今天记录的笔记是今日头条的适配方案原理以及开源库”AndroidAutoSize“的实现剖析！（备注：此文仅供自己参考，全文全是文字，如果读者读起来比较生涩难懂，建议阅读引入文章）
此篇文章是通过阅读《骚年你的屏幕适配方式该升级了!-今日头条适配方案》理解的整理。感谢作者JessYan
适配的前提是你需要知道安卓适配的基础知识和基本方法 《Android屏幕适配-第一篇（基础知识）》、《Android屏幕适配-第二篇（你要知道的适配基本操作）》
你需要知道的关键字：density、dip、px、dp(dpi)
今日头条适配原理：density=（当前屏幕分辨率宽或高(单位px)）/(ui设计稿宽或高(单位dp))
这个表示的是1dp在当前分辨率下的所对于的像素
真正的view大小： realWidth=(ui设计稿上的宽度)*density
如何使用，例子：如设置一个view大小为100dpx100dp，通过上面的公式可得到宽为100*density高为100*density
假设当前分辨率为720x1280,设计搞的尺寸为360x640,当前density=2
假设当前分辨率为480x800,设计搞的尺寸为360x640,当前density=1.333
分辨率为720x1280下 view宽度=100*2 px,占整体宽度的比例为0.278（约等于）
分辨率为480x800下 view宽度=100*1.33 px,占整体宽度的比例为0.278(约等于)
比例近乎相同
设置设计稿 宽或高
<!-- 如果您项目中的所有页面都只需要以高或宽中的一个作为基准进行适配的话, 那就只需要填写高或宽中的一个设计图尺寸即可 -->
<meta-data
android:name="design_width_in_dp"
android:value="360"/>
<meta-data
android:name="design_height_in_dp"
android:value="640"/>
初始化配置，通过启动一个ContenProvider来启动默认配置
/**
* ================================================
* 通过声明 {@link ContentProvider} 自动完成初始化
* Created by JessYan on 2018/8/19 11:55
* <a href="mailto:[email protected]">Contact me</a>
* <a href="https://github.com/JessYanCoding">Follow me</a>
* ================================================
*/
public class InitProvider extends ContentProvider {
@Override
public boolean onCreate() {
AutoSizeConfig.getInstance()
.setLog(true)
.init((Application) getContext().getApplicationContext())
.setUseDeviceSize(false);
return true;
}
//其他代码忽略...
}
然后会调用此方法
AutoSizeConfig init(final Application application, boolean isBaseOnWidth, AutoAdaptStrategy strategy) {
Preconditions.checkArgument(mInitDensity == -1, "AutoSizeConfig#init() can only be called once");
Preconditions.checkNotNull(application, "application == null");
this.mApplication = application;
this.isBaseOnWidth = isBaseOnWidth;
final DisplayMetrics displayMetrics = Resources.getSystem().getDisplayMetrics();
getMetaData(application);
isVertical = application.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT;
int[] screenSize = ScreenUtils.getScreenSize(application);
mScreenWidth = screenSize[0];
mScreenHeight = screenSize[1];
mStatusBarHeight = ScreenUtils.getStatusBarHeight();
LogUtils.d("designWidthInDp = " + mDesignWidthInDp + ", designHeightInDp = " + mDesignHeightInDp + ", screenWidth = " + mScreenWidth + ", screenHeight = " + mScreenHeight);
mInitDensity = displayMetrics.density;
mInitDensityDpi = displayMetrics.densityDpi;
mInitScaledDensity = displayMetrics.scaledDensity;
mInitXdpi = displayMetrics.xdpi;
application.registerComponentCallbacks(new ComponentCallbacks() {
@Override
public void onConfigurationChanged(Configuration newConfig) {
if (newConfig != null) {
if (newConfig.fontScale > 0) {
mInitScaledDensity =
Resources.getSystem().getDisplayMetrics().scaledDensity;
LogUtils.d("initScaledDensity = " + mInitScaledDensity + " on ConfigurationChanged");
}
isVertical = newConfig.orientation == Configuration.ORIENTATION_PORTRAIT;
int[] screenSize = ScreenUtils.getScreenSize(application);
mScreenWidth = screenSize[0];
mScreenHeight = screenSize[1];
}
}
@Override
public void onLowMemory() {
}
});
....
//注意看这句代码是
mActivityLifecycleCallbacks = new ActivityLifecycleCallbacksImpl(strategy == null ? new WrapperAutoAdaptStrategy(new DefaultAutoAdaptStrategy()) : strategy);
application.registerActivityLifecycleCallbacks(mActivityLifecycleCallbacks);
....
return this;
}
ActivityLifecycleCallbacksImpl这里面有很多核心代码
/**
* ================================================
* {@link ActivityLifecycleCallbacksImpl} 可用来代替在 BaseActivity 中加入适配代码的传统方式
* {@link ActivityLifecycleCallbacksImpl} 这种方案类似于 AOP, 面向接口, 侵入性低, 方便统一管理, 扩展性强, 并且也支持适配三方库的 {@link Activity}
* <p>
* Created by JessYan on 2018/8/8 14:32
* <a href="mailto:[email protected]">Contact me</a>
* <a href="https://github.com/JessYanCoding">Follow me</a>
* ================================================
*/
public class ActivityLifecycleCallbacksImpl implements Application.ActivityLifecycleCallbacks {
/**
* 屏幕适配逻辑策略类
*/
private AutoAdaptStrategy mAutoAdaptStrategy;
/**
* 让 {@link Fragment} 支持自定义适配参数
*/
private FragmentLifecycleCallbacksImpl mFragmentLifecycleCallbacks;
public ActivityLifecycleCallbacksImpl(AutoAdaptStrategy autoAdaptStrategy) {
mFragmentLifecycleCallbacks = new FragmentLifecycleCallbacksImpl(autoAdaptStrategy);
mAutoAdaptStrategy = autoAdaptStrategy;
}
@Override
public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
if (AutoSizeConfig.getInstance().isCustomFragment()) {
if (activity instanceof FragmentActivity) {
((FragmentActivity) activity).getSupportFragmentManager().registerFragmentLifecycleCallbacks(mFragmentLifecycleCallbacks, true);
}
}
//Activity 中的 setContentView(View) 一定要在 super.onCreate(Bundle); 之后执行
if (mAutoAdaptStrategy != null) {
mAutoAdaptStrategy.applyAdapt(activity, activity);
}
}
@Override
public void onActivityStarted(Activity activity) {
if (mAutoAdaptStrategy != null) {
mAutoAdaptStrategy.applyAdapt(activity, activity);
}
}
...
/**
* 设置屏幕适配逻辑策略类
*
* @param autoAdaptStrategy {@link AutoAdaptStrategy}
*/
public void setAutoAdaptStrategy(AutoAdaptStrategy autoAdaptStrategy) {
mAutoAdaptStrategy = autoAdaptStrategy;
mFragmentLifecycleCallbacks.setAutoAdaptStrategy(autoAdaptStrategy);
}
}
DefaultAutoAdaptStrategy里面干了什么事情
/**
* ================================================
* 屏幕适配逻辑策略默认实现类, 可通过 {@link AutoSizeConfig#init(Application, boolean, AutoAdaptStrategy)}
* 和 {@link AutoSizeConfig#setAutoAdaptStrategy(AutoAdaptStrategy)} 切换策略
*
* @see AutoAdaptStrategy
* Created by JessYan on 2018/8/9 15:57
* <a href="mailto:[email protected]">Contact me</a>
* <a href="https://github.com/JessYanCoding">Follow me</a>
* ================================================
*/
public class DefaultAutoAdaptStrategy implements AutoAdaptStrategy {
@Override
public void applyAdapt(Object target, Activity activity) {
//检查是否开启了外部三方库的适配模式, 只要不主动调用 ExternalAdaptManager 的方法, 下面的代码就不会执行
if (AutoSizeConfig.getInstance().getExternalAdaptManager().isRun()) {
if (AutoSizeConfig.getInstance().getExternalAdaptManager().isCancelAdapt(target.getClass())) {
LogUtils.w(String.format(Locale.ENGLISH, "%s canceled the adaptation!", target.getClass().getName()));
AutoSize.cancelAdapt(activity);
return;
} else {
ExternalAdaptInfo info = AutoSizeConfig.getInstance().getExternalAdaptManager()
.getExternalAdaptInfoOfActivity(target.getClass());
if (info != null) {
LogUtils.d(String.format(Locale.ENGLISH, "%s used %s for adaptation!", target.getClass().getName(), ExternalAdaptInfo.class.getName()));
AutoSize.autoConvertDensityOfExternalAdaptInfo(activity, info);
return;
}
}
}
//如果 target 实现 CancelAdapt 接口表示放弃适配, 所有的适配效果都将失效
if (target instanceof CancelAdapt) {
LogUtils.w(String.format(Locale.ENGLISH, "%s canceled the adaptation!", target.getClass().getName()));
AutoSize.cancelAdapt(activity);
return;
}
//如果 target 实现 CustomAdapt 接口表示该 target 想自定义一些用于适配的参数, 从而改变最终的适配效果
if (target instanceof CustomAdapt) {
LogUtils.d(String.format(Locale.ENGLISH, "%s implemented by %s!", target.getClass().getName(), CustomAdapt.class.getName()));
AutoSize.autoConvertDensityOfCustomAdapt(activity, (CustomAdapt) target);
} else {
LogUtils.d(String.format(Locale.ENGLISH, "%s used the global configuration.", target.getClass().getName()));
AutoSize.autoConvertDensityOfGlobal(activity);
}
}
}
AutoSize
public static void autoConvertDensityOfCustomAdapt(Activity activity, CustomAdapt customAdapt) {
Preconditions.checkNotNull(customAdapt, "customAdapt == null");
float sizeInDp = customAdapt.getSizeInDp();
//如果 CustomAdapt#getSizeInDp() 返回 0, 则使用在 AndroidManifest 上填写的设计图尺寸
if (sizeInDp <= 0) {
if (customAdapt.isBaseOnWidth()) {
sizeInDp = AutoSizeConfig.getInstance().getDesignWidthInDp();
} else {
sizeInDp = AutoSizeConfig.getInstance().getDesignHeightInDp();
}
}
autoConvertDensity(activity, sizeInDp, customAdapt.isBaseOnWidth());
}
/**
* 这里是今日头条适配方案的核心代码, 核心在于根据当前设备的实际情况做自动计算并转换 {@link DisplayMetrics#density}、
* {@link DisplayMetrics#scaledDensity}、{@link DisplayMetrics#densityDpi} 这三个值, 额外增加 {@link DisplayMetrics#xdpi}
* 以支持单位 {@code pt}、{@code in}、{@code mm}
*
* @param activity {@link Activity}
* @param sizeInDp 设计图上的设计尺寸, 单位 dp, 如果 {@param isBaseOnWidth} 设置为 {@code true},
* {@param sizeInDp} 则应该填写设计图的总宽度, 如果 {@param isBaseOnWidth} 设置为 {@code false},
* {@param sizeInDp} 则应该填写设计图的总高度
* @param isBaseOnWidth 是否按照宽度进行等比例适配, {@code true} 为以宽度进行等比例适配, {@code false} 为以高度进行等比例适配
* @see <a href="https://mp.weixin.qq.com/s/d9QCoBP6kV9VSWvVldVVwA">今日头条官方适配方案</a>
*/
public static void autoConvertDensity(Activity activity, float sizeInDp, boolean isBaseOnWidth) {
Preconditions.checkNotNull(activity, "activity == null");
float subunitsDesignSize = isBaseOnWidth ? AutoSizeConfig.getInstance().getUnitsManager().getDesignWidth()
: AutoSizeConfig.getInstance().getUnitsManager().getDesignHeight();
subunitsDesignSize = subunitsDesignSize > 0 ? subunitsDesignSize : sizeInDp;
int screenSize = isBaseOnWidth ? AutoSizeConfig.getInstance().getScreenWidth()
: AutoSizeConfig.getInstance().getScreenHeight();
String key = sizeInDp + "|" + subunitsDesignSize + "|" + isBaseOnWidth + "|"
+ AutoSizeConfig.getInstance().isUseDeviceSize() + "|"
+ AutoSizeConfig.getInstance().getInitScaledDensity() + "|"
+ screenSize;
DisplayMetricsInfo displayMetricsInfo = mCache.get(key);
float targetDensity = 0;
int targetDensityDpi = 0;
float targetScaledDensity = 0;
float targetXdpi = 0;
if (displayMetricsInfo == null) {
if (isBaseOnWidth) {
targetDensity = AutoSizeConfig.getInstance().getScreenWidth() * 1.0f / sizeInDp;
} else {
targetDensity = AutoSizeConfig.getInstance().getScreenHeight() * 1.0f / sizeInDp;
}
float scale = AutoSizeConfig.getInstance().isExcludeFontScale() ? 1 : AutoSizeConfig.getInstance().
getInitScaledDensity() * 1.0f / AutoSizeConfig.getInstance().getInitDensity();
targetScaledDensity = targetDensity * scale;
targetDensityDpi = (int) (targetDensity * 160);
if (isBaseOnWidth) {
targetXdpi = AutoSizeConfig.getInstance().getScreenWidth() * 1.0f / subunitsDesignSize;
} else {
targetXdpi = AutoSizeConfig.getInstance().getScreenHeight() * 1.0f / subunitsDesignSize;
}
mCache.put(key, new DisplayMetricsInfo(targetDensity, targetDensityDpi, targetScaledDensity, targetXdpi));
} else {
targetDensity = displayMetricsInfo.getDensity();
targetDensityDpi = displayMetricsInfo.getDensityDpi();
targetScaledDensity = displayMetricsInfo.getScaledDensity();
targetXdpi = displayMetricsInfo.getXdpi();
}
setDensity(activity, targetDensity, targetDensityDpi, targetScaledDensity, targetXdpi);
LogUtils.d(String.format(Locale.ENGLISH, "The %s has been adapted! \n%s Info: isBaseOnWidth = %s, %s = %f, %s = %f, targetDensity = %f, targetScaledDensity = %f, targetDensityDpi = %d, targetXdpi = %f"
, activity.getClass().getName(), activity.getClass().getSimpleName(), isBaseOnWidth, isBaseOnWidth ? "designWidthInDp"
: "designHeightInDp", sizeInDp, isBaseOnWidth ? "designWidthInSubunits" : "designHeightInSubunits", subunitsDesignSize
, targetDensity, targetScaledDensity, targetDensityDpi, targetXdpi));
}
由此可见autoConvertDensity()方法是核心代码
这里还匹配了pt in mm 为单位的适配
private static void setDensity(DisplayMetrics displayMetrics, float density, int densityDpi, float scaledDensity, float xdpi) {
if (AutoSizeConfig.getInstance().getUnitsManager().isSupportDP()) {
displayMetrics.density = density;
displayMetrics.densityDpi = densityDpi;
}
if (AutoSizeConfig.getInstance().getUnitsManager().isSupportSP()) {
displayMetrics.scaledDensity = scaledDensity;
}
switch (AutoSizeConfig.getInstance().getUnitsManager().getSupportSubunits()) {
case NONE:
break;
case PT:
displayMetrics.xdpi = xdpi * 72f;
break;
case IN:
displayMetrics.xdpi = xdpi;
break;
case MM:
displayMetrics.xdpi = xdpi * 25.4f;
break;
default:
}
}