我刚接触Android开发,刚刚两天,我想通过以pdf格式显示来从我的数据库中检索数据。我之前在netbeans上做过这个(有效),但是当我在android中尝试我的代码时,它给了我一个错误。我有SQLitExample.java文件触发我的btnPdf的动作,createPDF.java文件应该创建我的pdf。我尝试通过创建新intent来调用createPDF.java文件。但当我点击我的btnPdf时,它给了我这个错误:
dalvikvm(6097):找不到类'com.example.hotornot.createPDF $ 1',从方法com.example.hotornot.createPDF.pdf中引用
这是我在SQLitExample.java上的代码
package com.example.hotornot;
import java.io.IOException;
import java.sql.SQLException;
import com.lowagie.text.DocumentException;
import android.app.Activity;
import android.app.Dialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class SQLitExample extends Activity implements OnClickListener {
Button btnUpdate, btnView, btnPdf;
EditText SQLName,SQLNum;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.sqliteexample);
btnUpdate = (Button) findViewById(R.id.btnUpdate);
SQLName = (EditText) findViewById(R.id.etSQLName);
SQLNum = (EditText) findViewById(R.id.etSQLNum);
btnView = (Button) findViewById(R.id.btnView);
btnPdf = (Button) findViewById(R.id.btnPdf);
btnPdf.setOnClickListener(this);
btnView.setOnClickListener(this);
btnUpdate.setOnClickListener(this);
}
public void onClick(View arg0){
switch (arg0.getId())
{
case R.id.btnUpdate:
boolean diditwork = true;
try{
String name = SQLName.getText().toString();
String num = SQLNum.getText().toString();
Example entry = new Example(SQLitExample.this);
entry.open();
entry.createEntry(name,num);
entry.close();
}catch(Exception e){
diditwork = false;
String error = e.toString();
Dialog d = new Dialog(this);
d.setTitle("OW men! :(");
TextView tv = new TextView(this);
tv.setText(error);
d.setContentView(tv);
d.show();
}finally{
if(diditwork){
Dialog d = new Dialog(this);
d.setTitle("yehey");
TextView tv = new TextView(this);
tv.setText("Success");
d.setContentView(tv);
d.show();
}
}
break;
case R.id.btnView:
Intent i = new Intent("com.example.hotornot.SQLView");
startActivity(i);
break;
case R.id.btnPdf:
Intent i2 = new Intent("com.example.hotornot.createPDF");
startActivity(i2);
break;
}
}
}
这是我的createPDF.java代码:
package com.example.hotornot;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.TextView;
import com.lowagie.text.Cell;
import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.Element;
import com.lowagie.text.Font;
import com.lowagie.text.FontFactory;
import com.lowagie.text.Paragraph;
import com.lowagie.text.Table;
import com.lowagie.text.pdf.PdfPCell;
import com.lowagie.text.pdf.PdfPTable;
import com.lowagie.text.pdf.PdfWriter;
import com.example.hotornot.*;
import com.example.hotornot.Example.DbHelper;
public class createPDF extends Activity {
String DATABASE_NAME = Example.DATABASE_NAME;
String DATABASE_TABLE = Example.DATABASE_TABLE;
String KEY_NAME = Example.KEY_NAME;
String KEY_NUM = Example.KEY_NUM;
String KEY_ROWID = Example.KEY_ROWID;
public void pdf() throws ClassNotFoundException, SQLException, DocumentException{
try {
System.out.println("THIS SHOULD CREATE PDF!");
Document document=new Document () {};
PdfWriter.getInstance(document,new FileOutputStream("C:/Users/SERVER02/workspace/HotOrNot/samplePDF"));
document.open();
PdfPTable table = new PdfPTable(3);
table.addCell("Row_Id");
table.addCell("Name");
table.addCell("Number");
String[] columns = new String[]{ KEY_ROWID,KEY_NAME, KEY_NUM};
Example entry = new Example(createPDF.this);
Cursor c = entry.ourdatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(KEY_NAME);
int iNum = c.getColumnIndex(KEY_NUM);
String rownum = c.getString(iRow);
String name = c.getString(iName);
String num = c.getString(iNum);
for (c.moveToFirst(); ! c.isAfterLast(); c.moveToNext()){
result = result + rownum + " " + name + " " + num + "\n";
table.addCell(c.getString(iRow));
table.addCell(c.getString(iName));
table.addCell(c.getString(iNum));
}
document.add(table);
document.close();
Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + "C:\\samplePDF.pdf");
} catch (IOException ex) {
Logger.getLogger(createPDF.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
答案 0 :(得分:1)
在Manifest.xml文件中添加您要启动的其他活动 - createPDF。
<activity android:name=".createPDF" />
Intent语法如下,而不是您使用的语法:
Intent pdfIntent = new Intent(SQLitExample.this,createPDF.class);
startActivity(pdfIntent);
Android资源:
查看上面的Intent构造函数。您应该使用Intent(Context context, Class<?> cls)
构造函数。