Question

fragment的replace问题

在用fragment框架做app时候，用replace（）函数，想点击按钮切换到一个新的fragment，可是运行时候新的fragment显示在按钮的下方。。。求教！
在网上看有人说改一下activity_main的fragment改成FragmentLayout 试了也没用。。

Answer 1

使用FrameLayout+fragment的方式
<?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" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="a"
            android:text="Button" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="b"
            android:text="Button" />
    </LinearLayout>

    <FrameLayout
        android:id="@+id/myframe"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >
    </FrameLayout>

</LinearLayout>

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;

public class MainActivity extends FragmentActivity {

        private FragmentTransaction fragmentTransaction;
        private FragmentManager fragmentManager;

        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);
                fragmentManager = getSupportFragmentManager();

        }

        public void a(View view) {
                AFragment fragment = new AFragment();
                fragmentTransaction = fragmentManager.beginTransaction();
                fragmentTransaction.replace(R.id.myframe, fragment);
                fragmentTransaction.commit();
        }

        public void b(View view) {
                BFragment fragment = new BFragment();
                fragmentTransaction = fragmentManager.beginTransaction();
                fragmentTransaction.replace(R.id.myframe, fragment);
                fragmentTransaction.commit();
        }

}

Answer 2

通FragmentTransactionattachdetach实现
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
if (mLastFragment != null) {
//detachfragment
fragmentTransaction.detach(mLastFragment);
}
//找fragmentfindFragmentByTag自定义
Fragment fragment = fragmentManager.findFragmentByTag(tabName);
if (fragment == null) {
//add
fragmentTransaction.add(R.id.layout_fragment_id, fragment, tabName);
} else {
//attach
fragmentTransaction.attach(fragment);
}
//保存fragment
mLastFragment = fragment;
//事务commit
fragmentTransaction.commitAllowingStateLoss();
fragmentManager.executePendingTransactions();

追问

能稍微讲讲吗？ 看的我好晕