不幸的是，Organitza't（我的应用程序）已停止

Question

当我启动另一个名为Task的活动时，我收到错误消息。该应用程序有4个图像按钮（其他按钮图像打开正确。当我点击“TaskViewer”（ImageButton2）出现错误。

尝试打开的活动：（ViewTask）

public class ViewTask extends Activity {
protected TaskerDbHelper db;
List<Task> list;
MyAdapter adapt;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_view_task);
    db = new TaskerDbHelper(this);
    list = db.getAllTasks();
    adapt = new MyAdapter(this, R.layout.list_inner_view, list);
    ListView listTask = (ListView) findViewById(R.id.listView1);
    listTask.setAdapter(adapt);
}

public void addTaskNow(View v) {
    EditText t = (EditText) findViewById(R.id.editText1);
    String s = t.getText().toString();
    if (s.equalsIgnoreCase("")) {
        Toast.makeText(this, "enter the task description first!!",
                Toast.LENGTH_LONG);
    } else {
        Task task = new Task(s, 0);
        db.addTask(task);
        Log.d("tasker", "data added");
        t.setText("");
        adapt.add(task);
        adapt.notifyDataSetChanged();
    }

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_view_task, menu);
    return true;
}

private class MyAdapter extends ArrayAdapter<Task> {

    Context context;
    List<Task> taskList = new ArrayList<Task>();
    int layoutResourceId;

    public MyAdapter(Context context, int layoutResourceId,
            List<Task> objects) {
        super(context, layoutResourceId, objects);
        this.layoutResourceId = layoutResourceId;
        this.taskList = objects;
        this.context = context;
    }

    /**
     * This method will DEFINe what the view inside the list view will
     * finally look like Here we are going to code that the checkbox state
     * is the status of task and check box text is the task name
     */
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        CheckBox chk = null;
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.list_inner_view,
                    parent, false);
            chk = (CheckBox) convertView.findViewById(R.id.chkStatus);
            convertView.setTag(chk);

            chk.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    CheckBox cb = (CheckBox) v;
                    Task changeTask = (Task) cb.getTag();
                    changeTask.setStatus(cb.isChecked() == true ? 1 : 0);
                    db.updateTask(changeTask);
                    Toast.makeText(
                            getApplicationContext(),
                            "Clicked on Checkbox: " + cb.getText() + " is "
                                    + cb.isChecked(), Toast.LENGTH_LONG)
                            .show();
                }

            });
        } else {
            chk = (CheckBox) convertView.getTag();
        }
        Task current = taskList.get(position);
        chk.setText(current.getTaskName());
        chk.setChecked(current.getStatus() == 1 ? true : false);
        chk.setTag(current);
        Log.d("listener", String.valueOf(current.getId()));
        return convertView;
    }

}
}

主要活动：

public class MainActivity extends Activity {

private Context activity;

@Override
protected void onCreate (Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    entrarboton();
}

private void entrarboton() {
    ImageButton accionentrar = (ImageButton) findViewById(R.id.imageButton0);
    accionentrar.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent LaunchIntent = getPackageManager().getLaunchIntentForPackage("com.android.calendar");
            startActivity(LaunchIntent);


        }
    });
    ImageButton accionentrar2 = (ImageButton) findViewById(R.id.imageButton3);
    accionentrar2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            startActivity(new Intent(MainActivity.this,Notes.class));

        }
    });
    ImageButton accionentrar3 = (ImageButton) findViewById(R.id.imageButton2);
    accionentrar3.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            startActivity(new Intent(MainActivity.this,ViewTask.class));
        }
    });
    ImageButton accionentrar4 = (ImageButton) findViewById(R.id.imageButton4);
    accionentrar4.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            startActivity(new Intent(MainActivity.this,Altres.class));
        }
    });

    AutoCompleteTextView auto = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView);

    String[] noms = getResources() . getStringArray(R.array.noms_array);

    ArrayAdapter<String> adapter;
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, noms);

    auto.setThreshold(1);

    auto.setAdapter(adapter);


}

}

Android Manifest：

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.dppalvaplicacio.app.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name="com.dppalvaplicacio.app.Calendari"
        android:label="@string/title_activity_calendari" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>
    <activity
        android:name="com.dppalvaplicacio.app.Notes"
        android:label="@string/title_activity_notes" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>
    <activity
        android:name="com.dppalvaplicacio.app.ViewTask"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>
    <activity
        android:name="com.dppalvaplicacio.app.Altres"
        android:label="@string/title_activity_altres" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>
</application>

logcat的

Caused by: java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteDatabase: /data/data/com.dppalvaplicacio.app/databases/taskerManager
at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:55)
at android.database.sqlite.SQLiteDatabase.endTransaction(SQLiteDatabase.java:520)
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:263)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
at com.dppalvaplicacio.app.TaskerDbHelper.getAllTasks(TaskerDbHelper.java:70)
at com.dppalvaplicacio.app.ViewTask.onCreate(ViewTask.java:33)
at android.app.Activity.performCreate(Activity.java:5008)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)

TaskDbHelper

public class TaskerDbHelper extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 1;

// Database Name
private static final String DATABASE_NAME = "taskerManager";

// tasks table name
private static final String TABLE_TASKS = "tasks";

// tasks Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_TASKNAME = "taskName";
private static final String KEY_STATUS = "status";

public TaskerDbHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {

    String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_TASKS + " ( "
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_TASKNAME
            + " TEXT, " + KEY_STATUS + " INTEGER)";
    db.execSQL(sql);

    db.close();
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldV, int newV) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_TASKS);
    // Create tables again
    onCreate(db);
}

// Adding new task
public void addTask(Task task) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_TASKNAME, task.getTaskName()); // task name
    // status of task- can be 0 for not done and 1 for done
    values.put(KEY_STATUS, task.getStatus());

    // Inserting Row
    db.insert(TABLE_TASKS, null, values);
    db.close(); // Closing database connection
}

public List<Task> getAllTasks() {
    List<Task> taskList = new ArrayList<Task>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_TASKS;

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            Task task = new Task();
            task.setId(cursor.getInt(0));
            task.setTaskName(cursor.getString(1));
            task.setStatus(cursor.getInt(2));
            // Adding contact to list
            taskList.add(task);
        } while (cursor.moveToNext());
    }

    // return task list
    return taskList;
}

public void updateTask(Task task) {
    // updating row
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_TASKNAME, task.getTaskName());
    values.put(KEY_STATUS, task.getStatus());
    db.update(TABLE_TASKS, values, KEY_ID + " = ?",new String[] {String.valueOf(task.getId())});
    db.close();
}

}

Answer 1

问题出在您的TaskDBHelper课程中，更具体地说是onCreate方法。当您尝试对数据库执行操作时，此方法称为自动，但尚未创建数据库。因此，它首先调用onCreate方法，然后调用适用于它的方法 - getAllTasks。问题是您正在使用onCreate方法关闭数据库，从而阻止在此类实例中对数据库进行任何进一步操作。您的方法应如下所示：

public void onCreate(SQLiteDatabase db) {

    String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_TASKS + " ( "
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_TASKNAME
            + " TEXT, " + KEY_STATUS + " INTEGER)";
    db.execSQL(sql);
}