我在android编程时很讨厌，我在fourm上知道很多页面都在解决我的问题的解决方案，但是现在我输了2天，但仍然没有得到解决方案。请帮我!
首先我的错误:
01-02 11:08:27.314: D/AndroidRuntime(1045): Shutting down VM
01-02 11:08:27.314: W/dalvikvm(1045): threadid=1: thread exiting with uncaught exception (group=0x409e61f8)
01-02 11:08:27.324: E/AndroidRuntime(1045): FATAL EXCEPTION: main
01-02 11:08:27.324: E/AndroidRuntime(1045): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.wifiscan/com.example.wifiscan.activity_wifi_scan}: java.lang.ClassNotFoundException: com.example.wifiscan.activity_wifi_scan
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1880)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.app.ActivityThread.access$600(ActivityThread.java:123)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.os.Handler.dispatchMessage(Handler.java:99)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.os.Looper.loop(Looper.java:137)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.app.ActivityThread.main(ActivityThread.java:4424)
01-02 11:08:27.324: E/AndroidRuntime(1045): at java.lang.reflect.Method.invokeNative(Native Method)
01-02 11:08:27.324: E/AndroidRuntime(1045): at java.lang.reflect.Method.invoke(Method.java:511)
01-02 11:08:27.324: E/AndroidRuntime(1045): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-02 11:08:27.324: E/AndroidRuntime(1045): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-02 11:08:27.324: E/AndroidRuntime(1045): at dalvik.system.NativeStart.main(Native Method)
01-02 11:08:27.324: E/AndroidRuntime(1045): Caused by: java.lang.ClassNotFoundException: com.example.wifiscan.activity_wifi_scan
01-02 11:08:27.324: E/AndroidRuntime(1045): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61)
01-02 11:08:27.324: E/AndroidRuntime(1045): at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
01-02 11:08:27.324: E/AndroidRuntime(1045): at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
01-02 11:08:27.324: E/AndroidRuntime(1045): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1871)
01-02 11:08:27.324: E/AndroidRuntime(1045): ... 11 more
我的WifiScan:
public class WifiScan extends Activity implements OnClickListener {
WifiManager wifi;
ListView lv;
TextView textStatus;
Button buttonScan;
int size = 0;
List<ScanResult> results;
String ITEM_KEY = "key";
ArrayList<HashMap<String, String>> arraylist = new ArrayList<HashMap<String, String>>();
SimpleAdapter adapter;
/* Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_wifi_scan);
buttonScan = (Button) findViewById(R.id.scan);
buttonScan.setOnClickListener(this);
lv = (ListView)findViewById(R.id.list);
wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
if (wifi.isWifiEnabled() == false)
{
Toast.makeText(getApplicationContext(), "wifi is disabled..making it enabled", Toast.LENGTH_LONG).show();
wifi.setWifiEnabled(true);
}
wifi.startScan(); //js dopisal
// this.adapter = new SimpleAdapter(WiFiDemo.this, arraylist, R.layout.row, new String[] { ITEM_KEY }, new int[] { R.id.list_value });
lv.setAdapter(this.adapter);
registerReceiver(new BroadcastReceiver()
{
@Override
public void onReceive(Context c, Intent intent)
{
results = wifi.getScanResults();
size = results.size();
}
}, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
}
public void onClick(View view)
{
arraylist.clear();
wifi.startScan();
Toast.makeText(this, "Scanning...." + size, Toast.LENGTH_SHORT).show();
try
{
size = size - 1;
while (size >= 0)
{
HashMap<String, String> item = new HashMap<String, String>();
item.put(ITEM_KEY, results.get(size).SSID + " " + results.get(size).capabilities);
arraylist.add(item);
size--;
adapter.notifyDataSetChanged();
}
}
catch (Exception e)
{ }
}
}
我的activity_wifi_scan.xml文件:
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/TableLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
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=".WifiScan" >
<Button
android:id="@+id/scan"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="scan"
android:text="SCAN" />
<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
</TableLayout>
和我的AndroidManifest文件:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.wifiscan"
android:versionCode="1"
android:versionName="1.0" >
<uses-premission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>
<uses-permission android:name="android.permission.READ_PHONE_STATE"> </uses-permission>
<uses-permission android:name="android.permission.INTERNET"> </uses-permission>
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity android:name=".activity_wifi_scan">
<intent-filter>
<action android:name="android.intent.action.MAIN"></action>
<category android:name="android.intent.category.LAUNCHER"></category>
<data />
</intent-filter>
</activity>
<receiver android:name=".activity_wifi_scan">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER"/>
<action android:name="android.net.wifi.WIFI_STATE_CHANGED"/>
</intent-filter>
</receiver>
</application>
</manifest>
最佳答案
您的 Activity 名称为WifiScan，但已将其声明为.activity_wifi_scan，请对其进行更改，然后重试。
将<activity>元素更改为:
<activity android:name=".WifiScan">
<intent-filter>
<action android:name="android.intent.action.MAIN"></action>
<category android:name="android.intent.category.LAUNCHER"></category>
<data />
</intent-filter>
</activity>