利用DisplayMetrics获取屏幕信息

public static String getDisplayMetrics(Context cx) {   
           String str = "";   
           DisplayMetrics dm = new DisplayMetrics();   
           //取得DisplayMetrics对象方法一  
           //dm = cx.getApplicationContext().getResources().getDisplayMetrics();   
           //取得DisplayMetrics对象方法二  
           ((Activity)cx).getWindowManager().getDefaultDisplay().getMetrics(dm);  
           int screenWidth = dm.widthPixels;   
           int screenHeight = dm.heightPixels;   
           float density = dm.density;   
           float xdpi = dm.xdpi;   
           float ydpi = dm.ydpi;   

           //dm.DENSITY_DEVICE
            
           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;   
        }