Android关于Launcher的Activity启动两次的问题调查

忘是亡心i 2021-11-05 15:08 1039阅读 0赞

在开机的时候，发现launcher的Activity启动了两次。

经过开机打印Log发现：  
2019-08-05 16:37:31.891 1754-1800/system\_process W/WindowManager: Force clearing freeze: AppWindowToken\{f258030 token=Token\{59f4973 ActivityRecord\{ad731e2 u0 com.ad.launcher/.LauncherActivity t25\}\}\}

发现Launcher被停止掉了，然后重新启动。

经过调查发现，安卓机制，当Configuration配置发生变化是，Launcher会重新启动。详细参考官网说明：  
[https://developer.android.com/reference/android/content/res/Configuration][https_developer.android.com_reference_android_content_res_Configuration]  
[https://developer.android.com/guide/topics/manifest/activity-element][https_developer.android.com_guide_topics_manifest_activity-element]

根据文档：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bnhpYW9saW4yMDE2_size_16_color_FFFFFF_t_70]  
所以，只要AndroidManifest.xml中的Activity增加属性android:configChanges就可以保持Activity运行，不用重新启动Activity。

那么我的项目中到底哪个Configuration发生了变化呢？

继续查看卡机打印Log，发现：  
2019-08-05 16:37:28.043 1754-1848/system\_process I/ActivityManager: Config changes=8 \{1.0 ?mcc?mnc \[en\_US\] ldltr sw811dp w1442dp h675dp 213dpi lrg long land car night finger -keyb/v/h -nav/h winConfig=\{ mBounds=Rect(0, 0 - 0, 0) mAppBounds=Rect(0, 0 - 1920, 931) mWindowingMode=fullscreen mActivityType=undefined\} s.7\}  
2019-08-05 16:37:28.100 1754-1848/system\_process I/ActivityManager: Override config changes=8 \{1.0 ?mcc?mnc \[en\_US\] ldltr sw811dp w1442dp h675dp 213dpi lrg long land car night finger -keyb/v/h -nav/h winConfig=\{ mBounds=Rect(0, 0 - 1920, 931) mAppBounds=Rect(0, 0 - 1920, 931) mWindowingMode=fullscreen mActivityType=undefined\} s.7\} for displayId=0

Config changes=8，根据官方文档和代码：  
![在这里插入图片描述][20190807123256127.png]

/** * Bit in {@link #configChanges} that indicates that the activity * can itself handle changes to the touchscreen type. Set from the * {@link android.R.attr#configChanges} attribute. */
        public static final int CONFIG_TOUCHSCREEN = 0x0008;

发现发生变化的属性是CONFIG\_TOUCHSCREEN，所以在Activity属性中增加：  
android:configChanges=“screenSize”

监听变化来知道哪个CONFIG发生了变化：

@Override
        public void onConfigurationChanged(Configuration newConfig) { 
            super.onConfigurationChanged(newConfig);
    
            // Checks the orientation of the screen
            if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) { 
                Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
            } else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){ 
                Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
            }
    
            Log.i(TAG,"config" + newConfig);
            Log.i(TAG,"config.fontScale" + newConfig.fontScale);
            Log.i(TAG,"config.colorMode" + newConfig.colorMode);
            Log.i(TAG,"config.densityDpi" + newConfig.densityDpi);
            Log.i(TAG,"config.hardKeyboardHidden" + newConfig.hardKeyboardHidden);
            Log.i(TAG,"config.keyboard" + newConfig.keyboard);
            Log.i(TAG,"config.keyboardHidden" + newConfig.keyboardHidden);
            Log.i(TAG,"config.mcc" + newConfig.mcc);
            Log.i(TAG,"config.mnc" + newConfig.mnc);
            Log.i(TAG,"config.navigation" + newConfig.navigation);
            Log.i(TAG,"config.navigationHidden" + newConfig.navigationHidden);
            Log.i(TAG,"config.orientation" + newConfig.orientation);
            Log.i(TAG,"config.screenHeightDp" + newConfig.screenHeightDp);
            Log.i(TAG,"config.screenLayout" + newConfig.screenLayout);
            Log.i(TAG,"config.uiMode" + newConfig.uiMode);
            Log.i(TAG,"config.touchscreen" + newConfig.touchscreen);
            Log.i(TAG,"config.smallestScreenWidthDp" + newConfig.smallestScreenWidthDp);
            Log.i(TAG,"config.smallestScreenWidthDp" + newConfig.touchscreen);
        }

[https_developer.android.com_reference_android_content_res_Configuration]: https://developer.android.com/reference/android/content/res/Configuration
[https_developer.android.com_guide_topics_manifest_activity-element]: https://developer.android.com/guide/topics/manifest/activity-element
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bnhpYW9saW4yMDE2_size_16_color_FFFFFF_t_70]: /images/20211105/1e068c866b184a9484bea957c94f96de.png
[20190807123256127.png]: /images/20211105/e0e4365f24114d13997946a7f93e7cef.png