Fragment

本次作业个人方法
1.界面布局就很简单了，主界面用LinearLayout布局，分为两个板块，控件也只有一个button
代码如下：

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:id="@+id/show">

</LinearLayout>
<Button
    android:id="@+id/button1"
	android:text="show next page"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:onClick="onClick"/>
<LinearLayout
    android:id="@+id/button2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">
</LinearLayout>

第二第三个均用Fragment布局（代码如下）

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="cn.edu.niit.dazuoye.MainActivity"
    android:orientation="vertical">
<TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="20sp"
        android:text="this is the first fragment" />
</FrameLayout>

第三个界面跟第二个几乎相同

2.功能的实现：及首先点击按钮show next page出现“this first fragmant”；再次点击按钮show next page出现提示“this second fragmant”；再点击一次返回初始界面。（主要代码如下）

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private Fragment oneFragment;
private Fragment twoFragment;
private boolean skip = true;
private boolean exit = false;


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


    oneFragment = new oneFragment();
    FragmentManager manager = getFragmentManager();
    FragmentTransaction transaction = manager.beginTransaction();
    transaction.add(R.id.main, oneFragment);
    transaction.commit();
}

public void onClick(View view) {
    switch (view.getId()) {
        case R.id.button1:
            jump();
            break;
    }
}

private void jump() {
    boolean exit = true;

    if (skip) {
        FragmentManager manager = getFragmentManager();
        FragmentTransaction transaction = manager.beginTransaction();
        if (secondFragment == null) {
             twoFragment = new twoFragment();
            transaction.replace(R.id.main, twoFragment);
            transaction.commit();
            skip = false;
        } else {
            transaction.replace(R.id.main, secondFragment);
            transaction.commit();
            skip = false;
        }
    } else {
        Toast.makeText(this, "this is second fragmant", Toast.LENGTH_LONG).show();
    }
}