Fragment development of "Android development" 1

I. Introduction of Fragment

1.Fragment appears as part of the activity interface;

2. Multiple fragment can occur simultaneously in one activity, and a fragment may be used in multiple activity;

3. During activity operation, you can add, remove, or replace fragment (add (), remove (), replace ());

4.Fragment can respond to its own input events and have its own life cycle, and of course, their life cycle is directly affected by the activity's life cycle that they belong to.

Then why are we using fragment? The main purpose is to support a more dynamic and flexible UI design on large-screen devices, such as tablets. Tablet screens are much larger than phones, have more room to put more UI components, and create more interaction between these components. We can think of fragment as "small activity", fragment more concise.

Second, the simple use of fragment

So let's simply show 2 fragment as an example to explain.

　　　　

1. Add the fragment in the XML:

New Fragment1, Fragment2 (note that the android.app.Fragment fragment are imported here):

Fragment1 Code:

1  Packagecom.example.fragment;2 3 Importandroid.app.Fragment;4 ImportAndroid.os.Bundle;5 ImportAndroid.util.Log;6 ImportAndroid.view.LayoutInflater;7 ImportAndroid.view.View;8 ImportAndroid.view.ViewGroup;9 Ten ImportCOM.EXAMPLE.FRAGMENTDEMO.R; One  A  Public classFragment1extendsFragment { - @Override -      PublicView Oncreateview (layoutinflater inflater, ViewGroup container, the Bundle savedinstancestate) { -LOG.E ("TAG", "in"); -         returnInflater.inflate (R.layout.fragment1, container,false); -     } +}

View Code

Fragment2 Code:

1  Packagecom.example.fragment;2 3 Importandroid.app.Fragment;4 ImportAndroid.os.Bundle;5 ImportAndroid.view.LayoutInflater;6 ImportAndroid.view.View;7 ImportAndroid.view.ViewGroup;8 9 ImportCOM.EXAMPLE.FRAGMENTDEMO.R;Ten  One  Public classFragment2extendsFragment { A @Override -      PublicView Oncreateview (layoutinflater inflater, ViewGroup container, - Bundle savedinstancestate) { the         returnInflater.inflate (R.layout.fragment2, container,false); -     } -}

View Code

XML code for FRAGMENT1:

1<?xml version= "1.0" encoding= "Utf-8"?>2<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"3Android:layout_width= "Match_parent"4android:layout_height= "Match_parent"5Android:background= "#FF69B4"6android:orientation= "Vertical" >7 8<TextView9Android:layout_width= "Wrap_content"Tenandroid:layout_height= "Wrap_content" Oneandroid:layout_gravity= "Center" AAndroid:text= "This is the first fragment"/> -  -</LinearLayout>

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XML code for FRAGMENT2:

1<?xml version= "1.0" encoding= "Utf-8"?>2<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"3Android:layout_width= "Match_parent"4android:layout_height= "Match_parent"5Android:background= "#EECBAD"6android:orientation= "Vertical" >7 8<TextView9Android:layout_width= "Wrap_content"Tenandroid:layout_height= "Wrap_content" Oneandroid:layout_gravity= "Center" AAndroid:text= "This is a second fragment"/> -  -</LinearLayout>

View Code

We add two fragment in Activity_main.xml, the code is as follows:

1<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"2Android:layout_width= "Match_parent"3android:layout_height= "Match_parent"4Android:baselinealigned= "false" >5 6<Fragment7Android:id= "@+id/fragment1"8Android:name= "Com.example.fragment.Fragment1"9Android:layout_width= "Wrap_content"Tenandroid:layout_height= "Match_parent" Oneandroid:layout_weight= "1"/> A  -<Fragment -Android:id= "@+id/fragment2" theAndroid:name= "Com.example.fragment.Fragment2" -Android:layout_width= "Wrap_content" -android:layout_height= "Match_parent" -android:layout_weight= "1"/> +  -</LinearLayout>

View Code

The mainactivity code is as follows:

1  PackageCom.example.fragmentdemo;2 3 Importandroid.app.Activity;4 ImportAndroid.os.Bundle;5 6  Public classMainactivityextendsActivity {7 8 @Override9     protected voidonCreate (Bundle savedinstancestate) {Ten         Super. OnCreate (savedinstancestate); One Setcontentview (r.layout.activity_main); A     } -}

View Code

Then run the project to show fragment, below.

2. Add fragment dynamically:

　　　　　　

　　　　　　

Fragment development of "Android development" 1