片段到片段通信(寻呼机适配器)

Question

首先，我要说的是，我试过用各种方法将数据从一个片段发送到另一个片段，每次我都失败了。

我有一个带有寻呼机适配器和选项卡的主要活动，我有5个片段，我需要将数据从片段5发送到其余的片段，我尝试了接口和其他3种方法，最后在开始时崩溃或出错。

我使用了接口，它有时只起作用，为了找出为什么它在某些情况下不起作用，我来到这里，但没有得到任何答案。

提前谢谢你。

主要活动：

   package com.redot.puzzle3;

   import android.os.Bundle;
   import android.support.design.widget.FloatingActionButton;
   import android.support.design.widget.Snackbar;
   import android.support.design.widget.TabLayout;
   import android.support.v4.app.Fragment;
   import android.support.v4.app.FragmentManager;
   import android.support.v4.app.FragmentPagerAdapter;
   import android.support.v4.view.ViewPager;
   import android.support.v7.app.AppCompatActivity;
   import android.view.View;
   import android.view.WindowManager;


    public class MainActivity extends AppCompatActivity  {

    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //Remove title bar
    //  this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
    WindowManager.LayoutParams.FLAG_FULLSCREEN);
    this.setContentView(R.layout.activity_main);


    mSectionsPagerAdapter = new 
    SectionsPagerAdapter(getSupportFragmentManager());


    mViewPager = (ViewPager) findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);
    mViewPager.setCurrentItem(3);





    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(mViewPager);

    FloatingActionButton fab = (FloatingActionButton) 
     findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", 
  Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

}


    public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }
        @Override
        public int getCount() {
            return 5;
        }


        @Override
    public Fragment getItem(int arg0) {
        switch (arg0) {
            case 0:
                return new Frag1();
            case 1:
                return new Frag2();
            case 2:
                return new Frag3();
            case 3:
                return new Frag4();
            case 4:
                return new Frag5();
            case 5:


            default:
            return null;
        }

    }


    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "Inventory";
            case 1:
                return "3Men";
            case 2:
                return "Test";
            case 3:
                return "TheMan";
            case 4:
                return "King";

        }
        return null;
    }
}

}

主要活动布局：

   <?xml version="1.0" encoding="utf-8"?>
  <android.support.design.widget.CoordinatorLayout          
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.redot.puzzle3.MainActivity">

   <android.support.design.widget.AppBarLayout
    android:id="@+id/appbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingTop="@dimen/appbar_padding_top"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

   </android.support.design.widget.AppBarLayout>



   <android.support.v4.view.ViewPager
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />


   <android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="end|bottom"
    android:layout_margin="@dimen/fab_margin"
    app:srcCompat="@android:drawable/ic_dialog_email" />

  </android.support.design.widget.CoordinatorLayout>

片段的构建是类似的

碎片：

  public  class Frag1 extends Fragment  {


   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // TODO Auto-generated method stub
          View myInflatedView = inflater.inflate(R.layout.fragment_frag1, 
    container, false);

    return myInflatedView;

  }

更新

我使用了共享首选项( utils )，除了当我转到发送数据的页面时出现了这个错误外，所有操作都正常工作。

10-11 04:49:13.040 6734-6734/com.redot.puzzle3 E/AndroidRuntime: FATAL EXCEPTION: main
                                                             Process: com.redot.puzzle3, PID: 6734
                                                             java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String, int)' on a null object reference
                                                                 at com.redot.puzzle3.SharedPreferenceUtils.getData1(SharedPreferenceUtils.java:30)
                                                                 at com.redot.puzzle3.Frag1.<init>(Frag1.java:19)
                                                                 at com.redot.puzzle3.MainActivity$SectionsPagerAdapter.getItem(MainActivity.java:71)
                                                                 at android.support.v4.app.FragmentPagerAdapter.instantiateItem(FragmentPagerAdapter.java:101)
                                                                 at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:1005)
                                                                 at android.support.v4.view.ViewPager.populate(ViewPager.java:1153)
                                                                 at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:665)
                                                                 at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:627)
                                                                 at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:608)
                                                                 at android.support.design.widget.TabLayout$ViewPagerOnTabSelectedListener.onTabSelected(TabLayout.java:2169)
                                                                 at android.support.design.widget.TabLayout.dispatchTabSelected(TabLayout.java:1164)
                                                                 at android.support.design.widget.TabLayout.selectTab(TabLayout.java:1157)
                                                                 at android.support.design.widget.TabLayout.selectTab(TabLayout.java:1127)
                                                                 at android.support.design.widget.TabLayout$Tab.select(TabLayout.java:1426)
                                                                 at android.support.design.widget.TabLayout$TabView.performClick(TabLayout.java:1536)
                                                                 at android.view.View$PerformClick.run(View.java:21179)
                                                                 at android.os.Handler.handleCallback(Handler.java:739)
                                                                 at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                 at android.os.Looper.loop(Looper.java:145)
                                                                 at android.app.ActivityThread.main(ActivityThread.java:6873)
                                                                 at java.lang.reflect.Method.invoke(Native Method)
                                                                 at java.lang.reflect.Method.invoke(Method.java:372)
                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)

指的是这种方法：

 public static int getData1(Context context) {
    SharedPreferences sp = context.getSharedPreferences(SP_NAME, 
    Context.MODE_PRIVATE);
    return sp.getInt(DATA1, x);
}

获取数据的片段1: int Riddle= Riddle=

我只有一个数据，那就是int和我在寻找分享，我发现了很多好东西。

所以这就是我正在做的，它起作用了：

片段5(发送数据的片段)：

  Context context = getActivity();
    SharedPreferences SU = context.getSharedPreferences(
            "Riddle", Context.MODE_PRIVATE);
    SharedPreferences.Editor editor= SU.edit();
    editor.putString("riddle",""+riddle);
    editor.commit();

片段1(获取数据)：

     Context context = getActivity();
         SharedPreferences SU = context.getSharedPreferences(
            "Riddle", Context.MODE_PRIVATE);
            Riddle=  Integer.parseInt(SU.getString("riddle",""));

我在发送int时遇到了一些问题，所以我发送了字符串并转换为int。

Answer 1

您可以在代码中使用SharedPreferences。

试试这个。

public class SharedPreferenceUtils {

    private static final String SP_NAME = "sp";
    public static final String DATA1 = "data1";
    public static final String DATA2 = "data2";


    // create
    public static boolean createSP(Context context, String data1, String data2) {
        SharedPreferences.Editor editor = context.getSharedPreferences(SP_NAME, Context.MODE_PRIVATE).edit();
        editor.putString(DATA1, data1);
        editor.putString(DATA2, data2);
        return editor.commit();
    }

    // clear
    public static void clearSP(Context context) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(SP_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear().apply();
    }

    // get access info
    public static String getData1(Context context) {
        SharedPreferences sp = context.getSharedPreferences(SP_NAME, Context.MODE_PRIVATE);
        return sp.getString(DATA1, "");
    }
    // get branch info
    public static String getData2(Context context) {
        SharedPreferences sp = context.getSharedPreferences(SP_NAME, Context.MODE_PRIVATE);
        return sp.getString(DATA2, "");
    }
}

Frag5中的使用

SharedPreferenceUtils.createSP(getActivity(),data1,data2);

及其在其他中的应用

String data1 = SharedPreferenceUtils.getData1(getActivity());
String data2 = SharedPreferenceUtils.getData2(getActivity());

Note

• 将data1和data2更改为所需的值
• 将getData1和getData2更改为所需的方法

Answer 2

实际上，你有很多选项可以与片段沟通。我建议您使用CachePot - Android简单数据缓存缓存数据。

首先，推送您想要传递的数据。

CachePot.getInstance().push(data);

第二，从CachePot中弹出数据。

public class MainFragment extends Fragment{
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Data data = CachePot.getInstance().pop(Data.class);
    }