zoukankan      html  css  js  c++  java
  • 修改Android 4.2.2的原生Camera引出的java.lang.UnsatisfiedLinkError: Native method not found,及解决方法

    修改Android 4.2.2的原生Camera应用,做一些定制,将Camera的包名从之前的 package com.android.* 修改成了com.zhao3546.*。

    调整后,应用可以正常运行,但是Camera自带的特效编辑等功能,无法正常使用。一点图片编辑的图标,就出现了下面的异常:

    09-12 18:52:48.131: E/AndroidRuntime(6071): java.lang.UnsatisfiedLinkError: Native method not found: com.zhao3546.gallery3d.filtershow.filters.ImageFilterFx.nativeApplyFilter:(Landroid/graphics/Bitmap;IILandroid/graphics/Bitmap;II)V
    09-12 18:52:48.131: E/AndroidRuntime(6071): 	at com.zhao3546.gallery3d.filtershow.filters.ImageFilterFx.nativeApplyFilter(Native Method)
    09-12 18:52:48.131: E/AndroidRuntime(6071): 	at com.zhao3546.gallery3d.filtershow.filters.ImageFilterFx.apply(ImageFilterFx.java:58)
    09-12 18:52:48.131: E/AndroidRuntime(6071): 	at com.zhao3546.gallery3d.filtershow.presets.ImagePreset.apply(ImagePreset.java:291)
    09-12 18:52:48.131: E/AndroidRuntime(6071): 	at com.zhao3546.gallery3d.filtershow.cache.DirectPresetCache.compute(DirectPresetCache.java:156)
    09-12 18:52:48.131: E/AndroidRuntime(6071): 	at com.zhao3546.gallery3d.filtershow.cache.DelayedPresetCache.handleMessage(DelayedPresetCache.java:50)


    原来,ImageFilterFx.nativeApplyFilter() 的这个方法是通过JNI实现的,想想也是,不使用JNI的话,使用Java实现图片编辑的特效,效率要低不少。

    关于JNI的介绍,个人觉得写得最好的是《Android框架揭秘》这本书的 “第四章 JNI和NDK”,从示例出发,再将原理娓娓道来,很深入浅出。

    言归正传,看看怎么解决吧。

    如下是根据 nativeApplyFilter 关键字搜索,找到的结果如下,只保留一小部分:

    ---- nativeApplyFilter Matches (55 in 30 files) ----
    Bw.c (jnifilters):void JNIFUNCF(ImageFilterBW, nativeApplyFilter, jobject bitmap, jint width, jint height)
    Bw.c (jnifilters):void JNIFUNCF(ImageFilterBWRed, nativeApplyFilter, jobject bitmap, jint width, jint height)
    Bw.c (jnifilters):void JNIFUNCF(ImageFilterBWGreen, nativeApplyFilter, jobject bitmap, jint width, jint height)
    Bw.c (jnifilters):void JNIFUNCF(ImageFilterBWBlue, nativeApplyFilter, jobject bitmap, jint width, jint height)
    Bwfilter.c (jnifilters):void JNIFUNCF(ImageFilterBwFilter, nativeApplyFilter, jobject bitmap, jint width, jint height, jint rw, jint gw, jint bw)
    Contrast.c (jnifilters):void JNIFUNCF(ImageFilterContrast, nativeApplyFilter, jobject bitmap, jint width, jint height, jfloat bright)
    Exposure.c (jnifilters):void JNIFUNCF(ImageFilterExposure, nativeApplyFilter, jobject bitmap, jint width, jint height, jfloat bright)
    Fx.c (jnifilters):void JNIFUNCF(ImageFilterFx, nativeApplyFilter, jobject bitmap, jint width, jint height, jobject lutbitmap,jint lutwidth, jint lutheight )
    Geometry.c (jnifilters):void JNIFUNCF(ImageFilterGeometry, nativeApplyFilterFlip, jobject src, jint srcWidth, jint srcHeight, jobject dst, jint dstWidth, jint dstHeight, jint flip) {
    Geometry.c (jnifilters):void JNIFUNCF(ImageFilterGeometry, nativeApplyFilterRotate, jobject src, jint srcWidth, jint srcHeight, jobject dst, jint dstWidth, jint dstHeight, jint rotate) {
    Geometry.c (jnifilters):void JNIFUNCF(ImageFilterGeometry, nativeApplyFilterCrop, jobject src, jint srcWidth, jint srcHeight, jobject dst, jint dstWidth, jint dstHeight, jint offsetWidth, jint offsetHeight) {
    Geometry.c (jnifilters):void JNIFUNCF(ImageFilterGeometry, nativeApplyFilterStraighten, jobject src, jint srcWidth, jint srcHeight, jobject dst, jint dstWidth, jint dstHeight, jfloat straightenAngle) {
    Hue.c (jnifilters):void JNIFUNCF(ImageFilterHue, nativeApplyFilter, jobject bitmap, jint width, jint height, jfloatArray matrix)
    ImageFilterBW.java (srccomandroidgallery3dfiltershowfilters):    native protected void nativeApplyFilter(Bitmap bitmap, int w, int h);
    ImageFilterBW.java (srccomandroidgallery3dfiltershowfilters):        nativeApplyFilter(bitmap, w, h);


    Native方法的实现,肯定是在C或CPP中,直接看第一个结果吧:

    void JNIFUNCF(ImageFilterBW, nativeApplyFilter, jobject bitmap, jint width, jint height)
    {
        ...
    }


    JNIFUNCF这个函数名有点怪啊,怎么全是大写,C或C++中,全大写一般是都常量或宏,啥情况?

    看看是怎么定义的,再根据JNIFUNCF搜索下,在filters.h中有定义:

    #define JNIFUNCF(cls, name, vars...) Java_com_android_gallery3d_filtershow_filters_ ## cls ## _ ## name(JNIEnv* env, jobject obj, vars)
    

    原来是个宏,这个宏是啥意思如果你不明白,需要了解一些C的基础,

    此处将 “Java_com_android_gallery3d_filtershow_filters_” 和 cls 对应的实际值和 name 对应的实际值,拼接成一个字符串作为实际的方法名。


    之前我们修改了Java的包名,但是 Java_com_android_gallery3d_filtershow_filters_ 这个没有修改,所以导致最终生成的方法与修改后Java实现的Native方法的符号匹配不上了,将 Java_com_android_gallery3d_filtershow_filters_ 修改成 Java_com_zhao3546_gallery3d_filtershow_filters_ ,再放到源码编译环境上重新生成相应的so,再重新生成APK测试,ok,问题解决。

    了解JNI机制,才是解决此类问题的KEY。

  • 相关阅读:
    实现一个与内容合二为一的ActionBar动画效果
    hdoj 1506&&1505(City Game) dp
    remine chart2安装
    zoom的学习
    海哥:T2C时代的到来了,那么什么叫T2C?
    minhash算法
    动态创建按钮的JS
    socket编程在windows和linux下的区别
    http staus汇总
    MySQL HINT:Straight_JOIN
  • 原文地址:https://www.cnblogs.com/riskyer/p/3318116.html
Copyright © 2011-2022 走看看