接上文 Flutter PIP 插件 ---- Android

項目地址 PIP， pub.dev也已經同步發布 pip 0.0.3，你的加星和點贊，將是我繼續改進最大的動力

開發文檔 Add videos using picture-in-picture (PiP)介紹PIP功能從 Android 8.0 (API level 26) 引入，但是autoEnter功能從 Android 12 才開始支持，那么不支持的版本呢就需要通過監聽 onUserLeaveHint 主動調用 enterPictureInPictureMode 才能進入 PIP Mode，在之前的版本中因為 FlutterActivity 沒有轉發 onUserLeaveHint，導致我們只能在 dart 中通過 flutter 的 didChangeAppLifecycleState 事件，在應用進入后臺是主動調用的方式進入PIP Mode，但實際測下來，似乎無法區分通知欄下滑的通知，這導致即使應用在前臺，當用戶下滑通知欄的時候依然會自動進入PIP Mode, 這顯然不是我們想要的，優化后的效果如下：

修改PIP插件

• 新增PipActivity

  package org.opentraa.pip;import android.app.PictureInPictureUiState;
  import android.content.res.Configuration;
  import android.os.Build;
  import androidx.annotation.NonNull;
  import androidx.annotation.RequiresApi;
  import io.flutter.embedding.android.FlutterActivity;@RequiresApi(Build.VERSION_CODES.O)
  public class PipActivity extends FlutterActivity {public interface PipActivityListener {void onPictureInPictureModeChanged(boolean isInPictureInPictureMode,Configuration newConfig);void onPictureInPictureUiStateChanged(PictureInPictureUiState state);boolean onPictureInPictureRequested();void onUserLeaveHint();}private PipActivityListener mListener;public void setPipActivityListener(PipActivityListener listener) {mListener = listener;}// only available in API level 26 and above@RequiresApi(26)@Overridepublic void onPictureInPictureModeChanged(boolean isInPictureInPictureMode,Configuration newConfig) {super.onPictureInPictureModeChanged(isInPictureInPictureMode, newConfig);if (mListener != null) {mListener.onPictureInPictureModeChanged(isInPictureInPictureMode,newConfig);}}// only available in API level 30 and above@RequiresApi(30)@Overridepublic boolean onPictureInPictureRequested() {if (mListener != null) {return mListener.onPictureInPictureRequested();}return super.onPictureInPictureRequested();}// only available in API level 31 and above@RequiresApi(31)@Overridepublic voidonPictureInPictureUiStateChanged(@NonNull PictureInPictureUiState state) {super.onPictureInPictureUiStateChanged(state);if (mListener != null) {mListener.onPictureInPictureUiStateChanged(state);}}@Overridepublic void onUserLeaveHint() {super.onUserLeaveHint();if (mListener != null) {mListener.onUserLeaveHint();}}
  }
  

  主要思路就是如果PIP 插件的用戶想要在 Android 12 以下支持應用進入后臺自動進入 PIP Mode 的話，可以將自己 MainActivity 的父類修改為 PipActivity ，這樣在 PIP 插件被注冊時，可以通過判斷傳入的 Activity 是否是 PipActivity 來決定是否啟用相關的功能。

• 綁定 Activity 到 PipController
  PipPlugin 在 onAttachedToActivity 和 onReattachedToActivityForConfigChanges 的時候去初始化 PipController

  private void initPipController(@NonNull ActivityPluginBinding binding) {if (pipController == null) {pipController = new PipController(binding.getActivity(), new PipController.PipStateChangedListener() {@Overridepublic void onPipStateChangedListener(PipController.PipState state) {// put state into a json objectchannel.invokeMethod("stateChanged",new HashMap<String, Object>() {{ put("state", state.getValue()); }});}});} else {pipController.attachToActivity(binding.getActivity());}
  }@Override
  public void onAttachedToActivity(@NonNull ActivityPluginBinding binding) {initPipController(binding);
  }@Override
  public void onReattachedToActivityForConfigChanges(@NonNull ActivityPluginBinding binding) {initPipController(binding);
  }
  

• 在 PipController 構造函數和 attachToActivity 方法中去綜合當前的系統版本和綁定的 Activity 進行檢查是否支持 autoEnter

  public PipController(@NonNull Activity activity,@Nullable PipStateChangedListener listener) {setActivity(activity);//  ... Other code ...
  }private boolean checkAutoEnterSupport() {// Android 12 and above support to set auto enter enabled directlyif (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {return true;}// For android 11 and below, we need to check if the activity is kind of// PipActivity since we can enter pip mode when the onUserLeaveHint is// called to enter pip mode as a workaroundActivity activity = mActivity.get();return activity instanceof PipActivity;
  }private void setActivity(Activity activity) {mActivity = new WeakReference<>(activity);if (activity instanceof PipActivity) {((PipActivity)activity).setPipActivityListener(this);}mIsSupported = checkPipSupport();mIsAutoEnterSupported = checkAutoEnterSupport();
  }public void attachToActivity(@NonNull Activity activity) {setActivity(activity);
  }
  

修改Example項目中的MainActivity

• 孤伶伶的MainActivity

  package org.opentraa.pip_example;import io.flutter.embedding.android.FlutterActivity;
  import org.opentraa.pip.PipActivity;public class MainActivity extends PipActivity {
  }
  

如上，至此我們已經支持了全部版本的 PIP Mode autoEnter 功能。