原文地址：http://blog.csdn.net/wubihang/article/details/49991821
在玩音乐播放器时，排行榜界面 涉及到几个Fragment之间的跳转，通过查询自己做了一个小效果，感觉不错，利用一个简单的接口回调，
分享给初学者做着玩。大神勿喷！
点击左侧的按钮，右侧的内容随着点击变化。
简单介绍一下实现过程：首先界面由 左右两个Fragment构成，
左侧定义了5个Button，自定义一个接口，Button监听实现接口方法，传入int类型值
右侧定义一个ViewPager，在Activity中实现接口，根据Button传入的不同int，viewPager设置当前页为不同的index原理比较简单，看着挺好玩的，话不多说，直接上代码！
activity_main.xml
MainActivity.class
import android.support.v4.app.FragmentActivity;import android.os.Bundle;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentTransaction;import android.support.v4.view.ViewPager;public class MainActivity extends FragmentActivity implements LeftFragment.ToRightFragment{
private FragmentManager manager; private FragmentTransaction transaction; @Override
protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
manager = getSupportFragmentManager();
transaction = manager.beginTransaction(); // 替换占位布局为自定义Fragment，tag值为fragment的标示符
transaction.replace(R.id.left_view, new LeftFragment(), "left");
transaction.replace(R.id.right_view, new RightFragment(), "right");
transaction.commit();
} /**
* 接口回调方法（在类的声明中实现接口）
* @param index 实现接口方法时传的int值
*/
@Override
public void onToRightFragment(int index) { // 通过Tag，找到对应的Fragment
RightFragment rightFragment = (RightFragment) manager.findFragmentByTag("right"); // 通过viewPager的get方法，获得RightFragment中的viewPager
ViewPager viewPager = rightFragment.getViewPager(); switch (index){ case 0:
viewPager.setCurrentItem(0); break; case 1:
viewPager.setCurrentItem(1); break; case 2:
viewPager.setCurrentItem(2); break; case 3:
viewPager.setCurrentItem(3); break; case 4:
viewPager.setCurrentItem(4); break;
}
}
}12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455通过接口回调，设置ViewPager的当前页码，这样点击Button，ViewPager设置对应的页码，变相的实现了类似于跳转的功能LeftFragment.class
import android.content.Context;import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Button;public class LeftFragment extends Fragment implements View.OnClickListener {
private Button btn1, btn2, btn3, btn4, btn5; // 定义自定义接口
private ToRightFragment listener; /**
* 自定义接口
*/
public interface ToRightFragment {
// 接口中的方法，参数为int类型的值
void onToRightFragment(int index);
} /**
* fragment与activity发生关联
* @param context
*/
@Override
public void onAttach(Context context) { super.onAttach(context); // 将context转型为接口 赋值给接口对象
listener = (ToRightFragment) context;
} @Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_left, null);
} @Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState);
initView(getView());
} private void initView(View view) {
btn1 = (Button) view.findViewById(R.id.btn_1);
btn2 = (Button) view.findViewById(R.id.btn_2);
btn3 = (Button) view.findViewById(R.id.btn_3);
btn4 = (Button) view.findViewById(R.id.btn_4);
btn5 = (Button) view.findViewById(R.id.btn_5);
btn1.setOnClickListener(this);
btn2.setOnClickListener(this);
btn3.setOnClickListener(this);
btn4.setOnClickListener(this);
btn5.setOnClickListener(this);
} /**
* Button的监听事件
* 点击Button实现接口方法，传入一个int类型的值
*/
@Override
public void onClick(View v) { switch (v.getId()) { case R.id.btn_1:
listener.onToRightFragment(0); break; case R.id.btn_2:
listener.onToRightFragment(1); break; case R.id.btn_3:
listener.onToRightFragment(2); break; case R.id.btn_4:
listener.onToRightFragment(3); break; case R.id.btn_5:
listener.onToRightFragment(4); break;
}
}
}123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687左侧Fragment布局只有5个Button
右侧Fragment是一个ViewPager
import android.os.Bundle;import android.support.annotation.Nullable;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.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import java.util.ArrayList;public class RightFragment extends Fragment{
private ViewPager viewPager; // 给viewPager一个get方法
public ViewPager getViewPager() { return viewPager;
} @Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_right, null);
} @Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState);
viewPager = (ViewPager) getView().findViewById(R.id.view_pager);
ArrayList data = new ArrayList<>();
data.add(new InfoFragment("国内歌手"));
data.add(new InfoFragment("欧美歌手"));
data.add(new InfoFragment("外星歌手"));
data.add(new InfoFragment("太阳歌手"));
data.add(new InfoFragment("银河歌手"));
MyAdapter adapter = new MyAdapter(getActivity().getSupportFragmentManager(), data);
viewPager.setAdapter(adapter);
} /**
* 适配器
*/
private class MyAdapter extends FragmentPagerAdapter {
private ArrayList lists; public MyAdapter(FragmentManager fm, ArrayList lists) { super(fm); this.lists = lists;
} @Override
public Fragment getItem(int position) { return lists != null && lists.size() > 0 ? lists.get(position) : null;
} @Override
public int getCount() { return lists != null && lists.size() > 0 ? lists.size() : 0;
}
}
}123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869 xml
右侧Fragment的ViewPager显示的Fragment
package com.wu.blogdemo;import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;public class InfoFragment extends Fragment{
private String info; public InfoFragment() {
} public InfoFragment(String info) { this.info = info;
} @Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_info, null);
TextView tv = (TextView) v.findViewById(R.id.info_show);
tv.setText(info); return v;
}
}12345678910111213141516171819202122232425262728293031xml
如此利用接口回调，实现了Fragment之间的跳转，但是这种跳转有所限制，
Fragment2中是一个TabLayout，在跳转到TabLayout中的FragmentX，也可以实现
就是在实现接口时，一层一层的findFragmentByTag
同样Fragment与Activity之间的通信也可以采用接口回调
fragment向activity传值，通过接口回调传递给activity