生成pdf

Andrid端生成PDF侷限性太差，尚未有優雅的解決方案。但網上眾說紛紜，實踐者少之又少，高質量的博文也是鳳毛麟角，大家都是博文搬用工，也沒有誰做過詳細的探索。筆者就自己的一點經驗做點分享。

• 使用iText
  

iText不支援中文，要支援中文需要引入額外包需要新增一個額外的jar包：itext-asian.jar。親測較好的方案直接引入再次封裝過的jar包：http://download.csdn.net/detail/xuwenneng/9669969
在Android studio中不需要在引入包，把它加入即可。
例項程式碼（源於網路，本人親測）：

package com.dyb.createpdf;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com
 
.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Font;
import com.itextpdf.text.Image;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.pdf.BaseFont;
import com.itextpdf.text.pdf.PdfWriter;

import java.io.ByteArrayOutputStream;
import java.io
 
.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {
    private TextView mTextview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextview = (TextView) findViewById(R.id.create_pdf);

        mTextview.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Document doc = new Document();
                FileOutputStream fos;
                try {
                    fos = new FileOutputStream(new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/createLocal.pdf"));
                    PdfWriter.getInstance(doc, fos);
                    doc.open();
                    doc.setPageCount(1);
                    doc.add(new Paragraph("testpdf~~成功哩", setChineseFont()));

                    myImg.setAlignment(Image.MIDDLE);
                    doc.add(myImg);
                    //一定要記得關閉document物件
                    doc.close();
                    fos.flush();
                    fos.close();
                    Toast.makeText(MainActivity.this, "Environment.getExternalStorageDirectory()/createLocal.pdf ", Toast.LENGTH_LONG).show();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (DocumentException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    // 產生PDF字型
    public static Font setChineseFont() {
        BaseFont bf = null;
        Font fontChinese = null;
        try {
            bf = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);
            fontChinese = new Font(bf, 12, Font.NORMAL);
        } catch (DocumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return fontChinese;
    }
}

注意：
1.此種方案加入圖片生成PDF並未成功。

• 使用官方API中鮮為人知的api
  此種方式簡單粗暴，直接把xml佈局重新繪製在畫布上，儲存。顯然處理不當你的游標也被儲存了。（通俗點就是截圖）

package hu.autsoft.androidapidemos;

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.pdf.PdfDocument;
import android.os.Environment;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class PDFCreateActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pdfcreate);

        ButterKnife.bind(this);

        requestNeededPermission();
    }

    public void requestNeededPermission() {
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED) {
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                Toast.makeText(PDFCreateActivity.this,
                        "I need it for pdf creating", Toast.LENGTH_SHORT).show();
            }

            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    101);
        } else {
            Toast.makeText(PDFCreateActivity.this,
                    "WRITE_EXTERNAL_STORAGE perm granted", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case 101: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(PDFCreateActivity.this,
                            "WRITE_EXTERNAL_STORAGE perm granted", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(PDFCreateActivity.this,
                            "WRITE_EXTERNAL_STORAGE perm NOT granted", Toast.LENGTH_SHORT).show();
                }
                return;
            }
        }
    }

    @OnClick(R.id.btnCreatePdf)
    public void createPdfClicked(View v) {
        new Thread() {
            public void run() {
                // Get the directory for the app's private pictures directory.
                final File file = new File(
                        Environment.getExternalStorageDirectory(), "demo.pdf");
                if (file.exists()) {
                    file.delete();
                }

                FileOutputStream out = null;
                try {
                    out = new FileOutputStream(file);
                    PdfDocument document = new PdfDocument();
                    Point windowSize = new Point();
                    getWindowManager().getDefaultDisplay().getSize(windowSize);
                    PdfDocument.PageInfo pageInfo =
                            new PdfDocument.PageInfo.Builder(
                                    windowSize.x, windowSize.y, 1).create();
                    PdfDocument.Page page = document.startPage(pageInfo);
                    View content = getWindow().getDecorView();
                    content.draw(page.getCanvas());
                    document.finishPage(page);
                    document.writeTo(out);
                    document.close();
                    out.flush();

                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(PDFCreateActivity.this, "File created: " + file.getAbsolutePath(), Toast.LENGTH_LONG).show();
                        }
                    });
                } catch (Exception e) {
                    Log.d("TAG_PDF", "File was not created: " + e.getMessage());
                } finally {
                    try {
                        out.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }.start();
    }
}

webview讀取pdf

webview讀取PDF也是比較噁心的，因為原生webview是不支援PDF的。此處就要藉助一些磕磕巴巴第三方，同樣存在很多不完善之處。本人親測，使用了較為好的三方。

• 本地PDF
  com.github.barteksc.pdfviewer

package com.dyb.loadpdf;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;

import com.github.barteksc.pdfviewer.PDFView;
import com.github.barteksc.pdfviewer.listener.OnLoadCompleteListener;
import com.github.barteksc.pdfviewer.listener.OnPageChangeListener;

/**
 * android 載入本地pdf檔案
 * com.github.barteksc.pdfviewer
 */
public class MainActivity extends AppCompatActivity implements OnLoadCompleteListener, OnPageChangeListener {
    private TextView mTexview, mTexviewNet;
    private PDFView pdfView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTexview = (TextView) findViewById(R.id.pdf);
        mTexviewNet = (TextView) findViewById(R.id.textView_new_pdf);
        pdfView = (PDFView) findViewById(R.id.pdfView);
        mTexview.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                pdfView.fromAsset("sample.pdf")
                        .defaultPage(0)
                        .onPageChange(MainActivity.this)
                        .enableAnnotationRendering(true)
                        .onLoad(MainActivity.this)
                        .enableSwipe(true)
                        .swipeHorizontal(false)
                        .load();
            }
        });
    }

    @Override
    public void loadComplete(int nbPages) {

    }

    @Override
    public void onPageChanged(int page, int pageCount) {

    }
}

• 線上PDF
  com.lidong.pdf:android_pdf:1.0.1

package com.dyb.loadpdf;

import android.graphics.Canvas;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.lidong.pdf.PDFView;
import com.lidong.pdf.listener.OnDrawListener;
import com.lidong.pdf.listener.OnLoadCompleteListener;
import com.lidong.pdf.listener.OnPageChangeListener;

public class MainActivityNet extends AppCompatActivity implements OnPageChangeListener, OnLoadCompleteListener, OnDrawListener {
    private PDFView pdfViewNet;//網路
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_net);
        pdfViewNet = (PDFView) findViewById(R.id.pdfView_net_new);
        displayFromFile("http://file.chmsp.com.cn/colligate/file/00100000224821.pdf", "00100000224821.pdf");
    }

    private void displayFromFile(String fileUrl, String fileName) {
        pdfViewNet.fileFromLocalStorage(this, this, this, fileUrl, fileName);   //設定pdf檔案地址
    }


    @Override
    public void onLayerDrawn(Canvas canvas, float pageWidth, float pageHeight, int displayedPage) {

    }

    @Override
    public void loadComplete(int nbPages) {

    }

    @Override
    public void onPageChanged(int page, int pageCount) {

    }
}