android - 非法状态异常 : Could not execute method of the activity

Question

我正在尝试在 eclipse java android 中编写代码以将两个字段输入到数据库中。在数据库中输入 3 行条目后，我单击“查看列表”数据库，但出现错误。我已经将我认为的错误缩小到 DetailActivity.java

Intent intent = new Intent(this, RaceListActivity.class);

存在 RaceListActivity.class 和 RaceListActivity.java. 但我收到此错误。 DetailActivity.java 和 RaceListActivity.java 代码在错误退出的下方。 LogCat 在其下方。

详细Activity.java

// Shows/edits the data for one row.
public class DetailActivity extends Activity {
    private RaceDB mDB;
    private Long mRowId;
    private EditText mEditText1;
    private EditText mEditText2;
    private CheckBox mCheckBox;
    private static final String TAG = "INFORMATION";

    @Override
    protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        setContentView(R.layout.activity_main);

        mEditText1 = (EditText) findViewById(R.id.editText1);
        mEditText2 = (EditText) findViewById(R.id.editText2);
        mCheckBox = (CheckBox) findViewById(R.id.checkBox1);

        mRowId = null;

        if (bundle == null) {  // initially, Intent -> extras -> rowID
            Bundle extras = getIntent().getExtras();
            if (extras != null && extras.containsKey(RaceListActivity.EXTRA_ROWID)) {
                mRowId = extras.getLong(RaceListActivity.EXTRA_ROWID);
            }
        }
        else {  // tricky: recover mRowId from kill destroy/create cycle
            mRowId = bundle.getLong(SAVE_ROW);
        }

        mDB = new RaceDB(this);
        mDB.open();
        Log.d(TAG, "Database is now open and saved");
        dbToUI();
        Log.d(TAG, "Database is now able to be shown");
        onPause();
    }       

    public void view_races(View v){
        Log.d(TAG, "Database is now almost shown");
        Intent intent = new Intent(this, RaceListActivity.class);
        startActivity(intent);    
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mDB.close();
    }

    // Copies database state up to the UI.
    private void dbToUI() {
        if (mRowId != null) {
            Cursor cursor = mDB.query(mRowId);
            mEditText1.setText(cursor.getString(RaceDB.INDEX_TITLE));
            mEditText2.setText(cursor.getString(RaceDB.INDEX_BODY));
            mCheckBox.setChecked(cursor.getInt(RaceDB.INDEX_STATE) > 0);

            cursor.close();
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        save();
    }


    /** Save the state in the UI to the database, creating a new row or updating
     * an existing row.
     */
    private void save() {
        String title = mEditText1.getText().toString();
        String body = mEditText2.getText().toString();
        int done = 0;
        if (mCheckBox.isChecked()) done = 1;

        // Not null = edit of existing row, or it's new but we saved it previously,
        // so now it has a rowId anyway.
        if (mRowId != null) {
            mDB.updateRow(mRowId, mDB.createContentValues(title, body, done));
        }
        else {
            mRowId = mDB.createRow(mDB.createContentValues(title, body, done));
        }
    }

    public static final String SAVE_ROW = "saverow";
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putLong(SAVE_ROW, mRowId);
    }
}

RaceListActivity.java

// Main activity -- shows data list, has a few controls.
public class RaceListActivity extends ListActivity {
    private RaceDB mDB;  // Our connection to the database.
    private SimpleCursorAdapter mCursorAdapter;
    private static final String TAG = "INFORMATION";

    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        Log.d(TAG, "Database is now shown");
        setContentView(R.layout.activity_view_races);

/*        Button button = (Button) findViewById(R.id.button1);
        button.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                startDetail(0, true);  // true = create new
            }
        });*/

        // Start up DB connection (closed in onDestroy).


        mDB = new RaceDB(this);
        mDB.open();

        // Get the "all rows" cursor. startManagingCursor() is built in for the common case,
        // takes care of closing etc. the cursor.
        Cursor cursor = mDB.queryAll();
        startManagingCursor(cursor);

        // Adapter: maps cursor keys, to R.id.XXX fields in the row layout.
        String[] from = new String[] { RaceDB.KEY_TITLE, RaceDB.KEY_STATE };
        int[] to = new int[] { R.id.rowtext, R.id.rowtext2 };
        mCursorAdapter = new SimpleCursorAdapter(this, R.layout.row2, cursor, from, to);

        // Map "state" int to text in the row -- intercept the setup of each row view,
        // fiddle with the data for the state column.
        mCursorAdapter.setViewBinder(new SimpleCursorAdapter.ViewBinder() {
            public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
                if (columnIndex == RaceDB.INDEX_STATE) {
                    TextView textView = (TextView) view;
                    if (cursor.getInt(RaceDB.INDEX_STATE) > 0) {
                        textView.setText(" (done) ");
                    }
                    else {
                        textView.setText("");
                    }
                    return true;  // i.e. we handled it
                }
                return false;  // i.e. the system should handle it
            }
            });

        // Alternative: also have row.xml layout with just one text field. No ViewBinder
        // needed for that simpler approach.

        setListAdapter(mCursorAdapter);
        registerForContextMenu(getListView());

        // Placing a clickable control inside a list is nontrivial unfortunately.
        // see bug: http://code.google.com/p/android/issues/detail?id=3414

    }

    // Placing this next to onCreate(), help to remember to mDB.close().
    @Override
    protected void onDestroy() {
        super.onDestroy();
        mDB.close();
    }

    // Create menu when the select the menu button.
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.pref_menu, menu);
        return true;
    }

    // Called for menu item select. Return true if we handled it.
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle item selection
        switch (item.getItemId()) {
            case R.id.prefs:
                // open prefs, previous lecture
                return true;

            default:
                return super.onOptionsItemSelected(item);

        }
    }


    // Create context menu for click-hold in list.
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v,
                                    ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.list_menu, menu);
    }

    // Context menu item-select.
    @Override
    public boolean onContextItemSelected(MenuItem item) {
        AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
        switch (item.getItemId()) {
            case R.id.menu_detail:
                startDetail(info.id, false);
                return true;

            case R.id.menu_delete:
                remove(info.id);
                return true;                
            default:
                return super.onContextItemSelected(item);
        }
    }


    // Removes the given rowId from the database, updates the UI.
    public void remove(long rowId) {
        mDB.deleteRow(rowId);
        //mCursorAdapter.notifyDataSetChanged();  // confusingly, this does not work
        mCursorAdapter.getCursor().requery();  // need this
    }


    public static final String EXTRA_ROWID = "rowid";

    @Override
    protected void onListItemClick(ListView l, View v, int position, long rowId) {
        super.onListItemClick(l, v, position, rowId);
        startDetail(rowId, false);
    }

    // Starts the detail activity, either edit existing or create new.
    public void startDetail(long rowId, boolean create) {
        Intent intent = new Intent(this, DetailActivity.class);
        // Our convention: add rowId to edit existing. To create add nothing.
        if (!create) {
            intent.putExtra(EXTRA_ROWID, rowId);
        }
        startActivity(intent);
        // Easy bug: remember to add to add a manifest entry for the detail activity
    }
}


/*
Customizing how the data goes into each list/row (use with row2 layout)

        mCursorAdapter.setViewBinder(new SimpleCursorAdapter.ViewBinder() {
            public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
                if (columnIndex == RaceDB.INDEX_STATE) {
                    TextView tv = (TextView) view;
                    if (cursor.getInt(RaceDB.INDEX_STATE) > 0) {
                        tv.setText(" (done) ");
                    }
                    else {
                        tv.setText("");
                    }
                    return true;
                }
                return false;
            }
            });
*/

LogCat

12-02 22:37:47.785: D/INFORMATION(768): Database is now open and saved
12-02 22:37:47.785: D/INFORMATION(768): Database is now able to be shown
12-02 22:38:24.275: D/INFORMATION(768): Database is now almost shown
12-02 22:38:24.310: D/AndroidRuntime(768): Shutting down VM
12-02 22:38:24.310: W/dalvikvm(768): threadid=1: thread exiting with uncaught exception (group=0x40015560)
12-02 22:38:24.375: E/AndroidRuntime(768): FATAL EXCEPTION: main
12-02 22:38:24.375: E/AndroidRuntime(768): java.lang.IllegalStateException: Could not execute method of the activity
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.view.View$1.onClick(View.java:2144)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.view.View.performClick(View.java:2485)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.view.View$PerformClick.run(View.java:9080)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.os.Handler.handleCallback(Handler.java:587)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.os.Handler.dispatchMessage(Handler.java:92)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.os.Looper.loop(Looper.java:123)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.app.ActivityThread.main(ActivityThread.java:3683)
12-02 22:38:24.375: E/AndroidRuntime(768):  at java.lang.reflect.Method.invokeNative(Native Method)
12-02 22:38:24.375: E/AndroidRuntime(768):  at java.lang.reflect.Method.invoke(Method.java:507)
12-02 22:38:24.375: E/AndroidRuntime(768):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
12-02 22:38:24.375: E/AndroidRuntime(768):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
12-02 22:38:24.375: E/AndroidRuntime(768):  at dalvik.system.NativeStart.main(Native Method)
12-02 22:38:24.375: E/AndroidRuntime(768): Caused by: java.lang.reflect.InvocationTargetException
12-02 22:38:24.375: E/AndroidRuntime(768):  at java.lang.reflect.Method.invokeNative(Native Method)
12-02 22:38:24.375: E/AndroidRuntime(768):  at java.lang.reflect.Method.invoke(Method.java:507)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.view.View$1.onClick(View.java:2139)
12-02 22:38:24.375: E/AndroidRuntime(768):  ... 11 more
12-02 22:38:24.375: E/AndroidRuntime(768): Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {edu.CIS2818.TriTracker/edu.CIS2818.TriTracker.RaceListActivity}; have you declared this activity in your AndroidManifest.xml?
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1405)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.app.Instrumentation.execStartActivity(Instrumentation.java:1379)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.app.Activity.startActivityForResult(Activity.java:2827)
12-02 22:38:24.375: E/AndroidRuntime(768):  at android.app.Activity.startActivity(Activity.java:2933)
12-02 22:38:24.375: E/AndroidRuntime(768):  at edu.CIS2818.TriTracker.DetailActivity.view_races(DetailActivity.java:62)
12-02 22:38:24.375: E/AndroidRuntime(768):  ... 14 more
</pre>

Answer 1

不要手动调用 Activity 生命周期方法。在您当前的代码中，您正在调用 onPause(); 和 onCreate 的 Activity。所以将您的代码更改为:

    mDB = new RaceDB(this);
    mDB.open();
    Log.d(TAG, "Database is now open and saved");
    dbToUI();
    Log.d(TAG, "Database is now able to be shown");
   /// onPause();  remove this method from here this 
                   //will called automatically by system

并确保您已在 Manifest 中将 RaceListActivity Activity 声明为:

<activity android:name=".RaceListActivity" />