製作一個簡單的數據庫應用程序,該應用程序存儲帶有過期日期的食物項目。 無法設置數據庫,我終於認爲我已經對它進行了排序。然後我在開始用於添加項目的活動時忽略應用程序崩潰。java.lang.ClassCastException當在應用程序中啓動活動時
這裏的logcat的:
03-11 09:37:00.406:E/AndroidRuntime(410):致命異常:主03-11 09:37:00.406:E/AndroidRuntime(410) :java.lang.RuntimeException: 無法啓動活動 ComponentInfo {grocery.a2.app/grocery.a2.app.AddItems}: java.lang.ClassCastException:grocery.a2.app.AddItems 03-11 09: 37:00.406:E/AndroidRuntime(410):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 03-11 09:37:00.406:E/AndroidRuntime(410):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 03-11 09:37:00.406:E/AndroidRuntime(410):at android.app.ActivityThread.access $ 1500(ActivityThread.java:117)03 -11 09:37:00.406:E/AndroidRuntime(410):at android.app.ActivityThread $ H.handleMessage(ActivityThread.java:931) 03-11 09:37:00.406:E/AndroidRuntime(410) :at android.os.Handler.dispatchMessage(Handler.java:99)03-11 09:37:00.406:E/AndroidRuntime(410):at android.os.Looper.loop(Looper.java:123) 03-11 09:37:00.406: E/AndroidRuntime(410):at android.app.ActivityThread.main(ActivityThread.java:3683)03-11 09:37:00.406:E/AndroidRuntime(410)在 java.lang.reflect.Method.invokeNative(Native Method)03-11 09:37:00.406:E/AndroidRuntime(410):at java.lang.reflect.Method.invoke(Method.java:507)03 -11 09:37:00.406: E/AndroidRuntime(410):at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:839) 03-11 09:37:00.406:E/AndroidRuntime(410):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)03-11 09:37:00.406:E/AndroidRuntime(410):at dalvik.system.NativeStart。 main(Native Method)03-11 09:37:00.406: E/AndroidRuntime(410):引起:java.lang.ClassCastException: grocery.a2.app.AddItems 03-11 09:37:00.406:E/AndroidRuntime(410):在E/AndroidRuntime(410):at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)0317 09:37:00.406: E/AndroidRuntime(410):at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) (410): 03-11 09:37:00.406:E/AndroidRuntime(410):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 03-11 09:37:00.406:E/AndroidRuntime ... 11多個
而且活動未能啓動代碼:
public class AddItems extends Activity {
private EditText ItemName;
private Long mRowId;
Button btnAdd, btnView;
EditText txtName, txtDate;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.addnewitem);
btnAdd = (Button) findViewById(R.id.btnAdd);
txtName = (EditText) findViewById(R.id.txtName);
txtDate = (EditText) findViewById(R.id.txtDate);
btnView = (Button) findViewById(R.id.btnScan);
btnView.setOnClickListener((OnClickListener) this);
btnAdd.setOnClickListener((OnClickListener) this);
mRowId = null;
Bundle extras = getIntent().getExtras();
if (extras != null){
String name = extras.getString(ItemDBAdapter.KEY_ITEMNAME);
String date = extras.getString(ItemDBAdapter.KEY_ITEMEXP);
mRowId = extras.getLong(ItemDBAdapter.KEY_ID);
if (name != null){
ItemName.setText(name);
}
}
btnAdd.setOnClickListener(new OnClickListener(){
public void onClick(View view) {
Bundle bundle = new Bundle();
bundle.putString(ItemDBAdapter.KEY_ITEMNAME,ItemName.getText().toString());
if (mRowId != null){
bundle.putLong(ItemDBAdapter.KEY_ID, mRowId);
}
Intent mIntent = new Intent();
mIntent.putExtras(bundle);
setResult(RESULT_OK, mIntent);
finish();
}
});
}
而且佈局XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Item Name"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_marginTop="12dp"
android:textColor="#999999"
/>
<requestFocus />
<EditText
android:id="@+id/txtName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="textCapSentences" android:layout_marginTop="5dp"/>
<Button
android:id="@+id/btnScan"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="12dp"
android:text="Scan Barcode"
android:textColor="#000000" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Expiration Date"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_marginTop="12dp"
android:textColor="#999999"/>
<EditText
android:id="@+id/txtDate"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="date" />
<Button
android:id="@+id/btnAdd"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="Add Item"
android:layout_marginTop="12dp"
android:textColor="#000000"/>
<Button
android:id="@+id/btnBack"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
android:layout_marginRight="10dp"
android:text="@string/back"/>"
</LinearLayout>
任何幫助將不勝感激。
您可以發佈佈局XML嗎? – MByD 2012-03-11 09:53:08
我已經在佈局xml中添加了。 – Lundi 2012-03-11 09:57:46