我想创建一个存储屏幕坐标的应用程序并将其存储在数据库中，并希望通过点击按钮检索它们
这是我的数据库代码
package com.example.android.touchview;
/**
* Created by Vikas on 7/20/2016.
*/
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import java.sql.SQLException;
import java.util.ArrayList;
public class DataBase
{
public static final String KEY_ROWID = "_id";
public static final String KEY_X = "X";
public static final String KEY_Y = "Y";
private static final String DATABASE_NAME = "Details";
private static final String DATABASE_TABLE = "DetailsTable";
private static final int DATABASE_VERSION = 1;
private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;
private static class DbHelper extends SQLiteOpenHelper {
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
KEY_X + " TEXT, " + KEY_Y + " TEXT);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
onCreate(db);
}
}
public DataBase(Context c) {
ourContext = c;
}
public DataBase open() throws SQLException {
ourHelper = new DbHelper(ourContext);
ourDatabase = ourHelper.getWritableDatabase();
return this;
}
public void close() {
ourHelper.close();
}
public long createEntry(String x, String y) {
ContentValues cv = new ContentValues();
cv.put(KEY_X, x);
cv.put(KEY_Y, y);
return ourDatabase.insert(DATABASE_TABLE, null, cv);
}
public ArrayList<Float> getData() {
ourDatabase = ourHelper.getReadableDatabase();
Point p = new Point();
ArrayList<Float> dataPoints = new ArrayList<>();
String[] col = new String[]{KEY_ROWID, KEY_X, KEY_Y};
Cursor c = ourDatabase.query(DATABASE_TABLE, col, null, null, null, null, null);
float[] array = new float[c.getCount()];
float[] array1 = new float[c.getCount()];
int i = 0;
if (c.moveToFirst())
{
do {
float x = c.getFloat(c.getColumnIndex("X"));
p.setX(x);
dataPoints.add(p.getX());
float y = c.getFloat(c.getColumnIndex("Y"));
p.setY(y);
dataPoints.add(p.getY());
array[i] = x;
array1[i] = y;
i++;
} while (c.moveToNext());
}
Log.d("hi", "getData() called");
return dataPoints;
}
这是Point.java
package com.example.android.touchview;
/**
* Created by Vikas on 7/20/2016.
*/
public class Point
{
public float x;
public float y;
int id;
public Point() {}
public Point(int id, float x, float y) {
this.id = id;
this.x = x;
this.y = y;
}
public Point(float x, float y) {
this.x = x;
this.y = y;
}
public int getId(){
return this.id;
}
public void setId(int id){
this.id= id;
}
public float getX(){
return this.x;
}
public void setX(float x){
this.x=x;
}
public float getY(){
return this.y;
}
public void setY(float y){
this.y=y;
}
}
这是我的主要活动
package com.example.android.touchview;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
float x = 0, y = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addTouchListener();
// final CanvasView canvas = (CanvasView) findViewById(R.id.paint_view);
}
private void addTouchListener()
{
// TextView tx = (TextView)findViewById(R.id.SQLinfo);
RelativeLayout relativeLayout=(RelativeLayout)findViewById(R.id.activityView);
relativeLayout.setOnTouchListener(new OnTouchListener()
{
public boolean onTouch(View v, MotionEvent event)
{
x=event.getX();
y=event.getY();
String text = "You click at x = " + event.getX() + " and y = " + event.getY();
Toast.makeText(getApplicationContext(),text, Toast.LENGTH_LONG).show();
DataBase entry = new DataBase(MainActivity.this);
boolean flag = true;
try {
entry.open();
entry.createEntry(Float.toString(x), Float.toString(y));
entry.close();
} catch (Exception e) {
flag = false;
Toast.makeText(getApplicationContext(), "Not Working", Toast.LENGTH_LONG).show();
} finally {
if (flag)
Toast.makeText(getApplicationContext(), "Working", Toast.LENGTH_SHORT).show();
}
return false;
}
});
//Setting touch event listener for the PaintView
Button data = (Button) findViewById(R.id.db);
data.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(MainActivity.this, DbActivity.class);
startActivity(i);
}
});
}
}
这是我的Dbactivity.java
package com.example.android.touchview;
/**
* Created by Vikas on 7/20/2016.
*/
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import java.sql.SQLException;
import java.util.ArrayList;
public class DbActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_db);
TextView tv = (TextView) findViewById(R.id.SQLinfo);
DataBase db = new DataBase(this);
try {
db.open();
ArrayList<Float> data = db.getData();
db.close();
data.toString();
//Log.d("THE DATA IS ", "+ data.get(i)");
/* for(int i=0;i<data.size();i++)
{
tv.setText(data.get(i).toString());
Log.d("hi","data[i]");
}*/
} catch (SQLException e) {
e.printStackTrace();
}
}
}
请帮我修改此代码，以便我可以从数据库中获取检索到的值