Android7.0&8.0 Power Menu 添加截屏选项

首先介绍下这个Power长按，显示Power Menu的流程，然后再介绍如何去添加一个新的选项，新的选项的功能是截屏。

Power Menu长按的流程：
1.长按Power的处理在frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java

    private void powerLongPress() {
        final int behavior = getResolvedLongPressOnPowerBehavior();
        switch (behavior) {
        case LONG_PRESS_POWER_NOTHING:
            break;
        case LONG_PRESS_POWER_GLOBAL_ACTIONS:
            mPowerKeyHandled = true;
            if (!performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false)) {
                performAuditoryFeedbackForAccessibilityIfNeed();
            }
            showGlobalActionsInternal();
            break;
        case LONG_PRESS_POWER_SHUT_OFF:
        case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM:
            mPowerKeyHandled = true;
            performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
            sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
            mWindowManagerFuncs.shutdown(behavior == LONG_PRESS_POWER_SHUT_OFF);
            break;
        }
    }

2.下面会走到showGlobalActionsInternal()

    void showGlobalActionsInternal() {
        sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
        if (mGlobalActions == null) {
            mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);
        }
        final boolean keyguardShowing = isKeyguardShowingAndNotOccluded();
        mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned());
        if (keyguardShowing) {
            // since it took two seconds of long press to bring this up,
            // poke the wake lock so they have some time to see the dialog.
            mPowerManager.userActivity(SystemClock.uptimeMillis(), false);
        }
    }

3.showGlobalActionsInternal会去新建一个GlobalActions，然后去显示Menu这个对话框。对话框显示是在frameworks/base/services/core/core/java/com/android/server/policy/GlobalActions.java中的

    /**
     * Show the global actions dialog (creating if necessary)
     * @param keyguardShowing True if keyguard is showing
     */
    public void showDialog(boolean keyguardShowing, boolean isDeviceProvisioned) {
        mKeyguardShowing = keyguardShowing;
        mDeviceProvisioned = isDeviceProvisioned;
        if (mDialog != null) {
            mDialog.dismiss();
            mDialog = null;
            // Show delayed, so that the dismiss of the previous dialog completes
            mHandler.sendEmptyMessage(MESSAGE_SHOW);
        } else {
            handleShow();
        }
    }

4.然后会走handleShow()，handleShow()会去创建一个对话框。

    private void handleShow() {
        awakenIfNecessary();
        mDialog = createDialog();
        prepareDialog();

        // If we only have 1 item and it's a simple press action, just do this action.
        if (mAdapter.getCount() == 1
                && mAdapter.getItem(0) instanceof SinglePressAction
                && !(mAdapter.getItem(0) instanceof LongPressAction)) {
            ((SinglePressAction) mAdapter.getItem(0)).onPress();
        } else {
            WindowManager.LayoutParams attrs = mDialog.getWindow().getAttributes();
            attrs.setTitle("GlobalActions");
            mDialog.getWindow().setAttributes(attrs);
            mDialog.show();
            mDialog.getWindow().getDecorView().setSystemUiVisibility(View.STATUS_BAR_DISABLE_EXPAND);
        }
    }

5.最后就是这个createDialog()，它会去创建Power Menu对话框，对于添加新的选项，修改选项执行的内容等都可以在这做修改。

    /**
     * Create the global actions dialog.
     * @return A new dialog.
     */
    private GlobalActionsDialog createDialog() {
        // Simple toggle style if there's no vibrator, otherwise use a tri-state
        if (!mHasVibrator) {
            mSilentModeAction = new SilentModeToggleAction();
        } else {
            mSilentModeAction = new SilentModeTriStateAction(mContext, mAudioManager, mHandler);
        }
        mAirplaneModeOn = new ToggleAction(
                R.drawable.ic_lock_airplane_mode,
                R.drawable.ic_lock_airplane_mode_off,
                R.string.global_actions_toggle_airplane_mode,
                R.string.global_actions_airplane_mode_on_status,
                R.string.global_actions_airplane_mode_off_status) {

            void onToggle(boolean on) {
                if (mHasTelephony && Boolean.parseBoolean(
                        SystemProperties.get(TelephonyProperties.PROPERTY_INECM_MODE))) {
                    mIsWaitingForEcmExit = true;
                    // Launch ECM exit dialog
                    Intent ecmDialogIntent =
                            new Intent(TelephonyIntents.ACTION_SHOW_NOTICE_ECM_BLOCK_OTHERS, null);
                    ecmDialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                    mContext.startActivity(ecmDialogIntent);
                } else {
                    changeAirplaneModeSystemSetting(on);
                }
            }

            @Override
            protected void changeStateFromPress(boolean buttonOn) {
                if (!mHasTelephony) return;

                // In ECM mode airplane state cannot be changed
                if (!(Boolean.parseBoolean(
                        SystemProperties.get(TelephonyProperties.PROPERTY_INECM_MODE)))) {
                    mState = buttonOn ? State.TurningOn : State.TurningOff;
                    mAirplaneState = mState;
                }
            }

            public boolean showDuringKeyguard() {
                return true;
            }

            public boolean showBeforeProvisioning() {
                return false;
            }
        };
        onAirplaneModeChanged();

        mItems = new ArrayList();
        String[] defaultActions = mContext.getResources().getStringArray(
                com.android.internal.R.array.config_globalActionsList);

        ArraySet addedKeys = new ArraySet();
        for (int i = 0; i < defaultActions.length; i++) {
            String actionKey = defaultActions[i];
            if (addedKeys.contains(actionKey)) {
                // If we already have added this, don't add it again.
                continue;
            }
            if (GLOBAL_ACTION_KEY_POWER.equals(actionKey)) {
                mItems.add(new PowerAction());
            } else if (GLOBAL_ACTION_KEY_AIRPLANE.equals(actionKey)) {
                mItems.add(mAirplaneModeOn);
            } else if (GLOBAL_ACTION_KEY_BUGREPORT.equals(actionKey)) {
                if (Settings.Global.getInt(mContext.getContentResolver(),
                        Settings.Global.BUGREPORT_IN_POWER_MENU, 0) != 0 && isCurrentUserOwner()) {
                    mItems.add(new BugReportAction());
                }
            } else if (GLOBAL_ACTION_KEY_SILENT.equals(actionKey)) {
                if (mShowSilentToggle) {
                    mItems.add(mSilentModeAction);
                }
            } else if (GLOBAL_ACTION_KEY_USERS.equals(actionKey)) {
                if (SystemProperties.getBoolean("fw.power_user_switcher", false)) {
                    addUsersToMenu(mItems);
                }
            } else if (GLOBAL_ACTION_KEY_SETTINGS.equals(actionKey)) {
                mItems.add(getSettingsAction());
            } else if (GLOBAL_ACTION_KEY_LOCKDOWN.equals(actionKey)) {
                mItems.add(getLockdownAction());
            } else if (GLOBAL_ACTION_KEY_VOICEASSIST.equals(actionKey)) {
                mItems.add(getVoiceAssistAction());
            } else if (GLOBAL_ACTION_KEY_ASSIST.equals(actionKey)) {
                mItems.add(getAssistAction());
            } else if (GLOBAL_ACTION_KEY_RESTART.equals(actionKey)) {
                mItems.add(new RestartAction());
            } else if(GLOBAL_ACTION_KEY_SCREENSHOT.equals(actionKey)) {
                mItems.add(new ScreenshotAction());
            }
            else {
                Log.e(TAG, "Invalid global action key " + actionKey);
            }
            // Add here so we don't add more than one.
            addedKeys.add(actionKey);
        }

        if (mEmergencyAffordanceManager.needsEmergencyAffordance()) {
            mItems.add(getEmergencyAction());
        }

        mAdapter = new MyAdapter();

        AlertParams params = new AlertParams(mContext);
        params.mAdapter = mAdapter;
        params.mOnClickListener = this;
        params.mForceInverseBackground = true;

        GlobalActionsDialog dialog = new GlobalActionsDialog(mContext, params);
        dialog.setCanceledOnTouchOutside(false); // Handled by the custom class.

        dialog.getListView().setItemsCanFocus(true);
        dialog.getListView().setLongClickable(true);
        dialog.getListView().setOnItemLongClickListener(
                new AdapterView.OnItemLongClickListener() {
                    @Override
                    public boolean onItemLongClick(AdapterView parent, View view, int position,
                            long id) {
                        final Action action = mAdapter.getItem(position);
                        if (action instanceof LongPressAction) {
                            return ((LongPressAction) action).onLongPress();
                        }
                        return false;
                    }
        });
        dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);

        dialog.setOnDismissListener(this);

        return dialog;
    }

---

1.在Power Menu添加新的选项
在frameworks/base/core/res/res/values/config.xml，中添加新的选项。注意：如果这里添加了，最终没有出现，可能被overlay了，搜索config_globalActionsList找到真正的地方再修改。

    -- Defines the default set of global actions. Actions may still be disabled or hidden based
         on the current state of the device.
         Each item must be one of the following strings:
         "power" = Power off
         "settings" = An action to launch settings
         "airplane" = Airplane mode toggle
         "bugreport" = Take bug report, if available
         "silent" = silent mode
         "users" = list of users
         "restart" = restart device
         -->
    <string-array translatable="false" name="config_globalActionsList">
        <item>poweritem>
        <item>restartitem>
        <item>screenshotitem>
        <item>bugreportitem>
        <item>usersitem>
    string-array>

frameworks/base/services/core/core/java/com/android/server/policy/GlobalActions.java 添加声明，字符串要和config中的一直。

    //Aaron@20170712 F0020
    private static final String GLOBAL_ACTION_KEY_SCREENSHOT = "screenshot"; 

然后加载这个item

        for (int i = 0; i < defaultActions.length; i++) {
            String actionKey = defaultActions[i];
            if (addedKeys.contains(actionKey)) {
                // If we already have added this, don't add it again.
                continue;
            }
            if (GLOBAL_ACTION_KEY_POWER.equals(actionKey)) {
                mItems.add(new PowerAction());
            } else if (GLOBAL_ACTION_KEY_AIRPLANE.equals(actionKey)) {
                mItems.add(mAirplaneModeOn);
            } else if (GLOBAL_ACTION_KEY_BUGREPORT.equals(actionKey)) {
                if (Settings.Global.getInt(mContext.getContentResolver(),
                        Settings.Global.BUGREPORT_IN_POWER_MENU, 0) != 0 && isCurrentUserOwner()) {
                    mItems.add(new BugReportAction());
                }
            } else if (GLOBAL_ACTION_KEY_SILENT.equals(actionKey)) {
                if (mShowSilentToggle) {
                    mItems.add(mSilentModeAction);
                }
            } else if (GLOBAL_ACTION_KEY_USERS.equals(actionKey)) {
                if (SystemProperties.getBoolean("fw.power_user_switcher", false)) {
                    addUsersToMenu(mItems);
                }
            } else if (GLOBAL_ACTION_KEY_SETTINGS.equals(actionKey)) {
                mItems.add(getSettingsAction());
            } else if (GLOBAL_ACTION_KEY_LOCKDOWN.equals(actionKey)) {
                mItems.add(getLockdownAction());
            } else if (GLOBAL_ACTION_KEY_VOICEASSIST.equals(actionKey)) {
                mItems.add(getVoiceAssistAction());
            } else if (GLOBAL_ACTION_KEY_ASSIST.equals(actionKey)) {
                mItems.add(getAssistAction());
            } else if (GLOBAL_ACTION_KEY_RESTART.equals(actionKey)) {
                mItems.add(new RestartAction());
            } else if(GLOBAL_ACTION_KEY_SCREENSHOT.equals(actionKey)) {
                mItems.add(new ScreenshotAction());
            }
            else {
                Log.e(TAG, "Invalid global action key " + actionKey);
            }
            // Add here so we don't add more than one.
            addedKeys.add(actionKey);
        }

下面要定义ScreenshotAction类，可以按照RestartAction写。

    // Aaron@20170712 F0020
    private final class ScreenshotAction extends SinglePressAction implements LongPressAction {
        private ScreenshotAction() {
            super(R.drawable.ic_restart, R.string.global_action_screenshot);
        }

        @Override
        public boolean onLongPress() {
            return true;
        }

        @Override
        public boolean showDuringKeyguard() {
            return true;
        }

        @Override
        public boolean showBeforeProvisioning() {
            return true;
        }

        @Override
        public void onPress() {
            //实现截屏功能，后面会讲解
            mPolicy.Screenshot();
        }
    }
    // end

注意：添加完字符串global_action_screenshot，如果编译失败，记得在frameworks/base/core/res/res/values/symbols.xml中声明一下。

  type="string" name="global_action_power_off" />
  type="string" name="global_action_restart" />
  type="string" name="global_action_screenshot" />

到这里，长按power后就会出来我们添加的screenshot选项。

2.实现截屏功能
这个Screenshot()是我自己写的，定义在PhoneWindowManager.java中，因为那里已经有实现截屏的功能，就是组合键截屏。Power+VolumeDown

mPolicy.Screenshot();

frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java 在这里添加我们的截屏功能，因为PhoneWindowManager.java已经有实现了截屏功能，所以直接拿过来用就行。

    //Aaron@20170712 F0020
    public void Screenshot() {
        mScreenshotRunnable.setScreenshotType(TAKE_SCREENSHOT_FULLSCREEN);
        mHandler.post(mScreenshotRunnable);
    }
    //end

在创建GlobalActions的时候记得把PhoneWindowManager对象传过去，因为GlobalActions那里要调用PhoneWindowManager中的截屏方法。在GlobalActions那再定义一个构造函数，多个PhoneWindowManager参数，这样也不影响其他地方使用GlobalActions。

void showGlobalActionsInternal() {
        sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
        if (mGlobalActions == null) {
            //Aaron@20170712 F0020
            mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs,this);
            //mGlobalActions = new GlobalActions(mContext, mWindowManagerFuncs);
        }
        final boolean keyguardShowing = isKeyguardShowingAndNotOccluded();
        mGlobalActions.showDialog(keyguardShowing, isDeviceProvisioned());
        if (keyguardShowing) {
            // since it took two seconds of long press to bring this up,
            // poke the wake lock so they have some time to see the dialog.
            mPowerManager.userActivity(SystemClock.uptimeMillis(), false);
        }
    }