获取android手机屏幕的宽高、density

public static String getDisplayMetrics(Context cx) {        String str = "";        DisplayMetrics dm = new DisplayMetrics();        dm = cx.getApplicationContext().getResources().getDisplayMetrics();        int screenWidth = dm.widthPixels;        int screenHeight = dm.heightPixels;        float density = dm.density;        float xdpi = dm.xdpi;        float ydpi = dm.ydpi;        str += "The absolute width:" + String.valueOf(screenWidth) + "pixels\n";        str += "The absolute heightin:" + String.valueOf(screenHeight)                        + "pixels\n";        str += "The logical density of the display.:" + String.valueOf(density)                        + "\n";        str += "X dimension :" + String.valueOf(xdpi) + "pixels per inch\n";        str += "Y dimension :" + String.valueOf(ydpi) + "pixels per inch\n";        return str;}