我创建了一些自定义元素,并希望以编程方式将它们放置在右上角(距离上边缘n个像素,距离右边缘m个像素)。因此,我需要获得屏幕宽度和屏幕高度,然后设置位置:

int px = screenWidth - m;
int py = screenHeight - n;

如何在主活动中获取screenWidth和screenHeight?


当前回答

这里是Kotlin实现中对上面一些答案的简单改编。它需要清单中如上所述的windowsSoftInput=“adjustResize”:

class KeyboardWatcher(private val layoutRooView: View) {

    companion object {
        private const val MIN_KEYBOARD_HEIGHT = 200f
    }

    private val displayMetrics: DisplayMetrics = layoutRooView.resources.displayMetrics
    private var stateVisible = false

    var observer: ((Boolean) -> Unit)? = null

    init {
        layoutRooView.viewTreeObserver.addOnGlobalLayoutListener {
            val heightDiff = layoutRooView.rootView.height - layoutRooView.height
            if (!stateVisible && heightDiff > dpToPx(MIN_KEYBOARD_HEIGHT)) {
                stateVisible = true
                observer?.invoke(stateVisible)
            } else if(stateVisible) {
                stateVisible = false
                observer?.invoke(stateVisible)
            }
        }
    }

    private fun dpToPx(valueInDp: Float): Float {
        return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, valueInDp, displayMetrics)
    }
}

并使用:

val activityRootView = findViewById<ViewGroup>(R.id.activityRoot)
KeyboardWatcher(activityRootView).observer = { visible ->
    if (visible) do something here ...
}

其他回答

创建Kotlin扩展函数以获取屏幕宽度和高度-

fun Context?.screenWidthInPx(): Int {
    if (this == null) return 0
    val dm = DisplayMetrics()
    val wm = this.getSystemService(Context.WINDOW_SERVICE) as WindowManager
    wm.defaultDisplay.getMetrics(dm)
    return dm.widthPixels
}
//comment
fun Context?.screenHeightInPx(): Int {
    if (this == null) return 0
    val dm = DisplayMetrics()
    val wm = this.getSystemService(Context.WINDOW_SERVICE) as WindowManager
    wm.defaultDisplay.getMetrics(dm)
    return dm.heightPixels
}

它可能无法回答您的问题,但如果你需要一个视图的维度,但你的代码在尚未布局时(例如在onCreate()中)正在执行,你可以使用View.getViewTreeObserver().addOnGlobalLayoutListener()设置一个ViewTreeObserver.OnGlobalLayout侦听器,并将需要该视图的相关代码放入尺寸。布局布局完成后,将调用侦听器的回调。

以下是低于/高于API 30代码的Kotlin扩展函数:

fun Activity.getScreenWidth(): Int {
    return if (Build.VERSION.SDK_INT < 30) {
        val displayMetrics = DisplayMetrics()
        windowManager.defaultDisplay.getMetrics(displayMetrics)
        displayMetrics.widthPixels
    } else {
        val metrics = windowManager.currentWindowMetrics
        val insets = metrics.windowInsets
            .getInsetsIgnoringVisibility(WindowInsets.Type.systemBars())
        metrics.bounds.width() - insets.left - insets.right
    }
}

fun Activity.getScreenHeight(): Int {
    return if (Build.VERSION.SDK_INT < 30) {
        val displayMetrics = DisplayMetrics()
        windowManager.defaultDisplay.getMetrics(displayMetrics)
        displayMetrics.heightPixels
    } else {
        val metrics = windowManager.currentWindowMetrics
        val insets = metrics.windowInsets
            .getInsetsIgnoringVisibility(WindowInsets.Type.systemBars())
        metrics.bounds.height() - insets.top - insets.bottom
    }
}

对应的Java助手方法:

public int getScreenWidth(Activity activity) {
    if (Build.VERSION.SDK_INT < 30) {
        DisplayMetrics displayMetrics = new DisplayMetrics();
        activity.getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
        return displayMetrics.widthPixels;
    } else {
        WindowMetrics metrics = activity.getWindowManager().getCurrentWindowMetrics();
        Insets insets = metrics.getWindowInsets()
                .getInsetsIgnoringVisibility(WindowInsets.Type.systemBars());
        return metrics.getBounds().width() - insets.left - insets.right;
    }
}


public int getScreenHeight(Activity activity) {
    if (Build.VERSION.SDK_INT < 30) {
        DisplayMetrics displayMetrics = new DisplayMetrics();
        activity.getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
        return displayMetrics.heightPixels;
    } else {
        WindowMetrics metrics = activity.getWindowManager().getCurrentWindowMetrics();
        Insets insets = metrics.getWindowInsets()
                .getInsetsIgnoringVisibility(WindowInsets.Type.systemBars());
        return metrics.getBounds().height() - insets.bottom - insets.top;
    }
}

最简单的方法:

 int screenHeight = getResources().getDisplayMetrics().heightPixels;
 int screenWidth = getResources().getDisplayMetrics().widthPixels; 

这不是更好的解决方案吗?DisplayMetrics提供了您所需的一切,并从API 1开始工作。

public void getScreenInfo(){
    DisplayMetrics metrics = new DisplayMetrics();
    getActivity().getWindowManager().getDefaultDisplay().getMetrics(metrics);

    heightPixels = metrics.heightPixels;
    widthPixels = metrics.widthPixels;
    density = metrics.density;
    densityDpi = metrics.densityDpi;
}

您也可以使用getRealMetrics获得实际显示(包括屏幕装饰,如状态栏或软件导航栏),但这仅适用于17+。

我错过了什么吗?