安卓20作业 - 碎片吐司

碎片吐司

1.创建FirstFragment、SecondFragment、ThirdFragment以及FragmentList（这个直接JavaClass）

创建好了之后就会生成对应的XML资源文件

（1）编写FirstFragment

package net.zxj.hwork20;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import androidx.fragment.app.Fragment;

public class FirstFragment extends Fragment {

    private Button btnNextFragment;
    private Button btnToastOne;

    public FirstFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, final ViewGroup container,
                             Bundle savedInstanceState) {

        // 获取碎片视图
        final View view = inflater.inflate(R.layout.fragment_first, container, false);
        // 通过资源标识获得控件实例
        btnNextFragment = view.findViewById(R.id.btnNextFragment);
        btnToastOne = view.findViewById(R.id.btnToastOne);
        // 给按钮注册监听器
        btnNextFragment.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                getFragmentManager().beginTransaction()
                        .addToBackStack("next")
                        .replace(R.id.container, FragmentList.fragments.get(1))
                        .commit();
            }
        });

        btnToastOne.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Toast.makeText(getActivity(),"我是冠军",Toast.LENGTH_SHORT).show();

            }
        });

        // 返回视图
        return view;
    }

}

           

(2) 编写SecondFragment

package net.zxj.hwork20;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import androidx.fragment.app.Fragment;

public class SecondFragment extends Fragment {

    private Button btnNextFragment;
    private Button btnToastTwo;

    public SecondFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // 获取碎片视图
        View view = inflater.inflate(R.layout.fragment_second, container, false);
        // 通过资源标识获得控件实例
        btnNextFragment = view.findViewById(R.id.btnNextFragment);
        btnToastTwo = view.findViewById(R.id.btnToastTwo);
        // 给按钮注册监听器
        btnNextFragment.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                getFragmentManager().beginTransaction()
                        .addToBackStack("next")
                        .replace(R.id.container, FragmentList.fragments.get(2))
                        .commit();
            }
        });
        btnToastTwo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Toast.makeText(getActivity(),"我是亚军",Toast.LENGTH_SHORT).show();

            }
        });

        // 返回视图
        return view;
    }
}

           

(3)编写ThirdFragment

package net.zxj.hwork20;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import androidx.fragment.app.Fragment;

public class ThirdFragment extends Fragment {

    private Button btnNextFragment;
    private Button btnToastThird;

    public ThirdFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        // 获取碎片视图
        View view = inflater.inflate(R.layout.fragment_third, container, false);
        // 通过资源标识获得控件实例
        btnNextFragment = view.findViewById(R.id.btnNextFragment);
        btnToastThird = view.findViewById(R.id.btnToastThird);
        // 给按钮注册监听器
        btnNextFragment.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                getFragmentManager().beginTransaction()
                        .addToBackStack("next")
                        .replace(R.id.container, FragmentList.fragments.get(3))
                        .commit();
            }
        });
        btnToastThird.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Toast.makeText(getActivity(),"我是季军",Toast.LENGTH_SHORT).show();

            }
        });

        // 返回视图
        return view;
    }
}

           

(4)编写FragmentList

package net.zxj.hwork20;

import androidx.fragment.app.Fragment;

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

public class FragmentList {
    public static List<Fragment> fragments = new ArrayList<>();
}

           

2.编写对应的 XML文件

(1) 编写fragment_first.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
    android:gravity="center"
    android:orientation="vertical"
    tools:context=".FirstFragment">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="20dp"
        android:text="@string/first_fragment"
        android:textColor="#ff0000"
        android:textSize="25sp" />

    <Button
        android:id="@+id/btnNextFragment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/next_fragment"/>
    <Button
        android:id="@+id/btnToastOne"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/No1"/>
</LinearLayout>

           

(2) 编写fragment_second.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
    android:gravity="center"
    android:orientation="vertical"
    tools:context=".FirstFragment">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="20dp"
        android:text="@string/second_fragment"
        android:textColor="#00ff00"
        android:textSize="25sp" />

    <Button
        android:id="@+id/btnNextFragment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/next_fragment"/>
    <Button
        android:id="@+id/btnToastTwo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/No2"/>
</LinearLayout>

           

(3)编写fragment_third.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
    android:gravity="center"
    android:orientation="vertical"
    tools:context=".FirstFragment">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="20dp"
        android:text="@string/third_fragment"
        android:textColor="#0000ff"
        android:textSize="25sp" />

    <Button
        android:id="@+id/btnNextFragment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/next_fragment"/>

    <Button
        android:id="@+id/btnToastThird"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/No3"/>
</LinearLayout>

           

3. 编写Strings.xml 资源文件

<resources>
    <string name="app_name">Hwork20</string>
    <string name= "first_fragment">第一个碎片</string>
    <string name="second_fragment">第二个碎片</string>
    <string name="third_fragment">第三个碎片</string>
    <string name="next_fragment">下一个碎片</string>
    <string name="No1">冠军</string>
    <string name="No2">亚军</string>
    <string name="No3">季军</string>
</resources>
           

4. 编写MainActivity

package net.zxj.hwork20;

import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 利用布局资源文件设置用户界面
        setContentView(R.layout.activity_main);

        // 获取碎片管理器
        FragmentManager fm = getSupportFragmentManager();

        // 创建三个碎片，添加到碎片列表
        FragmentList.fragments.add(new FirstFragment());
        FragmentList.fragments.add(new SecondFragment());
        FragmentList.fragments.add(new ThirdFragment());

        // 在主容器里添加第一个碎片
        fm.beginTransaction().add(R.id.container, FragmentList.fragments.get(0)).commit();
    }
}

           

运行结果如下：