我遇到了以下错误 .
logUser("An error happend while creating graph:"+ getErrorMessage());
其中getErrorMessage()是无法在未调用Looper.prepare()的线程内创建处理程序,而logUser是一个只显示toast congaing消息的函数 .
void prepareGraph() {
logUser("loading graph (" + Helper.VERSION + "|" + Helper.VERSION_FILE
+ ") ... ");
new MyAsyncTask<Void, Void, Path>() {
protected Path saveDoInBackground(Void... v) throws Exception {
GraphHopper tmpHopp = new GraphHopper().forAndroid();
tmpHopp.contractionHierarchies(true);
tmpHopp.load(mapsFolder + currentArea);
logUser("found graph with " + tmpHopp.getGraph().nodes() + " nodes");
hopper = tmpHopp;
return null;
}
protected void onPostExecute(Path o) {
if (hasError()) {
logUser("An error happend while creating graph:"
+ getErrorMessage());
} else {
logUser("Finished loading graph. Touch to route.");
calcPath(52.534185, 13.348732, 52.53857,
13.41259);
}
finishPrepare();
}
}.execute();
}
2 回答
你不能从后台线程做UI操作 .
试试这个:
您需要在主线程上实例化
AsyncTask
.AsyncTask
源代码创建Handler
以调用onPreExecute()
,onPostExecute()
等方法,如果Handler
未在主线程上实例化,Android将抛出异常,告诉您Handler
正在与之交互的线程没有Looper.prepare()
方法叫做 .