EditText监听键盘输入

 第一步，先在布局中为EditText设置属性

<EditText
android:singleLine="true"
android:imeOptions="actionDone"/>

第二步：在java代码中监听：

myCourse_roomId_input.setOnEditorActionListener(new TextView.OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        //回车键
        if(actionId == EditorInfo.IME_ACTION_DONE){
            Intent intent = new Intent(getActivity(), TopicInfoActivity.class);
            intent.putExtra(IntentKey.topicId, myCourse_roomId_input.getText().toString());
            startActivity(intent);
        }
        return true;
    }
});

myCourse_roomId_input.addTextChangedListener(new TextWatcher() {
    private CharSequence temp;

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        temp = s;
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {

    }

    @Override
    public void afterTextChanged(Editable s) {
        if (temp.length() > 0) {//限制长度
            myCourse_roomId_clear.setVisibility(View.VISIBLE);
        } else {
            myCourse_roomId_clear.setVisibility(View.GONE);
        }
    }
});