Android项目结构和HelloWorld
1、搭建开发环境，见文配置Android开发环境2、新建工程：
1) New-->Android Project
http://dl.iteye.com/upload/attachment/241370/b37b1ad6-6ed5-3882-aa4b-1e1b74330ff3.jpg
http://dl.iteye.com/upload/attachment/241378/674c7e85-b9e8-3999-ad65-1e0eab5ee937.jpg
展开目录结构:
http://dl.iteye.com/upload/attachment/241383/cf26f88b-c203-3d06-bbda-d2f3f03bd627.jpg
src里com.leoms.hello下有一个HelloWorld.java,他的名字就来自于我们新建项目的时候填写的Acivity name, 这个HelloWorld就继承自Activity。
gen里com.leoms.hello的R.java,这个类是系统根据res文件夹中的内容自动生成的
res文件夹，res是resources的缩写，顾名思义，你程序中所需要的文字，图片，布局文件等等资源都是放在这个文件夹下面的，你现在看到这个文件夹下面有
drawable - 这个是放图片的
layout - 这个是放布局文件的
values - 下面放字符串(strings.xml ),颜色(colors.xml ),数组(arrays.xml )
res文件夹中内容变化，R.java都会重新编译同步更新，所以这个类不需要你去手动更新了。
最后是AndroidManifest.xml. 你每次添加一个Acivity都需要在这个文件中描述一下。
3、HelloWorld：
HelloWorld.java
import android.app.Activity;import android.os.Bundle;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); }}
R.java
public final class R { public static final class attr { } public static final class drawable { public static final int icon=0x7f020000; } public static final class layout { public static final int main=0x7f030000; } public static final class string { public static final int app_name=0x7f040001; public static final int hello=0x7f040000; }}
main.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" ><TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" /></LinearLayout>
strings.xml
<?xml version="1.0" encoding="utf-8"?><resources> <string name="hello">Hello World, HelloWorld!</string> <string name="app_name">HelloWorld</string></resources>
运行:
http://dl.iteye.com/upload/attachment/241400/07a56c6c-f0cd-39b8-9d58-56bfd37ac6c2.jpg
4、布局进阶，加入button按钮监听及dialog对话框
首先将res-->layout-->main.xml文件重命名为helloworld.xml。
TIP：如果项目中有多个Activity，最好将layout文件的名字与 Activity对应。
helloworld.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical" android:layout_width="fill_parent"android:layout_height="fill_parent"><Button android:id="@+id/Button01" android:text="@string/btn01_text"android:layout_width="wrap_content"android:layout_height="wrap_content" /></LinearLayout>
R.java
public final class R { public static final class attr { } public static final class drawable { public static final int icon=0x7f020000; } public static final class id { public static final int Button01=0x7f050000; } public static final class layout { public static final int helloworld=0x7f030000; } public static final class string { public static final int app_name=0x7f040002; public static final int btn01_text=0x7f040000; public static final int hello=0x7f040001; }}
HelloWorld.java
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{@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.helloworld);Button button = (Button) this.findViewById(R.id.Button01);// 监听button.setOnClickListener(new OnClickListener(){public void onClick(View arg0){openDialog();}});}/* * 对话框 */private void openDialog(){AlertDialog.Builder builder = new AlertDialog.Builder(this);builder.setTitle("Hello");builder.setMessage("Hello World \n");builder.setNegativeButton("OK", null);builder.show();}}
strings.xml
<?xml version="1.0" encoding="utf-8"?><resources> <string name="btn01_text">click</string> <string name="hello">Hello World, HelloWorld!</string> <string name="app_name">hello</string></resources>
运行：
http://dl.iteye.com/upload/attachment/241403/a397ed5b-4186-36d3-a6ab-63527d372c39.jpg
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