Android_Fragment和Activity之間的通訊

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Fragment 的生命週期是隨著activity變化而變化的。

如果activity要給在啟動並執行時候給fragment傳人資料則需要fragment實現一個自訂的介面，並且實現介面裡面的方法，在activity裡面儲存這個介面並且在需要傳人資料的時候調用這個方法即可。

如果fragment啟動並執行時候需要給activity傳資料了？activity先實現這個介面，然後在fragment裡面重寫onAttach(Activity act)這個方法，並在這個方法裡面講activity強制轉換為介面類，然後在fragment使用的時候調用這個介面類的方法。

請看下面的例子：

activity給fragment裡面傳人資料：

public class MainActivity extends Activity{    private TestFragment fragment;//fragment    private UpdateFragment updateFragment;//fragment實現的介面    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main_layout);        initView();            }        private void initView() {        FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();        fragment = new TestFragment();        updateFragment = fragment;        fragmentTransaction.add(R.id.main, fragment);        fragmentTransaction.addToBackStack(null);        fragmentTransaction.commitAllowingStateLoss();    }    @Override    protected void onResume() {        //改變fragment裡面textView的值        updateFragment.setData("王五");        super.onResume();    }}

介面類

public interface UpdateFragment {    void setData(String str);}

Fragment類：

public class TestFragment extends Fragment implements UpdateFragment{    private View view;    private TextView txt;    public TestFragment() {        super();    }    @Override    public void onAttach(Activity activity) {        super.onAttach(activity);    }    @Override    public void onViewCreated(View view, Bundle savedInstanceState) {        super.onViewCreated(view, savedInstanceState);    }    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,            Bundle savedInstanceState) {        if (null == view){            view = inflater.inflate(R.layout.activity_main, container, false);            txt = (TextView)view.findViewById(R.id.tv);        }        return view;    }    @Override    public void setData(String str) {        if (null != txt) {            txt.setText(str);        }    }}

 

 

Fragment給activity傳入資料demo：

Activity類：

public class MainActivity extends Activity implements UpdateFragment{    private static final String TAG = MainActivity.class.getSimpleName();    private TestFragment fragment;//fragment    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main_layout);        initView();            }        private void initView() {        FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();        fragment = new TestFragment();        fragmentTransaction.add(R.id.main, fragment);        fragmentTransaction.addToBackStack(null);        fragmentTransaction.commitAllowingStateLoss();    }    @Override    protected void onResume() {        super.onResume();    }    @Override    public void setData(String str) {        if (null != str ){            Log.d(TAG, "setData:"+str);        }    }

介面類和上面的是一樣的就不寫了

Fragment類：

public class TestFragment extends Fragment{    private View view;    private TextView txt;    private Button btn;    private UpdateFragment updateFragment;    public TestFragment() {        super();    }    @Override    public void onAttach(Activity activity) {        try {            updateFragment = (UpdateFragment)activity;        } catch (Exception e) {            e.printStackTrace();        }        super.onAttach(activity);    }    @Override    public void onViewCreated(View view, Bundle savedInstanceState) {        super.onViewCreated(view, savedInstanceState);    }    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,            Bundle savedInstanceState) {        if (null == view){            view = inflater.inflate(R.layout.activity_main, container, false);            txt = (TextView)view.findViewById(R.id.tv);            btn = (Button)view.findViewById(R.id.btn);            btn.setOnClickListener(clickListener);        }        return view;    }    private OnClickListener clickListener = new OnClickListener() {        @Override        public void onClick(View v) {            if (null != txt) {                updateFragment.setData(txt.getText().toString());            }                    }    };}

 

Android_Fragment和Activity之間的通訊