記錄下切換fragment不重新實例化的方法:像淘寶 京東都是這樣的效果.

PRivate WarnFragment mWarnFragment;         //申明3個fragment  //我的    private MyselfFragment mMyselfFragment;     //預警    private CloudFragment mCloudFragment;       //云//點擊事件mMainRbCloud.setOnClickListener(this);        mMainRbWarn.setOnClickListener(this);        mMainRbMine.setOnClickListener(this);//默認選中第一個setTabSelected(0);//點擊事件@Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.main_rb_cloud:                setTabSelected(0);                break;            case R.id.main_rb_warn:                               setTabSelected(1);                break;            case R.id.main_rb_mine:                setTabSelected(2);                break;        }    }//顯示fragment    private void setTabSelected(int index) {        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();        hideFragments(transaction);	//先隱藏所有的fragment        switch (index) {            case 0:                if(mCloudFragment == null) {                    mCloudFragment = new CloudFragment();                    transaction.add(R.id.main_fr_content,mCloudFragment);                } else {                    transaction.show(mCloudFragment);                }                break;            case 1:                if(mWarnFragment == null) {                    mWarnFragment = new WarnFragment();                    transaction.add(R.id.main_fr_content,mWarnFragment);                } else {                    transaction.show(mWarnFragment);                }                break;            case 2:                if(mMyselfFragment == null) {                    mMyselfFragment = new MyselfFragment();                    transaction.add(R.id.main_fr_content,mMyselfFragment);                } else {                    transaction.show(mMyselfFragment);                }                break;        }        transaction.commit();    }    //隱藏所有fragment防止顯示多個    private void hideFragments(FragmentTransaction transaction) {        if(mCloudFragment!=null) {            transaction.hide(mCloudFragment);        }        if(mWarnFragment!=null) {            transaction.hide(mWarnFragment);        }        if(mMyselfFragment!=null) {            transaction.hide(mMyselfFragment);        }    }
上面是核心代碼, 具體要切換按鈕的狀態(tài),自己隨意寫.