Android 从活动到当前加载的片段的接口未工作

我想在单击按钮时将数据从活动传递到当前加载的片段。 为此，我创建了接口，并在接口中定义为活动和实现，但无法在片段中获得响应

每当按钮在活动中单击fire时，我都需要输出

这是我的密码。请帮我解决这个问题

接口 主要活性 碎片 但我在主活动中遇到了错误 这是我的错误日志

05-09 10:30:49.09219101-19101/com.psk.interfacetest E/Btn点击：点击 05-09 10:30:49.095 19101-19101/com.psk.interfacetest E/AndroidRuntime:致命异常：main 进程：com.psk.interfacetest，PID:19101 java.lang.NullPointerException 位于com.psk.interfacetest.MainActivity$1.onClick（MainActivity.java:37） 在android.view.view.performClick（view.java:4471）中 在android.view.view$PerformClick.run（view.java:18778） 位于android.os.Handler.handleCallback（Handler.java:808） 位于android.os.Handler.dispatchMessage（Handler.java:103） 位于android.os.Looper.loop（Looper.java:193） 位于android.app.ActivityThread.main（ActivityThread.java:5345） 位于java.lang.reflect.Method.Invokenactive（本机方法） 位于java.lang.reflect.Method.invoke（Method.java:515） 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run上（ZygoteInit.java:824） 位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:640） 在dalvik.system.NativeStart.main（本机方法）

---

您的情况下，碎片替换无法完成。所以您应该从片段中注册接口。您可以检查此代码

      public class AActivity extends FragmentActivity {
            Click click;
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
 FragmentOne fragmentOne = new FragmentOne();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.flContainer, fragmentOne,"FragmentOne");
        ft.commit();
              DrawerLayout dlMain = (DrawerLayout)findViewById(R.id.dlMain);
            Button    btnClick = (Button) findViewById(R.id.btnClick);

                btnClick.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.e("Btn Click", "click");
                        click.onClick("Button Clicked!");
                    }
                });
            }

            public void setCallback(Click callback) {
                this.click=callback;
            }
            public interface Click {
                void onClick(String msg);
            }
        }

        public class AFragment extends Fragment implements AActivity.Click {
            @Override
            public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
                super.onViewCreated(view, savedInstanceState);
                if (getActivity() != null) {
                    ((AActivity)getActivity()).setCallback(this);
                }
            }

            @Override
            public void onClick(String msg) {

            }
        }

---

您的情况下，碎片替换无法完成。所以您应该从片段中注册接口。您可以检查此代码

      public class AActivity extends FragmentActivity {
            Click click;
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
 FragmentOne fragmentOne = new FragmentOne();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.flContainer, fragmentOne,"FragmentOne");
        ft.commit();
              DrawerLayout dlMain = (DrawerLayout)findViewById(R.id.dlMain);
            Button    btnClick = (Button) findViewById(R.id.btnClick);

                btnClick.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.e("Btn Click", "click");
                        click.onClick("Button Clicked!");
                    }
                });
            }

            public void setCallback(Click callback) {
                this.click=callback;
            }
            public interface Click {
                void onClick(String msg);
            }
        }

        public class AFragment extends Fragment implements AActivity.Click {
            @Override
            public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
                super.onViewCreated(view, savedInstanceState);
                if (getActivity() != null) {
                    ((AActivity)getActivity()).setCallback(this);
                }
            }

            @Override
            public void onClick(String msg) {

            }
        }

public class FragmentOne extends Fragment implements Click {
   @Nullable
   @Override
   public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
       View view = inflater.inflate(R.layout.fragment_one, container, false);
       return view;
   }

   @Override
   public void onClick(String msg) {
       Toast.makeText(getActivity(), msg, Toast.LENGTH_SHORT).show();
   }
}

      public class AActivity extends FragmentActivity {
            Click click;
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
 FragmentOne fragmentOne = new FragmentOne();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.flContainer, fragmentOne,"FragmentOne");
        ft.commit();
              DrawerLayout dlMain = (DrawerLayout)findViewById(R.id.dlMain);
            Button    btnClick = (Button) findViewById(R.id.btnClick);

                btnClick.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.e("Btn Click", "click");
                        click.onClick("Button Clicked!");
                    }
                });
            }

            public void setCallback(Click callback) {
                this.click=callback;
            }
            public interface Click {
                void onClick(String msg);
            }
        }

        public class AFragment extends Fragment implements AActivity.Click {
            @Override
            public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
                super.onViewCreated(view, savedInstanceState);
                if (getActivity() != null) {
                    ((AActivity)getActivity()).setCallback(this);
                }
            }

            @Override
            public void onClick(String msg) {

            }
        }

try this



public class MainActivity extends FragmentActivity {
    DrawerLayout dlMain;
    Button btnClick;

    Click click;
    private FragmentOne fragmentOne;

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


         fragmentOne = new FragmentOne();
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.imageTitleTextView, fragmentOne, "FragmentOne");
        ft.commit();

        //click = (Click) getSupportFragmentManager().findFragmentByTag("FragmentOne");

    dlMain = (DrawerLayout) findViewById(R.id.dlMain);
        btnClick = (Button) findViewById(R.id.btnClick);

        btnClick.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.e("Btn Click", "click");
                fragmentOne.listener.onClick("Button Clicked!");
            }
        });
    }
}


public class FragmentOne extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_one, container, false);
        return view;
    }
Click listener = new Click() {
    @Override
    public void onClick(String msg) {
        Toast.makeText(getActivity(), msg, Toast.LENGTH_SHORT).show();
    }
};

}