【Android】记录一次输入法位置修改思路

输入法是全屏dialog，且不会被dismiss，显示与隐藏系统调用方法为showWindow(true)和hide()，以下是输入法Window创建，SoftInputWindow继承Dialog

mWindow = new SoftInputWindow(this, "InputMethod", mTheme, null, null, mDispatcherState,
                WindowManager.LayoutParams.TYPE_INPUT_METHOD, Gravity.BOTTOM, false);
        mWindow.getWindow().getAttributes().setFitInsetsTypes(statusBars() | navigationBars());
        mWindow.getWindow().getAttributes().setFitInsetsSides(Side.all() & ~Side.BOTTOM);
        mWindow.getWindow().getAttributes().setFitInsetsIgnoringVisibility(true);

至于全屏的依据，可以看SoftInputWindow initDockWindow方法，

看，写入了WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;

这个Flag是将窗口放置在整个屏幕内，忽略父容器的限制，

private void initDockWindow() {

       WindowManager.LayoutParams lp = getWindow().getAttributes();

       lp.type = mWindowType;
       lp.setTitle(mName);

       lp.gravity = mGravity;
       updateWidthHeight(lp);

       getWindow().setAttributes(lp);

       int windowSetFlags = WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;
       int windowModFlags = WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN |
               WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE |
               WindowManager.LayoutParams.FLAG_DIM_BEHIND;

       if (!mTakesFocus) {
           windowSetFlags |= WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
       } else {
           windowSetFlags |= WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL;
           windowModFlags |= WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL;
       }
       getWindow().setFlags(windowSetFlags, windowModFlags);
   }

输入法布局如下：

如果要输入法上移，必须调整dialog中的布局，

在InputMethodService方法中，initView如下，

mWindow.setContentView(mRootView)，关键，

mWindow是SoftInputWindow，继承Dialog，因此这是设置视角；

如何，一些成员的初始化在此进行，如mInputFrame和mCandidatesFrame。在setInputView中回调onCreateView方法，拿到三方输入法自定义的View，

所以显示在我们面前的视野就是mInputFrame；

void initViews() {

       mInitialized = false;
       mViewsCreated = false;
       mShowInputRequested = false;
       mShowInputFlags =

 0;
       mThemeAttrs = obtainStyledAttributes(android.R.styleable.InputMethodService);
       mRootView = mInflater.inflate(
               com.android.internal.R.layout.input_method, null);
       mWindow.setContentView(mRootView);
       mRootView.getViewTreeObserver().removeOnComputeInternalInsetsListener(mInsetsComputer);
       mRootView.getViewTreeObserver().addOnComputeInternalInsetsListener(mInsetsComputer);
       if (Settings.Global.getInt(getContentResolver(),
               Settings.Global.FANCY_IME_ANIMATIONS, 0) != 0) {
           mWindow.getWindow().setWindowAnimations(
                   com.android.internal.R.style.Animation_InputMethodFancy);
       }
       mFullscreenArea = mRootView.findViewById(com.android.internal.R.id.fullscreenArea);
       mExtractViewHidden = false;
       mExtractFrame = mRootView.findViewById(android.R.id.extractArea);
       mExtractView = null;
       mExtractEditText = null;
       mExtractAccessories = null;
       mExtractAction = null;
       mFullscreenApplied = false;
       mCandidatesFrame = mRootView.findViewById(android.R.id.candidatesArea);
       mInputFrame = mRootView.findViewById(android.R.id.inputArea);
       mInputView = null;
       mIsInputViewShown = false;
       mExtractFrame.setVisibility(View.GONE);
       mCandidatesVisibility = getCandidatesHiddenVisibility();
       mCandidatesFrame.setVisibility(mCandidatesVisibility);
       mInputFrame.setVisibility(View.GONE);
   }

因为要上移输入法，尝试对window的attribute参数下手，失败告终，因为设置y参数无效，由于service的onCreate方法new SoftInputWindow时，传入Gravity和Bottom，输入法就默认显示底部？调试时改为Top，依然显示在底部，比较费解。

那么尝试上移mInputFrame，

怎么移？mInputFrame本身是Framelayout，而且位置在android资源文件中写死了，通过代码动态移动？

想过WindowManager的updateLayout，可是布局参数呢？

一般三方自定义输入法时，需要继承InputMethodService类，这是个标准，

重写其中onCreateVIew方法，也就传入自定义输入法布局，系统通过如下方法回调，

public void updateInputViewShown() {
       boolean isShown = mShowInputRequested && onEvaluateInputViewShown();
       if (mIsInputViewShown != isShown && mDecorViewVisible) {
           mIsInputViewShown = isShown;
           mInputFrame.setVisibility(isShown ? View.VISIBLE : View.GONE);
           if (mInputView == null) {
               initialize();
               View v = onCreateInputView();
               if (v != null) {
                   setInputView(v);
               }
           }
       }
   }

之后，通过setInputView方法设置显示在用户面前的视野，可以看到，视野添加到mInputFrame中，对于另外一个方法setCandidatesView，就是候选视图，暂不多说。

public void setInputView(View view) {
       mInputFrame.removeAllViews();
       mInputFrame.addView(view, new FrameLayout.LayoutParams(
               ViewGroup.LayoutParams.MATCH_PARENT,
               ViewGroup.LayoutParams.WRAP_CONTENT));
       mInputView = view;
   }

所以我们要挪动输入法，可以在这里做文章，即添加一点参数，让mInputView上移一点，

FrameLayout.LayoutParams提供了bottomMargin参数，即让咱们的mInputView相对bottom移动一点距离。

-------------------------------------------------------------------------------------------------------------------------

接下来，分析下输入法调用栈，

首先，窗口获得焦距后，才会调用输入法，这是起点，位于ViewRootImpl.handleWindowFocusChanged方法，

跟进其中，

// Note: must be done after the focus change callbacks,
            // so all of the view state is set up correctly.
            mImeFocusController.onPostWindowFocus(mView.findFocus(), hasWindowFocus,
                    mWindowAttributes);

跟进，

immDelegate.startInputAsyncOnWindowFocusGain(viewForWindowFocus,
                windowAttribute.softInputMode, windowAttribute.flags, forceFocus);

跟进，

                    mService.startInputOrWindowGainedFocus(
                            startInputReason, mClient,
                            focusedView.getWindowToken(), startInputFlags, softInputMode,
                            windowFlags,
                            null,
                            null,
                            0 /* missingMethodFlags */,
                            mCurRootView.mContext.getApplicationInfo().targetSdkVersion);

跟进，

 result = startInputOrWindowGainedFocusInternalLocked(startInputReason, client,
                        windowToken, startInputFlags, softInputMode, windowFlags, attribute,
                        inputContext, missingMethods, unverifiedTargetSdkVersion, userId);

跟进，

showCurrentInputLocked(windowToken, InputMethodManager.SHOW_IMPLICIT, null,
                            SoftInputShowHideReason.SHOW_AUTO_EDITOR_FORWARD_NAV);

发Message到IInputMethodWrapper，

case DO_SHOW_SOFT_INPUT: {
                final SomeArgs args = (SomeArgs)msg.obj;
                inputMethod.showSoftInputWithToken(
                        msg.arg1, (ResultReceiver) args.arg2, (IBinder) args.arg1);
                args.recycle();
                return;
            }

跟进，

public void showSoftInputWithToken(int flags, ResultReceiver resultReceiver,
                IBinder showInputToken) {
            mSystemCallingShowSoftInput = true;
            mCurShowInputToken = showInputToken;
            showSoftInput(flags, resultReceiver);
            mCurShowInputToken = null;
            mSystemCallingShowSoftInput = false;
        }

跟进showSoftInput，

 try {
                        showWindow(true);
                    } catch (BadTokenException e) {

跟进showWinodw，

先准备InputVIew，也就是在onCreateInputVIew中返回的View

startViews(prepareWindow(showInput));

跟进prepareWindow，

private boolean prepareWindow(boolean showInput) {
        boolean doShowInput = false;
        mDecorViewVisible = true;
        if (!mShowInputRequested && mInputStarted && showInput) {
            doShowInput = true;
            mShowInputRequested = true;
        }

        if (DEBUG) Log.v(TAG, "showWindow: updating UI");
        initialize();
        updateFullscreenMode();
        updateInputViewShown();

        if (!mViewsCreated) {
            mViewsCreated = true;
            initialize();
            if (DEBUG) Log.v(TAG, "CALL: onCreateCandidatesView");
            View v = onCreateCandidatesView();
            if (DEBUG) Log.v(TAG, "showWindow: candidates=" + v);
            if (v != null) {
                setCandidatesView(v);
            }
        }
        return doShowInput;
    }

跟进updateInputViewShow，

 public void updateInputViewShown() {
        boolean isShown = mShowInputRequested && onEvaluateInputViewShown();
        if (mIsInputViewShown != isShown && mDecorViewVisible) {
            mIsInputViewShown = isShown;
            mInputFrame.setVisibility(isShown ? View.VISIBLE : View.GONE);
            if (mInputView == null) {
                initialize();
                View v = onCreateInputView();
                if (v != null) {
                    setInputView(v);
                }
            }
        }
    }
    

ok，这里回调了onCreateInputVIew，接下来就是dialog的show过程，不在此赘述；