在我的项目中，有一项活动是在数据库中添加一些信息。当我单击活动中的“添加”按钮时，它应该返回到主活动，其中有一个列表视图，该列表视图以列表形式显示数据库中的任务名称。直到，我在数据库表中只有Task Name字段，一切正常。但现在，我在表中添加了更多字段，如任务描述，任务日期等，列表视图不会使用新任务进行更新。这是代码：
/ **********主要活动************ /
package com.apps.katz.doer;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.widget.SimpleCursorAdapter;
import android.support.v7.app.AlertDialog;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.List;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private ListView taskListView;
private DataModel data;
private DatabaseHandler db = new DatabaseHandler(this);
private SimpleCursorAdapter adapter;
private Cursor cursor;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
refreshListView();
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
int currentPosition;
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
switch (item.getItemId()) {
case R.id.edit:
Toast.makeText(this,"You chose Edit",Toast.LENGTH_LONG).show();
return true;
case R.id.delete:
Toast.makeText(this,"Task Deleted",Toast.LENGTH_LONG).show();
db.deleteTask((int)info.id);
refreshListView();
return true;
default:
return super.onContextItemSelected(item);
}
}
private void refreshListView() {
taskListView = (ListView) findViewById(R.id.task_list_view);
cursor = db.queueAllTasks();
String[] from = new String[] {"taskName"};
int[] to = new int[] {R.id.text};
adapter = new SimpleCursorAdapter(this, R.layout.row_item, cursor, from, to);
taskListView.setAdapter(adapter);
registerForContextMenu(taskListView);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
if (id == R.id.action_add_new_task) {
startActivity(new Intent(MainActivity.this, AddTask.class));
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
/ ************添加任务类************** /
package com.apps.katz.doer;
import android.app.DatePickerDialog;
import android.app.TimePickerDialog;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.TimePicker;
import android.widget.Toast;
import java.util.Calendar;
public class AddTask extends AppCompatActivity {
EditText input_task_title, input_task_desc, txtDate, txtTime;
int mYear, mMonth, mDay, mHour, mMinute;
Button btn_add_task;
CheckBox checkBox;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_task);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
final DatabaseHandler db = new DatabaseHandler(this);
input_task_title = (EditText) findViewById(R.id.input_task_title);
input_task_desc = (EditText) findViewById(R.id.input_task_desc);
txtDate = (EditText) findViewById(R.id.dateView);
txtTime = (EditText) findViewById(R.id.timeView);
checkBox = (CheckBox) findViewById(R.id.checkbox_add_reminder);
checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(((CheckBox)view).isChecked()) {
txtDate.setVisibility(View.VISIBLE);
txtTime.setVisibility(View.VISIBLE);
} else if (((CheckBox)view).isChecked() == false) {
txtDate.setVisibility(View.GONE);
txtTime.setVisibility(View.GONE);
}
}
});
txtDate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final Calendar calendar = Calendar.getInstance();
mYear = calendar.get(Calendar.YEAR);
mMonth = calendar.get(Calendar.MONTH);
mYear = calendar.get(Calendar.YEAR);
DatePickerDialog dateDialog = new DatePickerDialog(AddTask.this, new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker datePicker, int i, int i1, int i2) {
txtDate.setText(i2+"/"+(i1+1)+"/"+i);
}
},mYear,mMonth,mDay);
dateDialog.show();
}
});
txtTime.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final Calendar calendar = Calendar.getInstance();
mHour = calendar.get(Calendar.HOUR_OF_DAY);
mMinute = calendar.get(Calendar.MINUTE);
TimePickerDialog timeDialog = new TimePickerDialog(AddTask.this, new TimePickerDialog.OnTimeSetListener() {
@Override
public void onTimeSet(TimePicker timePicker, int i, int i1) {
txtTime.setText(i+":"+i1);
}
},mHour,mMinute,false);
timeDialog.show();
}
});
btn_add_task = (Button) findViewById(R.id.btn_add_task);
btn_add_task.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
db.addTask(new DataModel(input_task_title.getText().toString(),input_task_desc.getText().toString(),
checkBox.isChecked(),txtDate.getText().toString(),txtTime.getText().toString()));
Toast.makeText(getApplicationContext(),R.string.new_task_added,Toast.LENGTH_LONG).show();
startActivity(new Intent(AddTask.this,MainActivity.class));
}
});
}
}
/ **************** DBHandler班级***************** /
package com.apps.katz.doer;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.List;
/**
* Created by katz on 15/4/16.
*/
public class DatabaseHandler extends SQLiteOpenHelper{
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME="com.app.katz.doer";
private static final String TABLE_NAME="tasks";
private static final String KEY_ID="id";
private static final String KEY_COL_TASK_NAME="taskName";
private static final String KEY_COL_TASK_DESC="taskDesc";
private static final String KEY_COL_IS_REMINDER="isReminder";
private static final String KEY_COL_DATE="taskDate";
private static final String KEY_COL_TIME="taskTime";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
String CREATE_TASKS_TABLE = "create table "+TABLE_NAME+"("+KEY_ID+" integer primary key autoincrement, " +
""+KEY_COL_TASK_NAME+" text, " +
""+KEY_COL_TASK_DESC+" text, " +
""+KEY_COL_IS_REMINDER+" boolean, " +
""+KEY_COL_DATE+" text, " +
""+KEY_COL_TIME+" text)";
sqLiteDatabase.execSQL(CREATE_TASKS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("drop table if exists "+TABLE_NAME);
onCreate(sqLiteDatabase);
}
public void addTask(DataModel data) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_COL_TASK_NAME,data.getTaskTitle());
values.put(KEY_COL_TASK_DESC,data.getTaskDesc());
values.put(KEY_COL_IS_REMINDER,data.getReminder());
values.put(KEY_COL_DATE,data.getTaskDate());
values.put(KEY_COL_TIME,data.getTaskTime());
db.insert(TABLE_NAME,null,values);
db.close();
}
public Cursor queueAllTasks() {
String[] columns = new String[]{KEY_ID,KEY_COL_TASK_NAME};
Cursor cursor = getReadableDatabase().rawQuery("select id as _id, taskName from tasks", null);
return cursor;
}
public void deleteTask(int id) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_NAME, KEY_ID + " =?",
new String[] {String.valueOf(id)});
db.close();
}
}
/ ***************数据模型类************** /
package com.apps.katz.doer;
/**
* Created by katz on 14/4/16.
*/
public class DataModel {
int id;
private String taskTitle;
private String taskDesc;
private Boolean isReminder;
private String taskDate;
private String taskTime;
public DataModel(){
}
public DataModel(int id) {
this.id=id;
}
public DataModel(int id, String taskTitle, String taskDesc, Boolean isReminder,String taskDate, String taskTime){
this.id=id;
this.taskTitle=taskTitle;
this.taskDesc=taskDesc;
this.isReminder=isReminder;
this.taskDate=taskDate;
this.taskTime=taskTime;
}
public DataModel(String taskTitle, String taskDesc, Boolean isReminder, String taskDate, String taskTime) {
this.taskTitle = taskTitle;
this.taskDesc = taskDesc;
this.isReminder = isReminder;
this.taskDate = taskDate;
this.taskTime = taskTime;
}
public DataModel(int id, String taskTitle, String taskDesc) {
this.taskTitle = taskTitle;
this.taskDesc = taskDesc;
this.id=id;
}
public DataModel(String taskTitle, String taskDesc) {
this.taskTitle = taskTitle;
this.taskDesc = taskDesc;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTaskTitle() {
return taskTitle;
}
public void setTaskTitle(String taskTitle) {
this.taskTitle = taskTitle;
}
public String getTaskDesc() {
return taskDesc;
}
public void setTaskDesc(String taskDesc) {
this.taskDesc = taskDesc;
}
public Boolean getReminder() {
return isReminder;
}
public void setReminder(Boolean reminder) {
isReminder = reminder;
}
public String getTaskDate() {
return taskDate;
}
public void setTaskDate(String taskDate) {
this.taskDate = taskDate;
}
public String getTaskTime() {
return taskTime;
}
public void setTaskTime(String taskTime) {
this.taskTime = taskTime;
}
}
请在我出错的地方帮忙！
提前致谢。
这是日志错误
table tasks has no column named taskDesc
04-22 19:14:36.151 2897-2897/com.apps.katz.doer E/SQLiteDatabase: Error inserting taskDesc=TaskTask TaskerTasked taskTime=19:14 taskName=TaskTask taskDate=31/3/2016 isReminder=true
android.database.sqlite.SQLiteException: table tasks has no column named taskDesc (code 1): , while compiling: INSERT INTO tasks(taskDesc,taskTime,taskName,taskDate,isReminder) VALUES (?,?,?,?,?)
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:887)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:498)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1469)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1341)
at com.apps.katz.doer.DatabaseHandler.addTask(DatabaseHandler.java:61)
at com.apps.katz.doer.AddTask$4.onClick(AddTask.java:98)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
答案 0 :(得分：0)
通过从主机设备卸载应用程序，然后将数据库版本更改为2（除1以外的任何其他内容）解决了此问题。安装了应用程序，一切都像魅力一样。