Android下读取PDF文件的解决方案

代码修改自该处(开源 Android pdf 阅读器开发总结)作者分享到Google code的代码,经仔细阅读后整理出读取PDF文档的主要部分(vudroid so库的使用),原作者应该也是在vudroid项目下稍微进行了修改,代码有点乱,所以我整理了下,把关键地方抽了出来,项目中没有提供vudroid so库的源码,所以知道的接口只有那几个,想完整了解vudroid库接口的建议去下载vudroid官方源码,再自行通过ndk编译.(源码下载依然在最后)

1import android.os.Bundle;
2import android.app.Activity;
3import android.graphics.Bitmap;
4import android.graphics.RectF;
5import android.view.Menu;
6import android.view.MotionEvent;
7import android.widget.ImageView;
8import android.graphics.Matrix;
9import android.graphics.PointF;
10import android.util.FloatMath;
11
12import org.vudroid.pdfdroid.codec.*;
13
14
15public class MainActivity extends Activity {
16	private PdfContext pdf_conext;
17	private ImageView view;
18	
19	private float screen_width = 800;
20	private float screen_height = 1280;
21	
22    @Override
23    public void onCreate(Bundle savedInstanceState) {
24        super.onCreate(savedInstanceState);
25        setContentView(R.layout.activity_main);
26        view = (ImageView)findViewById(R.id.imageView1);
27        
28        pdf_conext = new PdfContext();
29        PdfDocument d = pdf_conext.openDocument("/sdcard/test.pdf");
30        
31        PdfPage vuPage = d.getPage(1);
32        RectF rf = new RectF();
33        rf.bottom = rf.right = (float)1.0;
34        //参数一二为生成图片的宽高,参数三Rect的top,left,bottom,right为截取部分在该页中的百分比位置
35        //例如top=0.5,left=0.5,right=1.0,1.0则截取右下角四分之一的部分
36        Bitmap bitmap = vuPage.renderBitmap((int)screen_width, (int)screen_height, rf);
37        view.setImageBitmap(bitmap);
38    }
39
40	@Override
41    public boolean onCreateOptionsMenu(Menu menu) {
42        getMenuInflater().inflate(R.menu.activity_main, menu);
43        return true;
44    }
45	
46	Matrix matrix = new Matrix();
47    Matrix savedMatrix = new Matrix();   
48    static final int NONE = 0;   
49    static final int DRAG = 1;   
50    static final int ZOOM = 2;   
51    int mode = NONE;   
52    PointF start = new PointF();   
53    PointF mid = new PointF();   
54    float oldDist = 1f;   
55	@Override
56	public boolean onTouchEvent(MotionEvent event) {
57		switch (event.getAction() & MotionEvent.ACTION_MASK) {
58		case MotionEvent.ACTION_DOWN:
59			matrix.set(view.getImageMatrix());
60			savedMatrix.set(matrix);
61			start.set(event.getX(), event.getY());
62			mode = DRAG;
63
64			break;
65		case MotionEvent.ACTION_POINTER_DOWN:
66			oldDist = spacing(event);
67			if (oldDist > 10f) {
68				savedMatrix.set(matrix);
69				midPoint(mid, event);
70				mode = ZOOM;
71			}
72			break;
73		case MotionEvent.ACTION_UP:
74		case MotionEvent.ACTION_POINTER_UP:
75			mode = NONE;
76			break;
77		case MotionEvent.ACTION_MOVE:
78			if (mode == DRAG) {
79				matrix.set(savedMatrix);
80				matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);
81				
82				keepInSight(matrix);
83				
84			} else if (mode == ZOOM) {
85				float newDist = spacing(event);
86				if (newDist > 10f) {
87					matrix.set(savedMatrix);
88					float scale = newDist / oldDist;
89					matrix.postScale(scale, scale, mid.x, mid.y);
90					
91					keepInSight(matrix);
92				}
93			}
94			break;
95		}
96		view.setImageMatrix(matrix);
97		return true;
98	}
99
100	private float spacing(MotionEvent event) {
101		float x = event.getX(0) - event.getX(1);
102		float y = event.getY(0) - event.getY(1);
103		return FloatMath.sqrt(x * x + y * y);
104	}
105
106	private void midPoint(PointF point, MotionEvent event) {
107		float x = event.getX(0) + event.getX(1);
108		float y = event.getY(0) + event.getY(1);
109		point.set(x / 2, y / 2);
110	}
111
112	private void keepInSight(Matrix m){
113		float f[] = new float[9];
114		m.getValues(f);
115		if(f[0]<1) f[0]=1;
116		if(f[4]<1) f[4]=1;
117		
118		if(f[2]>0) f[2]=0;
119		if(f[5]>0) f[5]=0;
120		
121		float l = screen_width-screen_width*f[0];
122		if(f[2]<l) f[2] = l;
123			
124		float t = screen_height-screen_height*f[0];
125		if(f[5]<t) f[5] = t;
126		
127		m.setValues(f);
128	}
129}

源码下载:

http://dl.vmall.com/c0x4dky4py