android ndk开发（二）实现一个官方demo
实现了一个官方的demo：bitmap-plasma（水波纹）
源代码就在samples文件夹下，可以自己去找。
界面：
建立项目的步骤和配置环境不明白的可以去看：http://www.cnblogs.com/jycboy/p/5393727.html
一、activity代码：
package example.user.plasmatest;
import android.os.Bundle;
import android.app.Activity;
import android.os.Bundle;
import android.content.Context;
import android.view.View;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.view.Display;
import android.view.WindowManager;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
Display display = getWindowManager().getDefaultDisplay();
setContentView(new PlasmaView(this, display.getWidth(), display.getHeight()));
}
/* load our native library */
static {
System.loadLibrary("plasma");
}
}
class PlasmaView extends View {
private Bitmap mBitmap;
private long mStartTime;
/* implementend by libplasma.so */
private static native void renderPlasma(Bitmap bitmap, long time_ms);
public PlasmaView(Context context, int width, int height) {
super(context);
mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
mStartTime = System.currentTimeMillis();
}
@Override
protected void onDraw(Canvas canvas) {
//canvas.drawColor(0xFFCCCCCC);
renderPlasma(mBitmap, System.currentTimeMillis() - mStartTime);
canvas.drawBitmap(mBitmap, 0, 0, null);
// force a redraw, with a different time-based pattern.
invalidate();
}
}
make project下，利用javah创建jni目录、.h头文件
在jni目录下创建c代码：
plasma.c:
/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "example_user_plasmatest_PlasmaView.h" #include <jni.h> #include <time.h> #include <android/log.h> #include <android/bitmap.h> #include <stdio.h> #include <stdlib.h> #include <math.h> #define LOG_TAG "libplasma" #define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__) #define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__) /* Set to 1 to enable debug log traces. */ #define DEBUG 0 /* Set to 1 to optimize memory stores when generating plasma. */ #define OPTIMIZE_WRITES 1 /* Return current time in milliseconds */ static double now_ms(void) { struct timeval tv; gettimeofday(&tv, NULL); return tv.tv_sec*1000. + tv.tv_usec/1000.; } /* We're going to perform computations for every pixel of the target * bitmap. floating-point operations are very slow on ARMv5, and not * too bad on ARMv7 with the exception of trigonometric functions. * * For better performance on all platforms, we're going to use fixed-point * arithmetic and all kinds of tricks */ typedef int32_t Fixed; #define FIXED_BITS 16 #define FIXED_ONE (1 << FIXED_BITS) #define FIXED_AVERAGE(x,y) (((x) + (y)) >> 1) #define FIXED_FROM_INT(x) ((x) << FIXED_BITS) #define FIXED_TO_INT(x) ((x) >> FIXED_BITS) #define FIXED_FROM_FLOAT(x) ((Fixed)((x)*FIXED_ONE)) #define FIXED_TO_FLOAT(x) ((x)/(1.*FIXED_ONE)) #define FIXED_MUL(x,y) (((int64_t)(x) * (y)) >> FIXED_BITS) #define FIXED_DIV(x,y) (((int64_t)(x) * FIXED_ONE) / (y)) #define FIXED_DIV2(x) ((x) >> 1) #define FIXED_AVERAGE(x,y) (((x) + (y)) >> 1) #define FIXED_FRAC(x) ((x) & ((1 << FIXED_BITS)-1)) #define FIXED_TRUNC(x) ((x) & ~((1 << FIXED_BITS)-1)) #define FIXED_FROM_INT_FLOAT(x,f) (Fixed)((x)*(FIXED_ONE*(f))) typedef int32_t Angle; #define ANGLE_BITS 9 #if ANGLE_BITS < 8 # error ANGLE_BITS must be at least 8 #endif #define ANGLE_2PI (1 << ANGLE_BITS) #define ANGLE_PI (1 << (ANGLE_BITS-1)) #define ANGLE_PI2 (1 << (ANGLE_BITS-2)) #define ANGLE_PI4 (1 << (ANGLE_BITS-3)) #define ANGLE_FROM_FLOAT(x) (Angle)((x)*ANGLE_PI/M_PI) #define ANGLE_TO_FLOAT(x) ((x)*M_PI/ANGLE_PI) #if ANGLE_BITS <= FIXED_BITS # define ANGLE_FROM_FIXED(x) (Angle)((x) >> (FIXED_BITS - ANGLE_BITS)) # define ANGLE_TO_FIXED(x) (Fixed)((x) << (FIXED_BITS - ANGLE_BITS)) #else # define ANGLE_FROM_FIXED(x) (Angle)((x) << (ANGLE_BITS - FIXED_BITS)) # define ANGLE_TO_FIXED(x) (Fixed)((x) >> (ANGLE_BITS - FIXED_BITS)) #endif static Fixed angle_sin_tab[ANGLE_2PI+1]; static void init_angles(void) { int nn; for (nn = 0; nn < ANGLE_2PI+1; nn++) { double radians = nn*M_PI/ANGLE_PI; angle_sin_tab[nn] = FIXED_FROM_FLOAT(sin(radians)); } } static __inline__ Fixed angle_sin( Angle a ) { return angle_sin_tab[(uint32_t)a & (ANGLE_2PI-1)]; } static __inline__ Fixed angle_cos( Angle a ) { return angle_sin(a + ANGLE_PI2); } static __inline__ Fixed fixed_sin( Fixed f ) { return angle_sin(ANGLE_FROM_FIXED(f)); } static __inline__ Fixed fixed_cos( Fixed f ) { return angle_cos(ANGLE_FROM_FIXED(f)); } /* Color palette used for rendering the plasma */ #define PALETTE_BITS 8 #define PALETTE_SIZE (1 << PALETTE_BITS) #if PALETTE_BITS > FIXED_BITS # error PALETTE_BITS must be smaller than FIXED_BITS #endif static uint16_t palette[PALETTE_SIZE]; static uint16_t make565(int red, int green, int blue) { return (uint16_t)( ((red << 8) & 0xf800) | ((green << 2) & 0x03e0) | ((blue >> 3) & 0x001f) ); } static void init_palette(void) { int nn, mm = 0; /* fun with colors */ for (nn = 0; nn < PALETTE_SIZE/4; nn++) { int jj = (nn-mm)*4*255/PALETTE_SIZE; palette[nn] = make565(255, jj, 255-jj); } for ( mm = nn; nn < PALETTE_SIZE/2; nn++ ) { int jj = (nn-mm)*4*255/PALETTE_SIZE; palette[nn] = make565(255-jj, 255, jj); } for ( mm = nn; nn < PALETTE_SIZE*3/4; nn++ ) { int jj = (nn-mm)*4*255/PALETTE_SIZE; palette[nn] = make565(0, 255-jj, 255); } for ( mm = nn; nn < PALETTE_SIZE; nn++ ) { int jj = (nn-mm)*4*255/PALETTE_SIZE; palette[nn] = make565(jj, 0, 255); } } static __inline__ uint16_t palette_from_fixed( Fixed x ) { if (x < 0) x = -x; if (x >= FIXED_ONE) x = FIXED_ONE-1; int idx = FIXED_FRAC(x) >> (FIXED_BITS - PALETTE_BITS); return palette[idx & (PALETTE_SIZE-1)]; } /* Angles expressed as fixed point radians */ static void init_tables(void) { init_palette(); init_angles(); } static void fill_plasma( AndroidBitmapInfo* info, void* pixels, double t ) { Fixed yt1 = FIXED_FROM_FLOAT(t/1230.); Fixed yt2 = yt1; Fixed xt10 = FIXED_FROM_FLOAT(t/3000.); Fixed xt20 = xt10; #define YT1_INCR FIXED_FROM_FLOAT(1/100.) #define YT2_INCR FIXED_FROM_FLOAT(1/163.) int yy; for (yy = 0; yy < info->height; yy++) { uint16_t* line = (uint16_t*)pixels; Fixed base = fixed_sin(yt1) + fixed_sin(yt2); Fixed xt1 = xt10; Fixed xt2 = xt20; yt1 += YT1_INCR; yt2 += YT2_INCR; #define XT1_INCR FIXED_FROM_FLOAT(1/173.) #define XT2_INCR FIXED_FROM_FLOAT(1/242.) #if OPTIMIZE_WRITES /* optimize memory writes by generating one aligned 32-bit store * for every pair of pixels. */ uint16_t* line_end = line + info->width; if (line < line_end) { if (((uint32_t)(uintptr_t)line & 3) != 0) { Fixed ii = base + fixed_sin(xt1) + fixed_sin(xt2); xt1 += XT1_INCR; xt2 += XT2_INCR; line[0] = palette_from_fixed(ii >> 2); line++; } while (line + 2 <= line_end) { Fixed i1 = base + fixed_sin(xt1) + fixed_sin(xt2); xt1 += XT1_INCR; xt2 += XT2_INCR; Fixed i2 = base + fixed_sin(xt1) + fixed_sin(xt2); xt1 += XT1_INCR; xt2 += XT2_INCR; uint32_t pixel = ((uint32_t)palette_from_fixed(i1 >> 2) << 16) | (uint32_t)palette_from_fixed(i2 >> 2); ((uint32_t*)line)[0] = pixel; line += 2; } if (line < line_end) { Fixed ii = base + fixed_sin(xt1) + fixed_sin(xt2); line[0] = palette_from_fixed(ii >> 2); line++; } } #else /* !OPTIMIZE_WRITES */ int xx; for (xx = 0; xx < info->width; xx++) { Fixed ii = base + fixed_sin(xt1) + fixed_sin(xt2); xt1 += XT1_INCR; xt2 += XT2_INCR; line[xx] = palette_from_fixed(ii / 4); } #endif /* !OPTIMIZE_WRITES */ // go to next line pixels = (char*)pixels + info->stride; } } /* simple stats management */ typedef struct { double renderTime; double frameTime; } FrameStats; #define MAX_FRAME_STATS 200 #define MAX_PERIOD_MS 1500 typedef struct { double firstTime; double lastTime; double frameTime; int firstFrame; int numFrames; FrameStats frames[ MAX_FRAME_STATS ]; } Stats; static void stats_init( Stats* s ) { s->lastTime = now_ms(); s->firstTime = 0.; s->firstFrame = 0; s->numFrames = 0; } static void stats_startFrame( Stats* s ) { s->frameTime = now_ms(); } static void stats_endFrame( Stats* s ) { double now = now_ms(); double renderTime = now - s->frameTime; double frameTime = now - s->lastTime; int nn; if (now - s->firstTime >= MAX_PERIOD_MS) { if (s->numFrames > 0) { double minRender, maxRender, avgRender; double minFrame, maxFrame, avgFrame; int count; nn = s->firstFrame; minRender = maxRender = avgRender = s->frames[nn].renderTime; minFrame = maxFrame = avgFrame = s->frames[nn].frameTime; for (count = s->numFrames; count > 0; count-- ) { nn += 1; if (nn >= MAX_FRAME_STATS) nn -= MAX_FRAME_STATS; double render = s->frames[nn].renderTime; if (render < minRender) minRender = render; if (render > maxRender) maxRender = render; double frame = s->frames[nn].frameTime; if (frame < minFrame) minFrame = frame; if (frame > maxFrame) maxFrame = frame; avgRender += render; avgFrame += frame; } avgRender /= s->numFrames; avgFrame /= s->numFrames; LOGI("frame/s (avg,min,max) = (%.1f,%.1f,%.1f) " "render time ms (avg,min,max) = (%.1f,%.1f,%.1f)\n", 1000./avgFrame, 1000./maxFrame, 1000./minFrame, avgRender, minRender, maxRender); } s->numFrames = 0; s->firstFrame = 0; s->firstTime = now; } nn = s->firstFrame + s->numFrames; if (nn >= MAX_FRAME_STATS) nn -= MAX_FRAME_STATS; s->frames[nn].renderTime = renderTime; s->frames[nn].frameTime = frameTime; if (s->numFrames < MAX_FRAME_STATS) { s->numFrames += 1; } else { s->firstFrame += 1; if (s->firstFrame >= MAX_FRAME_STATS) s->firstFrame -= MAX_FRAME_STATS; } s->lastTime = now; } JNIEXPORT void JNICALL Java_example_user_plasmatest_PlasmaView_renderPlasma(JNIEnv * env, jobject obj, jobject bitmap, jlong time_ms) { AndroidBitmapInfo info; void* pixels; int ret; static Stats stats; static int init; if (!init) { init_tables(); stats_init(&stats); init = 1; } if ((ret = AndroidBitmap_getInfo(env, bitmap, &info)) < 0) { LOGE("AndroidBitmap_getInfo() failed ! error=%d", ret); return; } if (info.format != ANDROID_BITMAP_FORMAT_RGB_565) { LOGE("Bitmap format is not RGB_565 !"); return; } if ((ret = AndroidBitmap_lockPixels(env, bitmap, &pixels)) < 0) { LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret); } stats_startFrame(&stats); /* Now fill the values with a nice little plasma */ fill_plasma(&info, pixels, time_ms ); AndroidBitmap_unlockPixels(env, bitmap); stats_endFrame(&stats); } // // Created by user on 2016/4/14. //
修改build.gradle文件: 添加ndk{......}
defaultConfig {
applicationId "example.user.plasmatest"
minSdkVersion 15
targetSdkVersion 23
versionCode 1
versionName "1.0"
ndk{
moduleName "plasma"
ldLibs "log"
ldLibs "jnigraphics"//新增
}
}
修改Android.mk文件：
添加：LOCAL_LDLIBS := -llog -ljnigraphics
这是我的Android.mk:
LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := plasma LOCAL_LDFLAGS := -Wl,--build-id LOCAL_LDLIBS := \ -llog \ -ljnigraphics \ LOCAL_SRC_FILES := \ D:\as_workspace\NDKDemo2\plasmatest\src\main\jni\plasma.c \ D:\as_workspace\NDKDemo2\plasmatest\src\main\jni\util.c \ LOCAL_C_INCLUDES += D:\as_workspace\NDKDemo2\plasmatest\src\main\jni LOCAL_C_INCLUDES += D:\as_workspace\NDKDemo2\plasmatest\src\debug\jni include $(BUILD_SHARED_LIBRARY)
运行即可。。。
遇到的问题：
问题一：Error:(383) undefined reference to `__android_log_print'：
1 修改 Android.mk 文件相关:
1
|
LOCAL_LDLIBS := -llog
|
2 如果使用 android studio，需要修改 gradle 脚本：
1
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android {
|
也就是添加了一句：ldLibs "log"
问题二：Error:(377) undefined reference to `AndroidBitmap_getInfo'
修改Android.mk文件：
添加：LOCAL_LDLIBS := -llog -ljnigraphics
修改 gradle 脚本如下：
ndk {
moduleName "webcam"
ldLibs "log"
ldLibs "jnigraphics"
}
其实这句的意思就是增加动态链接库 jnigraphics ，这样就搞定了呢，是的，就是这样。
问题三：找不到appcompatActivity
这时候你的activity应该继承的是appcompatActivity，
解决方法一：修改成继承Activity就可以
解决方法二：javah -d jni -classpath D:\ide\android-sdk\platforms\android-22\android.jar;D:\ide\android-sdk\extras\android\support\v7\appcompat\libs\android-support-v7-appcompat.jar;..\..\build\intermediates\classes\debug
在javah命令中加上android-support-v7-appcompat.jar这个的路径，在安装目录下，一级级找就可以。
几个很好的学习ndk的博客：
JNI官方规范中文版：http://blog.csdn.net/a345017062/article/category/1256568
Android 开发之 JNI入门 - NDK从入门到精通（说的很全）：http://www.hanshuliang.com/?post=3
http://blog.csdn.net/shulianghan/article/details/18964835（推荐）
NDK开发：http://blog.csdn.net/conowen/article/category/1127720
JNI实战：http://blog.csdn.net/yanbober/article/details/45309049（推荐）
极客学院的：http://wiki.jikexueyuan.com/project/jni-ndk-developer-guide/overview.html（推荐）
