头条AutoSize基本原理

Posted 2021-06-24 楠之枫雪

其实核心代码根简单，如下面显示，详情可以参考这个文章：屏幕适配：修改屏幕像素密度，随便设dp

 private final static float WIDTH = 960;

    public static void setDensity(Application application, AppCompatActivity activity) {
        //获取当前app的屏幕显示信息
        DisplayMetrics displayMetrics = application.getResources().getDisplayMetrics();

        float appDensity = displayMetrics.density;
        float appScaleDensity = displayMetrics.scaledDensity;

        //计算等比缩放后的density和scaleDensity
        //WIDTH相对于所有屏幕宽度都是相等的，它是用dp作为单位，所以 屏幕宽度/屏幕密度=WIDTH
        //targetDensity = targetWidht/WIDTH
        float targetDensity = displayMetrics.widthPixels / WIDTH;
        //appScaleDensity/appDensity=targetScaleDensity/targetDensity;
        float targetScaleDensity = targetDensity * (appScaleDensity / appDensity);
        int targetDensityDpi = (int) (targetDensity * 160);

        //替换activity的density，appdensity，densityDpi
        DisplayMetrics aDisplayMertics = activity.getResources().getDisplayMetrics();
        aDisplayMertics.density = targetDensity;
        aDisplayMertics.scaledDensity = targetScaleDensity;
        aDisplayMertics.densityDpi = targetDensityDpi;
    }