6.1学习内容 ndk编程释放内存，C语言中char*添加字符得方法，java二维数组的读取与生成

ndk的内存释放：

//回收
(*env)->ReleaseIntArrayElements(env,value, codeLineArray,0);
(*env)->ReleaseIntArrayElements(env,(jintArray)codeLineArray, codeLineData,0);

(*env)->DeleteLocalRef(env, value);
(*env)->DeleteLocalRef(env, codeLineArray);
(*env)->DeleteLocalRef(env, codeLineData);

value=NULL;
codeLineArray = NULL;
codeLineData=NULL;

往一个string添加char的方法：

//init
char *ret = malloc(1);
strcpy(ret, "");
//add char
char addchar[]={'\n'};
strcat(ret, addchar);

java二维数组的读取与生成
读取

jintArray textBinArr = (jintArray)(*env)->CallObjectMethod(env,code,valueGetMethod,firstKey);
int codeHeight = (*env)->GetArrayLength(env, textBinArr);
LOGI("codeHeight:%d",codeHeight);

int picHeight = (*env)->GetArrayLength(env, pic);
LOGI("picHeight==%d",picHeight);

for (i = 0; i < picHeight; i+=picHeight) {
jarray lineArray = ((*env)->GetObjectArrayElement(env, pic, i));
int picWidth =  (*env)->GetArrayLength(env, lineArray);
jboolean *lineData = (*env)->GetBooleanArrayElements(env, (jbooleanArray)lineArray, 0 );
for (j=0;j<picWidth;) {
//[i][j]=lineData[j]
}
}

生成：

//new boolean[][]
jobjectArray ret;
jclass boolArrCls = (*env)->FindClass(env, "[Z");
if ( NULL== boolArrCls) {
return NULL;
}

ret = (*env)->NewObjectArray(env, info.height , boolArrCls, NULL);
jboolean tmp[info.width];//固定数组，测试用,注意别溢出

for (int i=0 to 100) {
jbooleanArray boolArr = (*env)->NewBooleanArray(env,width);

for (j 0 to 1000) {
tem[j]=randonInt();

}
(*env)->SetBooleanArrayRegion(env,boolArr, 0, width, tmp);
(*env)->SetObjectArrayElement(env,ret, y, boolArr);
(*env)->DeleteLocalRef(env,boolArr);

}

吐槽一下今天：

几个20多岁的朋友都想过6.1，是不是脑子都抽水了？

NDK代码量比java多了好多；

打算去北京，好多人反对；

还没女朋友~