HandlerThread空异常-Android
我在我的应用程序中以这种方式使用ThreadHandlerHandlerThread空异常-Android,android,message-queue,android-handler,android-looper,android-handlerthread,Android,Message Queue,Android Handler,Android Looper,Android Handlerthread,我在我的应用程序中以这种方式使用ThreadHandler public class MessageThread extends HandlerThread { Handler mHandler; public MessageThread() { super("Message Thread"); } public void queueProcessMessage(msgObject mObj) { mHandler.obtai
public class MessageThread extends HandlerThread {
Handler mHandler;
public MessageThread() {
super("Message Thread");
}
public void queueProcessMessage(msgObject mObj) {
mHandler.obtainMessage(PROCESS_MESSAGE, mObj).sendToTarget();
}
@Override
protected void onLooperPrepared() {
Commons.logIt("OnLoopPrep");
mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case PROCESS_MESSAGE:
process_message((msgObject) msg.obj);
break;
default:
break;
}
}
};
}
process_message(msgObject obj) {
//Do stuff
}
}
我在onCreate()中初始化它,如下所示
public void onCreate(Bundle savedInstanceState) {
MessageThread mThread = new MessageThread();
mThread.start();
mThread.getLooper();
if (mThread != null)
mThread.queueProcessMessage(Object);// this is the line the compiler is pointing at.
}
它工作正常,问题是我需要添加一些其他东西,在那里我必须启动另一个等待结果的活动,所以我必须初始化/使用它,如下所示,因为onActivityResult在onCreate之前被调用。当我启动一个用于结果的活动时,这一次我得到了一个错误
java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Message android.os.Handler.obtainMessage(int, java.lang.Object)' on a null object reference
看起来线程没有初始化,我缺少什么
编辑1
在这里讨论了这个问题之后,处理程序的初始化似乎需要一点时间,我做了这个,这很难看,但它正在工作,我该怎么做
public void queueProcessMessage(msgObject mObj) {
while (mHandler == null)
Log.i(TAG, "Not init yet"); //It keeps on looping here
mHandler.obtainMessage(PROCESS_MESSAGE, mObj).sendToTarget();
}
什么是
对象
,在哪里定义/设置?另外,请告诉我您没有在对象
类之后命名变量引用…这只是我的示例,我将进行更新以避免混淆。“onActivityResult在onCreate之前被调用”这实际上是不可能的。有可能的,onResume()与onCreate()不同。在onCreate()之前调用ActivityResult()是不可能的
public void queueProcessMessage(msgObject mObj) {
while (mHandler == null)
Log.i(TAG, "Not init yet"); //It keeps on looping here
mHandler.obtainMessage(PROCESS_MESSAGE, mObj).sendToTarget();
}