搞了一个晚上不知道该怎么引用获取版本号。

 function.java

package com.test.module;

import android.content.Context;
import android.content.pm.PackageManager;

public class function {

 //获取版本号
public static int getVersionCode(Context context){
    try {
        return context.getPackageManager().getPackageInfo(context.getPackageName(), 0).versionCode;
    }catch(PackageManager.NameNotFoundException e){
        return 0;
    }
}

}

Layout.java

import com.testdevelop.module.function;

public class Layout extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout);
findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
public void onClick(View view) {
TextView versionView = (TextView) findViewById(R.id.versionView);
versionView.setText( function.getVersionCode(this) );

 }
    });
}

}