Android EditText获取光标位置并插入字符删除字符

1.获取光标位置
int index = editText.getSelectionStart();
2.在光标处插入字符

    int index = editText.getSelectionStart();
    Editable editable = editText.getText();
    editable.insert(index, "aaaa");

3.删除光标前字符

    int index = editText.getSelectionStart();
    Editable editable = editText.getText();
    editable.delete(index-1, index);