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Fragment与Activity的互相通讯

注意:在SDK 23以上的API中,Fragment的onAttach(Activity activity) is deprecated(过时了),取而代之的是onAttach(Context context),然而新的onAttach方法在API小于23的设备上运行,会出现不被调用的情况。


解决办法:
API小于19的设备上,用import android.support.v4.Fragment代替android.app.Fragment

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在慕课网学习到Fragment和Activity的通讯

习惯使用Fragment动态的加载办法,所以没有加上静态加载的办法。

当时在调用Onattach方法的时候自动调用的onattach(Context context)当在执行的时候报错Null pointer,后来改成Activity activity后就没有报错了,解决办法是用android.support.v4.Fragment包代替android.app.Fragment包

Activity的代码

 1 public class MainActivity extends AppCompatActivity implements Fragment1.Mylistener{ 2     private EditText editText; 3     private Button button; 4     @Override 5     protected void onCreate(Bundle savedInstanceState) { 6         super.onCreate(savedInstanceState); 7         setContentView(R.layout.activity_main); 8         editText=(EditText)findViewById(R.id.edit_text); 9         button=(Button)findViewById(R.id.button);10         button.setOnClickListener(new View.OnClickListener() {11             @Override12             public void onClick(View view) {13                 Bundle bundle= new Bundle();14                 String text= editText.getText()+"";15                 bundle.putString("key",text);16                 Fragment1 fragment1= new Fragment1();17                 fragment1.setArguments(bundle);18                 FragmentManager fragmentManager= getFragmentManager();19                 FragmentTransaction fragmentTransaction= fragmentManager.beginTransaction();20                 fragmentTransaction.add(R.id.frame,fragment1,"fragment1");21                 fragmentTransaction.commit();22                 Toast.makeText(MainActivity.this,"已接受text:"+text,Toast.LENGTH_SHORT).show();23             }24         });25     }26     @Override27     public void sendtext(String w) {28         Toast.makeText(MainActivity.this,"Received"+w,Toast.LENGTH_SHORT).show();29     }30 }

Fragment的代码

 1 public class Fragment1 extends Fragment{ 2     public String code="Thanks"; 3     public Mylistener mylistener; 4     public interface Mylistener{ 5         public void sendtext(String w); 6     } 7  8     @Override 9     public void onAttach(Context context) {10         mylistener=(Mylistener)context;11         super.onAttach(context);12     }13 14     @Nullable15     @Override16     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {17         View view=inflater.inflate(R.layout.fragment,container,false);18         String text=getArguments().get("key")+"";19         Toast.makeText(getActivity(),"已成功接收到"+text,Toast.LENGTH_SHORT).show();20         Toast.makeText(getActivity(),"sendMessageToActivity"+code,Toast.LENGTH_SHORT).show();21         mylistener.sendtext(code);22         return view;23 24     }25 26 }

 

Fragment与Activity的互相通讯