经常听到大家讨论类似的需求，怀疑大厂是不是用了此方案，据我个人了解，多数头部 app 其实都是发版来更新节假日的 icon。当然本方案也是一种可选的方案，以前我也调研过，存在问题和作者所述差不多，此外原文链接作者也回复了很多疑问，可以同时了解。

效果图

产品需求

市面上很多App能根据特定活动，动态切换应用图标达到宣传目的，例如淘宝双十一，国庆节等等。那么我们怎样才能在不发新版本的情况下，动态切换应用图标呢？

具体方案

1.图标更换：在AndroidManifest设置应用入口Activity的别名，然后通过setComponentEnabledSetting动态启用或禁用别名进行图标切换。

2.控制图标显示：冷启动App时，调用接口判断是否需要切换icon。

3.触发时机：监听App前后台切换，当App处于后台时切换图标，使得用户无感知。

代码实现

在AndroidManifest.xml中给入口Activity设置activity-alias

<applicationandroid:name=".MyApplication"android:allowBackup="true"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:supportsRtl="true"android:theme="@style/Theme.SwitchIcon"><!-- 原MainActivity --><activity android:name=".MainActivity" /><!-- 固定设置一个默认的别名，用来替代原MainActivity --><activity-aliasandroid:name=".DefaultAliasActivity"android:enabled="true"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:targetActivity=".MainActivity"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity-alias><!-- 别名1，特定活动需要的图标如：双11，国庆节等 --><activity-aliasandroid:name=".Alias1Activity"android:enabled="false"android:icon="@mipmap/ic_launcher_show"android:label="@string/app_name"android:targetActivity=".MainActivity"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity-alias></application>

activity-alias标签中的属性如下：

在MainActivity中，通过启用或禁用别名进行图标切换

/*** 设置默认的别名为启动入口*/
public void setDefaultAlias() {PackageManager packageManager = getPackageManager();ComponentName name1 = new ComponentName(this, "com.fengfeibiao.switchicon.DefaultAliasActivity");packageManager.setComponentEnabledSetting(name1, PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP);ComponentName name2 = new ComponentName(this, "com.fengfeibiao.switchicon.Alias1Activity");packageManager.setComponentEnabledSetting(name2, PackageManager.COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);}/*** 设置别名1为启动入口*/
public void setAlias1() {PackageManager packageManager = getPackageManager();ComponentName name1 = new ComponentName(this, "com.fengfeibiao.switchicon.DefaultAliasActivity");packageManager.setComponentEnabledSetting(name1, PackageManager.COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);ComponentName name2 = new ComponentName(this, "com.fengfeibiao.switchicon.Alias1Activity");packageManager.setComponentEnabledSetting(name2, PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP);
}

ForegroundCallbacks监听App前后台切换

/*** 监听App前后台切换*/
public class ForegroundCallbacks implements Application.ActivityLifecycleCallbacks {public static final long CHECK_DELAY = 500;public static final String TAG = ForegroundCallbacks.class.getName();public interface Listener {void onForeground();void onBackground();}private static ForegroundCallbacks instance;private boolean foreground = false, paused = true;private Handler handler = new Handler();private List<Listener> listeners = new CopyOnWriteArrayList<Listener>();private Runnable check;public static ForegroundCallbacks init(Application application) {if (instance == null) {instance = new ForegroundCallbacks();application.registerActivityLifecycleCallbacks(instance);}return instance;}public static ForegroundCallbacks get(Application application) {if (instance == null) {init(application);}return instance;}public static ForegroundCallbacks get(Context ctx) {if (instance == null) {Context appCtx = ctx.getApplicationContext();if (appCtx instanceof Application) {init((Application) appCtx);}throw new IllegalStateException("Foreground is not initialised and " +"cannot obtain the Application object");}return instance;}public static ForegroundCallbacks get() {if (instance == null) {throw new IllegalStateException("Foreground is not initialised - invoke " +"at least once with parameterised init/get");}return instance;}public boolean isForeground() {return foreground;}public boolean isBackground() {return !foreground;}public void addListener(Listener listener) {listeners.add(listener);}public void removeListener(Listener listener) {listeners.remove(listener);}@Overridepublic void onActivityResumed(Activity activity) {paused = false;boolean wasBackground = !foreground;foreground = true;if (check != null)handler.removeCallbacks(check);if (wasBackground) {Log.d(TAG, "went foreground");for (Listener l : listeners) {try {l.onForeground();} catch (Exception exc) {Log.d(TAG, "Listener threw exception!:" + exc.toString());}}} else {Log.d(TAG, "still foreground");}}@Overridepublic void onActivityPaused(Activity activity) {paused = true;if (check != null)handler.removeCallbacks(check);handler.postDelayed(check = new Runnable() {@Overridepublic void run() {if (foreground && paused) {foreground = false;Log.d(TAG, "went background");for (Listener l : listeners) {try {l.onBackground();} catch (Exception exc) {Log.d(TAG, "Listener threw exception!:" + exc.toString());}}} else {Log.d(TAG, "still foreground");}}}, CHECK_DELAY);}@Overridepublic void onActivityCreated(Activity activity, Bundle savedInstanceState) {}@Overridepublic void onActivityStarted(Activity activity) {}@Overridepublic void onActivityStopped(Activity activity) {}@Overridepublic void onActivitySaveInstanceState(Activity activity, Bundle outState) {}@Overridepublic void onActivityDestroyed(Activity activity) {}
}

需要在Application中调用ForegroundCallbacks.init(this)进行初始化。

在MainActivity中实现ForegroundCallbacks.Listener对App进行监听，当处于后台判断是否切换应用图标

完整的MainActivity代码：

public class MainActivity extends AppCompatActivity implements ForegroundCallbacks.Listener {private int position = 0;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//添加app前后台监听ForegroundCallbacks.get(this).addListener(this);findViewById(R.id.tv_default).setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {position = 0;}});findViewById(R.id.tv_alias1).setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {position = 1;}});}@Overrideprotected void onDestroy() {// 移除app前后台监听ForegroundCallbacks.get(this).removeListener(this);super.onDestroy();}@Overridepublic void onForeground() {}@Overridepublic void onBackground() {//根据具体业务需求设置切换条件,我公司采用接口控制icon切换if (position == 0) {setDefaultAlias();} else {setAlias1();}}/*** 设置默认的别名为启动入口*/public void setDefaultAlias() {PackageManager packageManager = getPackageManager();ComponentName name1 = new ComponentName(this, "com.fengfeibiao.switchicon.DefaultAliasActivity");packageManager.setComponentEnabledSetting(name1, PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP);ComponentName name2 = new ComponentName(this, "com.fengfeibiao.switchicon.Alias1Activity");packageManager.setComponentEnabledSetting(name2, PackageManager.COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);}/*** 设置别名1为启动入口*/public void setAlias1() {PackageManager packageManager = getPackageManager();ComponentName name1 = new ComponentName(this, "com.fengfeibiao.switchicon.DefaultAliasActivity");packageManager.setComponentEnabledSetting(name1, PackageManager.COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);ComponentName name2 = new ComponentName(this, "com.fengfeibiao.switchicon.Alias1Activity");packageManager.setComponentEnabledSetting(name2, PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP);}
}

具体缺陷

具体缺陷如下：

1. 切换icon会关闭应用进程，不是崩溃所以不会上报bugly。

2. 切换icon需要时间，部分华为机型要10s左右，之后能正常打开。

3. 切换icon过程中，部分机型点击图标无法打开应用，提示应用未安装。

Demo的github地址

https://github.com/FengFeiBiao/SwitchIcon