Android Fragment的使用

静态添加fragment

1.创建xml布局

activity_static_fragment

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f0f"
    >
 <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="staticFragment"
        android:textColor="#000"
        android:gravity="center"
        />
</android.support.constraint.ConstraintLayout>

2.创建fragment

StaticFragment

public class StaticFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view=inflater.inflate(R.layout.activity_static_fragment,container,false);
        return view;
    }
}

创建一个类继承Fragment,重写onCreateView()方法。fragment的OnCreateView类似于activity的onCreate();

3.布局中调用fragment

    <fragment
        android:layout_width="match_parent"
        android:layout_height="400dp"
        android:id="@+id/frag_test"
        android:name="com.example.test.fragment.StaticFragment"
        >
    </fragment>

通过name实例化要加载的碎片

4.效果

static.png

动态添加fragment

1.创建xml布局

activity_left_fragemnt

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#38d6b5"

    >
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="LeftFragment"
        android:textColor="#000"
        />
</android.support.constraint.ConstraintLayout>

activity_right_fragment

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f74747"
    >
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="RightFragment"
        android:textColor="#000"
        android:gravity="center"
        />
</android.support.constraint.ConstraintLayout>

2.创建fragment

LeftFragment

public class LeftFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view=inflater.inflate(R.layout.activity_left_fragemnt,container,false);
        initView();
        return  view;
    }
}

RightFragment

public class RightFragment  extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view=inflater.inflate(R.layout.activity_right_fragment,container,false);
        return  view;
    }
]

activity_main

<android.support.constraint.ConstraintLayout 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=".MainActivity">
    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintHeight_percent="0.9"
        android:id="@+id/cl_content"
        >
    </android.support.constraint.ConstraintLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintHeight_percent="0.1"
        app:layout_constraintTop_toBottomOf="@id/cl_content"
        >
        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="left_fragment"
            android:background="#f4d03e"
            android:id="@+id/bt_left"
            />
        <Button
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:text="right_fragment"
            android:background="#f4d03e"
            android:id="@+id/bt_right"
            />
    </LinearLayout>
</android.support.constraint.ConstraintLayout>

3.往Activity添加fragment

public class MainActivity extends AppCompatActivity {

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

    private void initView() {
        Button bt_left=findViewById(R.id.bt_left);
        Button bt_right=findViewById(R.id.bt_right);
        bt_left.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                changeFragment(new LeftFragment());
            }
        });
        bt_right.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                changeFragment(new RightFragment());
            }
        });
    }
    private void changeFragment(Fragment fragment){
        //实例化碎片管理器对象
        FragmentManager fm=getSupportFragmentManager();
        FragmentTransaction ft=fm.beginTransaction();
        //选择fragment替换的部分
        ft.replace(R.id.cl_content,fragment);
        ft.commit();
    }

}

4.效果图 效果.gif

其他补充

fragment获取当前对象:getActivity();
fragment可以往fragment里添加fragment:方法与往activity添加fragment方法一致,不同的是在fragment动态添加子fragment,碎片管理的获取方式为getChildFragmentManager();

   FragmentManager fm=getChildFragmentManager();