3.加载界面

public class HomeFragment extends Fragment {
 public static final int STATE_UNKOWN = 0;
 public static final int STATE_LOADING = 1;
 public static final int STATE_ERROR = 2;
 public static final int STATE_EMPTY = 3;
 public static final int STATE_SUCCESS = 4;
 public static int state = STATE_UNKOWN;
 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container,
 Bundle savedInstanceState) {
 if (frameLayout == null) { 
// 之前的frameLayout 已经记录了一个爹了 爹是之前的ViewPager，先干掉之前的爹
			frameLayout = new FrameLayout(getActivity());
			init(); // 在FrameLayout中 添加4种不同的界面
 } else {
 ViewUtils.removeParent(frameLayout);// 移除frameLayout之前的爹
 }
		show();// 根据服务器的数据 切换状态
 return frameLayout; // 拿到当前viewPager 添加这个framelayout
 }
 private View loadingView;// 加载中的界面
 private View errorView;// 错误界面
 private View emptyView;// 空界面
 private View successView;// 加载成功的界面
 private FrameLayout frameLayout;
 // 在FrameLayout中 添加几种不同的界面
 private void init() {
		loadingView = createLoadingView(); // 创建了加载中的界面
 if (loadingView != null) {
			frameLayout.addView(loadingView, new FrameLayout.LayoutParams(
 LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
 }
		errorView = createErrorView(); // 加载错误界面
 if (errorView != null) {
			frameLayout.addView(errorView, new FrameLayout.LayoutParams(
 LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
 }
		emptyView = createEmptyView(); // 加载空的界面
 if (emptyView != null) {
			frameLayout.addView(emptyView, new FrameLayout.LayoutParams(
 LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
 }
		showPage();// 根据不同的状态显示不同的界面
 }
 // 根据不同的状态显示不同的界面
 private void showPage() {
 if (loadingView != null) {
			loadingView.setVisibility(state == STATE_UNKOWN
 || state == STATE_LOADING ? View.VISIBLE : View.INVISIBLE);
 }
 if (errorView != null) {
			errorView.setVisibility(state == STATE_ERROR ? View.VISIBLE
 : View.INVISIBLE);
 }
 if (emptyView != null) {
			emptyView.setVisibility(state == STATE_EMPTY ? View.VISIBLE
 : View.INVISIBLE);
 }
 if (state == STATE_SUCCESS) {
			successView = createSuccessView();
 if (successView != null) {
				frameLayout.addView(successView, new FrameLayout.LayoutParams(
 LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
				successView.setVisibility(View.VISIBLE);
 }
 }
 }
 private View createSuccessView() {
 TextView tv = new TextView(getActivity());
		tv.setText("加载成功了....");
		tv.setTextSize(30);
 return tv;
 }
//枚举，相当于内部类
 public enum LoadResult {
		error(2), empty(3), success(4);
 int value;
 LoadResult(int value) {
 this.value = value;
 }
 public int getValue() {
 return value;
 }
 }
 // 根据服务器的数据 切换状态
 private void show() {
 if (state == STATE_ERROR || state == STATE_EMPTY) {
			state = STATE_LOADING;
 }
 // 请求服务器 获取服务器上数据 进行判断，模拟服务器
 // 请求服务器 返回一个结果
 new Thread() {
 public void run() {
 SystemClock.sleep(2000);//这个方法也能睡
 final LoadResult result = load();
 if (getActivity() != null) {
					getActivity().runOnUiThread(new Runnable() {//主线程刷新ui
 @Override
 public void run() {
 if (result != null) {
								state = result.getValue();
								showPage(); // 状态改变了,重新判断当前应该显示哪个界面
 }
 }
 });
 }
 };
 }.start();
		showPage();
 }
 private LoadResult load() {
 return LoadResult.success;
 }
 /* 创建了空的界面 */
 private View createEmptyView() {
 View view = View.inflate(getActivity(), R.layout.loadpage_empty, null);
 return view;
 }
 /* 创建了错误界面 */
 private View createErrorView() {
 View view = View.inflate(getActivity(), R.layout.loadpage_error, null);
 Button page_bt = (Button) view.findViewById(R.id.page_bt);
		page_bt.setOnClickListener(new OnClickListener() {
 @Override
 public void onClick(View v) {
				show();
 }
 });
 return view;
 }
 /* 创建加载中的界面 */
 private View createLoadingView() {
 View view = View
 .inflate(getActivity(), R.layout.loadpage_loading, null);
 return view;
 }
}

public class ViewUtils {
 public static void removeParent(View v){
 //  先找到爹 在通过爹去移除孩子
 ViewParent parent = v.getParent();
 //所有的控件 都有爹  爹一般情况下 就是ViewGoup
 if(parent instanceof ViewGroup){
 ViewGroup group=(ViewGroup) parent;
			group.removeView(v);
 }
 }
}