一,首先写一个类继承fragment
package com.example.pateo.boke;
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;
/**
* Created by pateo on 18-4-9.
*/
public class FirstFragment extends Fragment {
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
//引用创建好的布局
View view = inflater.inflate(R.layout.fragment_first,container,false);
return view;
}
}
二,activity中的代码
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import butterknife.ButterKnife;
import butterknife.OnClick;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.bind(this);
}
@OnClick({R.id.bt_first, R.id.bt_second})
public void onViewClicked(View view) {
switch (view.getId()) {
case R.id.bt_first:
//获取fragmentmanager,在v4包中getsupportfragmentmanager,
//在系统中原生fragment是通过 getFragmentManager 获得的
FragmentManager fragmentManager = getSupportFragmentManager();
//2.开启一个事务,通过begintransaction方法开启
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
// 创建fragment对象
FirstFragment firstFragment = new FirstFragment();
//向容器内加入fragment, 一般用add 或者replace方法,传入容器的id,或者是fragment实例
fragmentTransaction.add(R.id.fragment_container,firstFragment);
fragmentTransaction.commit();
break;
case R.id.bt_second:
//获取fragmentmanager,在v4包中getsupportfragmentmanager,
//在系统中原生fragment是通过 getFragmentManager 获得的
FragmentManager fragmentManager1 = getSupportFragmentManager();
//2.开启一个事务,通过begintransaction方法开启
FragmentTransaction fragmentTransaction1 = fragmentManager1.beginTransaction();
// 创建fragment对象
SecondFragment secondFragment = new SecondFragment();
//向容器内加入fragment, 一般用add 或者replace方法,传入容器的id,或者是fragment实例
fragmentTransaction1.add(R.id.fragment_container,secondFragment);
fragmentTransaction1.commit();
break;
}
}
}
发现:
第一种:
fragmentTransaction1.add(R.id.fragment_container,secondFragment);
app改成replace()方法
第二种:
if(FMs.findFragmentById(R.id.fragment_buju)==null){
//如果没有使用过
MfragmentTransactions.add(R.id.fragment_buju,f2);
}else {
//如果有使用过,就把老的fragment替换掉。
MfragmentTransactions.replace(R.id.fragment_buju,f2);
}
也就是做个判断 , 看是否存在 , 采用不同的方式:
源码:点击打开链接