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我面临一个问题，我无法从服务启动活动。当服务接收数据时，它会调用handler.sendEmptyMessage(0)发送处理程序消息。然后接收者开始新的活动。但现在活动无法开始。有人可以阅读下面的代码并给我一些建议吗？

package com.testBlueTooth;

import java.io.InputStream;
import android.app.Service;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.provider.SyncStateContract.Constants;
import android.util.Log;
import android.view.SurfaceView;
import android.widget.Toast;

public class ClsWaveDiagram extends Service{

private boolean isRecording = false;
private InputStream btInput = null;

public int rateX = 1;

public int rateY = 1;

public int baseLine = 0;

public ClsWaveDiagram(InputStream btInput, int rateX, int rateY,
        int baseLine) {
    this.btInput = btInput;
    this.rateX = rateX;
    this.rateY = rateY;
    this.baseLine = baseLine;
}


public void Start(SurfaceView sfv, Paint mPaint, int wait) {
    isRecording = true;
    new DrawThread(sfv, mPaint, wait).start();
}

public void Stop() {
    isRecording = false;
}


class DrawThread extends Thread {

    private int oldX = 0;
    private int oldY = 0;
    private SurfaceView sfv;
    private int X_index = 0;
    private Paint mPaint;
    private int wait = 50;

    public DrawThread(SurfaceView sfv, Paint mPaint, int wait) {
        this.sfv = sfv;
        this.mPaint = mPaint;
        this.wait = wait;
    }

    public void run() {
        while (isRecording) {
            try {

                byte[] temp = new byte[1024];

                int len = btInput.read(temp);
                Log.e("available", String.valueOf(len));

                System.out.println("alarm!");

                handler.sendEmptyMessage(0);

                if (len > 0) {
                    byte[] btBuf = new byte[len];
                    System.arraycopy(temp, 0, btBuf, 0, btBuf.length);
                    SimpleDraw(X_index, btBuf, rateX, rateY, baseLine);
                    X_index = X_index + (btBuf.length/rateX) - 1;
                    if (X_index > sfv.getHeight()) {
                        X_index = 0;
                    }
                }
                Thread.sleep(wait);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    }   



    void SimpleDraw(int start, byte[] inputBuf, int rateX, int rateY,
            int baseLine) {
        if (start == 0)
            oldX = 0;

        byte[] buffer = new byte[inputBuf.length / rateX];
        for (int i = 0, ii = 0; i < buffer.length; i++, ii = i * rateX)
            buffer[i] = inputBuf[ii];

        Canvas canvas = sfv.getHolder().lockCanvas(
                new Rect(0, start, sfv.getWidth(), start + buffer.length));
        canvas.drawColor(Color.BLACK);

        for (int i = 0; i < buffer.length; i++) {
            int y = i + start;
            int x = (0xFF - (buffer[i] & 0xFF))

                    / rateY + baseLine;
            canvas.drawLine(oldX, oldY, x, y, mPaint);
            oldX = x;
            oldY = y;
        }
        sfv.getHolder().unlockCanvasAndPost(canvas);
    }
}
private Handler handler = new Handler(){
    public void handleMessage(android.os.Message msg) {
        Intent intent = new Intent();


        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        intent.setClass(ClsWaveDiagram.this.getApplicationContext(), AlertActivity.class);


        ClsWaveDiagram.this.startActivity(intent);

    };};

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

}

logcat 错误如下：

04-16 12:34:50.559: D/AndroidRuntime(3706): Shutting down VM
04-16 12:34:50.559: W/dalvikvm(3706): threadid=3: thread exiting with uncaught     exception (group=0x4001b170)
04-16 12:34:50.559: E/AndroidRuntime(3706): Uncaught handler: thread main exiting due     to uncaught exception
04-16 12:34:50.559: E/AndroidRuntime(3706): java.lang.NullPointerException
04-16 12:34:50.559: E/AndroidRuntime(3706):     at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:100)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at com.testBlueTooth.ClsWaveDiagram$1.handleMessage(ClsWaveDiagram.java:199)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at android.os.Looper.loop(Looper.java:123)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at android.app.ActivityThread.main(ActivityThread.java:4363)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at java.lang.reflect.Method.invokeNative(Native Method)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at java.lang.reflect.Method.invoke(Method.java:521)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-16 12:34:50.559: E/AndroidRuntime(3706):     at dalvik.system.NativeStart.main(Native Method)
04-16 12:34:50.590: I/dalvikvm(3706): threadid=7: reacting to signal 3
04-16 12:34:50.614: I/dalvikvm(3706): Wrote stack trace to '/data/anr/traces.txt'
04-16 12:34:54.789: E/available(3706): 2
04-16 12:34:54.789: I/System.out(3706): alarm!
04-16 12:34:54.903: E/available(3706): 20
04-16 12:34:54.903: I/System.out(3706): alarm!
04-16 12:34:59.034: E/available(3706): 1
04-16 12:34:59.034: I/System.out(3706): alarm!

主要活动：

package com.testBlueTooth;

import java.io.IOException;
import java.io.InputStream;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnTouchListener;

public class WaveDiagram extends Activity {
ClsWaveDiagram clsWaveDiagram;
SurfaceView sfvWave;
Paint mPaint;
InputStream btInput;
Context context = WaveDiagram.this;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.wavediagram);

    sfvWave = (SurfaceView) this.findViewById(R.id.sfvWave);
    sfvWave.setOnTouchListener(new TouchEvent());

    mPaint = new Paint();
    mPaint.setColor(Color.GREEN);
    mPaint.setStrokeWidth(2);

    try {
        if (testBlueTooth.btSocket.getInputStream() != null) {
            clsWaveDiagram = new ClsWaveDiagram(
                    testBlueTooth.btSocket.getInputStream(),
                    3,
                    1,
                    sfvWave.getWidth()/2);

            clsWaveDiagram.Start(sfvWave, mPaint,80);
            Log.e("clsWaveDiagram","start");

        }
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

@Override
public void onDestroy()  
{  
    clsWaveDiagram.Stop();
    try {
        testBlueTooth.btSocket.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
    super.onDestroy();  
}
class TouchEvent implements OnTouchListener {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        clsWaveDiagram.baseLine = (int) event.getX();
        return true;
    }

}
}
4

3 回答 3

1

试试这个希望它对你有帮助。

Intent intent = new Intent(this.ctx, AlertActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

this.ctx.startActivity(intent);

链接在这里

标准服务代码在这里

于 2012-05-09T06:33:13.710 回答
0

DrawThread之前不要跑Service.onStartCommand()

于 2012-05-09T06:23:09.363 回答
0

在处理程序函数中，您只需像打击和尝试一样修改，

Intent intent = new Intent(ClsWaveDiagram.this, AlertActivity.class);

        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        ClsWaveDiagram.this.startActivity(intent);

我想这会对你有所帮助。

于 2012-05-09T06:26:13.310 回答