dp) }

/**
 * Returns boundary of the physical screen including system decor elements (if any) like navigation
 * bar in pixels (px).
 */
val Context.physicalScreenRectPx: Rect
    get() = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
        (applicationContext.getSystemService(Context.WINDOW_SERVICE) as WindowManager)
            .run { DisplayMetrics().also { defaultDisplay.getRealMetrics(it) } }
            .run { Rect(0, 0, widthPixels, heightPixels) }
    } else screenRectPx

/**
 * Returns boundary of the physical screen including system decor elements (if any) like navigation
 * bar in density independent pixels (dp).
 */
val Context.physicalScreenRectDp: RectF
    get() = physicalScreenRectPx.run { RectF(0f, 0f, right.px2dp, bottom.px2dp) }

/**
 * Converts any given number from pixels (px) into density independent pixels (dp).
 */
val Number.px2dp: Float
    get() = this.toFloat() / displayMetrics.density

/**
 * Converts any given number from density independent pixels (dp) into pixels (px).
 */
val Number.dp2px: Int
    get() = (this.toFloat() * displayMetrics.density).roundToInt()

用法:

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val widthPx = screenRectPx.width()
        val heightPx = screenRectPx.height()
        println("[PX] screen width: $widthPx , height: $heightPx")

        val widthDp = screenRectDp.width()
        val heightDp = screenRectDp.height()
        println("[DP] screen width: $widthDp , height: $heightDp")

        println()
        
        val physicalWidthPx = physicalScreenRectPx.width()
        val physicalHeightPx = physicalScreenRectPx.height()
        println("[PX] physical screen width: $physicalWidthPx , height: $physicalHeightPx")

        val physicalWidthDp = physicalScreenRectDp.width()
        val physicalHeightDp = physicalScreenRectDp.height()
        println("[DP] physical screen width: $physicalWidthDp , height: $physicalHeightDp")
    }
}

结果:

当设备处于纵向方向时:

[PX] screen width: 1440 , height: 2392
[DP] screen width: 360.0 , height: 598.0

[PX] physical screen width: 1440 , height: 2560
[DP] physical screen width: 360.0 , height: 640.0

当设备处于横向时:

[PX] screen width: 2392 , height: 1440
[DP] screen width: 598.0 , height: 360.0

[PX] physical screen width: 2560 , height: 1440
[DP] physical screen width: 640.0 , height: 360.0

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;
}