0
我是Android新手。當我使用這個代碼。我的模擬器變得「不幸Myapp已停止」。 在這段代碼中，我試圖在Sqlite中添加某種常見的細節，並且還從Sqlite中進行選擇和刪除。 這是我正在使用的XML文件。我是Android新手。當我使用這個代碼。我的模擬器變得「不幸Myapp已停止」。
<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="wrap_content"
android:layout_height="wrap_content"
android:text="First Name:"
android:id="@+id/textView" />
<EditText
android:id="@+id/name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Last Name:"
android:id="@+id/textlastname" />
<EditText
android:id="@+id/editlastname"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Gender:"
android:id="@+id/textgender" />
<EditText
android:id="@+id/editgender"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Age:"
android:id="@+id/textage" />
<EditText
android:id="@+id/editage"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Address:"
android:id="@+id/textaddress" />
<EditText
android:id="@+id/editaddress"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/add"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Add New Person"
/>
<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</LinearLayout>
這是我使用它的MainActivity.java文件。
package com.example.gaurang.myhomes;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import java.text.SimpleDateFormat;
import java.util.Date;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
class MyDbHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "mydb";
private static final int DB_VERSION = 1;
public static final String TABLE_NAME = "students";
public static final String COL_NAME = "pName";
public static final String COL_LAST = "pLast";
public static final String COL_GENDER = "pGender";
public static final String COL_AGE = "pAge";
public static final String COL_ADDRESS = "pAddress";
public static final String COL_DATE = "pDate";
private static final String STRING_CREATE = "CREATE TABLE "+TABLE_NAME+" (_id INTEGER PRIMARY KEY AUTOINCREMENT, "
+COL_NAME+" TEXT, "+COL_LAST+" TEXT, "+COL_GENDER+" TEXT, "+COL_AGE+" TEXT, "+COL_ADDRESS+" TEXT, "+COL_DATE+" DATE);";
public MyDbHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(STRING_CREATE);
ContentValues cv = new ContentValues(6);
cv.put(COL_NAME, "New Entry");
cv.put(COL_LAST, "New Entry");
cv.put(COL_GENDER, "New Entry");
cv.put(COL_AGE, "New Entry");
cv.put(COL_ADDRESS, "New Entry");
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
cv.put(COL_DATE, dateFormat.format(new Date()));
db.insert(TABLE_NAME, null, cv);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS "+TABLE_NAME);
onCreate(db);
}
}
public class MainActivity extends AppCompatActivity implements View.OnClickListener, AdapterView.OnItemClickListener {
EditText mText;
EditText mLast;
EditText mGender;
EditText mAge;
EditText mAddress;
Button mAdd;
ListView mList;
MyDbHelper mHelper;
SQLiteDatabase mDb;
Cursor mCursor;
SimpleCursorAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mText = (EditText)findViewById(R.id.name);
mLast = (EditText)findViewById(R.id.editlastname);
mGender = (EditText)findViewById(R.id.editgender);
mAge = (EditText)findViewById(R.id.editage);
mAddress = (EditText)findViewById(R.id.editaddress);
mAdd = (Button)findViewById(R.id.add);
mAdd.setOnClickListener(this);
mList = (ListView)findViewById(R.id.list);
mList.setOnItemClickListener(this);
mHelper = new MyDbHelper(this);
}
@Override
public void onResume() {
super.onResume();
mDb = mHelper.getWritableDatabase();
String[] columns = new String[] {"_id", MyDbHelper.COL_NAME,MyDbHelper.COL_LAST,MyDbHelper.COL_GENDER,MyDbHelper.COL_AGE ,MyDbHelper.COL_ADDRESS, MyDbHelper.COL_DATE};
mCursor = mDb.query(MyDbHelper.TABLE_NAME, columns, null, null, null, null, null, null);
String[] headers = new String[] {MyDbHelper.COL_NAME,MyDbHelper.COL_LAST,MyDbHelper.COL_GENDER,MyDbHelper.COL_AG E,MyDbHelper.COL_ADDRESS, MyDbHelper.COL_DATE};
mAdapter = new SimpleCursorAdapter(this, android.R.layout.two_line_list_item,
mCursor, headers, new int[]{android.R.id.text1, android.R.id.text2});
mList.setAdapter(mAdapter);
}
@Override
public void onPause() {
super.onPause();
mDb.close();
mCursor.close();
}
@Override
public void onClick(View v) {
ContentValues cv = new ContentValues(6);
cv.put(MyDbHelper.COL_NAME, mText.getText().toString());
cv.put(MyDbHelper.COL_LAST, mLast.getText().toString());
cv.put(MyDbHelper.COL_GENDER, mGender.getText().toString());
cv.put(MyDbHelper.COL_AGE, mAge.getText().toString());
cv.put(MyDbHelper.COL_ADDRESS, mAddress.getText().toString());
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
cv.put(MyDbHelper.COL_DATE, dateFormat.format(new Date())); //Insert 'now' as the date
mDb.insert(MyDbHelper.TABLE_NAME, null, cv);
mCursor.requery();
mAdapter.notifyDataSetChanged();
mText.setText(null);
}
@Override
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
mCursor.moveToPosition(position);
String rowId = mCursor.getString(0); //Column 0 of the cursor is the id
mDb.delete(MyDbHelper.TABLE_NAME, "_id = ?", new String[]{rowId});
mCursor.requery();
mAdapter.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.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;
}
return super.onOptionsItemSelected(item);
}
}
查看日誌文件 - 應該有一個例外。 –