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POAndroid - C++ compile errors in cygwin/android-ndk
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  1. POAndroid - C++ compile errors in cygwin/android-ndk
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    copied!<p>Ive created a simple app to help me learn the ndk, jni, and get my c++ skills back up to par. However Im kind of stuck because Im getting some compile errors when I run ndk-build on my project from the cygwin command line. Its been a while since Ive used c++ to any extent so I know that my syntax is probably way off so if some one could help me clean this up or explain how I could do so then that would be awesome.....so heres my c++ code:</p> <p>EDIT: latest code</p> <pre><code>#include &lt;iostream&gt; #include &lt;Eigen/Dense&gt; #include &lt;math.h&gt; #include &lt;jni.h&gt; using namespace Eigen; Vector3f vec; Vector3f vec2; Vector3f vecRtrn; void vecLoad(float x, float y, float z, float x2, float y2, float z2){ vec(0) = x; vec(1) = y; vec(2) = z; vec2(0) = x2; vec2(1) = y2; vec2(2) = z2; } void vecAdd(Vector3f vecA, Vector3f vecB){ vecRtrn = vecA+vecB; } extern "C" { JNIEXPORT jfloatArray JNICALL Java_jnimath_act_JnimathActivity_test (JNIEnv *env, jobject obj, jfloatArray fltarray1, jfloatArray fltarray2){ float array1[3]; jfloatArray flt1 = fltarray1; jfloatArray flt2 = fltarray2; //flt1 = env-&gt;GetFloatArrayElements( fltarray1,0); //flt2 = env-&gt;GetFloatArrayElements( fltarray2,0); vecLoad(flt1[0], flt1[1], flt1[2], flt2[0], flt2[1], flt2[2]); vecAdd(vec, vec2); array1[0] = vecRtrn[0]; array1[1] = vecRtrn[1]; array1[2] = vecRtrn[2]; return array1; }; } </code></pre> <p>Now Im pretty sure Im not using the correct way to return the array back to java through jni but thats a separate problem......but please feel free to comment on that as well ;)</p> <p>Heres an updated list of the last couple of build errors I have.....its definitely a lot shorter than the original list :) </p> <pre><code>$ /cygdrive/c/android-ndk-r7/ndk-build Compile++ thumb : test &lt;= test.cpp jni/test.cpp: In function '_jfloatArray* Java_jnimath_act_JnimathActivity_test(JNIEnv*, _jobject*, _jfloatArray*, _jfloatArray*)': jni/test.cpp:42: error: cannot convert '_jfloatArray' to 'float' for argument '1' to 'void vecLoad(float, float, float, float, float, float)' jni/test.cpp:49: error: cannot convert 'float*' to '_jfloatArray*' in return make: *** [obj/local/armeabi/objs/test/test.o] Error 1 </code></pre> <p>EDIT: heres my java code......</p> <pre><code>package jnimath.act; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class JnimathActivity extends Activity { /** Called when the activity is first created. */ public EditText x; public EditText y; public EditText z; public EditText x2; public EditText y2; public EditText z2; public float[] vecArray; public TextView textView1; public Button run; float[] array3 = new float[3]; float[] array1 = new float[3]; float[] array2 = new float[3]; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); x = (EditText)findViewById(R.id.x); y = (EditText)findViewById(R.id.y); z = (EditText)findViewById(R.id.z); x2 = (EditText)findViewById(R.id.x); y2 = (EditText)findViewById(R.id.y); z2 = (EditText)findViewById(R.id.z); textView1 = (TextView)findViewById(R.id.textView1); run = (Button)findViewById(R.id.run); run.setOnClickListener(new OnClickListener(){ @Override public void onClick(View v) { array1[0] = Float.parseFloat(x.getText().toString()); array1[1] = Float.parseFloat(y.getText().toString()); array1[2] = Float.parseFloat(z.getText().toString()); array2[0] = Float.parseFloat(x2.getText().toString()); array2[1] = Float.parseFloat(y2.getText().toString()); array2[2] = Float.parseFloat(z2.getText().toString()); array3 = test(array1, array2); String text = array3[0]+" "+array3[1]+" "+array3[2]; textView1.setText(text); } }); } public native float[] test(float[] array1, float[] array2); static { System.loadLibrary("test"); } } </code></pre>
 

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