setText() 和 append() 的区别

我对 setText() 和 append() 产生的差异很好奇.我正在编写一个带有行号的非常基本的编辑器.我有一个 TextView 在左边保存行号，在右边有一个 EditText 来保存数据.这是 XML:

I'm curious about the difference setText() and append() are creating. I'm writing a very basic editor with line numbers. I have a TextView to hold line numbers on the left, paired with an EditText on the right to hold the data. Here's the XML:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:gravity="top">
    <TextView
        android:id="@+id/line_numbers"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginRight="0dip"
        android:gravity="top"
        android:textSize="14sp"
        android:textColor="#000000"
        android:typeface="monospace"
        android:paddingLeft="0dp"/>
    <EditText
        android:id="@+id/editor"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:inputType="text|textMultiLine|textNoSuggestions"
        android:imeOptions="actionNone"
        android:gravity="top"
        android:textSize="14sp"
        android:textColor="#000000"
        android:typeface="monospace"/>
</LinearLayout>

忽略我正在做的其他一些事情，我遇到的最奇怪的事情是当我使用 append() 时出现的额外间距(假设事情已经初始化等等).

Ignoring some of the other things I'm doing, the most curious thing I came across was the extra spacing that showed up when I used append() (assuming things have been initialized and all that).

下面结合 XML，在 TextView 和 EditText 之间设置了一个齐平的边框.

This below, in combination with the XML, sets a flush border between the TextView and EditText.

theEditor = (EditText) findViewById(R.id.editor);
lineNumbers = (TextView) findViewById(R.id.line_numbers);
theLineCount = theEditor.getLineCount();
lineNumbers.setText(String.valueOf(theLineCount)+"\n");

不过，将最后一行更改为此，TextView 中的每一行突然在 EditText 之前的右侧都有填充.

Change the last line to this, though, and suddenly each line in the TextView has padding on the right before the EditText.

lineNumbers.append(String.valueOf(theLineCount)+"\n");

这不是世界末日.但我很好奇是什么导致了这种行为.由于我是该语言的新手，我唯一能想到的可能是，当 append 在那里抛出 Editable 时，它​​会添加填充.如果我能得到答案，我就可以用更简单的附加内容替换所有这些讨厌的行:

It's not the end of the world. but I was curious what was causing this behavior. Since I'm new to the language, the only thing I could think of was maybe, when append throws the Editable on there, it adds the padding. If I can get an answer, I get to replace all of these nasty lines with simpler appends:

lineNumbers.setText(lineNumbers.getText().toString()+String.valueOf(newLineCount)+"\n");