Navigation1

要想用navigation组件首先要添加两个依赖，尤其是要先添加依赖，不然会特别特别特别卡卡卡

implementation "androidx.navigation:navigation-fragment:2.3.5"
implementation "androidx.navigation:navigation-ui:2.3.5"

然后就是添加fragment

 

 DetailFragment

package com.example.navigationdemo;


import android.os.Bundle;

import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;

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


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


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


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_detail, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Button button;
        button=getView().findViewById(R.id.button2);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                NavController navController=Navigation.findNavController(view);
                navController.navigate(R.id.action_detailFragment_to_homeFragment);
            }
        });
    }
}

HomeFragment

package com.example.navigationdemo;


import android.os.Bundle;

import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;

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


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


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


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_home, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Button button;
        button=getView().findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                NavController controller= Navigation.findNavController(view);
                controller.navigate(R.id.action_homeFragment_to_detailFragment);
            }
        });
    }
}

MainActivity　　

package com.example.navigationdemo;

import androidx.appcompat.app.AppCompatActivity;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.NavigationUI;

import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        NavController controller= Navigation.findNavController(this,R.id.fragment);
        NavigationUI.setupActionBarWithNavController(this,controller);
    }

    @Override
    public boolean onSupportNavigateUp() {
        NavController controller=Navigation.findNavController(this,R.id.fragment);
        return controller.navigateUp();
    }
}