在项目中,都会用到ListView或GridView等列表控件。一般会用来展示从网络请求的数据 。如果请求的数据为空或者在请求的时候正好无没有网络了,我们的界面应该如何展示呢?数据为空的时候,ListView可以使用setEmptyView (View emptyView) 方法来我们需要的统一界面。数据加载失败呢?我们也可以统一进行处理。
//下面这个类是简单地封装用于无数据及加载错误的一个页面。public class CommonShowView { private Context mContext;// 上下文 private ViewGroup mEmptyOrErrorView;// 页面加载无数据或加载错误时显示 private ViewGroup mContentView;// 加载成功时显示的内容 private ViewGroup mParentView;// 父布局viewGroup private LayoutInflater mInflater; private TextView no_net; private Button load_btn; private boolean mViewsAdded; private ViewGroup.LayoutParams mLayoutParams = new ViewGroup.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT); public final static int TYPE_EMPTY = 1;// 数据为空 public final static int TYPE_ERROR = 2;// 加载数据失败 public final static int TYPE_CONTENT = 3;// 直接显示内容 private int mType = TYPE_EMPTY;// 数据类型,默认是无数据 /** * 构造方法,传入上下文及内容GroupView */ public CommonShowView(Context context, ViewGroup mContentView) { mContext = context; mInflater = LayoutInflater.from(mContext); this.mContentView = mContentView; mParentView = (ViewGroup) mContentView.getParent(); initViews(); } @SuppressLint("InflateParams") private void initViews() { mEmptyOrErrorView = (ViewGroup) mInflater.inflate(R.layout.common_show, null); no_net = (TextView) mEmptyOrErrorView.findViewById(R.id.no_net); load_btn = (Button) mEmptyOrErrorView.findViewById(R.id.load_btn); if (!mViewsAdded) { mViewsAdded = true; mParentView.addView(mEmptyOrErrorView, mLayoutParams); } load_btn.setOnClickListener(new OnClickListener() {// 检查网络,进行网络设置 @Override public void onClick(View v) { Intent intent = null; // 判断手机系统的版本 即API大于10 就是3.0或以上版本及魅族手机 if (android.os.Build.VERSION.SDK_INT > 10 && !android.os.Build.MANUFACTURER.equals("Meizu")) { intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS); } else if (android.os.Build.VERSION.SDK_INT > 17 && android.os.Build.MANUFACTURER.equals("Meizu")) { intent = new Intent(android.provider.Settings.ACTION_SETTINGS); } else { intent = new Intent(); ComponentName component = new ComponentName("com.android.settings", "com.android.settings.WirelessSettings"); intent.setComponent(component); intent.setAction("android.intent.action.VIEW"); } mContext.startActivity(intent); } }); } public ViewGroup getEmptyOrErrorView() { return mEmptyOrErrorView; } /** * 设置无数据或加载错误view * @description: */ public void setEmptyOrErrorView(ViewGroup emptyOrErrorView) { this.mParentView.removeView(this.mEmptyOrErrorView); this.mParentView.addView(emptyOrErrorView, mLayoutParams); this.mEmptyOrErrorView = emptyOrErrorView; } /** * 设置无数据或加载错误view * @description: */ public void setEmptyOrErrorView(int res) { ViewGroup vg = (ViewGroup) mInflater.inflate(res, null); this.mParentView.removeView(this.mEmptyOrErrorView); this.mParentView.addView(vg, mLayoutParams); this.mEmptyOrErrorView = vg; } /** * 获取内容view * @description: */ public ViewGroup getContextView() { return mContentView; } /** * 方法概述:获取内容View的父布局 */ public ViewGroup getRootView() { return mParentView; } /** * 方法概述:设置展示内容的视图 */ public void setContextView(ViewGroup contentView) { this.mType = TYPE_CONTENT; showByType(mType); } /** * 根据类型进行对应展示 * @description: * @date 2016-2-19 下午3:02:20 */ public void showByType(int mType) { hideAllViews(); if (mContentView != null) { switch (mType) { case TYPE_EMPTY: if (mEmptyOrErrorView != null) { mEmptyOrErrorView.setVisibility(View.VISIBLE); no_net.setText("这里空空也野哦~"); load_btn.setVisibility(View.GONE); } break; case TYPE_ERROR: if (mEmptyOrErrorView != null) { mEmptyOrErrorView.setVisibility(View.VISIBLE); no_net.setText("网络加载失败哦~"); load_btn.setVisibility(View.VISIBLE); } break; case TYPE_CONTENT: if (mContentView != null) { mContentView.setVisibility(View.VISIBLE); } break; default: break; } } } /** * 方法概述:将所有的子View隐藏起来 */ private void hideAllViews() { if (mParentView != null) { if (mParentView.getChildCount() > 0) { for (int i = 0; i < mParentView.getChildCount(); i++) { View childView = mParentView.getChildAt(i); if (childView != null) { childView.setVisibility(View.GONE); } } } } }}//错误页面及空页面时布局<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/rel_null" android:layout_width="match_parent" android:layout_height="match_parent" > <TextView android:id="@+id/no_net" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_centerInParent="true" android:gravity="center" android:text="好像没网哦~" android:textColor="#333333" android:textSize="16sp" /> <Button android:id="@+id/load_btn" android:layout_width="112dp" android:layout_height="40dp" android:layout_below="@+id/no_net" android:layout_centerHorizontal="true" android:layout_marginTop="15dp" android:background="#E12228" android:gravity="center" android:text="检查网络" android:textColor="#ffffff" android:textSize="14sp" /></RelativeLayout>//在Activity中使用public class MainActivity extends Activity { private ListView listview; private CommonShowView mShowView; private List<String> datas; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listview = (ListView) findViewById(R.id.listview); mShowView = new CommonShowView(this, listview); // ----------有数据的时情况下-------------- // datas = getDatas(true); // listview.setAdapter(new MyAdapter(this, datas)); // mShowView.setContextView(listview);//显示数据,也可以不调用,直接显示 // --------无数据的情况下---------------- // datas = getDatas(false);//无数据 // mShowView.showByType(CommonShowView.TYPE_EMPTY); // ---------数据加载失败的情况下--------------- mShowView.showByType(CommonShowView.TYPE_ERROR); } private List<String> getDatas(boolean flag) { List<String> datas = new ArrayList<>(); datas.add("这是第一行的data"); datas.add("这是第2行的data"); datas.add("这是第三行的data"); datas.add("这是第4行的data"); if (flag) { return datas; } else { return null; } } class MyAdapter extends BaseAdapter { private List<String> datas; private Context mContext; public MyAdapter(Context mContext, List<String> datas) { this.mContext = mContext; this.datas = datas; } @Override public int getCount() { // TODO Auto-generated method stub return datas.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return datas.get(position); } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { // 这里只举个小例子,没有考虑性能 优化 TextView tv = new TextView(mContext); tv.setTextSize(16f); tv.setText(datas.get(position)); return tv; } }}
目前只是做了个超级简单的样式,具体的展示根据需求再改再封装。帖个图:
以上就是ListView数据为空及加载错误处理的方法,希望对大家的学习有所帮助。