我如何在main.java中更改eclipse中的應用程序標題

我想要做的是創建一個非常簡單的應用程序，該應用程序顯示「Welcome to Android，[NAME]！」作爲文本字段和應用的標題。但是，我希望應用程序僅在按下按鈕後才顯示此內容，如果用戶將該字段留空，則會顯示「歡迎使用Android」。我設法讓按鈕和文本正確顯示，而不是標題。我試着在網上尋找答案，但只有使用string.xml的方法。我如何編寫java代碼來更改應用程序的標題？我如何在main.java中更改eclipse中的應用程序標題

這是我到目前爲止有：

package com.helloandroidbutton; 

import android.os.Bundle; 
import android.app.Activity; 
import android.view.*; 
import android.widget.*; 
import android.view.View.OnClickListener; 

public class MainActivity extends Activity implements OnClickListener{ 
/**Called when activity is created. */ 
private Button btn; 
private EditText edit; 
private TextView view; 
private RelativeLayout title; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    edit = (EditText)findViewById(R.id.editText1); 
    view = (TextView)findViewById(R.id.textView1); 
    btn = (Button)findViewById(R.id.button1); 
    btn.setOnClickListener(this); 
    title = (RelativeLayout)findViewById(R.string.app_name); 
} 

@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; 
} 

@Override 
public void onClick(View v) { 
    if(btn==v){ 
     if(edit.getText().toString().equals("")){ 
      String msg ="Welcome to Android!"; 
      Toast toast = Toast.makeText(this, msg, Toast.LENGTH_SHORT); 
       toast.show(); 
       view.setText(msg); 
           //This was my attempt to change the title 
       /*title.setText(msg);*/ 
     } 
     else{ 
      String msg ="Welcome to Android, " + edit.getText() + "!"; 
      Toast toast = Toast.makeText(this, msg, Toast.LENGTH_SHORT); 
       toast.show(); 
       view.setText(msg); 
       /*title.setText(msg);*/ 


    } 


} 
} 
}

來源

2013-10-10 Brian Patino