Android Framework系列之IMF（三）

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我们知道当一个编辑框获得焦点的时候，将会create一个新的IME客户端，那么IMF框架是怎样处理这个事件的呢？

 

首先调用EditText的构造函数EditTex->TextView->setText()           

 InputMethodManager imm = InputMethodManager.peekInstance();
 if (imm != null) imm.restartInput(this);

 

->startInputInner

 

    void startInputInner() {
        final View view;
        synchronized (mH) {
            view = mServedView;
            
            // Make sure we have a window token for the served view.
            if (DEBUG) Log.v(TAG, "Starting input: view=" + view);
            if (view == null) {
                if (DEBUG) Log.v(TAG, "ABORT input: no served view!");
                return;
            }
        }
        
        // Now we need to get an input connection from the served view.
        // This is complicated in a couple ways: we can't be holding our lock
        // when calling out to the view, and we need to make sure we call into
        // the view on the same thread that is driving its view hierarchy.
        Handler vh = view.getHandler();
        if (vh == null) {
            // If the view doesn't have a handler, something has changed out
            // from under us, so just bail.
            if (DEBUG) Log.v(TAG, "ABORT input: no handler for view!");
            return;
        }
        if (vh.getLooper() != Looper.myLooper()) {
            // The view is running on a different thread than our own, so
            // we need to reschedule our work for over there.
            if (DEBUG) Log.v(TAG, "Starting input: reschedule to view thread");
            vh.post(new Runnable() {
                public void run() {
                    startInputInner();
                }
            });
            return;
        }
        
        // Okay we are now ready to call into the served view and have it
        // do its stuff.
        // Life is good: let's hook everything up!
        EditorInfo tba = new EditorInfo();
        tba.packageName = view.getContext().getPackageName();
        tba.fieldId = view.getId();
        InputConnection ic = view.onCreateInputConnection(tba); //create 新的InputConnection 
        if (DEBUG) Log.v(TAG, "Starting input: tba=" + tba + " ic=" + ic);
        
        synchronized (mH) {
            // Now that we are locked again, validate that our state hasn't
            // changed.
            if (mServedView != view || !mServedConnecting) {
                // Something else happened, so abort.
                if (DEBUG) Log.v(TAG, 
                        "Starting input: finished by someone else (view="
                        + mServedView + " conn=" + mServedConnecting + ")");
                return;
            }
            
            // If we already have a text box, then this view is already
            // connected so we want to restart it.
            final boolean initial = mCurrentTextBoxAttribute == null;
            
            // Hook 'em up and let 'er rip.
            mCurrentTextBoxAttribute = tba;
            mServedConnecting = false;
            mServedInputConnection = ic;
            IInputContext servedContext;
            if (ic != null) {
                mCursorSelStart = tba.initialSelStart;
                mCursorSelEnd = tba.initialSelEnd;
                mCursorCandStart = -1;
                mCursorCandEnd = -1;
                mCursorRect.setEmpty();
                servedContext = new ControlledInputConnectionWrapper(vh.getLooper(), ic);
            } else {
                servedContext = null;
            }
            
            try {
                if (DEBUG) Log.v(TAG, "START INPUT: " + view + " ic="
                        + ic + " tba=" + tba + " initial=" + initial);
                InputBindResult res = mService.startInput(mClient,
                        servedContext, tba, initial, mCurMethod == null); //启动IMEservice
                if (DEBUG) Log.v(TAG, "Starting input: Bind result=" + res);
                if (res != null) {
                    if (res.id != null) {
                        mBindSequence = res.sequence;
                        mCurMethod = res.method;
                    } else {
                        // This means there is no input method available.
                        if (DEBUG) Log.v(TAG, "ABORT input: no input method!");
                        return;
                    }
                }
                if (mCurMethod != null && mCompletions != null) {
                    try {
                        mCurMethod.displayCompletions(mCompletions);
                    } catch (RemoteException e) {
                    }
                }
            } catch (RemoteException e) {
                Log.w(TAG, "IME died: " + mCurId, e);
            }
        }
    

 那么到了IME部分的流程又是如何的呢？

首先收到configure change的event调用onConfigurationChanged->inputmethodservice.onConfigurationChanged(conf)

 @Override public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        
        boolean visible = mWindowVisible;
        int showFlags = mShowInputFlags;
        boolean showingInput = mShowInputRequested;
        CompletionInfo[] completions = mCurCompletions;
        initViews();
        mInputViewStarted = false;
        mCandidatesViewStarted = false;
        if (mInputStarted) {
            doStartInput(getCurrentInputConnection(),
                    getCurrentInputEditorInfo(), true);  //调用startinput，创建IME的input
        }
        if (visible) {
            if (showingInput) {
                // If we were last showing the soft keyboard, try to do so again.
                if (onShowInputRequested(showFlags, true)) {
                    showWindow(true);
                    if (completions != null) {
                        mCurCompletions = completions;
                        onDisplayCompletions(completions);
                    }
                } else {
                    hideWindow();
                }
            } else if (mCandidatesVisibility == View.VISIBLE) {
                // If the candidates are currently visible, make sure the
                // window is shown for them.
                showWindow(false);
            } else {
                // Otherwise hide the window.
                hideWindow();
            }
        }
    }

 doStartInput->initialize->onInitializeInterface->onStartInput->onStartInputView.

onStartInputView中会handle各种IME的event并进一步调用IME自身的onCreate函数，做进一步的初始化以及receiver的rigister。