如何在android中使用文本生成PDF

Question

我是android开发新手，刚出生两天，我想通过在pdf格式上显示数据库来检索数据。我以前在netbeans(工作)上做过这个，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，它触发我的btnPdf的动作，和createPDF.java文件，它应该创建我的pdf。我尝试通过创建一个新的意图来调用createPDF.java文件。但是当我点击我的btnPdf时，它给了我这个错误:

dalvikvm(6097):找不到com.example.hotornot类。createPDF$1'，引用自方法com.example.hotornot.createPDF.pdf

这是我的代码在SQLitExample.java

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;
    }
}
}

下面是我的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);
    }
}

}

Answer 1

在Manifest.xml文件中添加您想要启动的其他活动- createPDF。

    <activity android:name=".createPDF" />

和Intent的语法是这样的，不是你用的那个:

    Intent pdfIntent = new Intent(SQLitExample.this,createPDF.class);
    startActivity(pdfIntent);

Android资源:

Intent Developer Docs

查看上面的Intent构造函数。您应该使用Intent(Context context, Class<?> cls)构造函数。