Question

我想使用interface来实现从片段传递数据到包含onClick事件的activity按钮的通信。我可以看到Map可以编写在editText字段上有效的数据，但这些值不能发送到活动。它显示错误并在我触发活动onClick事件后停止。

程序是：

用户填写了editText字段
一旦editText字段聚焦，带有验证的TextWatcher将检查（如果无效，editText将不会放入HashMap并提示用户编辑，如果用户单击提交按钮，它将重新加热用户更改正确首先回答）
当用户填写所有字段并单击按钮时，片段上的值将作为Hashmap返回，并检查它是否具有空字段，并将值和putExtra（）分解为下一个活动。

我对界面的使用感到困惑，尽管在解决此问题时我已经阅读了很多来源和案例。或者我可以使用其他解决方案来实现此功能吗？

感谢您的帮助。

主要活动：

......
Fragment_step_1 getHashMapStep1 = new Fragment_step_1();
Fragment_step_2 getHashMapStep2 = new Fragment_step_2();

public interface onPassValue{
    public Map<Object, String> onPassValueStep1(Map<Object, String> insureApplicant);
}

public interface onPassValue2{
    Map<Object, String> onPassValueStep2(Map<Object, String> insureApplicant2);
}

protected void onCreate(Bundle savedInstanceState) {
    ......
    btn_sendInsureInfo.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View view){

            Fragment_step_1.onPassValueStep1();
            Fragment_step_2.onPassValueStep2();
            //NullPointerException on those two calling interface method
            ......
        }
}
......

Fragment_step_1 :( xxx是活动名称）

public class Fragment_step_1 extends Fragment implements xxx.onPassValue {
    ......
     Map<Object, String> insureApplicant = new HashMap<>(4);

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

@Override
public void onAttach(Context xxx){
    super.onAttach(xxx);

    try {
       passValue = (onPassValue) xxx;
    } catch (ClassCastException e) {
        throw new ClassCastException(pingan_insure_info.toString()
                + " didn't implement onPassValue");
    }
    //THROW EXCEPTION ALWAYS
}

@Override
public Map<Object, String> onPassValueStep1(Map<Object, String> insureResult) {
    for (Object key : insureResult.entrySet()) {
        //System.out.println(key + " fragment_1 : " + insureResult.get(key));
        System.out.println(" fragment_1 : " + key);
        Log.e("map", String.valueOf(insureResult));
    }
    return insureResult;
}
    ......

Fragment_step_2 :( xxx是活动名称）

public class Fragment_step_2 extends Fragment implements xxx.onPassValue2{
......
RelativeLayout correspondence;
HashMap insureApplicant2 = new HashMap<>(3);

@Override
public void onAttach(Context xxx){
    super.onAttach(xxx);

    try {
        passValueStep2 = (onPassValueStep2) xxx;
    } catch (ClassCastException e) {
        throw new ClassCastException(xxx.toString()
                + " didn't implement onPassValue");
    }
    //THROW EXCEPTION ALWAYS
}

@Override
public Map<Object, String> onPassValueStep2(Map<Object, String> insureApplicantStep2){
    for (Object key : insureApplicantStep2.entrySet()) {
        System.out.println("fragment_2 : " + key);
        Log.e("Hashmap2", String.valueOf(insureApplicantStep2));
    }
    return insureApplicant2;
}

所有片段的editText将在editText有效后填写，并由用户输入并发送到该函数并存储在HashMap中。

例如：（AddTextChangedListener with TextWatcher）

residentAddress.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {}

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {}

        @Override
        public void afterTextChanged(Editable editable) {
            residentAddress.setOnFocusChangeListener(new View.OnFocusChangeListener(){
                @Override
                public void onFocusChange(View view, boolean isFocus){
                    if(!isFocus){
                        if("".trim().equals(residentAddress.getText().toString())){
                            rAddress.setError("Resident Address is required.");
                            strAddress = "";
                            insureApplicant2.put(2, strAddress);
                        } else {
                            rAddress.setErrorEnabled(false);
                            rAddress.setError(null);
                            strAddress = residentAddress.getText().toString().trim();
                            insureApplicant2.put(2, strAddress);

                            onPassValueStep2(insureApplicant2);
                            //CAN PUT THE VALUE TO HASHMAP BUT CANNOT be RETURNED TO ACTIVITY :(
                        }
                    }
                }
            });

        }
    });

Answer 1

要将值从片段传递到活动，请在活动中的fragment.not中创建接口。

片段A

public class FragmentA extends Fragment {

    public interface InterfaceTest{
        void passValue(String passval);
    }

    InterfaceTest interfaceTest;

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);


        interfaceTest= (InterfaceTest) context;


    }

    public FragmentA() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View rootView= inflater.inflate(R.layout.fragment_, container, false);



        return  rootView;

    }
//
    public void passToActivity(){
        interfaceTest.passValue("yourvalues");
    }

}

活性

public class MainActivity extends AppCompatActivity implements FragmentA.InterfaceTest {

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

        //create code for add fragment in activity


    }

    @Override
    public void passValue(String passval) {
        Log.e("print",passval);
    }
}

使用接口从ClassCastException

1 个答案:

片段A

活性