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?
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
我尝试了所有可能的“解决方案”,但都失败了,我注意到Elliott Hughes的“Dalvik Explorer”应用程序在任何Android设备/操作系统版本上都始终显示正确的维度。我最后看了他的开源项目,可以在这里找到:https://code.google.com/p/enh/
以下是所有相关代码:
WindowManager w = activity.getWindowManager();
Display d = w.getDefaultDisplay();
DisplayMetrics metrics = new DisplayMetrics();
d.getMetrics(metrics);
// since SDK_INT = 1;
widthPixels = metrics.widthPixels;
heightPixels = metrics.heightPixels;
try {
// used when 17 > SDK_INT >= 14; includes window decorations (statusbar bar/menu bar)
widthPixels = (Integer) Display.class.getMethod("getRawWidth").invoke(d);
heightPixels = (Integer) Display.class.getMethod("getRawHeight").invoke(d);
} catch (Exception ignored) {
}
try {
// used when SDK_INT >= 17; includes window decorations (statusbar bar/menu bar)
Point realSize = new Point();
Display.class.getMethod("getRealSize", Point.class).invoke(d, realSize);
widthPixels = realSize.x;
heightPixels = realSize.y;
} catch (Exception ignored) {
}
EDIT:略有改进的版本(避免在不受支持的OS版本上触发异常):
WindowManager w = activity.getWindowManager();
Display d = w.getDefaultDisplay();
DisplayMetrics metrics = new DisplayMetrics();
d.getMetrics(metrics);
// since SDK_INT = 1;
widthPixels = metrics.widthPixels;
heightPixels = metrics.heightPixels;
// includes window decorations (statusbar bar/menu bar)
if (Build.VERSION.SDK_INT >= 14 && Build.VERSION.SDK_INT < 17)
try {
widthPixels = (Integer) Display.class.getMethod("getRawWidth").invoke(d);
heightPixels = (Integer) Display.class.getMethod("getRawHeight").invoke(d);
} catch (Exception ignored) {
}
// includes window decorations (statusbar bar/menu bar)
if (Build.VERSION.SDK_INT >= 17)
try {
Point realSize = new Point();
Display.class.getMethod("getRealSize", Point.class).invoke(d, realSize);
widthPixels = realSize.x;
heightPixels = realSize.y;
} catch (Exception ignored) {
}
其他回答
遵循以下方法:
public static int getWidthScreen(Context context) {
return getDisplayMetrics(context).widthPixels;
}
public static int getHeightScreen(Context context) {
return getDisplayMetrics(context).heightPixels;
}
private static DisplayMetrics getDisplayMetrics(Context context) {
DisplayMetrics displayMetrics = new DisplayMetrics();
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
wm.getDefaultDisplay().getMetrics(displayMetrics);
return displayMetrics;
}
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 ...
}
有一种使用DisplayMetrics(API 1)来实现这一点的方法并不过时,它可以避免try/catch混乱:
// initialize the DisplayMetrics object
DisplayMetrics deviceDisplayMetrics = new DisplayMetrics();
// populate the DisplayMetrics object with the display characteristics
getWindowManager().getDefaultDisplay().getMetrics(deviceDisplayMetrics);
// get the width and height
screenWidth = deviceDisplayMetrics.widthPixels;
screenHeight = deviceDisplayMetrics.heightPixels;
在“活动”中使用以下代码。
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
int height = metrics.heightPixels;
int wwidth = metrics.widthPixels;
此函数以英寸为单位返回近似屏幕大小。
public double getScreenSize()
{
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int width=dm.widthPixels;
int height=dm.heightPixels;
int dens=dm.densityDpi;
double wi=(double)width/(double)dens;
double hi=(double)height/(double)dens;
double x = Math.pow(wi,2);
double y = Math.pow(hi,2);
double screenInches = Math.sqrt(x+y);
return screenInches;
}