HelloWorld及Android项目结构介绍

setContentView(R.layout.hello_world);

}

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.hello_world);

}

R.layout.hello_world 就指向 hello_world.xml，同理 R.string.click_me就向Click

me, 运行一下(右键点击你的项目，run as -> Android Application)看到一个按钮了吧

6 为按钮添加点击事件:

要为按钮添加点击事件,我们需要先得到这个对象,然后设置监听器，再编写onClick事件

完成后代码如下：

Java代码

import android.app.Activity;

import android.app.AlertDialog;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class HelloWorld extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Button button = (Button)findViewById(R.id.Button01);

button.setOnClickListener(new OnClickListener(){

public void onClick(View arg0) {

openDialog();

}

});

}

private void openDialog(){

AlertDialog.Builder builder = new AlertDialog.Builder(this);

builder.setTitle(Hello);

builder.setMessage(Hello World n);

builder.setNegativeButton(OK,null);

builder.show();

}

}

import android.app.Activity;

import android.app.AlertDialog;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class HelloWorld extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Button button = (Button)findViewById(R.id.Button01);

button.setOnClickListener(new OnClickListener(){

public void onClick(View arg0) {

openDialog();

}

});

}

private void openDialog(){

AlertDialog.Builder builder = new AlertDialog.Builder(this);

builder.setTitle(Hello);

builder.setMessage(Hello World n);

builder.setNegativeButton(OK,null);

builder.show();

}

}

Button button = (Button)findViewById(R.id.Button01);这句话就是用来获取layout中设置的界面控件对象的，这个id是在button中指定的android:id=@+id/Button01 。

Android的UI用起来跟SWT是很像的，以后我会挑一些常用的，有趣的UI控件详细地介绍一下。今天先写到这里，每次我都会把相应项目的源代码贴到最下面。