如何使用底部导航活动更改片段？ [英] How to change fragment with the Bottom Navigation Activity?

问题描述

我创建了 底部导航活动 的新项目：
https://gyazo.com/f5efaecffd5adfd05e512921d3b8a19d

I created a new project with the "Bottom Navigation Activity": https://gyazo.com/f5efaecffd5adfd05e512921d3b8a19d

这是生成的代码：

package com.aaron.waller.mrpolitik;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView mTextMessage;

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.navigation_home:
                    mTextMessage.setText(R.string.title_home);
                case R.id.navigation_dashboard:
                    mTextMessage.setText(R.string.title_dashboard);
                case R.id.navigation_notifications:
                    mTextMessage.setText(R.string.title_notifications);
            }
            return true;
        }

    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTextMessage = (TextView) findViewById(R.id.message);
        BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
    }

}

如何更改为新碎片与底栏？
例如我有3个碎片：
Fragment1
Fragment2和
Fragment3
我想用底栏中的3个按钮更改它们。
另外我想要我可以通过向左和向右滑动我的手指来切换碎片我该怎么做？

How can I change to new Fragments with the Bottom Bar? For example I have 3 Fragments: Fragment1 Fragment2 and Fragment3 And I want to change to them with the 3 buttons from the Bottom Bar. Also I want that I can switch the Fragments by swiping my finger left and right how can I do that?

PS
我是Android新手Studio。

P.S Im new to Android Studio.

推荐答案

我会这样做，我会先添加三个类似于这个的方法（每个方法都是一个将布局名称和片段对象替换为正在切换到的相应片段：

The way I would do it is, I would first add three methods similar to this one (each for a single fragment. Replace the layout name and the fragment object to the appropriate fragment that is being switched to):

public void switchToFragment1() {
    FragmentManager manager = getSupportFragmentManager();
    manager.beginTransaction().replace(R.id.your_fragment_layout_name, new Fragment1()).commit();
}

所以你的switch语句最终会如下所示：

So your switch statement would end up looking like this:

        switch (item.getItemId()) {
            case R.id.navigation_home:
                mTextMessage.setText(R.string.title_home);
                switchToFragment1();
                break;

            case R.id.navigation_dashboard:
                mTextMessage.setText(R.string.title_dashboard);                    
                switchToFragment2();
                break;

            case R.id.navigation_notifications:
                mTextMessage.setText(R.string.title_notifications);                     
                switchToFragment3();
                break;
        }

至于通过向侧面滑动来切换碎片，我相信你需要 ViewPager 。

As for switching the fragments by swiping to the sides, I believe you would need a ViewPager.

希望这会有所帮助。 ：D

Hope this helps. :D

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