本章另一个要点：Fragment 之间通讯使用 setArguments
TestFragment newFragment = new TestFragment();
Bundle bundle = new Bundle();
bundle.putString("hello", s);
newFragment.setArguments(bundle);
使用 getArguments()进行获取
Bundle args = getArguments();
String tHello=args.getString("hello");
ViewPager 结合 Fragment 实现一个 Activity 里包含多个可滑动的标签页，每个标签页可以有独立的布局及响应。
activity_main.xml
<!-- ViewPager + Fragment 滑动布局 -->
<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"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<TextView
android:id="@+id/tvGuid1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:gravity="center"
android:text="特性1"
android:textSize="18sp" />
<TextView
android:id="@+id/tvGuid2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:gravity="center"
android:text="特性2"
android:textSize="18sp" />
<TextView
android:id="@+id/tvGuid3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:gravity="center"
android:text="特性3 "
android:textSize="18sp" />
<TextView
android:id="@+id/tvGuid4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:gravity="center"
android:text="特性4"
android:textSize="18sp" />
</LinearLayout>
<ImageView
android:id="@+id/ivCursor"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="matrix"
android:src="@drawable/cursor" />
<android.support.v4.view.ViewPager
android:id="@+id/vpSlideFragment"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:flipInterval="30"
android:persistentDrawingCache="animation" />
</LinearLayout>
/**
* @ClassName: SlideFragmentActivity
* @author Xiao JinLai
* @Date 2015-4-5 下午5:55:09
* @Description：主 Activity
*/
public class SlideFragmentActivity extends FragmentActivity {
private ViewPager mPager;
private ArrayList<Fragment> mFragments;
private ImageView mIvCursor;
private TextView view1, view2, view3, view4;
private int currIndex;// 当前页卡编号
private int bmpW;// 横线图片宽度
private int offset;// 图片移动的偏移量
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_slide_fragment);
initTextView();
initImage();
initViewPager();
}
/**
* 初始化标签名
*/
public void initTextView() {
view1 = (TextView) findViewById(R.id.tvGuid1);
view2 = (TextView) findViewById(R.id.tvGuid2);
view3 = (TextView) findViewById(R.id.tvGuid3);
view4 = (TextView) findViewById(R.id.tvGuid4);
view1.setOnClickListener(new txListener(0));
view2.setOnClickListener(new txListener(1));
view3.setOnClickListener(new txListener(2));
view4.setOnClickListener(new txListener(3));
}
public class txListener implements View.OnClickListener {
private int index = 0;
public txListener(int i) {
index = i;
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
mPager.setCurrentItem(index);
}
}
/**
* 初始化图片的位移像素
*/
public void initImage() {
mIvCursor = (ImageView) findViewById(R.id.ivCursor);
bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.cursor)
.getWidth();
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int screenW = dm.widthPixels;
offset = (screenW / 4 - bmpW) / 2;
// imgageview设置平移，使下划线平移到初始位置（平移一个offset）
Matrix matrix = new Matrix();
matrix.postTranslate(offset, 0);
mIvCursor.setImageMatrix(matrix);
}
/**
* 初始化ViewPager
*/
public void initViewPager() {
mPager = (ViewPager) findViewById(R.id.vpSlideFragment);
mFragments = new ArrayList<Fragment>();
Fragment btFragment = new ButtonFragment();
Fragment secondFragment = TestFragment
.newInstance("this is second fragment");
Fragment thirdFragment = TestFragment
.newInstance("this is third fragment");
Fragment fourthFragment = TestFragment
.newInstance("this is fourth fragment");
mFragments.add(btFragment);
mFragments.add(secondFragment);
mFragments.add(thirdFragment);
mFragments.add(fourthFragment);
// 给ViewPager设置适配器
mPager.setAdapter(new SlideFragmentAdapter(getSupportFragmentManager(),
mFragments));
mPager.setCurrentItem(0);// 设置当前显示标签页为第一页
mPager.setOnPageChangeListener(new MyOnPageChangeListener());// 页面变化时的监听器
}
public class MyOnPageChangeListener implements OnPageChangeListener {
private int one = offset * 2 + bmpW;// 两个相邻页面的偏移量
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
@Override
public void onPageSelected(int arg0) {
Animation animation = new TranslateAnimation(currIndex * one, arg0
* one, 0, 0);// 平移动画
currIndex = arg0;
animation.setFillAfter(true);// 动画终止时停留在最后一帧，不然会回到没有执行前的状态
animation.setDuration(200);// 动画持续时间0.2秒
mIvCursor.startAnimation(animation);// 是用ImageView来显示动画的
int i = currIndex + 1;
Toast.makeText(SlideFragmentActivity.this, "您选择了第" + i + "个页卡",
Toast.LENGTH_SHORT).show();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.fragment_menu, menu);
return true;
}
}
谷歌官方认为，ViewPager 应该和 Fragment 一起使用时，此时 ViewPager 的适配器是 FragmentPagerAdapter，当你实现一个 FragmentPagerAdapter,你必须至少覆盖以下方法:
getCount()
getItem()
如果 ViewPager 没有和 Fragment 一起，ViewPager 的适配器是 PagerAdapter，它是基类提供适配器来填充页面ViewPager 内部，当你实现一个 PagerAdapter,你必须至少覆盖以下方法:
instantiateItem(ViewGroup, int)
destroyItem(ViewGroup, int, Object)
getCount()
isViewFromObject(View, Object)
/**
* @ClassName: SlideFragmentAdapter
* @author Xiao JinLai
* @Date 2015-4-5 下午6:15:37
* @Description：ViewPager与Fragment适配器
*/
public class SlideFragmentAdapter extends FragmentPagerAdapter {
ArrayList<Fragment> mList;
public SlideFragmentAdapter(FragmentManager fm, ArrayList<Fragment> list) {
super(fm);
this.mList = list;
}
/**
* 返回一个 Fragment
*/
@Override
public Fragment getItem(int item) {
return mList.get(item);
}
/**
* Fragment 总数
*/
@Override
public int getCount() {
return mList.size();
}
}
/**
* @ClassName: ButtonFragment
* @author Xiao JinLai
* @Date 2015-4-5 下午6:17:15
* @Description：有按钮的Fragment
*/
public class ButtonFragment extends Fragment {
private Button mBtnGuide;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_guide1, container,
false);// 关联布局文件
mBtnGuide = (Button) rootView.findViewById(R.id.btnGuide);// 根据rootView找到button
// 设置按键监听事件
mBtnGuide.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(ButtonFragment.this.getActivity(),
"button is click!", Toast.LENGTH_SHORT).show();
}
});
return rootView;
}
}
<!-- 带按钮的 Fragment 布局 -->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ff0000ff" >
<Button
android:id="@+id/btnGuide"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:text="hit me" />
</RelativeLayout>
/**
* @ClassName: TestFragment
* @author Xiao JinLai
* @Date 2015-4-5 下午6:18:40
* @Description：创建多个 Fragment 用来测试
*/
public class TestFragment extends Fragment {
private static final String TAG = "TestFragment";
private String hello;// = "hello android";
private String defaultHello = "default value";
static TestFragment newInstance(String s) {
TestFragment newFragment = new TestFragment();
Bundle bundle = new Bundle();
bundle.putString("hello", s);
newFragment.setArguments(bundle);
// bundle还可以在每个标签里传送数据
return newFragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d(TAG, "TestFragment-----onCreateView");
Bundle args = getArguments();
hello = args != null ? args.getString("hello") : defaultHello;
View view = inflater
.inflate(R.layout.fragment_guide2, container, false);
TextView viewhello = (TextView) view.findViewById(R.id.tvGuide2);
viewhello.setText(hello);
return view;
}
}
<!-- 测试用的多个 Fragment 的界面 -->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#158684"
android:orientation="vertical" >
<TextView
android:id="@+id/tvGuide2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView" />
</RelativeLayout>
