Data transmission of different fragments in the same activity

Reference article ：http://blog.csdn.net/harvic880925/article/details/44966913

Recently, such a requirement needs to be implemented in the project ：

The same Activity There are two Fragment, Then there are two Fragment. two Fragment There are different ListView.

Then realize from Fragment1 Medium ListView Click on item Then add to Fragment2 Of ListView in

Let's first understand the situation .

About Fragment Data transfer , There are actually two situations

Situation 1 ：Fragment Between show and hide is to use replace To achieve the

Situation two ：Fragment Between show and hide is to use hide and show Method

Everyone knows this , See your project needs specifically .

There are different solutions for specific situations ,

For case one , We can use fragment.setArgument() Method to transfer data （ Refer to the great God's blog）

Let's focus on the second case , adopt Interface callback Method to realize data transmission

Literature reference ：http://www.cnblogs.com/kissazi2/p/3440257.html

Steps of setting interface callback :

1.Fragment1 Define an interface in

public interface onDataChangedListener {
        void onDataChanged(HarvestBean bean);   // Parameters are the data content that users need to pass , Here I use a Bean object 	
    }

2. At the same time Fragment1 A method in instantiates the interface

onDataChangedListener listener = (onDataChangedListener) getActivity();
listener.onDataChanged((HarvestBean) msg.obj);

PS： Here I am directly introducing a Bean Object's , Because I'm here onDataChanged(HarvestBean bean); The parameters set in the method are Bean

3. In the father Activity Implement the interface in and rewrite onDataChanged(); Method , At the same time, by calling Fragment2 Of updateData(); Method update Fragment2 The data of

@Override
    public void onDataChanged(HarvestBean bean) {
        if (expressFragment != null) {
            expressFragment.updateData(bean);
        } else {
            Log.i("harvest", " It's empty ？");
        }
    }

4. stay Fragment2 Create a public method in updateData(HarvestBean bean) Method is used to update Fragment2 in LitView The data of

List<HarvestBean> data = new ArrayList<>();

public void updateData(HarvestBean harvestBean) {
   

        bean = harvestBean;
        data.add(bean);
        mLv_express.setAdapter(new ExpressAdapter(getActivity(), data));
    }

In this way, our needs are realized .

About interface callback , There is another interesting sentence in the forum to understand why we use interface callback

Why use callback functions ？ Examples are as follows
You are hungry , I want to eat , Just ask your mother later " There's no dinner ?" This is the normal function call .

But today your mother made dumplings , It takes a long time , You run and run , I'm tired of it . So you said to your mother , I'll go out and play first , Call me on my cell phone at dinner . After a while , Your mother called you and said " It's dinner , Come back for dinner !"
among , You told your mother to call you on her cell phone , It's an action where you save the callback function handle to your mother . Your mother called you , It's a callback process .
from ：http://hi.baidu.com/%CE%E2_%F0%A9/blog/item/eec507cf7e72d20f92457eb2.html