屏幕适配工具类

public class Density {
    private static float appDensity;
    private static float appScaledDensity;
    private static DisplayMetrics appDisplayMetrics;
    private static int barHeight;

    public static void setDensity(@NonNull final Activity application){
        //获取application的DisplayMetrics
        appDisplayMetrics=application.getResources().getDisplayMetrics();
        //获取状态栏高度
        barHeight=AppUtils.getStateBar2(application);

        if(appDensity==0){
            //初始化的时候赋值
            appDensity=appDisplayMetrics.density;
            appScaledDensity=appDisplayMetrics.scaledDensity;

            //添加字体变化的监听
            application.registerComponentCallbacks(new ComponentCallbacks(){
                @Override
                public void onConfigurationChanged(Configuration newConfig){
                    //字体改变后,将appScaledDensity重新赋值
                    if(newConfig!=null&&newConfig.fontScale>0){
                        appScaledDensity=application.getResources().getDisplayMetrics().scaledDensity;
                    }
                }

                @Override
                public void onLowMemory(){
                }
            });
        }
    }

    //此方法在BaseActivity中做初始化(如果不封装BaseActivity的话,直接用下面那个方法就好了)
    public static void setDefault(Activity activity){
        setAppOrientation(activity,AppUtils.HEIGHT);
    }

    //此方法用于在某一个Activity里面更改适配的方向
    public static void setOrientation(Activity activity, String orientation){
        setAppOrientation(activity,orientation);
    }

    /**
     * targetDensity
     * targetScaledDensity
     * targetDensityDpi
     * 这三个参数是统一修改过后的值
     * <p>
     * orientation:方向值,传入width或height
     */
    private static void setAppOrientation(@Nullable Activity activity, String orientation){

        float targetDensity;

        if(orientation.equals("height")){
            targetDensity=(appDisplayMetrics.heightPixels-barHeight)/1280f;
        }else{
            targetDensity=appDisplayMetrics.widthPixels/800f;
        }

        float targetScaledDensity=targetDensity*(appScaledDensity/appDensity);
        int targetDensityDpi=(int)(160*targetDensity);

        /**
         *
         * 最后在这里将修改过后的值赋给系统参数
         *
         * 只修改Activity的density值
         */

        DisplayMetrics activityDisplayMetrics=activity.getResources().getDisplayMetrics();
        activityDisplayMetrics.density=targetDensity;//相对密度 dp和px的比例
        activityDisplayMetrics.scaledDensity=targetScaledDensity;
        activityDisplayMetrics.densityDpi=targetDensityDpi;
    }

}

状态栏,dp和px转换

public class AppUtils {

    public final static String WIDTH = "1080";

    public final static String HEIGHT = "1920";

    /**
     * px转dp
     *
     * @param context The context
     * @param px      the pixel value
     * @return value in dp
     */
    public static int pxToDp(Context context, float px) {
        DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
        return (int) ((px / displayMetrics.density) + 0.5f);
    }

    /**
     * dp转px
     *
     * @param context
     * @param dp
     * @return
     */
    public static int dpToPx(Context context, float dp) {
        DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
        return (int) ((dp * displayMetrics.density) + 0.5f);
    }

    public static int getStateBar3(Context context){
        int result = 0;
        int resourceId = context.getResources().getIdentifier("status_bar_height", "dimen", "android");
        if (resourceId > 0) {
            result = context.getResources().getDimensionPixelSize(resourceId);
        }
        return result;
    }

    public static int getStateBar2(Context context) {
        Class c = null;
        try {
            c = Class.forName("com.android.internal.R$dimen");
            Object obj = c.newInstance();
            Field field = c.getField("status_bar_height");
            int x = Integer.parseInt(field.get(obj).toString());
            int statusBarHeight = context.getResources().getDimensionPixelSize(x);
            return statusBarHeight;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return 0;
    }

    /**
     * 获取状态栏高度
     *
     * @param context
     * @return
     */
    public static int getStatusBarHeight(Context context) {
        int result = 0;
        int resourceId = context.getResources().getIdentifier("status_bar_height", "dimen",
                "android");
        if (resourceId > 0) {
            result = context.getResources().getDimensionPixelSize(resourceId);
        }
        return result;
    }

}

界面设置

       super.onCreate(savedInstanceState);
        //无title
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        //全屏
        getWindow().setFlags(WindowManager.LayoutParams. FLAG_FULLSCREEN ,
                WindowManager.LayoutParams. FLAG_FULLSCREEN);
        setContentView(R.layout.activity_sw);