使用Fragment 实现动态UI 和 动态添加Fragment

时间:2023-03-08 15:51:22
使用Fragment 实现动态UI 和 动态添加Fragment

首先写好每个Fragment:

1.在第一个Fragment写一个按钮,使其加载下一个Fragment

布局:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="horizontal" > <Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="加载"/> </LinearLayout>

java代码:

public class LeftFragment extends Fragment{

    OnClickButton mCallback;
//定义一个接口
public interface OnClickButton{
//并实现一个方法,用来传值并在(onAttach()中绑定activity)
public void onClickB();
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
//绑定布局文件并获取到里面的控件,特别 注意里面的 view
View view = inflater.inflate(R.layout.fragment_left,null);
Button button = (Button) view.findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mCallback.onClickB();
}
});
return view;
} /**
* 绑定到activity
* @param activity
*/
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallback = (OnClickButton) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnHeadlineSelectedListener");
}
}
}

加载显示出来的布局文件:

<?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" > <TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="新闻内容" /> <Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" /> </LinearLayout>

java文件:

public class RightFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_right, null);
Button button = (Button) view.findViewById(R.id.button2);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//getActivity() 获取父类的activity
Toast.makeText(getActivity(), "我是fragment", Toast.LENGTH_SHORT).show();
}
});
return view;
}
}

主类:

布局

给Fragment创建一个容器activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"/>

注意:一定要写明id。

然后就在activity中实现Fragment add进去就行了!

//实现LeftFragment中定义的接口,主要用来传值或者按钮点击事件
public class MainActivity extends Activity implements LeftFragment.OnClickButton {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); //初始化第一个Fragment
if (findViewById(R.id.fragment_container) != null){
if (savedInstanceState != null) {
return;
}
LeftFragment leftFragment = new LeftFragment();
leftFragment.setArguments(getIntent().getExtras());
getFragmentManager().beginTransaction().add(R.id.fragment_container,leftFragment).commit();
}
} /**
* 实现接口中的方法和点击按钮后加载的fragment
*/
@Override
public void onClickB() {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
RightFragment rightFragment = new RightFragment();
transaction.replace(R.id.fragment_container, rightFragment);
transaction.addToBackStack(null);
transaction.commit();
}
}

这样就实现了一个很小的demo!

动态添加Fragment


首先新建两个fragment的布局文件

fragment1

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#00ff00" > <TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="This is fragment 1"
android:textColor="#000000"
android:textSize="25sp" /> </LinearLayout>

fragment2

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#0000ff" > <TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="This is fragment 2"
android:textColor="#000000"
android:textSize="25sp" /> </LinearLayout>

新建两个Fragment类继承Fragment

Fragment1

public class Fragmet1 extends Fragment {

    @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment1,container,false);
}
}

Fragment2

public class Fragmet2 extends Fragment {

    @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment2,container,false);
}
}

然后定义一个显示fragment的mainactivity.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:baselineAligned="false" > <Button
android:id="@+id/btn_show_fragment1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="显示Fragment1"/> <Button
android:id="@+id/btn_show_fragment2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="显示Fragment2"/> <FrameLayout
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"/> </LinearLayout>

其中FrameLayout是用来显示Fragment的,在MainActivity中实现

public class MainActivity extends FragmentActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity); Button button1 = (Button) findViewById(R.id.btn_show_fragment1);
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//动态添加Fragment
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction ft = manager.beginTransaction();
Fragmet1 fragmet1 = new Fragmet1();
ft.add(R.id.fragment_container,fragmet1);
ft.commit();
}
});
Button button2 = (Button) findViewById(R.id.btn_show_fragment2);
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction ft = manager.beginTransaction();
Fragmet2 fragmet2 = new Fragmet2();
ft.add(R.id.fragment_container,fragmet2);
ft.commit();
}
});
}
}

ok 基本就完成了。

注意:

动态添加Fragment主要分为4步:

    • 1.获取到FragmentManager,在V4包中通过getSupportFragmentManager,在系统中原生的Fragment是通过getFragmentManager获得的。
    • 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。