我正在制作一个包含5个碎片的应用程序，与底部导航菜单相连。为了简单起见，我将使用其中的两个作为示例。
package com.example.ssresilience;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
/**
* A simple {@link Fragment} subclass.
* Use the {@link GoalsFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class GoalsFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private Button fg_goals_socialize;
private Button fg_goals_study;
private Button fg_goals_exercise;
private Button fg_goals_setgoal;
private TextView fg_goals_placeholder;
private int check = 0;
public GoalsFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment GoalsFragment.
*/
// TODO: Rename and change types and number of parameters
public static GoalsFragment newInstance(String param1, String param2) {
GoalsFragment fragment = new GoalsFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate((R.layout.fragment_goals), container, false);
fg_goals_socialize = (Button)rootView.findViewById(R.id.fg_goals_socialize);
fg_goals_socialize.setOnClickListener(this::onClick);
fg_goals_study = (Button)rootView.findViewById(R.id.fg_goals_study);
fg_goals_study.setOnClickListener(this::onClick);
fg_goals_exercise = (Button)rootView.findViewById(R.id.fg_goals_exercise);
fg_goals_exercise.setOnClickListener(this::onClick);
fg_goals_setgoal = (Button)rootView.findViewById(R.id.fg_goals_setgoal);
fg_goals_setgoal.setOnClickListener(this::onClick);
fg_goals_placeholder = (TextView)rootView.findViewById(R.id.fg_goals_placeholder);
return rootView;
}
@SuppressLint({"UseCompatLoadingForDrawables", "ResourceAsColor", "UseCompatLoadingForColorStateLists", "NonConstantResourceId", "SetTextI18n"})
public void onClick(View v) {
switch (v.getId()) {
case R.id.fg_goals_socialize:
fg_goals_placeholder.setText("• Talk to 3 or more people, other than your family.nn" +
"• Engage in phone or video calls from any device.nn" +
"• Exit your house for more than 2 hours.nn" +
"• Meet new people online or via your phone.");
fg_goals_socialize.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect));
fg_goals_socialize.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text));
fg_goals_study.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect_reset));
fg_goals_study.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text_reset));
fg_goals_exercise.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect_reset));
fg_goals_exercise.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text_reset));
check = 1;
break;
case R.id.fg_goals_study:
fg_goals_placeholder.setText("• Study for 1 or more hours today.nn" +
"• Work for at least 1 hour on your projects.nn" +
"• Talk to friends or relatives about your projects.nn" +
"• Dedicate study time for the course of your liking.");
fg_goals_socialize.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect_reset));
fg_goals_socialize.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text_reset));
fg_goals_study.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect));
fg_goals_study.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text));
fg_goals_exercise.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect_reset));
fg_goals_exercise.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text_reset));
check = 2;
break;
case R.id.fg_goals_exercise:
fg_goals_placeholder.setText("• Dedicate more than 1 hour on physical exercise.nn" +
"• Participate in physical exercises with friends or others.nn" +
"• Achieve your physical exercise-related goal.nn" +
"• Track your fitness-related progress in any way.");
fg_goals_socialize.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect_reset));
fg_goals_socialize.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text_reset));
fg_goals_study.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect_reset));
fg_goals_study.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text_reset));
fg_goals_exercise.setBackgroundDrawable(getResources().getDrawable(R.drawable.buttoncolor_rect));
fg_goals_exercise.setTextColor(getResources().getColorStateList(R.color.buttoncolor_text));
check = 3;
break;
default:
break;
}
switch (v.getId()) {
case R.id.fg_goals_setgoal:
if(check == 0) {
Toast.makeText(getActivity(), "Please select one of the 3 Goals!",
Toast.LENGTH_LONG).show();
}
if(check == 1) {
Bundle args = new Bundle();
args.putInt("goal", 1);
ProgressFragment newFragment = new ProgressFragment();
newFragment.setArguments(args);
Toast.makeText(getActivity(), "Current Goal: Socialize More",
Toast.LENGTH_LONG).show();
}
if(check == 2) {
Bundle args = new Bundle();
args.putInt("goal", 2);
ProgressFragment newFragment = new ProgressFragment();
newFragment.setArguments(args);
Toast.makeText(getActivity(), "Current Goal: Enhance Study Motives",
Toast.LENGTH_LONG).show();
}
if(check == 3) {
Bundle args = new Bundle();
args.putInt("goal", 3);
ProgressFragment newFragment = new ProgressFragment();
newFragment.setArguments(args);
Toast.makeText(getActivity(), "Current Goal: Physical Exercise",
Toast.LENGTH_LONG).show();
}
break;
default:
break;
}
}
}
在GoalsFragment.java上面，有2个开关方法，它突出显示按钮并分配检查变量，而下面的另一个包含if语句，用于确定按下哪个按钮。这两个都工作得很完美，所以问题不存在。按下按钮，在第二个切换方法，我们有3个不同的bundle，用于将数据传递给FragmentProgressFragment.java，当"设定目标"时;按下按钮
package com.example.ssresilience;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
/**
* A simple {@link Fragment} subclass.
* Use the {@link ProgressFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class ProgressFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
public ProgressFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment ProgressFragment.
*/
// TODO: Rename and change types and number of parameters
public static ProgressFragment newInstance(String param1, String param2) {
ProgressFragment fragment = new ProgressFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_progress, container, false);
// Get the Selected Goal data from the GoalsFragment
Bundle b = getArguments();
int goal = b.getInt("goal");
System.out.println(goal);
// Set the Progress Fragment Text according to the selected Goal
TextView fg_progress_header2 = (TextView) rootView.findViewById(R.id.fg_progress_header2);
if (goal == 1) {
fg_progress_header2.setText("Socialize More");
} if (goal == 2) {
fg_progress_header2.setText("Enhance Study Motives");
} if (goal == 3) {
fg_progress_header2.setText("Physical Exercise");
}
return rootView;
}
}
System.out.println(goal);，它返回0，表示没有从第一个Fragment正确地检索到bundle数据。
我甚至试过把包关于GoalsFragment.java的onCreateView方法，只是为了防止下面的错误代码，但它仍然不能工作。
提前感谢!
您需要通过ViewModel或片段监听器与多个片段通信
from yourGoalFragment
Bundle result = new Bundle();
result.putInt("goal", 1);
getParentFragmentManager().setFragmentResult("progress", result);
In YourProgressFragment
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getParentFragmentManager().setFragmentResultListener("requestKey", this, new FragmentResultListener() {
@Override
public void onFragmentResult(@NonNull String requestKey, @NonNull Bundle bundle) {
// We use a String here, but any type that can be put in a Bundle is supported
String result = bundle.getInt("goal");
// Do something with the result
}
});
}
您可以查看文档了解详细实现https://developer.android.com/guide/fragments/communicate java