片段不会改变其他片段的背景颜色答案

【问题标题】：Fragment wont change other fragments background color片段不会改变其他片段的背景颜色
【发布时间】：2020-03-16 08:24:46
【问题描述】：

我有一个具有不同颜色选项的微调器。我想让上半部分只包括微调器，下半部分将其背景颜色更改为从微调器中选择的颜色。例如：从微调器中选择的蓝色下半部分显示：背景为蓝色，文字为蓝色

我在 PaletteFragment（包括微调器） 中创建了一个捆绑包，它使用 setArguments() 将点击的位置传递给 CanvasFragment（它应该使用适当的位置更改颜色背景）接收）

无法理解为什么它没有改变底部布局的背景颜色，因为即使我从微调器中选择了一种颜色，我在 Logcat 中也没有出现错误。

调色板片段：

package edu.temple.coloractivity;


import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;

import java.util.Locale;


/**
 * A simple {@link Fragment} subclass.
 * Use the {@link PaletteFragment #newInstance} factory method to
 * create an instance of this fragment.
 */
public class PaletteFragment 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 static PaletteFragment newIntance(){
        return new PaletteFragment();
    }
    public PaletteFragment() {
        // 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 PaletteFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static PaletteFragment newInstance(String param1, String param2) {
        PaletteFragment fragment = new PaletteFragment();
        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) {
        View view = inflater.inflate(R.layout.fragment_palette, container, false);
        Spinner spinner = (Spinner) view.findViewById(R.id.spinner);
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
                getActivity(), R.array.myColors, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(
                android.R.layout.simple_spinner_dropdown_item);
        ArrayAdapter<CharSequence> stringNames = ArrayAdapter.createFromResource(getActivity(), R.array.myStrings, android.R.layout.simple_spinner_item);
        stringNames.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        ArrayAdapter<CharSequence> stringName = ArrayAdapter.createFromResource(getActivity(),R.array.myStrings, android.R.layout.simple_spinner_item);
        stringName.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        View v = inflater.inflate(R.layout.fragment_palette,container,false);
        spinner = v.findViewById(R.id.spinner);
        spinner.setAdapter(new ColorAdapter(getActivity()));

        spinner = v.findViewById(R.id.spinner);
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                ViewGroup container;
                if(position == 0){
                }
                else if(position == 1){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 2){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 3){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 4){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 5){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 6){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 7){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 8){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 9){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }else if(position == 10){
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);
                }

            }
            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });
        return v;
    }

}

画布活动：

package edu.temple.coloractivity;

import android.content.Context;
import android.net.Uri;
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 org.w3c.dom.Text;

import java.util.Locale;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link CanvasFragment.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link CanvasFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class CanvasFragment 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 OnFragmentInteractionListener mListener;

    public CanvasFragment() {
        // 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 CanvasFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static CanvasFragment newInstance(String param1, String param2) {
        CanvasFragment fragment = new CanvasFragment();
        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) {
        View view = inflater.inflate(R.layout.fragment_canvas, container, false);
        String CurrentLang = Locale.getDefault().getLanguage();
        TextView text = (TextView) view.findViewById(R.id.newColor);
        Fragment fragment = (Fragment) getFragmentManager().findFragmentById(R.id.secondLayout);
        final View newBackground;
        fragment.getView().setBackgroundResource(R.color.white);
        System.out.println(Locale.getDefault().getLanguage());
        Bundle b = getArguments();
        int pos = b.getInt("position");
        if(pos == 1){
            fragment.getView().setBackgroundResource(R.color.silver);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 2){
            fragment.getView().setBackgroundResource(R.color.pink);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 3){
            fragment.getView().setBackgroundResource(R.color.red);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 4){
            fragment.getView().setBackgroundResource(R.color.orange);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 5){
            fragment.getView().setBackgroundResource(R.color.yellow);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 6){
            fragment.getView().setBackgroundResource(R.color.green);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 7){
            fragment.getView().setBackgroundResource(R.color.blue);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 8){
            fragment.getView().setBackgroundResource(R.color.indigo);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 9){
            fragment.getView().setBackgroundResource(R.color.violet);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }else if(pos == 10){
            fragment.getView().setBackgroundResource(R.color.brown);
            if(CurrentLang=="es"){
                displayColorName(pos,text);
            }else{
                displayColorName(pos,text);
            }
        }
        return view;
    }
    private void displayColorName(int pos, TextView text){
        String retrieve[] = getResources().getStringArray(R.array.myStrings);
        String color = retrieve[pos];
        text.setText(color);
    }


    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

画布活动：

package edu.temple.coloractivity;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;

import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Build;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Locale;

public class CanvasActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_canvas);
        CanvasFragment CanvasFragment = new CanvasFragment();
        FragmentManager manager = getSupportFragmentManager();
        manager.beginTransaction().replace(R.id.secondLayout,CanvasFragment,CanvasFragment.getTag())
                .commit();
    }
}

调色板活动：

package edu.temple.coloractivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;

import java.util.Locale;


public class PaletteActivity extends AppCompatActivity {
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        PaletteFragment PaletteFragment = new PaletteFragment();
        FragmentManager manager = getSupportFragmentManager();
        manager.beginTransaction().replace(R.id.firstLayout,PaletteFragment,PaletteFragment.getTag())
                .commit();
    }
}

颜色适配器：

package edu.temple.coloractivity;

import android.content.Context;
import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.graphics.Color;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.SpinnerAdapter;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Locale;

public class ColorAdapter extends BaseAdapter {
    ArrayList<Integer> colors;
    Context context;

    public ColorAdapter(Context context){

        this.context=context;
        colors = new ArrayList<Integer>();
        int retrieve []=context.getResources().getIntArray(R.array.myColors);
        for(int i:retrieve)
        {
            colors.add(i);
        }
    }
    @Override
    public int getCount() {
        return colors.size();
    }

    @Override
    public Object getItem(int args) {
        return colors.get(args);
    }

    @Override
    public long getItemId(int args) {
        return args;
    }

    public String getElementFromColors(int position){
        String CurrentLang = Locale.getDefault().getLanguage();
        if(CurrentLang.equals("es")){
            String retrieve[] = context.getResources().getStringArray(R.array.myStrings);
            return retrieve[position];
        }else{

            String retrieve[] = context.getResources().getStringArray(R.array.myStrings);
            return retrieve[position];
        }
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater=LayoutInflater.from(context);
        convertView=inflater.inflate(android.R.layout.simple_spinner_dropdown_item, null);
        TextView txv=(TextView)convertView.findViewById(android.R.id.text1);
        txv.setBackgroundColor(colors.get(position));
        txv.setText(getElementFromColors(position));
        return convertView;
    }

}

上半部分仅包括微调器下拉菜单

一旦我选择了一种颜色，我希望下半部分将该布局的背景更改为所选颜色

【问题讨论】：

标签： android android-fragments spinner android-spinner

【解决方案1】：

您的问题：

您的代码为微调器中的每个项目选择创建一个CanvasFragment，但对它没有任何作用。 必须将片段添加到 FragmentManager 才能可见！

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                ViewGroup container;
                if(position == 0){
                }
                else if(position == 1){

                    // New fragment is created, arguments are set, and then ... nothing.
                    // That's it. It's just left hanging.
                    Bundle args = new Bundle();
                    args.putInt("position",position);
                    CanvasFragment newFragment = new CanvasFragment();
                    newFragment.setArguments(args);

             // MORE CODE LIKE THIS

您的解决方案：

您必须更新您的代码，以便PaletteFragment 通知 CanvasActivity 做出了新的选择，然后让它更新当前的CanvasFragment。

你应该有一个 Activity 拥有两个 Fragment。您的活动应该实现一个在选择颜色时调用的接口。 PaletteFragment 应该访问其 Activity，将其转换为接口类型，并调用其上的方法以通知已进行选择。然后，在 Activity 中，接口方法应根据给定的参数更新 CanvasFragment 上当前选择的颜色。

希望有帮助！

See the documentation for details on communicating between fragments.

【讨论】：