活动和片段之间的通信

问题描述：

大家好我开发一个应用程序，以解释我创建简单的插画我的处境。当我点击另一个活动里面的按钮，我想将数据发送到片段。我用它捆绑给我NullPointerException异常。我试图用方法的另一个活动再次给了我的错误中。如何从活动传递数据提前到碎片的感谢。

Hello Everyone I'm developing an app,in order to explain my situation I've created simple illustrator. When i click the button inside another activity i want to send data to fragment. I use bundle its gives me nullpointerexception. I tried to use method inside another activity it gives me error again. How can i pass data from Activity to Fragment thanks in advance.

下面我codeS。

EDIT1：我想我解释错了。瞧，我已经上传的照片。当我点击白色按钮anotheractivity正在打开。当我打字里面anotheractivity一些文字，然后点击里面的anotheractivity按钮，然后我想送DATAS片段类。我希望我能解释的。谢谢你。

Edit1 : I think i explained wrong. Look at photo that i've uploaded. When i click the white button anotheractivity is opening. When i typing some text inside anotheractivity and click the button inside anotheractivity, then i want to send datas Fragment class. I hope i was able to explained. Thanks.

MainActivity

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn = (Button) findViewById(R.id.button2);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(MainActivity.this,AnotherActivity.class);
                startActivity(i);

            }
        });
    }
}

AnotherActivity

public class AnotherActivity extends Activity {
    EditText et;
    Button btn;
    public String ets;
    FragmentClass myFragment = new FragmentClass();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.anotheractivity);
        btn = (Button) findViewById(R.id.button);
        et= (EditText) findViewById(R.id.editText);
        ets = et.getText().toString();
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myFragment.Test(ets);

            }
        });
    }
}

片段

public class FragmentClass extends Fragment {
    TextView tv;
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment,container,false);
        tv = (TextView)v.findViewById(R.id.textView);

        return v;
    }


    public void Test(String name){
       Toast.makeText(getActivity(),name,Toast.LENGTH_SHORT).show();
    }
}

答

这是活动和片段之间沟通的最佳实践

public class TestFragment extends Fragment {

    private static final String ATAG = "atag";

    public static TestFragment getFragment(int value){
        TestFragment fragment = new TestFragment();
        Bundle bundle = new Bundle();
        bundle.putInt(ATAG, 100);
        fragment.setArguments(bundle);

        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View view  = inflater.inflate(R.layout.layout_fragment, container,false);
        Bundle  b = getArguments();
            if(b!= null)
                YOUR DATA = b.getInt(ATAG);
        return view;
    }
}

和活动：

public class MainActivity extends Activity{

    private static final String FOO = "foofragment";

    TestFragment newFragment;
    Button mButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if(savedInstanceState == null){
            newFragment = TestFragment.getFragment(100);    
        }else {
            newFragment = (TestFragment) getFragmentManager().findFragmentByTag(FOO);
        }

        mButton.setOnClickListener(new OnClickListener() {
            FragmentManager manager = getFragmentManager();     
            FragmentTransaction transaction = manager.beginTransaction();   
            transaction.add(R.id.container, newFragment, FOO);          
            transaction.commit();
        }
    }
}

活动和片段之间的通信

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