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) {
mCursorSe