Android屏幕适配很难嘛？其实也就那么回事

private static float sRoncompatScaledDensity; 
private void setCustomDensity(@NonNull Activity activity, final @NonNull Application application) { 

 //application 
 final DisplayMetrics appDisplayMetrics = application.getResources().getDisplayMetrics(); 

 if (sRoncompatDennsity == 0) { 
 sRoncompatDennsity = appDisplayMetrics.density; 
 sRoncompatScaledDensity = appDisplayMetrics.scaledDensity; 
 application.registerComponentCallbacks(new ComponentCallbacks() { 
 @Override 
 public void onConfigurationChanged(Configuration newConfig) { 
 if (newConfig != null && newConfig.fontScale > 0) { 
 sRoncompatScaledDensity = application.getResources().getDisplayMetrics().scaledDensity; 
 } 
 } 

 @Override 
 public void onLowMemory() { 

 } 
 }); 
 } 

 //计算宽为360dp 同理可以设置高为640dp的根据实际情况 
 final float targetDensity = appDisplayMetrics.widthPixels / 360; 
 final float targetScaledDensity = targetDensity * (sRoncompatScaledDensity / sRoncompatDennsity); 
 final int targetDensityDpi = (int) (targetDensity * 160); 

 appDisplayMetrics.density = targetDensity; 
 appDisplayMetrics.densityDpi = targetDensityDpi; 
 appDisplayMetrics.scaledDensity = targetScaledDensity; 

 //activity 
 final DisplayMetrics activityDisplayMetrics = activity.getResources().getDisplayMetrics(); 

 activityDisplayMetrics.density = targetDensity; 
 activityDisplayMetrics.densityDpi = targetDensityDpi; 
 activityDisplayMetrics.scaledDensity = targetScaledDensity; 
} 

final float targetDensity = appDisplayMetrics.widthPixels / 360; 

final float targetDensity = appDisplayMetrics.heightPixels / 667; 

float targetDensity = 0; 
try { 
 Double division = Operation.division(appDisplayMetrics.heightPixels, 667); 
 //由于手机的长宽不尽相同,肯定会有除不尽的情况,有失精度,所以在这里把所得结果做了一个保留两位小数的操作 
 DecimalFormat df = new DecimalFormat("0.00"); 
 String s = df.format(division); 
 targetDensity = Float.parseFloat(s); 
} catch (NumberFormatException e) { 
 e.printStackTrace(); 
} 

private static float appDensity; 
private static float appScaledDensity; 
private static DisplayMetrics appDisplayMetrics; 

//此方法在Application的onCreate方法中调用 Density.setDensity(this); 
public static void setDensity(@NonNull Application application) { 
 //获取application的DisplayMetrics 
 appDisplayMetrics = application.getResources().getDisplayMetrics(); 

 if (appDensity == 0) { 
 //初始化的时候赋值（只在Application里面初始化的时候会调用一次） 
 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() { 
 } 
 }); 
 } 

 //调用修改density值的方法(默认以宽度作为基准) 
 setAppOrientation(null, AppUtils.WIDTH); 
} 

//此方法用于在某一个Activity里面更改适配的方向 Density.setOrientation(mActivity, "width/height"); 
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 
 * 
 * orientation:方向值,传入width或height 
 */ 
private static void setAppOrientation(@Nullable Activity activity, String orientation) { 

 float targetDensity = 0; 
 try { 
 Double division; 
 //根据带入参数选择不同的适配方向 
 if (orientation.equals("height")) { 
 //appDisplayMetrics.heightPixels/667 
 division = Operation.division(appDisplayMetrics.heightPixels, 667); 
 } else { 
 division = Operation.division(appDisplayMetrics.widthPixels, 360); 
 } 
 //由于手机的长宽不尽相同,肯定会有除不尽的情况,有失精度,所以在这里把所得结果做了一个保留两位小数的操作 
 DecimalFormat df = new DecimalFormat("0.00"); 
 String s = df.format(division); 
 targetDensity = Float.parseFloat(s); 
 } catch (NumberFormatException e) { 
 e.printStackTrace(); 
 } 

 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 
 * 
 * (因为最开始初始化的时候,activity为null,所以只设置application的值就可以了... 
 * 所以在这里判断了一下,如果传有activity的话,再设置Activity的值) 
 */ 
 if (activity != null) { 
 DisplayMetrics activityDisplayMetrics = activity.getResources().getDisplayMetrics(); 
 activityDisplayMetrics.density = targetDensity; 
 activityDisplayMetrics.scaledDensity = targetScaledDensity; 
 activityDisplayMetrics.densityDpi = targetDensityDpi; 
 } else { 
 appDisplayMetrics.density = targetDensity; 
 appDisplayMetrics.scaledDensity = targetScaledDensity; 
 appDisplayMetrics.densityDpi = targetDensityDpi; 
 } 
} 

/** 
 * 
 * 由于是个人封装,此方法需要写在onCreate()中的setContentView()方法前面,切换方向的效果才会生效 
 */ 
@Override 
public void setOrientation() { 
 Density.setOrientation(this, AppUtils.HEIGHT); 
} 

/** 
 * 
 * 如果在一个Activity里面切换了适配方向的话,需要在destroy里面将方向设置为默认的方向, 
 * 因为切换方向修改的是Activity的值,但是application的也会覆盖掉(原因还没有搞清楚...), 
 * 权衡利弊之后就在onDestroy这个生命周期里面重新初始化了一下方向(因为用高度作为适配基准的页面 
 * 少之又少,这样可以最大程度的减少对程序功能性的影响) 
 */ 
@Override 
protected void onDestroy() { 
 super.onDestroy(); 
 Density.setOrientation(this, AppUtils.WIDTH); 
}