Navigation3

2023-11-08 12:00:16

两个页面可以通过连接ViewModel来共享数据。

这里也用了databinding

MasterFragment

package com.example.navviewmodel;


import android.os.Bundle;

import androidx.databinding.DataBindingUtil;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.lifecycle.SavedStateViewModelFactory;
import androidx.lifecycle.ViewModelProvider;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.SeekBar;

import com.example.navviewmodel.databinding.FragmentMasterBinding;


/**
 * A simple {@link Fragment} subclass.
 */
public class MasterFragment extends Fragment {


    public MasterFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, final ViewGroup container,
                             Bundle savedInstanceState) {
        final MyViewModel myViewModel;
        myViewModel=new ViewModelProvider(getActivity()).get(MyViewModel.class);
        FragmentMasterBinding binding;
        binding= DataBindingUtil.inflate(inflater,R.layout.fragment_master,container,false);
        binding.setData(myViewModel);
        binding.setLifecycleOwner(getActivity());
        binding.button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                NavController controller= Navigation.findNavController(view);
                controller.navigate(R.id.action_masterFragment_to_detailFragment);
            }
        });
        binding.seekBar.setProgress(myViewModel.getNumber().getValue());
        binding.seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                myViewModel.getNumber().setValue(i);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
        // Inflate the layout for this fragment
        //return inflater.inflate(R.layout.fragment_master, container, false);
        return  binding.getRoot();
    }

}

DetailFragment

package com.example.navviewmodel;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;

import androidx.databinding.DataBindingUtil;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.SavedStateViewModelFactory;
import androidx.lifecycle.ViewModelProvider;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.navviewmodel.databinding.FragmentDetailBinding;


/**
 * A simple {@link Fragment} subclass.
 */
public class DetailFragment extends Fragment {



    public DetailFragment() {
        // Required empty public constructor
    }
    @Override
    public View onCreateView(LayoutInflater inflater, final ViewGroup container,
                             Bundle savedInstanceState) {
        MyViewModel myViewModel;
        myViewModel=new ViewModelProvider(getActivity()).get(MyViewModel.class);
        FragmentDetailBinding binding;
        binding= DataBindingUtil.inflate(inflater,R.layout.fragment_detail,container,false);
        binding.setData(myViewModel);
        binding.setLifecycleOwner(getActivity());
        binding.button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                NavController controller= Navigation.findNavController(view);
                controller.navigate(R.id.action_detailFragment_to_masterFragment);
            }
        });
        return binding.getRoot();
        // Inflate the layout for this fragment
        //return inflater.inflate(R.layout.fragment_detail, container, false);
    }

}

MyViewModel

package com.example.navviewmodel;

import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;

public class MyViewModel extends ViewModel {
    private MutableLiveData<Integer> number;
    public MutableLiveData<Integer> getNumber(){
        if(number==null){
            number=new MutableLiveData<>();
            number.setValue(0);
        }
        return number;
    }
    public void add(int x){
        number.setValue(number.getValue()+x);
        if(number.getValue()<0){
            number.setValue(0);
        }
    }
}

Master.xml

<?xml version="1.0" encoding="utf-8"?>
<layout 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">

    <data>
        <variable
            name="data"
            type="com.example.navviewmodel.MyViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MasterFragment">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{String.valueOf(data.number)}"
            android:textSize="30sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.181" />

        <SeekBar
            android:id="@+id/seekBar"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:max="10"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.366" />

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="进入"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

Detail.xml

<?xml version="1.0" encoding="utf-8"?>
<layout 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">

    <data>
        <variable
            name="data"
            type="com.example.navviewmodel.MyViewModel" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".DetailFragment">

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{String.valueOf(data.number)}"
            android:textSize="30sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.538"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.172" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="76dp"
            android:text="-"
            android:onClick="@{()->data.add(-1)}"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="+"
            android:onClick="@{()->data.add(1)}"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/button2"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/button4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="返回"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.507"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.711" />
    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

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