1 
    mainListView.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
             String item = ((TextView)view).getText().toString();
             Toast.makeText(getBaseContext(), item, Toast.LENGTH_LONG).show();
            tcpSocket.SendMessage(FramePacket.FramesendMessageCmd(item));


        }
    });

这是我的代码。单击消息项后，我想开始另一个活动。我尝试了很多。但不工作。任何知道的人请帮助我。如何解决这个问题。我尝试了很多。它给出空指针异常错误。

目录错误在这里

 09-02 13:36:44.364: E/AndroidRuntime(28601): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dispatchsystem/com.dispatchsystem.JobStartedScreen}: java.lang.NullPointerException
 09-02 13:36:44.364: E/AndroidRuntime(28601):   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.app.ActivityThread.access$600(ActivityThread.java:127)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.os.Handler.dispatchMessage(Handler.java:99)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.os.Looper.loop(Looper.java:137)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at  android.app.ActivityThread.main(ActivityThread.java:4448)
 09-02 13:36:44.364: E/AndroidRuntime(28601):   at java.lang.reflect.Method.invokeNative(Native Method)
 09-02 13:36:44.364: E/AndroidRuntime(28601):   at java.lang.reflect.Method.invoke(Method.java:511)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:823)
 09-02 13:36:44.364: E/AndroidRuntime(28601):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:590)
 09-02 13:36:44.364: E/AndroidRuntime(28601):   at dalvik.system.NativeStart.main(Native Method)
09-02 13:36:44.364: E/AndroidRuntime(28601): Caused by: java.lang.NullPointerException
09-02 13:36:44.364: E/AndroidRuntime(28601):    at com.dispatchsystem.JobStartedScreen.onCreate(JobStartedScreen.java:65)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.app.Activity.performCreate(Activity.java:4465)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
09-02 13:36:44.364: E/AndroidRuntime(28601):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1931)

工作开始画面

 public class JobStartedScreen extends Activity  implements OnMessageReceived{

TextView tv_JobNo;
static TextView tv_JobKm;
static TextView tv_JobwaitngTime;
TextView tvjobstartedtime;
Button btn_jobFinsh;
Button btn_msg;
boolean _ThreadFlag=false;
boolean _ResumeThread=false;
private Window w;
Thread t=null;
String tag="Jobstartscreen";
private static MyThread sThread;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
     requestWindowFeature(Window.FEATURE_NO_TITLE);
     setContentView(R.layout.jobstartedscreen);
    if (savedInstanceState==null){
        Contsants.VehicleStartOdometer=0.0F;
        sThread=new MyThread(mHandler);
        sThread.start();
    }
    StateManager.DeviceStatus=StateManager.hired;
    tcpSocket.setmMessageListener(this);
    tv_JobNo =(TextView)findViewById(R.id.tvJobid);
    Bundle bundle = getIntent().getExtras();
    tv_JobNo.setText(bundle.get("Jobno").toString());

    tv_JobKm =(TextView)findViewById(R.id.tvjobKm);
    tv_JobwaitngTime =(TextView)findViewById(R.id.tvjobWaittime);

    tv_JobwaitngTime.setText("Waiting Time : 0:0");
    //update the Km every 1 sec
    Log.d(tag, "On created "+_ResumeThread);
    tvjobstartedtime=(TextView)findViewById(R.id.tv_jobStarttime);
    tvjobstartedtime.setText("Start Time :"+Contsants.jobStartTime);

    btn_jobFinsh= (Button)findViewById(R.id.btn_jobFinsh);
    btn_jobFinsh.setOnClickListener(onClickListener);

    btn_msg= (Button)findViewById(R.id.btn_msg);
    btn_msg.setOnClickListener(onClickListener);


    // TODO Auto-generated method stub
}
@Override
public void onStart()
{
    super.onStart();

}
@Override
public void onResume()
{
    super.onResume();
    w = this.getWindow();
    w.addFlags(LayoutParams.FLAG_DISMISS_KEYGUARD);
    w.addFlags(LayoutParams.FLAG_SHOW_WHEN_LOCKED);
    w.addFlags(LayoutParams.FLAG_TURN_SCREEN_ON);
    Log.d("job start on resume",_ThreadFlag+" "+_ResumeThread);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState){
    super.onRestoreInstanceState(savedInstanceState);
    if (sThread.isAlive()){
        sThread.setHandler(mHandler);
    }
}

@Override
protected void onDestroy(){
    super.onDestroy();
    if (sThread.isAlive()){
        sThread.setHandler(null);
    }
}

boolean _Paused=false;
@Override
public void onPause()
{
    super.onPause();
    _Paused=true;
}
@Override
public void onBackPressed() {
    // do nothing.
}

private OnClickListener onClickListener = new OnClickListener() {
    @Override
    public void onClick(final View v) {
        switch(v.getId()){
        case R.id.btn_jobFinsh:
            //DO something
            _ThreadFlag=true;
            StateManager.JobStatus=StateManager.jobstatus_dropped;
            tcpSocket.SendMessage(FramePacket.FrameJobStatusCmd(Contsants.Jobno,StateManager.JobStatus) );
             SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yy HH:mm");
             String currentDateandTime = sdf.format(new Date());
             Contsants.jobEndTime=currentDateandTime;
            Intent i = new Intent(getApplicationContext(),JobCompletionScreen.class);
            startActivity(i);
            sThread.setHandler(null);
            finish();
            break;
        case R.id.btn_msg:
            /*Intent iNAV = new Intent(Intent.ACTION_VIEW,
                    Uri.parse("http://maps.google.com/maps?saddr=12.920629,77.610643&daddr=12.990346, 77.589521")
                    );
            startActivity(iNAV);*/
            Intent imsg = new Intent(getApplicationContext(),MessageList.class);
            startActivity(imsg);
            break;

        }
    }
};

static Handler mHandler =new Handler(){
    @Override
    public void handleMessage(Message message){
        //update UI
        Bundle b = message.getData();
        float odometer = b.getFloat("My Odometer");
        int waiting =b.getInt("waiting Time");
        tv_JobKm.setText(odometer+" Km");
        tv_JobwaitngTime.setText("Waiting Time : "+Integer.toString((waiting / 60)) +":"+ Integer.toString((waiting% 60)));
    }
};

private class MyThread extends Thread{
    private Handler mHandler;

    public MyThread(Handler handler){
        super();
        mHandler=handler;
    }

    @Override
    public void run(){
        //some long operation
        if (mHandler!=null)
            mHandler.sendEmptyMessage(0);

        _ResumeThread=true;
        while(!_ThreadFlag)
        {
            try {
                Thread.sleep(1000);   
                Message msg = new Message();
                Bundle b = new Bundle();
                b.putFloat("My Odometer", (float) (gpsdataElements.Distance-Contsants.jobStartKm));
                if(gpsdataElements.Speed==0.0)
                {
                    Contsants.cont_WaitingTimeInSec++;
                }
                b.putInt("waiting Time",  Contsants.cont_WaitingTimeInSec);
                //  tv_JobwaitngTime.setText("Waiting Time : "+Integer.toString((Contsants.cont_WaitingTimeInSec / 60)) +":"+ Integer.toString((Contsants.cont_WaitingTimeInSec % 60)));
                //send message to the handler with the current message handler          
                msg.setData(b);
                // send message to the handler with the current message handler
                mHandler.sendMessage(msg);

            } catch (Exception e) {
                Log.v("Error", e.toString());
            }
        }
    }

    public void setHandler(Handler handler){
        mHandler=handler;
    }
}

@Override
public void messageReceived(String message) {
    // TODO Auto-generated method stub
    //Toast.makeText(getApplicationContext(), "Job StartScreem : Recived data :"+message, Toast.LENGTH_LONG).show();        
}

 }
4

3 回答 3

2

您可以在 onClick 中使用 Handler

mainListView.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
             String item = ((TextView)view).getText().toString();
             Toast.makeText(getBaseContext(), item, Toast.LENGTH_LONG).show();
            tcpSocket.SendMessage(FramePacket.FramesendMessageCmd(item));
          new Handler().postDelayed(new Runnable() {

                @Override
                public void run() {
                    MyAct.this.startActivity(new Intent(MyAct.this,Abc.class));

                }
            }, 5000);

        }
    });

public void run() { 在这里插入你的下一个活动

于 2013-09-02T09:06:29.167 回答
1

将您的代码编辑为：

mainListView.setOnItemClickListener(new OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View view,
            int position, long id) {
         String item = ((TextView)view).getText().toString();
         Toast.makeText(getBaseContext(), item, Toast.LENGTH_LONG).show();

         Intent intent= new Intent(youractivitycontext, AnotherActivity.class); 
         startActivity(intent);

    }
});

这将带您进入由您的AnotherActivity.class指定的另一个活动。您也可以将数据传递给您的下一个活动，因为您似乎正在尝试这样做。有几种方法可以做到这一点。去这里了解 Intents

于 2013-09-02T08:29:49.713 回答
0

在展示你的吐司之后。 

Intent intent= new Intent(youractivitycontext, AnotherActivity.class); 
startActivity(intent);
于 2013-09-02T08:02:50.107 回答