Android关于EditText的坑[光标,软键盘]

在项目中经常的一个需求是监听用户输入的内容变化，然后做响应。

1.首先的想到的一个监听回调肯定是

addTextChangedListener（）该方法可以监听到EditText中的所有的文字的变化，只要调用setText或者用户输入就响应。

2.肯定是setOnFocusChangeListener（）该方法可以监听当前控件的焦点变化

如何自如地控制着两者呢，用到一个标记，以及两个方法，具体代码如下：

mSearchEt.requestFocus();
//监听输入文字变化请求后台
mSearchEt.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        if (mIsEtFocused) {
            //当文字内容变化就请求后台
            if (s.length() > 0) {
                mKeyword = s.toString();
                startLoading();
                //请求联想搜索
                mNovelPresenter.novelSearchImagine(mKeyword);
                mNovelSearchImagineAdapter.setSearchText(mKeyword);
                mClearInputIb.setVisibility(View.VISIBLE);
                mSearchIv.setVisibility(View.GONE);
            } else {
                hideLoading();
                mSearchResultRl.setVisibility(View.VISIBLE);
                mSearchResultNoBookRl.setVisibility(View.GONE);
                mSearchIv.setVisibility(View.VISIBLE);
                mClearInputIb.setVisibility(View.GONE);
                mNovelSearchImagineBeanList.clear();
                mSearchHistoryLl.setVisibility(View.VISIBLE);
                mRecyclerView.setVisibility(View.GONE);
            }
        }
    }

    @Override
    public void afterTextChanged(Editable s) {

    }
});

/**
 * 监听当前是否有焦点
 */
mSearchEt.setOnFocusChangeListener(new View.OnFocusChangeListener() {
    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus) {
            mIsEtFocused = true;
        } else {
            mIsEtFocused = false;
        }
    }
});

mSearchEt.clearFocus();

上面这个方法是重点，查看源码发现并不是单纯得清空当前的焦点，而是清空并重新置位当前界面的第一个控件。

/**
 * Called when this view wants to give up focus. If focus is cleared
 * {@link #onFocusChanged(boolean, int, android.graphics.Rect)} is called.
 * <p>
 * <strong>Note:</strong> When a View clears focus the framework is trying
 * to give focus to the first focusable View from the top. Hence, if this
 * View is the first from the top that can take focus, then all callbacks
 * related to clearing focus will be invoked after which the framework will
 * give focus to this view.
 * </p>
 */
public void clearFocus() {
    if (DBG) {
        System.out.println(this + " clearFocus()");
    }

    clearFocusInternal(null, true, true);
}

此处的技巧是设置当前的EditText的直接父容器可以获取焦点，代码如下：

Android关于EditText的坑[光标,软键盘]

用这两个结合就可以轻松处理焦点以及内容变化并作出响应。

还有软键盘的控制：

mInputManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);

//隐藏软键盘
mInputManager.hideSoftInputFromWindow(mSearchEt.getWindowToken(), 0);

<activity
    android:name=".novel.view.activity.NovelSearchActivity"
    android:screenOrientation="portrait"
    android:windowSoftInputMode="stateVisible|adjustPan"/>