错误

错误1
This fragment should provide a default constructor (a public constructor wit

代码不规范，这个错误是在提示你需要添加一个空的构造函数

错误2  Avoid non-default constructors in fragments: use a default constructor plus Fragment#setArguments(Bundle) instead（Error when building APK in android studio打包时报错） 

这个错误说要使用默认构造函数外加setArguments(Bundle)来代替，去android的官网上查看Fragment的例子都是下面这个样子的

  /** 
     * Create a new instance of MyFragment that will be initialized 
     * with the given arguments. 
     */  
    static MyFragment newInstance(CharSequence label) {  
        MyFragment f = new MyFragment();  
        Bundle b = new Bundle();  
        b.putCharSequence("label", label);  
        f.setArguments(b);  
        return f;  
    }

既然人家这么写例子肯定还是有道理的，我们只需要依葫芦画瓢就可以了，去掉带参的构造函数，创建一个newInstance.

public class TestFragment extends Fragment   
{  
    private String name;  
    private String passwd;  
    public static TestFragment newInstance(String name, string passwd) {  
        TestFragment newFragment = new TestFragment();  
        Bundle bundle = new Bundle();  
        bundle.putString("name", name);  
        bundle.putString("passwd", passwd);  
        newFragment.setArguments(bundle);  
        return newFragment;    
    }  
    @Override  
    public View onCreateView(LayoutInflater inflater, ViewGroup container,  
            Bundle savedInstanceState) {  
        // TODO Auto-generated method stub  
        View view = inflater.inflate(R.layout.main, null);            
        return view;  
    } 
  } 

这个错误就消失了，在Fragment所依赖的Activity中，用以下语句创建Fragment实例即可

Fragment testFragment=TestFragment.newInstance(“name”,”passwd”);
对于从Activity传递到Fragment中的参数我们只需要在Fragment的onCreate中获取就可以了

public void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState);    
        Bundle args = getArguments();  
        if (args != null) {  
            name = args.getString("name");  
        passwd = args.getstring("passwd");  
}