Android 首页Fragment切换常用姿势

package com.homepagedemo; import android.os.Bundle; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentTransaction; import android.support.v7.app.AppCompatActivity; import android.widget.RadioGroup; import butterknife.Bind; import butterknife.ButterKnife; public class RadioGroupActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener { private Fragment1 fragment1; private Fragment2 fragment2; private Fragment3 fragment3; private Fragment4 fragment4; @Bind(R.id.rg) RadioGroup radioGroup; private FragmentManager fragmentManager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_radio_group); ButterKnife.bind(this); fragmentManager = getSupportFragmentManager(); //默认选中第一个tab showFragment(1); radioGroup.check(R.id.rb_1); radioGroup.setOnCheckedChangeListener(this); } private void showFragment(int page) { FragmentTransaction ft = fragmentManager.beginTransaction(); // 想要显示一个fragment,先隐藏所有fragment，防止重叠 hideFragments(ft); switch (page) { case 1: // 如果fragment1已经存在则将其显示出来 if (fragment1 != null) ft.show(fragment1); // 否则添加fragment1，注意添加后是会显示出来的，replace方法也是先remove后add else { fragment1 = new Fragment1(); ft.add(R.id.fl_content_main, fragment1); } break; case 2: if (fragment2 != null) ft.show(fragment2); else { fragment2 = new Fragment2(); ft.add(R.id.fl_content_main, fragment2); } break; case 3: if (fragment3 != null) { ft.show(fragment3); } else { fragment3 = new Fragment3(); ft.add(R.id.fl_content_main, fragment3); } break; case 4: if (fragment4 != null){ ft.show(fragment4); } else { fragment4 = new Fragment4(); ft.add(R.id.fl_content_main, fragment4); } break; } ft.commit(); } // 当fragment已被实例化，相当于发生过切换，就隐藏起来 public void hideFragments(FragmentTransaction ft) { if (fragment1 != null) ft.hide(fragment1); if (fragment2 != null) ft.hide(fragment2); if (fragment3 != null) ft.hide(fragment3); if (fragment4 != null) ft.hide(fragment4); } @Override public void onCheckedChanged(RadioGroup group, int checkedId) { switch (checkedId){ case R.id.rb_1: showFragment(1); break; case R.id.rb_2: showFragment(2); break; case R.id.rb_3: showFragment(3); break; case R.id.rb_4: showFragment(4); break; } } }