I am trying to create a triangle in openGL 2.0 but some some reason background is shows up but no triangle. I am following this tutorial: Building an OpenGL ES Environment | Android Developers
i have the same code as on tutorial but for some reason the triangle is not showing up.
may be i missed some thing or i am doing some thing wrong?

i have two class.
GlRender.java
GLTriangle.java

public class GlRender implements Renderer {
 
	private GLTriangle glTriangleObj;
 
	private final float[] mModelMatrix = new float[16];
	private final float[] mProjectionMatrix = new float[16];
	private final float[] mViewMatrix = new float[16];
	private final float[] mRotationMatrix = new float[16];
 
	/************************/
	/*** create() method ***/
	/************************/
	@Override
	public void onSurfaceCreated(GL10 gl, EGLConfig config) {
		// Set the background color
		// 0 to 1
		// 1 = no transparent
		GLES20.glClearColor(0.8f, 0.2f, 0.2f, 1f);
		gl.glClearDepthf(1f);
 
		glTriangleObj = new GLTriangle();
		// glSquare = new Square(); //etc...
 
		// postion the eye behind the origin
		final float eyeX = 0.0f;
		final float eyeY = 0.0f;
		final float eyeZ = 1.5f;
 
		// we are looking toward the distance
		final float lookX = 0.0f;
		final float lookY = 0.0f;
		final float lookZ = -5.0f;
 
		// Set our up vector. This is where our head would be pointing were we
		// holding the camera.
		final float upX = 0.0f;
		final float upY = 1.0f;
		final float upZ = 0.0f;
 
		// Set the view matrix. This matrix can be said to represent the camera
		// position.
		// NOTE: In OpenGL 1, a ModelView matrix is used, which is a combination
		// of a model and
		// view matrix. In OpenGL 2, we can keep track of these matrices
		// separately if we choose.
		Matrix.setLookAtM(mViewMatrix, 0, eyeX, eyeY, eyeZ, lookX, lookY,
				lookZ, upX, upY, upZ);
	}
 
	/********************/
	/*** paint method ***/
	/********************/
	@Override
	public void onDrawFrame(GL10 gl) {
		// Redraw background color
		GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
 
		// do a complete rotation every 10 seconds
		// long time = SystemClock.uptimeMillis() % 10000L;
		// float angleInDegree = (360.0f / 10000.0f) * ((int) time);
		// draw the triangle face straight on
		// Matrix.setIdentityM(mModelMatrix, 0);
		// Matrix.rotateM(mModelMatrix, 0, angleInDegree, 0.0f, 0.0f, 1.0f);
 
		// Set the camera position (View matrix)
		Matrix.setLookAtM(mViewMatrix, 0, 0, -2, 0, 0f, 0f, 0f, 0f, 2.0f, 0.0f);
 
		// Calculate the projection and view transformation
		Matrix.multiplyMM(mModelMatrix, 0, mProjectionMatrix, 0, mViewMatrix, 0);
 
		glTriangleObj.draw(mModelMatrix);
	}
 
	/*****************************/
	/*** landscape to portrait ***/
	/*****************************/
	@Override
	public void onSurfaceChanged(GL10 gl, int width, int height) {
		if (height == 0)
			height = 1;
 
		// Set the OpenGL viewport to the same size as the surface.
		GLES20.glViewport(0, 0, width, height);
 
		// while the width will vary as per aspect ratio.
		final float ratio = (float) width / height;
		final float left = -ratio;
		final float right = ratio;
		final float bottom = -1.0f;
		final float top = 1.0f;
		final float near = 1.0f;
		final float far = 25.0f;
 
		Matrix.frustumM(mProjectionMatrix, 0, left, right, bottom, top, near,
				far);
	}
}



GLTriangle.java

public class GLTriangle {
	// always same
	private final String vertexShaderCode = "attribute vec4 vPosition;"
			+ "void main() {" + "  gl_Position = vPosition;" + "}";
 
	private final String fragmentShaderCode = "precision mediump float;"
			+ "uniform vec4 vColor;" + "void main() {"
			+ "  gl_FragColor = vColor;" + "}";
 
	// always start at zero when ploting a point as defult
	// trinagle Coordinates - vertex = 3(x y z)
	private float trinagleCoords[] = { 0f, 1f, // V 0 - top
			1f, -1, // V 1 - right bottom
			-1f, 1f // V 2 - left bottom
	};
	private int COORDS_PER_VERTEX = 2; // number of points
	private FloatBuffer vertexBuffer;
 
	private short[] drawOrder = { 0, 1, 2 }; // order
	private ShortBuffer orderBuffer;
 
	float color[] = { 0.5f, 1f, 0f, 1f };
 
	private int vertexCount = trinagleCoords.length / COORDS_PER_VERTEX;
	private int vertexStride = COORDS_PER_VERTEX * 4; // bytes per vertex
 
	// used to pass in the transformation matrix
	private final int mProgram;
	// used to pass in model poition information
	private int mPositionHandle;
	// used to pass inmodel color information
	private int mColorHandle;
 
	private int mMVPMatrixHandle;
 
	public GLTriangle() {
		// vertices - has to be 4
		ByteBuffer byteBuffer = ByteBuffer
				.allocateDirect(trinagleCoords.length * 4);
		byteBuffer.order(ByteOrder.nativeOrder());
		vertexBuffer = byteBuffer.asFloatBuffer();
		vertexBuffer.put(trinagleCoords);
		vertexBuffer.position(0);
 
		// draw order - has to be 2
		ByteBuffer pointByteBuffer = ByteBuffer
				.allocateDirect(drawOrder.length * 2);
		pointByteBuffer.order(ByteOrder.nativeOrder());
		orderBuffer = pointByteBuffer.asShortBuffer();
		orderBuffer.put(drawOrder);
		orderBuffer.position(0);
 
		// shader - always same
		int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
		int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER,
				fragmentShaderCode);
		// create empty OpenGL ES Program
		mProgram = GLES20.glCreateProgram();
		// add the vertex shader to program
		GLES20.glAttachShader(mProgram, vertexShader);
		// add the fragment shader to program
		GLES20.glAttachShader(mProgram, fragmentShader);
		// creates OpenGL ES program executables
		GLES20.glLinkProgram(mProgram);
	}
 
	/************/
	/*** same ***/
	/************/
	public static int loadShader(int type, String shaderCode) {
 
		// create a vertex shader type (GLES20.GL_VERTEX_SHADER)
		// or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
		int shader = GLES20.glCreateShader(type);
 
		// add the source code to the shader and compile it
		GLES20.glShaderSource(shader, shaderCode);
		GLES20.glCompileShader(shader);
 
		return shader;
	}
 
	public void draw(float[] mModelMatrix) {
		// Add program to OpenGL environment
		GLES20.glUseProgram(mProgram);
 
		// get handle to vertex shader's vPosition member
		mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
 
		// Enable a handle to the triangle vertices
		GLES20.glEnableVertexAttribArray(mPositionHandle);
 
		// Prepare the triangle coordinate data
		GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
				GLES20.GL_FLOAT, false, vertexStride, vertexBuffer);
 
		// get handle to fragment shader's vColor member
		mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
 
		// Set color for drawing the triangle
		GLES20.glUniform4fv(mColorHandle, 1, color, 0);
 
		// Draw the triangle
		GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
 
		// Disable vertex array
		GLES20.glDisableVertexAttribArray(mPositionHandle);
 
		// get handle to shape's transformation matrix
		mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
 
		// Apply the projection and view transformation
		GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mModelMatrix, 0);
 
		// Draw the triangle
		GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
 
 
 
 
		/////
		 // Draw the square
        GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length,
                              GLES20.GL_UNSIGNED_SHORT, orderBuffer);
 
        // Disable vertex array
        GLES20.glDisableVertexAttribArray(mPositionHandle);
	}
}