Fragment

主文件的XML

fragment1的XML

fragment2的XML

主文件的JAVA代码

package com.example.mpyypm.fragmentzy;
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
fragment1 fragment1;
fragment2 fragment2;
private boolean qiehuan = true;
private boolean back = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
fragment1 = new fragment1();
transaction.add(R.id.bnt_show,fragment1);
transaction.commit();
}
@Override
public void onClick(View view) {
if(view.getId() == R.id.bnt1){
back = true;
if(qiehuan){
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
if (fragment2 == null){
fragment2 = new fragment2();
transaction.replace(R.id.bnt_show,fragment2);
transaction.commit();
qiehuan = false;
}
else{
transaction.replace(R.id.bnt_show,fragment2);
transaction.commit();
qiehuan = false;
}
}
else{
Toast.makeText(this,"This is second fragment",Toast.LENGTH_SHORT).show();
}

}
}
public boolean onKeyDown(int keyCode, KeyEvent event) {

if(event.getKeyCode()==KeyEvent.KEYCODE_BACK&&back){

FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
qiehuan = true;
back = false;
transaction.replace(R.id.bnt_show,fragment1);
transaction.commit();
return false;
}
else {
finish();
}
return super.onKeyDown(keyCode, event);
}

}

fragment1的JAVA代码

package com.example.mpyypm.fragmentzy;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class fragment1 extends Fragment {

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_fragment1, container, false);
return view;
}
}

fragment2的JAVA代码

package com.example.mpyypm.fragmentzy;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class fragment2 extends Fragment {

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View view = inflater.inflate(R.layout.fragment_fragment2,container,false);
return view;
}
}