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我已經在一些網站上下載了一些示例程序，並試圖執行該程序。那時候我沒有找到類Exception.i試圖在很多方面解決錯誤。但我不能得到解決方案。如何解決classNotFoundException？
public class DataBaseDemoActivity extends Activity {
/** Called when the activity is first created. */
SQLiteDatabase db;
Button btnInsert;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnInsert=(Button)findViewById(R.id.button1);
try{
db=openOrCreateDatabase("StudentDB",SQLiteDatabase.CREATE_IF_NECESSARY,null);
db.execSQL("Create Table Temp(id integer,name text)");
}catch(SQLException e)
{
}
btnInsert.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
EditText eid=(EditText) findViewById(R.id.edit1);
EditText ename=(EditText)findViewById(R.id.edit2);
ContentValues values=new ContentValues();
values.put("id", eid.getText().toString());
values.put("name", ename.getText().toString());
if((db.insert("temp", null, values))!=-1)
{
Toast.makeText(DataBaseDemoActivity.this, "Record Successfully Inserted", 2000).show();
}
else
{
Toast.makeText(DataBaseDemoActivity.this, "Insert Error", 2000).show();
}
eid.setText("");
ename.setText("");
Cursor c=db.rawQuery("SELECT * FROM temp",null);
c.moveToFirst();
while(!c.isAfterLast())
{
Toast.makeText( DataBaseDemoActivity.this,c.getString(0)+ " "+c.getString(1), 1000).show();
c.moveToNext();
}
c.close();
}
});
}
@Override
protected void onStop() {
db.close();
super.onStop();
}
}
logcat的：
09-08 11:15:09.841: E/AndroidRuntime(932): FATAL EXCEPTION: main
09-08 11:15:09.841: E/AndroidRuntime(932): java.lang.RuntimeException: Unable to instantiate activity
ComponentInfo{com.example.databasedemo/com.example.databasedemo.MainActivity}: java.lang.ClassNotFoundException: com.example.databasedemo.MainActivity
09-0 8 11:15:09.841: E/AndroidRuntime(932): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1983)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.app.ActivityThread.access$600(ActivityThread.java:130)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.os.Handler.dispatchMessage(Handler.java:99)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.os.Looper.loop(Looper.java:137)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.app.ActivityThread.main(ActivityThread.java:4745)
09-08 11:15:09.841: E/AndroidRuntime(932): at java.lang.reflect.Method.invokeNative(Native Method)
09-08 11:15:09.841: E/AndroidRuntime(932): at java.lang.reflect.Method.invoke(Method.java:511)
09-08 11:15:09.841: E/AndroidRuntime(932): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-08 11:15:09.841: E/AndroidRuntime(932): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-08 11:15:09.841: E/AndroidRuntime(932): at dalvik.system.NativeStart.main(Native Method)
09-08 11:15:09.841: E/AndroidRuntime(932): Caused by: java.lang.ClassNotFoundException: com.example.databasedemo.MainActivity
09-08 11:15:09.841: E/AndroidRuntime(932): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61)
09-08 11:15:09.841: E/AndroidRuntime(932): at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
09-08 11:15:09.841: E/AndroidRuntime(932): at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
09-08 11:15:09.841: E/AndroidRuntime(932): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
09-08 11:15:09.841: E/AndroidRuntime(932): ... 11 more
main.xml中：
<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"/>
<TextView
android:id="@+id/textView1"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="@string/si"
android:layout_marginTop="20dp"/>
<EditText
android:id="@+id/edit1"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:inputType="number"
android:hint="@string/esi"
>
<requestFocus android:layout_width="wrap_content" />
</EditText>
<TextView
android:id="@+id/textView2"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="@string/sn"/>
<EditText
android:id="@+id/edit2"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:hint="@string/esn"/>
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/ir" />
</LinearLayout>
的Manifest.xml：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.databasedemo"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
感謝事先
請把你的logcat的。 –
我們需要看到你的logcat的輸出甚至開始有機會找出發生了什麼。 – Barak
@ V.J。我已經上傳LOGCAT – USER5762