正文

21天学习android开发教程之SurfaceView与多线程的混搭

︶ㄣ米米素材网 メ
米米素材网V管理员 / 阅读
0717

21天学习android开发教程之SurfaceView与多线程的混搭，感兴趣的小伙伴们可以参考一下

简单介绍了surfaceview的基本使用，这次就介绍surfaceview与的混搭。surfaceview与多线程混搭，是为了防止动画闪烁而实现的一种多线程应用。的多线程用法与java的多线程用法完全一样，本文不做多线程方面的介绍了。直接讲解surfaceview与多线程的混合使用，即开一条线程专门读取图片，另外一条线程专门绘图。
        本文程序运行截图如下，左边是开单个线程读取并绘图，右边是开两个线程，一个专门读取图片，一个专门绘图：

 21天学习android开发教程之SurfaceView与多线程的混搭

对比一下，右边动画的帧速明显比左边的快，左右两者都没使用thread.sleep()。为什么要开两个线程一个读一个画，而不去开两个线程像左边那样都“边读边画”呢？因为surfaceview每次绘图都会锁定canvas,也就是说同一片区域这次没画完下次就不能画，因此要提高动画播放的效率，就得开一条线程专门画图，开另外一条线程做预处理的工作。
main.xml的源码：

?
1
2
3
4
5
6
7
8
9
10
11
12
13
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:orientation="vertical">
 
    <linearlayout android:id="@+id/linearlayout01"
        android:layout_width="wrap_content" android:layout_height="wrap_content">
        <button android:id="@+id/button01" android:layout_width="wrap_content"
            android:layout_height="wrap_content" android:text="单个独立线程">
        <button android:id="@+id/button02" android:layout_width="wrap_content"
            android:layout_height="wrap_content" android:text="两个独立线程">
    
    <surfaceview android:id="@+id/surfaceview01"
        android:layout_width="fill_parent" android:layout_height="fill_parent">

本文程序的源码：

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
package com.testsurfaceview;
 
import java.lang.reflect.field;
import java.util.arraylist;
import android.app.activity;
import android.graphics.bitmap;
import android.graphics.bitmapfactory;
import android.graphics.canvas;
import android.graphics.paint;
import android.graphics.rect;
import android.os.bundle;
import android.util.log;
import android.view.surfaceholder;
import android.view.surfaceview;
import android.view.view;
import android.widget.button;
 
public class testsurfaceview extends activity {
    /** called when the activity is first created. */
    button btnsinglethread, btndoublethread;
    surfaceview sfv;
    surfaceholder sfh;
    arraylist imglist = new arraylist();
    int imgwidth, imgheight;
    bitmap bitmap;//独立线程读取，独立线程绘图
 
    @override
    public void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.main);
 
        btnsinglethread = (button) this.findviewbyid(r.id.button01);
        btndoublethread = (button) this.findviewbyid(r.id.button02);
        btnsinglethread.setonclicklistener(new clickevent());
        btndoublethread.setonclicklistener(new clickevent());
        sfv = (surfaceview) this.findviewbyid(r.id.surfaceview01);
        sfh = sfv.getholder();
        sfh.addcallback(new mycallback());// 自动运行surfacecreated以及surfacechanged
    }
 
    class clickevent implements view.onclicklistener {
 
        @override
        public void onclick(view v) {
 
            if (v == btnsinglethread) {
                new load_drawimage(0, 0).start();//开一条线程读取并绘图
            } else if (v == btndoublethread) {
                new loadimage().start();//开一条线程读取
                new drawimage(imgwidth + 10, 0).start();//开一条线程绘图
            }
 
        }
 
    }
 
    class mycallback implements surfaceholder.callback {
 
        @override
        public void surfacechanged(surfaceholder holder, int format, int width,
                int height) {
            log.i("surface:", "change");
 
        }
 
        @override
        public void surfacecreated(surfaceholder holder) {
            log.i("surface:", "create");
 
            // 用反射机制来获取资源中的图片id和尺寸
            field[] fields = r.drawable.class.getdeclaredfields();
            for (field field : fields) {
                if (!"icon".equals(field.getname()))// 除了icon之外的图片
                {
                    int index = 0;
                    try {
                        index = field.getint(r.drawable.class);
                    } catch (illegalargumentexception e) {
                        // todo auto-generated catch block
                        e.printstacktrace();
                    } catch (illegalaccessexception e) {
                        // todo auto-generated catch block
                        e.printstacktrace();
                    }
                    // 保存图片id
                    imglist.add(index);
                }
            }
            // 取得图像大小
            bitmap bmimg = bitmapfactory.decoderesource(getresources(),
                    imglist.get(0));
            imgwidth = bmimg.getwidth();
            imgheight = bmimg.getheight();
        }
 
        @override
        public void surfacedestroyed(surfaceholder holder) {
            log.i("surface:", "destroy");
 
        }
 
    }
 
    /*
     * 读取并显示图片的线程
     */
    class load_drawimage extends thread {
        int x, y;
        int imgindex = 0;
 
        public load_drawimage(int x, int y) {
            this.x = x;
            this.y = y;
        }
 
        public void run() {
            while (true) {
                canvas c = sfh.lockcanvas(new rect(this.x, this.y, this.x
                        + imgwidth, this.y + imgheight));
                bitmap bmimg = bitmapfactory.decoderesource(getresources(),
                        imglist.get(imgindex));
                c.drawbitmap(bmimg, this.x, this.y, new paint());
                imgindex++;
                if (imgindex == imglist.size())
                    imgindex = 0;
 
                sfh.unlockcanvasandpost(c);// 更新屏幕显示内容
            }
        }
    };
 
    /*
     * 只负责绘图的线程
     */
    class drawimage extends thread {
        int x, y;
 
        public drawimage(int x, int y) {
            this.x = x;
            this.y = y;
        }
 
        public void run() {
            while (true) {
                if (bitmap != null) {//如果图像有效
                    canvas c = sfh.lockcanvas(new rect(this.x, this.y, this.x
                            + imgwidth, this.y + imgheight));
 
                    c.drawbitmap(bitmap, this.x, this.y, new paint());
 
                    sfh.unlockcanvasandpost(c);// 更新屏幕显示内容
                }
            }
        }
    };
 
    /*
     * 只负责读取图片的线程
     */
    class loadimage extends thread {
        int imgindex = 0;
 
        public void run() {
            while (true) {
                bitmap = bitmapfactory.decoderesource(getresources(),
                        imglist.get(imgindex));
                imgindex++;
                if (imgindex == imglist.size())//如果到尽头则重新读取
                    imgindex = 0;
            }
        }
    };
}

以上就是本文的全部内容，希望对大家学习android软件编程有所帮助。