学习笔记----实现底部引导菜单:
1、启动页面
1)布局:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.atguigu.android.atguigu.MainActivity"
android:background="#ffffff">
<ImageView
android:id="@+id/iv"
android:layout_centerInParent="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/atguigu_logo"/>
<TextView
android:textColor="#000000"
android:textSize="20sp"
android:layout_centerHorizontal="true"
android:layout_below="@id/iv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="欢迎..."/>
</RelativeLayout>
2)代码:设置两秒之后跳转到主界面
public class WelcomeActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_welcome);
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
//主线程中执行
startMainActivity();
}
},2000);
}
private void startMainActivity() {
Intent intent = new Intent(this,MainActivity.class);
startActivity(intent);
finish();
}
}
2、主页面
1)布局
垂直的线性布局,分为三部分,第一部分是标题 titlebar.xml,第二部分是一个FrameLayout,用来加载fragment,第三部分是一个RadioGroup。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.atguigu.android.atguigu.MainActivity"
android:orientation="vertical">
<!--标题栏-->
<include layout="@layout/titlebar"/>
<!--FrameLayout-->
<FrameLayout
android:id="@+id/fl"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1">
</FrameLayout>
<!--底部的RadioGroup-->
<RadioGroup
android:id="@+id/rg"
android:gravity="center_vertical"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dp">
<RadioButton
android:id="@+id/rb_common_frame"
android:text="常用框架"
android:drawableTop="@drawable/rb_common_frame_drawable_selector"
style="@style/bottom_tag_style"
/>
<RadioButton
android:id="@+id/rb_thirdparty"
android:text="第三方框架"
android:drawableTop="@drawable/rb_thirdparty_drawable_selector"
style="@style/bottom_tag_style"
/>
<RadioButton
android:id="@+id/rb_custom"
android:text="自定义控件"
android:drawableTop="@drawable/rb_custom_drawable_selector"
style="@style/bottom_tag_style"
/>
<RadioButton
android:id="@+id/rb_other"
android:text="其他"
android:drawableTop="@drawable/rb_other_drawable_selector"
style="@style/bottom_tag_style"
/>
</RadioGroup>
</LinearLayout>
titlebar.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="@android:color/holo_blue_light"
android:gravity="center">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="知识库"
android:textSize="20sp"
android:textColor="@android:color/white"/>
</LinearLayout>
以bottom_textcolor_drawable_selector.xml为例:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_checked="true" android:color="@android:color/holo_blue_light"/>
<item android:state_checked="false" android:color="@android:color/darker_gray"/>
</selector>
设置选中的时候是蓝色,未选中是灰色。
以rb_common_frame_drawable_selector.xml为例:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_checked="true" android:drawable="@drawable/ic_tab_video_press"/>
<item android:state_checked="false" android:drawable="@drawable/ic_tab_video"/>
</selector>
设置选中的时候是一张蓝色的图片,未选中的时候是一张灰色的图片。
style="@style/bottom_tag_style" ----把相同的代码写在style.xml中
<style name="bottom_tag_style" >
<!-- Customize your theme here. -->
<item name="android:gravity">center</item>
<item name="android:layout_weight">1</item>
<item name="android:drawablePadding">3dp</item>
<item name="android:button">@android:color/transparent</item>
<item name="android:textColor">@drawable/bottom_textcolor_drawable_selector</item>
<item name="android:textSize">15sp</item>
<item name="android:layout_width">wrap_content</item>
<item name="android:layout_height">wrap_content</item>
</style>
3、创建各个子页面
1)创建一个基类BaseFragment
一个公共类,CommonFrameFragment,ThirdPartyFragment,CustomFragment,OtherFragment等都要继承该类。
public abstract class BaseFragment extends Fragment{
protected Context mContext;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mContext = getActivity();
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return initView();
}
//强制子类重写,实现子类特有的UI
protected abstract View initView();
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
initData();
}
//当孩子需要需要初始化数据,联网请求绑定数据,展示数据等等 可以重写该方法
protected void initData(){
}
}
2)定义各个子页面
CommonFrameFragment.java
public class CommonFrameFragment extends BaseFragment {
private static final String TAG =CustomFragment.class.getSimpleName();
private TextView textView;
@Override
protected View initView() {
Log.w(TAG,"常用框架initView()");
textView = new TextView(mContext);
textView.setTextSize(20);
textView.setGravity(Gravity.CENTER);
textView.setTextColor(Color.RED);
return textView;
}
@Override
protected void initData() {
Log.w(TAG,"常用框架initData()");
textView.setText("常用框架");
super.initData();
}
}
其他类似...
3)初始化fragment
//初始化fragment
initFragment();
private void initFragment() {
baseFragments = new ArrayList<>();
baseFragments.add(new CommonFrameFragment());//常用框架fragment
baseFragments.add(new ThirdPartyFragment());//第三方fragment
baseFragments.add(new CustomFragment());//自定义fragment
baseFragments.add(new OtherFragment());//其他fragment
}
4)设置RadioGroup的监听
//设置RadioGroup的监听
setListener();
private void setListener() {
rg.setOnCheckedChangeListener(new MyOnCheckedChangeListener());
//默认选中第一个
rg.check(R.id.rb_common_frame);
}
class MyOnCheckedChangeListener implements RadioGroup.OnCheckedChangeListener{
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId){
case R.id.rb_common_frame://常用框架
position = 0;
break;
case R.id.rb_thirdparty://第三方
position = 1;
break;
case R.id.rb_custom://自定义
position = 2;
break;
case R.id.rb_other://其他
position = 3;
break;
default:
position = 0;
break;
}
//根据位置得到对应的fragment
BaseFragment to = getFragment();
//替换
switchFragment(to);
}
}
5)得到fragment
public BaseFragment getFragment() {
BaseFragment fragment = baseFragments.get(position);
return fragment;
}
6)切换fragment
private void switchFragment(BaseFragment fragment) {
//1.得到fragmentManager
FragmentManager fragmentManager = getSupportFragmentManager();
//2.开启事务
FragmentTransaction transaction = fragmentManager.beginTransaction();
//3.替换
transaction.replace(R.id.fl,fragment);
//4.提交事务
transaction.commit();
}
4、出现的问题
1)解决切换fragment导致重新创建fragment的问题
问题:上面切换fragment的方法会导致fragment重建。
解决:设置两个fragment对象,一个(from)表示刚刚显示的fragment,即将要被替换掉。一个(to)表示即将要显示的fragment。
//替换
switchFragment(mFragment,to);
用show()和add()代替原来的replay()。首先判断有没有添加,如果没有,就添加to,隐藏from。如果有,就显示to。隐藏from。
private void switchFragment(Fragment from, Fragment to) {
//如果两个fragment不相等才切换,相等就不用切换了
if(from != to){
//1.得到fragmentManager
FragmentManager fragmentManager = getSupportFragmentManager();
//2.开启事务
FragmentTransaction transaction = fragmentManager.beginTransaction();
mFragment = to;
//判断有没有被添加
if(!to.isAdded()) {
//to没有被添加
//掩藏from
if (from != null) {
transaction.hide(from);
}
//添加to
if (to != null) {
transaction.add(R.id.fl, to).commit();
}
}else {
//to已经被添加
//隐藏from
if (from != null) {
transaction.hide(from);
}
//显示to
if (to != null) {
transaction.show(to).commit();
}
}
}
}
只创建一次:
2)解决横竖屏切换fragment导致内容重叠的问题
问题:横竖屏切换fragment导致内容重叠
解决:在AndroidManifest.xml中添加:
<activity android:name=".MainActivity"
android:configChanges="orientation|screenSize|keyboardHidden">
</activity>
5、源码
链接:https://pan.baidu.com/s/1DvFsEJEObIrsE8LQz8aTYw
提取码:ks3o