Android -- TabHost、Fragment、狀態保存、通訊

時間  2019-12-01
標籤 android tabhost fragment 狀態 保存 通訊 欄目 Android 简体版
原文   原文鏈接

工程結構                                                                                       html

image

TabAFm到TabEFm都是Fragment，而且每一個Fragment對應一個佈局文件。java

 

 

 

 

 

 

 

TabAFm.java                                                                             android

package com.yydcdut.tabhoststudy;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class TabAFm extends Fragment {

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        System.out.println("AAAAAAAAAA____onAttach");
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        System.out.println("AAAAAAAAAA____onCreate");
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        System.out.println("AAAAAAAAAA____onCreateView");
        return inflater.inflate(R.layout.tab_a, container, false);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        System.out.println("AAAAAAAAAA____onActivityCreated");
    }

    @Override
    public void onStart() {
        super.onStart();
        System.out.println("AAAAAAAAAA____onStart");
    }

    @Override
    public void onResume() {
        super.onResume();
        System.out.println("AAAAAAAAAA____onResume");
    }

    @Override
    public void onPause() {
        super.onPause();
        System.out.println("AAAAAAAAAA____onPause");
    }

    @Override
    public void onStop() {
        super.onStop();
        System.out.println("AAAAAAAAAA____onStop");
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        System.out.println("AAAAAAAAAA____onDestroyView");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        System.out.println("AAAAAAAAAA____onDestroy");
    }

    @Override
    public void onDetach() {
        super.onDetach();
        System.out.println("AAAAAAAAAA____onDetach");
    }
    
}

如上述代碼所示，TabAFm是一個Fragment，對應的佈局文件是tab_a.xml，並實現了他的全部的生命週期回調函數並打印，便於調試。tab_a.xml佈局中有個EditText，其餘的Fragment大同小異，這裏就不貼出代碼了app

MainActivity                                                                              ide

package com.yydcdut.tabhoststudy;

import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.widget.RadioGroup;

public class MainActivity extends FragmentActivity {

    private RadioGroup rgs;
    public List<Fragment> fragments = new ArrayList<Fragment>();

    public String hello = "hello ";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        fragments.add(new TabAFm());
        fragments.add(new TabBFm());
        fragments.add(new TabCFm());
        fragments.add(new TabDFm());
        fragments.add(new TabEFm());

        rgs = (RadioGroup) findViewById(R.id.tabs_rg);

        FragmentTabAdapter2 tabAdapter = new FragmentTabAdapter2(this, fragments, R.id.tab_content, rgs);
        tabAdapter.setOnRgsExtraCheckedChangedListener(new FragmentTabAdapter2.OnRgsExtraCheckedChangedListener(){
            @Override
            public void OnRgsExtraCheckedChanged(RadioGroup radioGroup, int checkedId, int index) {
                System.out.println("Extra---- " + index + " checked!!! ");
            }
        });
    }
}

MainActivity上述代碼所示函數

MainActivity是包含Fragment的Activity（也就是這裏的5個Fragment）佈局

他繼承了FragmentActivity（由於我這裏用的是android-support-v4.jar）學習

用一個List<Fragment>去維護5個Fragment，也就是5個tab動畫

main佈局                                                                                     this

有一個id爲tab_content的FrameLayout，用來存放要顯示的Fragment。底部有一個RadioGroup，用於tab的切換

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@android:color/white"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical" >

        <FrameLayout
            android:id="@+id/tab_content"
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="1.0"
            android:background="#77557799" />

        <RadioGroup
            android:id="@+id/tabs_rg"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:orientation="horizontal"
            android:paddingBottom="7dp"
            android:paddingTop="7dp" >

            <RadioButton
                android:id="@+id/tab_rb_a"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1.0"
                android:background="@drawable/selector_tab"
                android:button="@null"
                android:checked="true"
                android:drawableTop="@drawable/tablatestalert"
                android:gravity="center"
                android:singleLine="true"
                android:text="Tab1"
                android:textColor="#000000"
                android:textSize="13sp" />

            <RadioButton
                android:id="@+id/tab_rb_b"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1.0"
                android:background="@drawable/selector_tab"
                android:button="@null"
                android:drawableTop="@drawable/tabsearch"
                android:gravity="center"
                android:singleLine="true"
                android:text="Tab2"
                android:textColor="#000000"
                android:textSize="13sp" />

            <RadioButton
                android:id="@+id/tab_rb_c"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1.0"
                android:background="@drawable/selector_tab"
                android:button="@null"
                android:drawableTop="@drawable/tabrecommd"
                android:gravity="center"
                android:singleLine="true"
                android:text="Tab3"
                android:textColor="#000000"
                android:textSize="13sp" />

            <RadioButton
                android:id="@+id/tab_rb_d"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1.0"
                android:background="@drawable/selector_tab"
                android:button="@null"
                android:drawableTop="@drawable/tabconfigicon"
                android:gravity="center"
                android:singleLine="true"
                android:text="Tab4"
                android:textColor="#000000"
                android:textSize="13sp" />

            <RadioButton
                android:id="@+id/tab_rb_e"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1.0"
                android:background="@drawable/selector_tab"
                android:button="@null"
                android:drawableTop="@drawable/tababoutus"
                android:gravity="center"
                android:singleLine="true"
                android:text="Tab5"
                android:textColor="#000000"
                android:textSize="13sp" />
        </RadioGroup>
    </LinearLayout>

</LinearLayout>

如今回到MainActivity中，下面這個FragmentTabAdapter類是關鍵，是我本身編寫的用於綁定和處理fragments和RadioGroup之間的邏輯關係

FragmentTabAdapter2 tabAdapter = new FragmentTabAdapter2(this, fragments, R.id.tab_content, rgs);

FragmentTabAdapter2                                                             

package com.yydcdut.tabhoststudy;

import java.util.List;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;

public class FragmentTabAdapter2 {
    private List<Fragment> fragments; // 一個tab頁面對應一個Fragment
    private RadioGroup rgs; // 用於切換tab
    private FragmentActivity fragmentActivity; // Fragment所屬的Activity
    private int fragmentContentId; // Activity中所要被替換的區域的id

    private int currentTab; // 當前Tab頁面索引

    private OnRgsExtraCheckedChangedListener onRgsExtraCheckedChangedListener; // 用於讓調用者在切換tab時候增長新的功能

    /**
     * 構造函數
     * 
     * @param fragmentActivity
     * @param fragments
     * @param fragmentContentId
     * @param rgs
     */
    public FragmentTabAdapter2(FragmentActivity fragmentActivity,
            List<Fragment> fragments, int fragmentContentId, RadioGroup rgs) {
        this.fragments = fragments;
        this.rgs = rgs;
        this.fragmentActivity = fragmentActivity;
        this.fragmentContentId = fragmentContentId;

        // 默認顯示第一頁
        FragmentTransaction ft = fragmentActivity.getSupportFragmentManager()
                .beginTransaction();
        ft.add(fragmentContentId, fragments.get(0));
        ft.commit();
        // 設置監聽事件
        MyCheckedChangeListener myCheckedChangeListener = new MyCheckedChangeListener();
        rgs.setOnCheckedChangeListener(myCheckedChangeListener);

    }

    /**
     * 監聽器內部類
     * 
     * @author sansung
     * 
     */
    class MyCheckedChangeListener implements OnCheckedChangeListener {

        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            for (int i = 0; i < rgs.getChildCount(); i++) {
                if (rgs.getChildAt(i).getId() == checkedId) {
                    Fragment fragment = fragments.get(i);
                    FragmentTransaction ft = obtainFragmentTransaction(i);

                    getCurrentFragment().onPause(); // 暫停當前tab
                    // getCurrentFragment().onStop(); // 暫停當前tab

                    if (fragment.isAdded()) {
                        // fragment.onStart(); // 啓動目標tab的onStart()
                        fragment.onResume(); // 啓動目標tab的onResume()
                    } else {
                        ft.add(fragmentContentId, fragment);
                    }
                    showTab(i); // 顯示目標tab
                    ft.commit();

                    // 若是設置了切換tab額外功能功能接口
                    if (null != onRgsExtraCheckedChangedListener) {
                        onRgsExtraCheckedChangedListener
                                .OnRgsExtraCheckedChanged(group, checkedId, i);
                    }
                }
            }
        }
    }

    /**
     * 切換tab
     * 
     * @param idx
     */
    private void showTab(int idx) {
        for (int i = 0; i < fragments.size(); i++) {
            Fragment fragment = fragments.get(i);
            FragmentTransaction ft = obtainFragmentTransaction(idx);

            if (idx == i) {
                ft.show(fragment);
            } else {
                ft.hide(fragment);
            }
            ft.commit();
        }
        currentTab = idx; // 更新目標tab爲當前tab
    }

    /**
     * 獲取一個帶動畫的FragmentTransaction
     * 
     * @param index
     * @return
     */
    private FragmentTransaction obtainFragmentTransaction(int index) {
        FragmentTransaction ft = fragmentActivity.getSupportFragmentManager()
                .beginTransaction();
        // 設置切換動畫
        if (index > currentTab) {
            ft.setCustomAnimations(R.anim.slide_left_in, R.anim.slide_left_out);
        } else {
            ft.setCustomAnimations(R.anim.slide_right_in,
                    R.anim.slide_right_out);
        }
        return ft;
    }

    public int getCurrentTab() {
        return currentTab;
    }

    public Fragment getCurrentFragment() {
        return fragments.get(currentTab);
    }

    public OnRgsExtraCheckedChangedListener getOnRgsExtraCheckedChangedListener() {
        return onRgsExtraCheckedChangedListener;
    }

    public void setOnRgsExtraCheckedChangedListener(
            OnRgsExtraCheckedChangedListener onRgsExtraCheckedChangedListener) {
        this.onRgsExtraCheckedChangedListener = onRgsExtraCheckedChangedListener;
    }

    /**
     * 切換tab額外功能功能接口
     */
    static class OnRgsExtraCheckedChangedListener {
        public void OnRgsExtraCheckedChanged(RadioGroup radioGroup,
                int checkedId, int index) {
        }
    }
}

這裏解決Fragment切換從新加載佈局的辦法，用的是把幾個Fragment所有Add，而後根據要顯示的哪一個Fragment設置show或者hide

10-10 11:55:41.168: INFO/System.out(18368): AAAAAAAAAA____onAttach　　　　　　// 第一次進入，顯示TabA
10-10 11:55:41.168: INFO/System.out(18368): AAAAAAAAAA____onCreate
10-10 11:55:41.168: INFO/System.out(18368): AAAAAAAAAA____onCreateView
10-10 11:55:41.175: INFO/System.out(18368): AAAAAAAAAA____onActivityCreated
10-10 11:55:41.179: INFO/System.out(18368): AAAAAAAAAA____onStart
10-10 11:55:41.179: INFO/System.out(18368): AAAAAAAAAA____onResume
10-10 11:55:44.980: INFO/System.out(18368): AAAAAAAAAA____onPause　　　　　　// 從TabA切換到TabB（TabA調用onPause）
10-10 11:55:44.980: INFO/System.out(18368): Extra---- 1 checked!!!
10-10 11:55:44.996: INFO/System.out(18368): BBBBBBBBBBB____onAttach
10-10 11:55:44.996: INFO/System.out(18368): BBBBBBBBBBB____onCreate
10-10 11:55:44.996: INFO/System.out(18368): BBBBBBBBBBB____onCreateView
10-10 11:55:45.004: INFO/System.out(18368): BBBBBBBBBBB____onActivityCreated
10-10 11:55:45.004: INFO/System.out(18368): BBBBBBBBBBB____onStart
10-10 11:55:45.004: INFO/System.out(18368): BBBBBBBBBBB____onResume
10-10 11:55:52.062: INFO/System.out(18368): BBBBBBBBBBB____onPause　　　　　　// 從TabB切換到TabC（TabB調用onPause）
10-10 11:55:52.062: INFO/System.out(18368): Extra---- 2 checked!!!
10-10 11:55:52.082: INFO/System.out(18368): CCCCCCCCCC____onAttach
10-10 11:55:52.082: INFO/System.out(18368): CCCCCCCCCC____onCreate
10-10 11:55:52.086: INFO/System.out(18368): CCCCCCCCCC____onCreateView
10-10 11:55:52.090: INFO/System.out(18368): CCCCCCCCCC____onActivityCreated
10-10 11:55:52.090: INFO/System.out(18368): CCCCCCCCCC____onStart
10-10 11:55:52.090: INFO/System.out(18368): CCCCCCCCCC____onResume
10-10 11:56:06.535: INFO/System.out(18368): CCCCCCCCCC____onPause　　　　　　// 從TabC切換到TabB（TabC調用onPause）
10-10 11:56:06.535: INFO/System.out(18368): BBBBBBBBBBB____onResume　　　　// 從TabC切換到TabB（TabB調用onResume）
10-10 11:56:06.535: INFO/System.out(18368): Extra---- 1 checked!!!

好了，到此爲止，咱們已經用Fragment實現了相似TabHost的功能了，下面來看下各個Fragment之間的通訊

如今的狀況是TabAFm中有個EditText，TabBFm中有個Button，MainActivity中有個變量「hello」

要作的是，切換到TabA，輸入「I'm TabA」，切換到B，點擊Button後，Toast顯示「hello I'm TabA」

MainActivity中沒什麼好說的，就一個hello變量：

public String hello = "hello ";

TabAFm在佈局文件tab_a.xml中加個EditText，設置個id就能夠了

TabBFm中：

@Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        System.out.println("BBBBBBBBBBB____onActivityCreated");
        this.getView().findViewById(R.id.clickme).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // 得到綁定的FragmentActivity
                MainActivity activity = ((MainActivity)getActivity());
                // 得到TabAFm的控件
                EditText editText = (EditText) activity.fragments.get(0).getView().findViewById(R.id.edit);

                Toast.makeText(activity, activity.hello + editText.getText(), Toast.LENGTH_SHORT).show();
            }
        });
    }
// 得到綁定的FragmentActivity
MainActivity activity = ((MainActivity)getActivity());

經過getActivity()便可獲得Fragment所在的FragmentActivity

我是天王蓋地虎的分割線                                                                 

1

源代碼：http://pan.baidu.com/s/1dD1Qx01

tabhost學習.zip

 

 

 

 

 

 

參考：http://www.cnblogs.com/tiantianbyconan/p/3360938.html

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