//主活动
package com.mycompany.myapp;
import android.app.*;
import android.content.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.widget.AdapterView.*;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
String[] companies = new String[] { "测试", "打包","发布",};
ListAdapter adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, companies);
ListView listView = (ListView) findViewById(R.id.s1);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> l, View v, int position, long id)
{
String s = (String) l.getItemAtPosition(position);
//Toast.makeText(MainActivity.this, s, Toast.LENGTH_LONG).show() ;
if(s=="测试"){
Toast.makeText(MainActivity.this,s+"中", Toast.LENGTH_SHORT).show() ;
}
else if(s=="打包"){
Toast.makeText(MainActivity.this,s+"中", Toast.LENGTH_SHORT).show() ;
}
else if(s== "发布"){
Toast.makeText(MainActivity.this,s+"中", Toast.LENGTH_SHORT).show() ;
}else{
finish();
}
}
});
}
// public void change(View view){
//setContentView(R.layout.layout);
//}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
checkExit();
Toast.makeText(MainActivity.this,"回到主菜单", Toast.LENGTH_SHORT).show() ;
return true;
}
return super.onKeyDown(keyCode, event);
}
private void checkExit()
// TODO: Implement this method
{
//Intent intent = new Intent(this, layoutActivity.class);
//startActivity(intent) ;
//未完待续
}
public void g (){
Intent intent = new Intent(this, testactivity.class);
startActivity(intent);
}
}

(XML)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<Button
android:layout_height="wrap_content"
android:text="按钮"
android:layout_width="wrap_content"/>
</LinearLayout>

//清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mycompany.myapp"
android:versionCode="2"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<application
android:icon="@drawable/bq2"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:label="@string/app_name"
android:name=".MainActivity"
android:theme="@android:style/Theme.NoTitleBar"
>
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:label="test"
android:name=".testactivity"
android:theme="@android:style/Theme.Holo.Light">
</activity>
</application>
</manifest>

程序根本走不到g()方法