Java 完成搜索后不显示ListView
我试图将ArrayList中的项显示到ListView，但遇到问题。当包含ListView的SearchActivity开始时，我会看到一个空白屏幕。有人能告诉我为什么吗 这里是SearchActivity.Java（顺便说一下，prettyprint函数用字符串填充ArrayList）Java 完成搜索后不显示ListView,java,android,listview,youtube-api,Java,Android,Listview,Youtube Api,我试图将ArrayList中的项显示到ListView，但遇到问题。当包含ListView的SearchActivity开始时，我会看到一个空白屏幕。有人能告诉我为什么吗 这里是SearchActivity.Java（顺便说一下，prettyprint函数用字符串填充ArrayList） package com.example.activity2； 导入java.util.ArrayList； 导入java.util.Iterator； 导入android.app.Activity； 导入and
package com.example.activity2；
导入java.util.ArrayList；
导入java.util.Iterator；
导入android.app.Activity；
导入android.app.SearchManager；
导入android.content.Intent；
导入android.os.Bundle；
导入android.view.Menu；
导入android.view.MenuItem；
导入android.widget.ArrayAdapter；
导入android.widget.ListView；
导入com.google.api.services.youtube.model.SearchResult；
公共类SearchActivity扩展了活动{
ListView lst；
@凌驾
创建时受保护的void（Bundle savedInstanceState）
{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity\u search\u activity）；
Intent=getIntent（）；
if（Intent.ACTION_SEARCH.equals（Intent.getAction（）））{
String query=intent.getStringExtra（SearchManager.query）；
ArrayList结果=新建ArrayList（）；
Iterator it=results.Iterator（）；
prettyPrint（it，query）；
lst=（ListView）findViewById（R.id.list）；
ArrayAdapter=newArrayAdapter（这个，android.R.layout.simple\u list\u item\u 1，SearchYoutube.ytstuff）；
lst.setAdapter（适配器）；
}
}
@凌驾
公共布尔onCreateOptions菜单（菜单）{
//为菜单充气；这会将项目添加到操作栏（如果存在）。
getMenuInflater（）.充气（R.menu.search，menu）；
返回true；
}
@凌驾
公共布尔值onOptionsItemSelected（菜单项项）{
//处理操作栏项目单击此处。操作栏将
//自动处理Home/Up按钮上的点击，只要
//在AndroidManifest.xml中指定父活动时。
int id=item.getItemId（）；
if（id==R.id.action\u设置）{
返回true；
}
返回super.onOptionsItemSelected（项目）；
}
}
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.activity2.SearchActivity"
android:orientation="vertical" >
<ListView
android:id="@+id/list"
android:layout_width="309dp"
android:layout_height="309dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="52dp" >
</ListView>
</LinearLayout>
package com.example.activity2;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import com.google.api.client.googleapis.json.GoogleJsonResponseException;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.services.youtube.YouTube;
import com.google.api.services.youtube.model.ResourceId;
import com.google.api.services.youtube.model.SearchListResponse;
import com.google.api.services.youtube.model.SearchResult;
import com.google.api.services.youtube.model.Thumbnail;
/**
* Print a list of videos matching a search term.
*
* @author Jeremy Walker
*/
public class SearchYoutube {
public static ArrayList<String> ytstuff = new ArrayList();
/**
* Define a global variable that identifies the name of a file that
* contains the developer's API key.
*/
private static final String PROPERTIES_FILENAME = "youtube.properties";
private static final long NUMBER_OF_VIDEOS_RETURNED = 25;
/**
* Define a global instance of a Youtube object, which will be used
* to make YouTube Data API requests.
*/
private static YouTube youtube;
/**
* Initialize a YouTube object to search for videos on YouTube. Then
* display the name and thumbnail image of each video in the result set.
*
* @param args command line args.
*/
public static void main(String[] args) {
// Read the developer key from the properties file.
Properties properties = new Properties();
try {
InputStream in = SearchActivity.class.getResourceAsStream("/" + PROPERTIES_FILENAME);
properties.load(in);
} catch (IOException e) {
System.err.println("There was an error reading " + PROPERTIES_FILENAME + ": " + e.getCause()
+ " : " + e.getMessage());
System.exit(1);
}
try {
// This object is used to make YouTube Data API requests. The last
// argument is required, but since we don't need anything
// initialized when the HttpRequest is initialized, we override
// the interface and provide a no-op function.
youtube = new YouTube.Builder(Auth.HTTP_TRANSPORT, Auth.JSON_FACTORY, new HttpRequestInitializer() {
public void initialize(HttpRequest request) throws IOException {
}
}).setApplicationName("youtube-cmdline-search-sample").build();
// Prompt the user to enter a query term.
String queryTerm = getInputQuery();
// Define the API request for retrieving search results.
YouTube.Search.List search = youtube.search().list("id,snippet");
// Set your developer key from the Google Developers Console for
// non-authenticated requests. See:
// https://console.developers.google.com/
String apiKey = properties.getProperty("youtube.apikey");
search.setKey(apiKey);
search.setQ(queryTerm);
// Restrict the search results to only include videos. See:
// https://developers.google.com/youtube/v3/docs/search/list#type
search.setType("video");
// To increase efficiency, only retrieve the fields that the
// application uses.
search.setFields("items(id/kind,id/videoId,snippet/title,snippet/thumbnails/default/url)");
search.setMaxResults(NUMBER_OF_VIDEOS_RETURNED);
// Call the API and print results.
SearchListResponse searchResponse = search.execute();
List<SearchResult> searchResultList = searchResponse.getItems();
if (searchResultList != null) {
prettyPrint(searchResultList.iterator(), queryTerm);
}
} catch (GoogleJsonResponseException e) {
System.err.println("There was a service error: " + e.getDetails().getCode() + " : "
+ e.getDetails().getMessage());
} catch (IOException e) {
System.err.println("There was an IO error: " + e.getCause() + " : " + e.getMessage());
} catch (Throwable t) {
t.printStackTrace();
}
}
/*
* Prompt the user to enter a query term and return the user-specified term.
*/
private static String getInputQuery() throws IOException {
String inputQuery = "";
System.out.print("Please enter a search term: ");
BufferedReader bReader = new BufferedReader(new InputStreamReader(System.in));
inputQuery = bReader.readLine();
if (inputQuery.length() < 1) {
// Use the string "YouTube Developers Live" as a default.
inputQuery = "YouTube Developers Live";
}
return inputQuery;
}
/*
* Prints out all results in the Iterator. For each result, print the
* title, video ID, and thumbnail.
*
* @param iteratorSearchResults Iterator of SearchResults to print
*
* @param query Search query (String)
*/
public static void prettyPrint(Iterator<SearchResult> iteratorSearchResults, String query) {
if (!iteratorSearchResults.hasNext()) { }
while (iteratorSearchResults.hasNext()) {
SearchResult singleVideo = iteratorSearchResults.next();
ResourceId rId = singleVideo.getId();
// Confirm that the result represents a video. Otherwise, the
// item will not contain a video ID.
if (rId.getKind().equals("youtube#video")) {
Thumbnail thumbnail = singleVideo.getSnippet().getThumbnails().getDefault();
for (int i=0;i<27;i=i+2)
for (int j= 1;j <28;i=i+2)
if (j-i == 1)
{
ytstuff.set(i,rId.getVideoId()); //first thing is video id
ytstuff.set(j,singleVideo.getSnippet().getTitle()); //second thing is title
}
}
}
}
}
package com.example.activity2；
导入java.io.BufferedReader；
导入java.io.IOException；
导入java.io.InputStream；
导入java.io.InputStreamReader；
导入java.util.ArrayList；
导入java.util.Iterator；
导入java.util.List；
导入java.util.Properties；
导入com.google.api.client.googleapis.json.GoogleJsonResponseException；
导入com.google.api.client.http.HttpRequest；
导入com.google.api.client.http.HttpRequestInitializer；
导入com.google.api.services.youtube.youtube；
导入com.google.api.services.youtube.model.ResourceId；
导入com.google.api.services.youtube.model.SearchListResponse；
导入com.google.api.services.youtube.model.SearchResult；
导入com.google.api.services.youtube.model.缩略图；
/**
*打印与搜索词匹配的视频列表。
*
*@作者杰里米·沃克
*/
公共类搜索YouTube{
公共静态ArrayList=新ArrayList（）；
/**
*定义一个全局变量，该变量标识
*包含开发人员的API密钥。
*/
私有静态最终字符串属性\u FILENAME=“youtube.PROPERTIES”；
返回的私有静态最终长视频数=25；
/**
*定义将要使用的Youtube对象的全局实例
*发出YouTube数据API请求。
*/
私有静态YouTube YouTube；
/**
*初始化YouTube对象以搜索YouTube上的视频。然后
*显示结果集中每个视频的名称和缩略图。
*
*@param args命令行args。
*/
公共静态void main（字符串[]args）{
//从属性文件中读取开发人员密钥。
属性=新属性（）；
试一试{
InputStream in=SearchActivity.class.getResourceAsStream（“/”+属性\u文件名）；
属性。荷载（in）；
}捕获（IOE异常）{
System.err.println（“读取“+PROPERTIES\u FILENAME+”：“+e.getCause（）时出错）
+“：”+e.getMessage（））；
系统出口（1）；
}
试一试{
//此对象用于发出YouTube数据API请求
//争论是必需的，但既然我们什么都不需要
//初始化当HttpRequest初始化时，我们重写
//接口并提供无操作功能。
youtube=new youtube.Builder（Auth.HTTP_传输，Auth.JSON_工厂，新的HttpRequestInitializer（）{
公共无效初始化（HttpRequest请求）引发IOException{
}
}).setApplicationName（“youtube cmdline搜索示例”）.build（）；
//提示用户输入查询术语。
字符串queryTerm=getInputQuery（）；
//定义检索搜索结果的API请求。
YouTube.Search.List Search=YouTube.Search（）.List（“id，snippet”）；
//从Google开发者控制台为设置开发者密钥
//未经身份验证的请求。请参阅：
// https://console.developers.google.com/
字符串apiKey=properties.getProperty（“youtube.apiKey”）；
search.setKey（apiKey）；
search.setQ（queryTerm）；
//将搜索结果限制为仅包含视频。请参阅：
// https://developers.google.com/youtube/v3/docs/search/list#type
search.setType（“视频”）；
//为了提高效率，只检索
//应用程序使用。
search.setFields（“项（id/kind、id/videoId、片段/标题、片段/缩略图/默认值/url）”；
search.setMaxResults（视频数量）
package com.example.activity2;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import com.google.api.client.googleapis.json.GoogleJsonResponseException;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.services.youtube.YouTube;
import com.google.api.services.youtube.model.ResourceId;
import com.google.api.services.youtube.model.SearchListResponse;
import com.google.api.services.youtube.model.SearchResult;
import com.google.api.services.youtube.model.Thumbnail;
/**
* Print a list of videos matching a search term.
*
* @author Jeremy Walker
*/
public class SearchYoutube {
public static ArrayList<String> ytstuff = new ArrayList();
/**
* Define a global variable that identifies the name of a file that
* contains the developer's API key.
*/
private static final String PROPERTIES_FILENAME = "youtube.properties";
private static final long NUMBER_OF_VIDEOS_RETURNED = 25;
/**
* Define a global instance of a Youtube object, which will be used
* to make YouTube Data API requests.
*/
private static YouTube youtube;
/**
* Initialize a YouTube object to search for videos on YouTube. Then
* display the name and thumbnail image of each video in the result set.
*
* @param args command line args.
*/
public static void main(String[] args) {
// Read the developer key from the properties file.
Properties properties = new Properties();
try {
InputStream in = SearchActivity.class.getResourceAsStream("/" + PROPERTIES_FILENAME);
properties.load(in);
} catch (IOException e) {
System.err.println("There was an error reading " + PROPERTIES_FILENAME + ": " + e.getCause()
+ " : " + e.getMessage());
System.exit(1);
}
try {
// This object is used to make YouTube Data API requests. The last
// argument is required, but since we don't need anything
// initialized when the HttpRequest is initialized, we override
// the interface and provide a no-op function.
youtube = new YouTube.Builder(Auth.HTTP_TRANSPORT, Auth.JSON_FACTORY, new HttpRequestInitializer() {
public void initialize(HttpRequest request) throws IOException {
}
}).setApplicationName("youtube-cmdline-search-sample").build();
// Prompt the user to enter a query term.
String queryTerm = getInputQuery();
// Define the API request for retrieving search results.
YouTube.Search.List search = youtube.search().list("id,snippet");
// Set your developer key from the Google Developers Console for
// non-authenticated requests. See:
// https://console.developers.google.com/
String apiKey = properties.getProperty("youtube.apikey");
search.setKey(apiKey);
search.setQ(queryTerm);
// Restrict the search results to only include videos. See:
// https://developers.google.com/youtube/v3/docs/search/list#type
search.setType("video");
// To increase efficiency, only retrieve the fields that the
// application uses.
search.setFields("items(id/kind,id/videoId,snippet/title,snippet/thumbnails/default/url)");
search.setMaxResults(NUMBER_OF_VIDEOS_RETURNED);
// Call the API and print results.
SearchListResponse searchResponse = search.execute();
List<SearchResult> searchResultList = searchResponse.getItems();
if (searchResultList != null) {
prettyPrint(searchResultList.iterator(), queryTerm);
}
} catch (GoogleJsonResponseException e) {
System.err.println("There was a service error: " + e.getDetails().getCode() + " : "
+ e.getDetails().getMessage());
} catch (IOException e) {
System.err.println("There was an IO error: " + e.getCause() + " : " + e.getMessage());
} catch (Throwable t) {
t.printStackTrace();
}
}
/*
* Prompt the user to enter a query term and return the user-specified term.
*/
private static String getInputQuery() throws IOException {
String inputQuery = "";
System.out.print("Please enter a search term: ");
BufferedReader bReader = new BufferedReader(new InputStreamReader(System.in));
inputQuery = bReader.readLine();
if (inputQuery.length() < 1) {
// Use the string "YouTube Developers Live" as a default.
inputQuery = "YouTube Developers Live";
}
return inputQuery;
}
/*
* Prints out all results in the Iterator. For each result, print the
* title, video ID, and thumbnail.
*
* @param iteratorSearchResults Iterator of SearchResults to print
*
* @param query Search query (String)
*/
public static void prettyPrint(Iterator<SearchResult> iteratorSearchResults, String query) {
if (!iteratorSearchResults.hasNext()) { }
while (iteratorSearchResults.hasNext()) {
SearchResult singleVideo = iteratorSearchResults.next();
ResourceId rId = singleVideo.getId();
// Confirm that the result represents a video. Otherwise, the
// item will not contain a video ID.
if (rId.getKind().equals("youtube#video")) {
Thumbnail thumbnail = singleVideo.getSnippet().getThumbnails().getDefault();
for (int i=0;i<27;i=i+2)
for (int j= 1;j <28;i=i+2)
if (j-i == 1)
{
ytstuff.set(i,rId.getVideoId()); //first thing is video id
ytstuff.set(j,singleVideo.getSnippet().getTitle()); //second thing is title
}
}
}
}
}