DisplayMetrics dimension = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dimension);
int w = dimension.widthPixels;
int h = dimension.heightPixels;

首先加载XML文件，然后编写以下代码：

setContentView(R.layout.main);      
Display display = getWindowManager().getDefaultDisplay();
final int width = (display.getWidth());
final int height = (display.getHeight());

根据屏幕分辨率显示宽度和高度。

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;

一种方法是：

Display display = getWindowManager().getDefaultDisplay(); 
int width = display.getWidth();
int height = display.getHeight();

它已被弃用，您应该尝试以下代码。前两行代码提供DisplayMetrics对象。此对象包含高度像素、宽度像素等字段。

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

Api级别30更新

final WindowMetrics metrics = windowManager.getCurrentWindowMetrics();
 // Gets all excluding insets
 final WindowInsets windowInsets = metrics.getWindowInsets();
 Insets insets = windowInsets.getInsetsIgnoringVisibility(WindowInsets.Type.navigationBars()
         | WindowInsets.Type.displayCutout());

 int insetsWidth = insets.right + insets.left;
 int insetsHeight = insets.top + insets.bottom;

 // Legacy size that Display#getSize reports
 final Rect bounds = metrics.getBounds();
 final Size legacySize = new Size(bounds.width() - insetsWidth,
         bounds.height() - insetsHeight);

（2012年的答案，可能已经过时了）如果你想支持前蜂窝，你需要在API 13之前引入向后兼容性。类似于：

int measuredWidth = 0;
int measuredHeight = 0;
WindowManager w = getWindowManager();

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
    Point size = new Point();
    w.getDefaultDisplay().getSize(size);
    measuredWidth = size.x;
    measuredHeight = size.y;
} else {
    Display d = w.getDefaultDisplay();
    measuredWidth = d.getWidth();
    measuredHeight = d.getHeight();
}

当然，被弃用的方法最终会从最新的SDK中删除，但尽管我们仍然依赖大多数拥有Android 2.1、2.2和2.3的用户，但这就是我们剩下的。

如果Display类不工作，则上面的答案将不起作用，那么您可以通过下面的方法获得宽度和高度。

private static final int WIDTH_INDEX = 0;
private static final int HEIGHT_INDEX = 1;

    public static int[] getScreenSize(Context context) {
        int[] widthHeight = new int[2];
        widthHeight[WIDTH_INDEX] = 0;
        widthHeight[HEIGHT_INDEX] = 0;

        try {
            WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
            Display display = windowManager.getDefaultDisplay();

            Point size = new Point();
            display.getSize(size);
            widthHeight[WIDTH_INDEX] = size.x;
            widthHeight[HEIGHT_INDEX] = size.y;

            if (!isScreenSizeRetrieved(widthHeight))
            {
                DisplayMetrics metrics = new DisplayMetrics();
                display.getMetrics(metrics);
                widthHeight[0] = metrics.widthPixels;
                widthHeight[1] = metrics.heightPixels;
            }

            // Last defense. Use deprecated API that was introduced in lower than API 13
            if (!isScreenSizeRetrieved(widthHeight)) {
                widthHeight[0] = display.getWidth(); // deprecated
                widthHeight[1] = display.getHeight(); // deprecated
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return widthHeight;
    }

    private static boolean isScreenSizeRetrieved(int[] widthHeight) {
        return widthHeight[WIDTH_INDEX] != 0 && widthHeight[HEIGHT_INDEX] != 0;
    }