如何在 FAB 按钮单击时将数据从多个片段发送到单个活动答案

【问题标题】：How to send data from Multiple Fragments to single activity on FAB button click如何在 FAB 按钮单击时将数据从多个片段发送到单个活动
【发布时间】：2020-09-02 11:49:33
【问题描述】：

我的问题是点击b4(fab)只有 Fragment B 数据进入 SecondActivity.I 希望同时收集 Fragment A 和 Fragment B 数据当单击片段 A 和可用的b4Fab 按钮时片段 B。

也代替 Fragment A 数据 t4.setText(vres);,t5.setText(vres1);,t6.setText(vres2); 的第二个活动得到一个值null。我不明白为什么会这样？而且总是从 Fragment B 获取数据。我想要 Fragment A 和当 b4(fab) 为时，在 SecondActivity 处获取的片段 B 数据已点击。提前致谢。

片段 A

公共类 Fragment_nonveg 扩展 Fragment {

    TextView t,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10;
    CheckBox c1,c2,c3,c4,c5;
    Button b1,b2,b5,b6,b7,b8,b9,b10,b11,b12;
    ImageButton b3;
    int x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,g1,g2,g3,g4,g5,g6,g7,g8,g9,g10;
    String res,res1,res2,res3,res4,re,re1,re2,re3,re4;
    FloatingActionButton b4;


    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        Bundle bundle = this.getArguments();

        return inflater.inflate(R.layout.fragment_nonveg, null);
    }
@Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {

        super.onActivityCreated(savedInstanceState);
        b4 = getActivity().findViewById(R.id.fab);
b4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent obj4 = new Intent(getActivity(), Bill.class);
                //obj4.putExtra("k", r1);

                int total = 0;
                String item = "", qty = "", amt = "";
                if (c1.isChecked() == true) {

                    item = item + c1.getText().toString() + "\n";
                    qty = qty + t2.getText().toString() + "\n";
                    amt = amt + t1.getText().toString() + "\n";
                    String t = t1.getText().toString();
                    total = total + Integer.parseInt(t);
                }
                if (c2.isChecked() == true) {
                    item = item + c2.getText().toString() + "\n";
                    qty = qty + t4.getText().toString() + "\n";
                    amt = amt + t3.getText().toString() + "\n";
                    String t = t3.getText().toString();
                    total = total + Integer.parseInt(t);
                }
                if (c3.isChecked() == true) {
                    item = item + c3.getText().toString() + "\n";
                    qty = qty + t6.getText().toString() + "\n";
                    amt = amt + t5.getText().toString() + "\n";
                    String t = t5.getText().toString();
                    total = total + Integer.parseInt(t);
                }
                if (c4.isChecked() == true) {
                    item = item + c4.getText().toString() + "\n";
                    qty = qty + t8.getText().toString() + "\n";
                    amt = amt + t7.getText().toString() + "\n";
                    String t = t7.getText().toString();
                    total = total + Integer.parseInt(t);

                }
                if (c5.isChecked() == true) {
                    item = item + c5.getText().toString() + "\n";
                    qty = qty + t10.getText().toString() + "\n";
                    amt = amt + t9.getText().toString() + "\n";
                    String t = t9.getText().toString();
                    total = total + Integer.parseInt(t);

                }

                int T=total;
                obj4.putExtra("key", item);
                obj4.putExtra("key2", qty);
                obj4.putExtra("key3", amt);
                obj4.putExtra("key16", T);
                getActivity().startActivity(obj4);
            }
       });

    }
}

片段 B

public class Fragment_veg extends Fragment {


    FloatingActionButton b4;


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

        return inflater.inflate(R.layout.fragment_veg,null);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
b4 = getActivity().findViewById(R.id.fab);
b4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Do what you want
                Intent obj4 = new Intent(getActivity(), Bill.class);


                int total = 0;
                String vitem = "", vqty = "", vamt = "";
                if (vc1.isChecked() == true) {

                    vitem = vitem + vc1.getText().toString() + "\n";
                    vqty = vqty + t2.getText().toString() + "\n";
                    vamt = vamt + t1.getText().toString() + "\n";
                    String t = t1.getText().toString();
                    total = total + Integer.parseInt(t);
                }
                if (vc2.isChecked() == true) {
                    vitem = vitem + vc2.getText().toString() + "\n";
                    vqty = vqty + t4.getText().toString() + "\n";
                    vamt = vamt + t3.getText().toString() + "\n";
                    String t = t3.getText().toString();
                    total = total + Integer.parseInt(t);
                }
                if (vc3.isChecked() == true) {
                    vitem = vitem + vc3.getText().toString() + "\n";
                    vqty = vqty + t6.getText().toString() + "\n";
                    vamt = vamt + t5.getText().toString() + "\n";
                    String t = t5.getText().toString();
                    total = total + Integer.parseInt(t);
                }
                if (vc4.isChecked() == true) {
                    vitem = vitem + vc4.getText().toString() + "\n";
                    vqty = vqty + t8.getText().toString() + "\n";
                    vamt = vamt + t7.getText().toString() + "\n";
                    String t = t7.getText().toString();
                    total = total + Integer.parseInt(t);

                }
                if (vc5.isChecked() == true) {
                    vitem = vitem + vc5.getText().toString() + "\n";
                    vqty = vqty + t10.getText().toString() + "\n";
                    vamt = vamt + t9.getText().toString() + "\n";
                    String t = t9.getText().toString();
                    total = total + Integer.parseInt(t);

                }
                int vT;
                vT = total;
                obj4.putExtra("vkey", vitem);
                obj4.putExtra("vkey2", vqty);
                obj4.putExtra("vkey3", vamt);
                obj4.putExtra("vkey16", vT);
                startActivity(obj4);
            }

        });
    }

}

主活动

public class Menu extends AppCompatActivity {

    TextView nonveg,veg,snacks,desert,beverges;
    ViewPager viewPager;
    PageViewAdapter pageViewAdapter;
    public FloatingActionButton b4;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu);
        nonveg=(TextView)findViewById(R.id.nonveg);
        veg=(TextView)findViewById(R.id.veg);
        snacks=(TextView)findViewById(R.id.snacks);
        desert=(TextView)findViewById(R.id.desert);
        beverges=(TextView)findViewById(R.id.beverges);
        viewPager=(ViewPager)findViewById(R.id.fragment_container);
        pageViewAdapter=new PageViewAdapter(getSupportFragmentManager());
        viewPager.setAdapter(pageViewAdapter);

        nonveg.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewPager.setCurrentItem(0);
            }
        });

        veg.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewPager.setCurrentItem(1);
            }
        });

        snacks.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewPager.setCurrentItem(2);
            }
        });

        desert.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewPager.setCurrentItem(3);
            }
        });

        beverges.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                viewPager.setCurrentItem(4);
            }
        });

        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @RequiresApi(api = Build.VERSION_CODES.M)
            @Override
            public void onPageSelected(int position) {
                onChangeTab(position);

            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

    }

第二个活动

public class Bill extends AppCompatActivity {

    TextView t,t1,t2,t3,t16,t17,t4,t5,t6;
    Button b,b1;
    static   String res,res1,res2,/*res15,*/vres,vres1,vres2/*vres15*/;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bill);
        t = findViewById(R.id.textView);
        t1 = findViewById(R.id.textView5);
        t2 = findViewById(R.id.textView10);
        t3 = findViewById(R.id.textView15);
        t4 = findViewById(R.id.textView6);
        t5 = findViewById(R.id.textView11);
        t6 = findViewById(R.id.textView16);
        t16 = findViewById(R.id.textView20);
        t17 = findViewById(R.id.textView21);
        b = findViewById(R.id.button22);
        b1 = findViewById(R.id.button23);
        Intent obj2 = getIntent();
        res = obj2.getStringExtra("key");
        res1 = obj2.getStringExtra("key2");
        res2 = obj2.getStringExtra("key3");
        int res15 = getIntent().getIntExtra("key16",0);
        vres = obj2.getStringExtra("vkey");
        vres1 = obj2.getStringExtra("vkey2");
        vres2 = obj2.getStringExtra("vkey3");
        int vres15 = getIntent().getIntExtra("vkey16",0);
        //vres15 = obj2.getStringExtra("vkey16");
        t1.setText(res);
        t2.setText(res1);
        t3.setText(res2);
        t4.setText(vres);
        t5.setText(vres1);
        t6.setText(vres2);
        t16.setText("Total Price:");
        int total2 = res15+vres15;
        t17.setText(String.valueOf(total2));
}
}

【问题讨论】：

标签： android android-activity fragment floating-action-button

【解决方案1】：

为了在片段和活动之间传递数据，您应该声明接口，然后在片段中创建该接口的变量，并在按钮单击时调用接口的功能之一，同时在您的活动中实现这些方法，这样您就可以通过通过接口函数和这些函数的参数从片段到您的活动的任何数据

 interface Test{
    void onSthHappend(String str);

} 
class fragment extends Fragment{
private Test interface;
 @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        interface= (Test ) context;
    }
   fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
interface.onSthHappend("hi");
            }
        });
}
clas activity Extends Activity implements Test{
@override onSthHappend(String str){
//do your stuff
}
}

【讨论】：

通过这样做，它会获取多个片段数据并将其传递给单个活动吗？因为我已经在 stackoverflow 上经历了许多这种类型的解决方案，但它们是针对单个片段的。
我通过在以下参考答案中对所有其他片段处理相同的编码Fragment A 找到了此问题所需的内容。请参阅此 [stackoverflow.com/questions/61868402/…

【解决方案2】：

在这个问题中，需要的是sharedpreferences。

第1步：- 在不同Fragment中的Activity片段容器中实现如下：-

public class Fragment_class_name extends Fragment {
public static int totalp;
    public static String itemp, qtyp, amtp;
    SharedPreferences sp;
    private static Fragment_nonveg instance;
@Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        Bundle bundle = this.getArguments();
        instance = this;
        return inflater.inflate(R.layout.fragment_nonveg, null);
    }
public void onActivityCreated(@Nullable Bundle savedInstanceState) {

            super.onActivityCreated(savedInstanceState);
     //do your code
}
     public static Fragment_nonveg getInstance() {
            return instance;
        }
        public void yourfuncname(){//any calculative function you want to calculate or //pass data
sp=this.getActivity().getSharedPreferences("calis", Context.MODE_PRIVATE);
            SharedPreferences.Editor editor=sp.edit();
editor.putString("key1",value1);
            editor.putString("key2",value2);
editor.commit();
        }
    }

第 2 步：- 然后在您的 Activity 中执行以下操作：-

public class Activity_class_name extends AppCompatActivity {

   
    ViewPager viewPager;
    PageViewAdapter pageViewAdapter;
    public FloatingActionButton b4;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu);
        b4 = findViewById(R.id.fab);
b4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent obj4 = new Intent(Menu.this, Bill.class);
                Fragment_class_name.getInstance().yourfuncname();
                startActivity(obj4);
            }
        });
}

第 3 步：- 对片段容器的所有片段执行此操作

【讨论】：