我相信下面的代码会做你想做的事，但我看不到只有在 xml 布局中才能做到这一点的方法。基本上，我已经将一个 textChangedListener 添加到两个不同的 TextView，它们具有我相信您正在寻找的两种不同的布局选项，它们都在它们自己的相对布局中，日期显示 textview。设置字幕时，第一个用于保存文本，如果它需要多于一行，则使用第二个 TextView，并且在任何一种情况下，另一个都将其可见性选项设置为 GONE。在我的示例中，我使用单独的线程来更改字幕，希望这不会使事情混淆太多。
布局xml如下：
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="@+id/title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:ellipsize="end"
android:textAppearance="?android:attr/textAppearanceSearchResultTitle"
android:background="#FF009999"
android:textIsSelectable="false"
android:text="@string/my_title" />
<RelativeLayout
android:id="@+id/resizingTextContainer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/title" >
<TextView
android:id="@+id/date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:textAppearance="?android:attr/textAppearanceSearchResultSubtitle"
android:textIsSelectable="false"
android:textColor="#FFFFFFFF"
android:background="#FF000000" />
<TextView
android:id="@+id/subtitle1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_toLeftOf="@+id/date"
android:textAppearance="?android:attr/textAppearanceSearchResultSubtitle"
android:textIsSelectable="false"
android:textColor="#FFFFFF"
android:background="#FF00FF00" />
<TextView
android:id="@+id/subtitle2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/date"
android:textAppearance="?android:attr/textAppearanceSearchResultSubtitle"
android:textIsSelectable="false"
android:visibility="gone"
android:textColor="#FFFFFF"
android:background="#FF00FF00" />
</RelativeLayout>
<Button
android:id="@+id/startTestBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/resizingTextContainer"
android:layout_centerHorizontal="true"
android:text="Click To Begin"
/>
</RelativeLayout>
以及带有 textview 切换逻辑的主要活动代码：
package com.example.code.examples.changelayoutwithtextlength;
import android.os.Bundle;
import android.app.Activity;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
TextWatcher textChangeDisplayCheck = new TextWatcher(){
@Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
// TODO Auto-generated method stub
}
@Override
public void onTextChanged(CharSequence s, int start, int before,
int count) {
displayLatestSubtitle(s);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView DateTextView = (TextView)findViewById(R.id.date);
DateTextView.setText("29th April 2013");
Button b = (Button)findViewById(R.id.startTestBtn);
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v)
{
v.setEnabled(false);
Thread thread = new testSubtitleThread();
thread.start();
}
});
TextView tv = (TextView)findViewById(R.id.subtitle1);
tv.addTextChangedListener(textChangeDisplayCheck);
TextView tv2 = (TextView)findViewById(R.id.subtitle2);
tv2.addTextChangedListener(textChangeDisplayCheck);
}
private void displayLatestSubtitle(CharSequence newSubtitle)
{
TextView tv = (TextView)findViewById(R.id.subtitle1);
TextView tv2 = (TextView)findViewById(R.id.subtitle2);
tv.removeTextChangedListener(textChangeDisplayCheck);
tv2.removeTextChangedListener(textChangeDisplayCheck);
tv.setVisibility(View.GONE);
tv2.setVisibility(View.GONE);
tv2.setText("");
tv.setText(newSubtitle);
if(tv.getLineCount() > 1)
{
tv.setText("");
tv2.setText(newSubtitle);
tv2.setVisibility(View.VISIBLE);
}
else
{
tv.setVisibility(View.VISIBLE);
}
tv.addTextChangedListener(textChangeDisplayCheck);
tv2.addTextChangedListener(textChangeDisplayCheck);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public class testSubtitleThread extends Thread
{
String[] subtitles = new String[] { "a short one", "a really long winded subtitle that will take over more than the allowed space", "tiny",
"Really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, really, long.",
".....", "text just to long to fit on my device"};
private android.os.Handler handler = new android.os.Handler()
{
@Override
public void handleMessage(android.os.Message msg)
{
if(msg.what < subtitles.length)
{
TextView tv = (TextView)findViewById(R.id.subtitle1);
tv.setText(subtitles[msg.what]);
}
else
{
Button b = (Button)findViewById(R.id.startTestBtn);
b.setEnabled(true);
}
}
};
@Override
public void run()
{
for(int i = 0; i <= subtitles.length; i++)
{
handler.sendEmptyMessage(i);
try
{
Thread.sleep(3000);
}
catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
我希望这有帮助。