Fragment学习记录二 动态创建fragment

动态创建Fragment
步骤：
1.获取到FragmentManager，V4包中 getSupportFragmentManager，系统中 getFragmentManager
2.开启一个事务，通过调用beginTransaction方法开启。
3.向容器内加入Fragment，一般使用add或者replace方法实现，需要传入容器的id和Fragment的实例。
4.提交事务，调用commit方法提交。

create_dynamic_activity.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"              android:layout_width="match_parent"              android:layout_height="match_parent"              android:orientation="vertical"    >    <Button        android:id="@+id/button"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_weight="1"        android:gravity="center"        android:text="fragment1"/>    <Button        android:id="@+id/button2"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_weight="1"        android:gravity="center"        android:text="fragment2"/>    <FrameLayout        android:id="@+id/fragment"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_weight="3">    </FrameLayout></LinearLayout>

CreateDynamicActivityActivity.java

package com.mytest.fragmentall.create;import android.os.Bundle;import android.support.v4.app.FragmentActivity;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentTransaction;import android.view.View;import android.widget.FrameLayout;import com.mytest.fragmentall.R;public class CreateDynamicActivityActivity extends FragmentActivity implements View.OnClickListener {    private FrameLayout fragment;    FragmentManager manager ;    FragmentTransaction transaction;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.create_dynamic_activity);        findViewById(R.id.button).setOnClickListener(this);        findViewById(R.id.button2).setOnClickListener(this);        fragment = (FrameLayout) findViewById(R.id.fragment);        manager = getSupportFragmentManager();    }    @Override    public void onClick(View view) {        switch (view.getId()) {            case R.id.button:                transaction = manager.beginTransaction();                TitleFragment                 fragment = new TitleFragment();                transaction.add(R.id.fragment, fragment);                transaction.commit();                break;            case R.id.button2:                transaction = manager.beginTransaction();                ContentFragment                 fragment2 = new ContentFragment();                transaction.add(R.id.fragment, fragment2);                transaction.commit();                break;        }    }}

参考记录一
fragment_1.xml
TitleFragment.java
fragment_2.xml
ContentFragment.java

fragment_2.xml 简单修改

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"                android:orientation="vertical"                android:layout_width="match_parent"                android:layout_height="match_parent"                android:background="#e6a0a0">    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="fragment2"        android:id="@+id/textView2"        android:gravity="center"        android:textSize="20sp"        android:layout_gravity="center_horizontal"/></RelativeLayout>

注意事项：

......transaction 在点击事件前赋值transaction = manager.beginTransaction();......public void onClick(View view) {        switch (view.getId()) {            case R.id.button:                TitleFragment                 fragment = new TitleFragment();                transaction.add(R.id.fragment, fragment);                transaction.commit();                break;            case R.id.button2:                ContentFragment                 fragment2 = new ContentFragment();                transaction.add(R.id.fragment, fragment2);                transaction.commit();                break;        }    }报异常java.lang.IllegalStateException: commit already called

原因是：
commit不能被同一个FragmentTransaction调用多次