3.加载界面

1.  四种界面: 加载中, 加载错误,加载为空 ,加载成功
2.  根据不同的状态去切换界面

HomeFragment 

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;
	}
}

ViewUtils 

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);
		}
	}
}

 

来自为知笔记(Wiz)