很抱歉我发布了Worng Logcat信息。我更新了问题。我想单击"开始"启动一个线程,然后当单击enter时,我希望thad继续并获取消息并在线程中处理消息,然后将其输出到主线程并更新文本视图。我该如何启动一个线程来等待按下回车键并获取处理程序的捆绑包?这是我的代码:
public class MainActivity extends Activity implements OnClickListener {
Handler mHandler;
Button enter;
Button start;
TextView display;
String dateString;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
enter = (Button) findViewById(R.id.enter);
start = (Button) findViewById(R.id.start);
display = (TextView) findViewById(R.id.Display);
enter.setOnClickListener(this);
start.setOnClickListener(this);
mHandler = new Handler() { <=============================This is Line 31
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
super.handleMessage(msg);
Bundle bundle = msg.getData();
String string = bundle.getString("outKey");
display.setText(string);
}
};
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.enter:
Message msgin = Message.obtain();
Bundle bundlein = new Bundle();
String in = "It Works!";
bundlein.putString("inKey", in);
msgin.setData(bundlein);
notifyAll();
break;
case R.id.start:
new myThread().hello.start();
break;
}
}
public class myThread extends Thread {
Thread hello = new Thread() {
@Override
public void run() {
// TODO Auto-generated method stub
super.run();
Looper.prepare();
try {
wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Handler Mhandler = new Handler() {
@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
super.handleMessage(msg);
Bundle bundle = msg.getData();
dateString = bundle.getString("inKey");
}
};
Looper.loop();
Message msg = Message.obtain();
Bundle bundle = new Bundle();
bundle.putString("outKey", dateString);
msg.setData(bundle);
mHandler.sendMessage(msg);
}
};
}
}
这是logcat信息:
06-27 00:00:24.832: E/AndroidRuntime(18513): FATAL EXCEPTION: Thread-1210
06-27 00:00:24.832: E/AndroidRuntime(18513): java.lang.IllegalMonitorStateException: object not locked by thread before wait()
06-27 00:00:24.832: E/AndroidRuntime(18513): at java.lang.Object.wait(Native Method)
06-27 00:00:24.832: E/AndroidRuntime(18513): at java.lang.Object.wait(Object.java:364)
06-27 00:00:24.832: E/AndroidRuntime(18513): at com
.example.learninghandlers.MainActivity$myThread$1.run(MainActivity.java:77)
您在发布时的当前错误,
java.lang.IllegalMonitorStateException: object not locked by thread before wait()
发生这种情况是因为调用线程在尝试wait()时没有自己的监视器。
要拥有监视器,您需要在这个类的对象上同步的代码块中,或者在类的同步方法中。
然而,您对线程的总体使用看起来相当不规则,而且很可能在这个线程后面隐藏着其他问题。
如果查看堆栈跟踪,您会得到答案:onCreate方法中对象的of为null。
06-26 21:48:55.387: E/AndroidRuntime(15578): Caused by: java.lang.NullPointerException
06-26 21:48:55.387: E/AndroidRuntime(15578): at com.example.learninghandlers.MainActivity.onCreate(MainActivity.java:31)
问题在于这两条线之间:
setContentView(R.layout.activity_main);
enter.setOnClickListener(this);
因为堆栈告诉我们,所以其中一个评估为空:
enter = (Button) findViewById(R.id.enter);
start = (Button) findViewById(R.id.start);
display = (TextView) findViewById(R.id.Display);
所以问题肯定在这里,有些东西是空的:
R.id.enter
R.id.start
你可以不通过调试来检查哪个对象为空吗?