android studio fragment onclick 无法访问 edittext

Question

我有类似的东西：

public class EditCustomer extends Fragment implements OnClickListener {
    public void onClick(View v) {
        //this is what runs when you click the button
         EditText editName=(EditText) v.findViewById(R.id.edit_name);
         System.out.println(editName.getText()); //FAILS

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment4
    View v=inflater.inflate(R.layout.fragment_edit_customer, container, false);
    Button a = (Button) v.findViewById(R.id.update_cust_btn);
    a.setOnClickListener(this);  //adds button listener
    EditText editText = (EditText)v.findViewById(R.id.edit_name);
    System.out.print(editText.getText().toString());


    return v;
}
...

由于某种原因，EditText 中出现空指针异常。当我在同一片段的 onCreateView() 中尝试同一行时，它工作得很好。有什么我没说到的吗？

Answer 1

步骤 1 导入这两个包。

import android.view.View;
import android.view.View.OnClickListener;

步骤 2 在您的 class

中实施 OnClickListener

public class SettingsFragment extends Fragment implements OnClickListener

步骤3在onCreateView()中定义Button和EditText；

注意：-全局声明按钮和EditText

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

        View rootView = inflater.inflate(R.layout.fragment_settings, container,
                false);

        Admin_Email = (EditText) rootView.findViewById(R.id.et_admin_email);

        btn_SET = (Button) rootView.findViewById(R.id.btn_SET);
        btn_ChangePassword = (Button) rootView
                .findViewById(R.id.btn_ChangePassword);

        btn_SET.setOnClickListener(this);
        btn_ChangePassword.setOnClickListener(this);


        return rootView;

    }

步骤 4 在 OnCreateView() 之外使用 Id

定义 Onclick() 方法

@Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.btn_SET:

            Toast toast = Toast.makeText(getActivity(), ""+Admin_Email.getText().toString(),
                            Toast.LENGTH_SHORT);

                break;
            case R.id.btn_ChangePassword:

                break;

            default:
                break;
        }
    }

我的完整代码

mport android.annotation.SuppressLint;
import android.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.util.Patterns;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ToggleButton;

import java.util.regex.Pattern;



public class SettingsFragment extends Fragment implements OnClickListener {



    Button btn_SET, btn_ChangePassword;
    static EditText Admin_Email;

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

        View rootView = inflater.inflate(R.layout.fragment_settings, container,
                false);

        Admin_Email = (EditText) rootView.findViewById(R.id.et_admin_email);

        btn_SET = (Button) rootView.findViewById(R.id.btn_SET);
        btn_ChangePassword = (Button) rootView
                .findViewById(R.id.btn_ChangePassword);

        btn_SET.setOnClickListener(this);
        btn_ChangePassword.setOnClickListener(this);


        return rootView;

    }


    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.btn_SET:

            Toast toast = Toast.makeText(getActivity(), ""+Admin_Email.getText().toString(),
                            Toast.LENGTH_SHORT);



                break;
            case R.id.btn_ChangePassword:

//          

                break;

            default:
                break;
        }
    }



}

android studio fragment onclick 无法访问 edittext

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