R cannot be resolved
package com.example.android_listview;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.os.Build;
public class MainActivity extends Activity {
private ListView listView;
private ArrayAdapter<String>arr_adapter;
private SimpleAdapter simp_adapter;
private Object android;
? ? @Override
? ? protected void onCreate(Bundle savedInstanceState) {
? ? ? ? super.onCreate(savedInstanceState);
? ? ? ? setContentView(R.layout.main);
? ? ? ? listView=(ListView) findViewById(R.id.listView);
? ? ? ? //1.新建一個(gè)數(shù)據(jù)適配器
? ? ? ? //ArrayAdapter(上下文，當(dāng)前LisView加載的每一個(gè)列表項(xiàng)所對(duì)應(yīng)的布局文件,數(shù)據(jù)源)
? ? ? ? //2、適配器加載數(shù)據(jù)源
? ? ? ? String[]arr_data={"慕課網(wǎng)1","慕課網(wǎng)2","慕課網(wǎng)3","慕課網(wǎng)4"};
? ? ? ? arr_adapter=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,data_object); ? ? ? ? ? ? //提示我R cannot be resolved....咋回事.?報(bào)錯(cuò)也是這行。
? ? ? ? //3.視圖（ListView）加載適配器
? ? ? ? listView.setAdapter(arr_adapter);
? ? } ??
}
2022-03-25
是不是安裝完成后沒有啟動(dòng)Wamp服務(wù)？您說的課程的收藏嗎
2016-09-02
R文件沒了，clean一下就好了，工具欄project，有個(gè)clean，選擇選中的項(xiàng)目clean
2016-07-04
package com.example.shipeiqi;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
public class MainActivity extends Activity implements OnItemClickListener,OnScrollListener{
ListView listview;
ArrayAdapter<String> arr_adapter;
SimpleAdapter simp_leAdapter;
List<Map<String,Object>>dataList;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listview=(ListView) this.findViewById(R.id.listView1);
//1.新建一個(gè)數(shù)據(jù)適配器
//ArrayAdapter(上下文，當(dāng)前ListView加載的每一個(gè)列表項(xiàng)所對(duì)應(yīng)的布局文件，數(shù)據(jù)源)
? //2.適配器加載數(shù)據(jù)源
/*
* context:上下文，
* data：數(shù)據(jù)源 一個(gè)map所組成的List集合
* ? ? ?每一個(gè)Map都會(huì)去對(duì)應(yīng)Listview列表中的一行。
*/
String []arr_adap={"慕課網(wǎng)1","慕課網(wǎng)2","慕課網(wǎng)3","慕課網(wǎng)4"};
dataList=new ArrayList<Map<String,Object>>();
arr_adapter=new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, arr_adap );
? //3.視圖（listview）加載適配器
simp_leAdapter=new SimpleAdapter(this, getdata(), R.layout.activity_atap_adapter, new String []{"pic","text"}, new int []{R.id.imageView1,R.id.textView1});
//listview.setAdapter(arr_adapter);
listview.setAdapter(simp_leAdapter);
listview.setOnItemClickListener(this);
? ? ? ? listview.setOnScrollListener(this);
}
private List<Map<String,Object>> getdata(){
for(int i=0;i<20;i++){
Map<String,Object>map=new HashMap<String,Object>();
map.put("pic", R.drawable.ic_launcher);
map.put("text", "慕課網(wǎng)"+i);
dataList.add(map);
}
return dataList;
}
@Override
public void onScroll(AbsListView arg0, int arg1, int arg2, int arg3) {
// TODO Auto-generated method stub
switch(arg1){
case SCROLL_STATE_FLING:
Log.i("Main","用戶在手指離開屏幕之前，由于用力滑了一下，視圖還會(huì)");
Map<String,Object>map=new HashMap<String,Object>();
? ? ? ?map.put("pic",R.drawable.ic_launcher);
? ? ? ?map.put("txet", "再加一項(xiàng)");
? ? ? ?dataList.add(map);
? ? ? ?simp_leAdapter.notifyDataSetInvalidated();
? ? ? ?break;
case SCROLL_STATE_IDLE:
break;
case SCROLL_STATE_TOUCH_SCROLL:
break;
}
}
@Override
public void onScrollStateChanged(AbsListView arg0, int arg1) {
// TODO Auto-generated method stub
}
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
// TODO Auto-generated method stub
String text=listview.getItemAtPosition(arg2)+""; ?
Toast.makeText(this, "arg2="+arg2+"text="+text, Toast.LENGTH_LONG).show();
}
}