Question

我刚刚开始在Android上使用open GL，而且我对整个编程仍然很陌生。我收到了标题中提到的错误（

07-07 14:58:37.776: E/AndroidRuntime(884): FATAL EXCEPTION: main
07-07 14:58:37.776: E/AndroidRuntime(884): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.imlearningnow/com.example.imlearningnow.GLRenderEx}: java.lang.ClassCastException: com.example.imlearningnow.GLRenderEx

）当我尝试打开活动时。该程序旨在呈现三角形。这是代码+ logcat：

GLRenderEx：

package com.example.imlearningnow;

import java.util.Random;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL;
import javax.microedition.khronos.opengles.GL10;

import android.opengl.GLSurfaceView.Renderer;

public class GLRenderEx  implements Renderer{

    private GLTriangleEx tri;

    public GLRenderEx(){
        tri = new GLTriangleEx();
    }


    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig eglConfig) {
    // TODO Auto-generated method stub
    gl.glDisable(GL10.GL_DITHER);   
    gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
    gl.glClearColor(.8f, 0f, .2f, 1f);
    gl.glClearDepthf(1f);


    }

    @Override
    public void onDrawFrame(GL10 gl) {
        // TODO Auto-generated method stub
        gl.glDisable(GL10.GL_DITHER);
        gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

        tri.draw(gl);
    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {
        // TODO Auto-generated method stub

    }




}

GLTriangleEX：

 package com.example.imlearningnow;

    import java.nio.ByteBuffer;
    import java.nio.ByteOrder;
    import java.nio.FloatBuffer;
    import java.nio.ShortBuffer;

    import javax.microedition.khronos.opengles.GL10;

    public class GLTriangleEx {

        private float vertices[] = {
            0f, 1f,  //p0
            1f, -1f, //p1
            -1f, -1f //p2

        };

        private FloatBuffer vertBuff;

        private short[] pIndex = {0,1, 2};

        private ShortBuffer pBuff;

        public GLTriangleEx(){
            ByteBuffer bBuff = ByteBuffer.allocateDirect(vertices.length * 4);
            bBuff.order(ByteOrder.nativeOrder());
             vertBuff = bBuff.asFloatBuffer();
             vertBuff.put(vertices);
             vertBuff.position(0);

             ByteBuffer pbBuff = ByteBuffer.allocateDirect(pIndex.length *2);
             pbBuff.order(ByteOrder.nativeOrder());
             pBuff = pbBuff.asShortBuffer();
             pBuff.put(pIndex);
             pBuff.position(0);
        }

        public void draw(GL10 gl){
            gl.glFrontFace(GL10.GL_CW);
            gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
            gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertBuff);
            gl.glDrawElements(GL10.GL_TRIANGLES, pIndex.length, GL10.GL_UNSIGNED_SHORT, pBuff);
            gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
        }

    }

logcat的：

07-07 14:58:37.776: E/AndroidRuntime(884): FATAL EXCEPTION: main
07-07 14:58:37.776: E/AndroidRuntime(884): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.imlearningnow/com.example.imlearningnow.GLRenderEx}: java.lang.ClassCastException: com.example.imlearningnow.GLRenderEx
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.os.Handler.dispatchMessage(Handler.java:99)
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.os.Looper.loop(Looper.java:123)
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.app.ActivityThread.main(ActivityThread.java:4627)
07-07 14:58:37.776: E/AndroidRuntime(884):  at java.lang.reflect.Method.invokeNative(Native Method)
07-07 14:58:37.776: E/AndroidRuntime(884):  at java.lang.reflect.Method.invoke(Method.java:521)
07-07 14:58:37.776: E/AndroidRuntime(884):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-07 14:58:37.776: E/AndroidRuntime(884):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-07 14:58:37.776: E/AndroidRuntime(884):  at dalvik.system.NativeStart.main(Native Method)
07-07 14:58:37.776: E/AndroidRuntime(884): Caused by: java.lang.ClassCastException: com.example.imlearningnow.GLRenderEx
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
07-07 14:58:37.776: E/AndroidRuntime(884):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
07-07 14:58:37.776: E/AndroidRuntime(884):  ... 11 more
07-07 14:58:45.207: I/Process(884): Sending signal. PID: 884 SIG: 9

Answer 1

您在清单文件中将GLRenderEx声明为Activity，但它不是一个。

无法实例化活动ComponentInfo由以下原因引起：java.lang.ClassCastException

1 个答案: