Android JNI get Two Fields from Java class

Question

Before I post any code or anything, let me explain what I'm trying to accomplish: what I'm trying to do is get load shaders from an assets folder, and pass an array of `PongDroidShader` objects to C++ so it can compile and load them. In my Java class, I have a function which goes through each shader file in the shaders folder and parses it loads it into a `String` object, while also checking for what kind of shader type it is via its file extension (.e.g, a vertex would have a `.vert` extension). Once I've accomplished that, I then send it to my native `compileShaders` function, which takes the array of `PongDroidShader` objects, and the size of the array. After that, I parse and link the shaders from the JNI code. So far, I'm having trouble getting the JNI to recognize the Java code and load it into variables. What I have so far is as follows: Java Code ``` public final class PongDroidShader { public String mShaderSrc; public ShaderType mType; } private class ShaderHandler { ... priv…

Accepted Answer

I believe you should be using this to get your fields:

```
env->GetFieldID( clazz, "mType", "Lcom/grepwise/pongdroid/ShaderType;" );
env->GetFieldID( clazz, "mShaderSrc", "Ljava/lang/String;" )
```

And move the class & field getting out of the loop.

EDIT: Also this:

```
const jchar jShaderChr = env->GetCharField(...)
```

to get String value from mShaderSrc is wrong.

You should be using:

```
jstring jShaderStr = (jstring)env->GetObjectField(...);
const char* shaderSrc = env->GetStringUTFChars(jShaderStr, 0);
// ... here use shaderSrc
env->ReleaseStringUTFChars(hShaderStr, shaderSrc);
```

Android JNI get Two Fields from Java class

Solution

Problem