我有一个问题，我有一个方法，我调用processInfo()。该方法主要处理从NFC标签或QR码收集的信息，并将其写入数据库。根据某些情况，processInfo方法处理如何将信息写入数据库。processInfo方法返回一个布尔值，如果设置为true，则数据库中的信息将被发送到web服务器。
我在processInfo中有一些逻辑，说如果条件A，那么写到DB并返回true。然后将其发送到webservice。如果条件B，则显示一个警告对话框。Alertdialog对话框中有一个OK和CANCEL按钮。如果按下ok键，则执行条件A中发生的操作，如果按下CANCEL键，则取消对话框并返回false。
发生的情况是，如果条件B发生，则对话框按预期显示，但在按下任何按钮之前它返回到调用方法。我如何使应用程序挂起，直到至少一个按钮被按下?
我试过使用while(! alertDialog.isShowing == true) -> return boolean。但在alertDialog.show()后退出并返回到调用方法。
success = false;
if(condition A) {
// write to DB and return to caller
return success = true;
} else {
success = false;
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(NfcscannerActivity.this);
// set title
alertDialogBuilder.setTitle("Please logout after ");
// set dialog message
alertDialogBuilder.setMessage("Click Ok to return to the menu")
.setCancelable(false)
.setPositiveButton("Ok",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
success = true;
// write to DB
}
})
.setNegativeButton("Cancel",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// if this button is clicked, just close
// the dialog box and do nothing
success = false;
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
return success;
}
你可以使用回调方法。比如onResultObtained(boolean result):
boolean onResultObtained(boolean result) {
if(result) {
//write to DB and return to caller
return true;
} else {
return false;
}
}
if(condition A){
onResultChanged(true);
}else{
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
NfcscannerActivity.this);
// set title
alertDialogBuilder.setTitle("Please logout after ");
// set dialog message
alertDialogBuilder
.setMessage("Click Ok to return to the menu")
.setCancelable(false)
.setPositiveButton("Ok",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
onResultChanged(true);
}
})
.setNegativeButton("Cancel",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.dismiss();
onResultChanged(false);
}
});
alertDialogBuilder.show();
}
}
另一种方法是将变量success设为全局。
boolean success;
processInfo ()
private void processInfo() {
if (condition A) {
success = true;
//Save data to DB
} else {
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
MainActivity.this);
// set title
alertDialogBuilder.setTitle("Please logout after ");
// set dialog message
alertDialogBuilder
.setMessage("Click Ok to return to the menu")
.setCancelable(false)
.setPositiveButton("Ok",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
success = true;
//Save data to DB
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.dismiss();
success = false;
}
});
alertDialogBuilder.show();
}
}
And, in your calling()
private void callingMethod(){
if(success){
//do your stuff
} else {
//do your stuff
}
}
@turtleboy这是一个简单的例子
公共类TestActivity扩展Activity {
static final String TAG="TestActivity";
static final int MSG_SEND_INFO_TO_SERVER = 1;
static final int MSG_INFO_NOT_SEND_TO_SERVER = 2;
boolean condition=false;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.i(TAG, "0000000000000000");
your_methode();
}
Handler communication_handler =new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_SEND_INFO_TO_SERVER:
//send info to the web server
Log.i(TAG, "11111111111111111");
Toast.makeText(getApplicationContext(), "send msg to the server", Toast.LENGTH_SHORT).show();
break;
case MSG_INFO_NOT_SEND_TO_SERVER:
//send info to the web server
Log.i(TAG, "222222222222222222");
Toast.makeText(getApplicationContext(), "no msg to send to the server", Toast.LENGTH_SHORT).show();
break;
default:
break;
}
}
};
public void your_methode()
{
if(condition) {
// write to DB
communication_handler.sendMessage(Message.obtain(null,MSG_INFO_NOT_SEND_TO_SERVER,0));
return ;
} else {
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
// set title
alertDialogBuilder.setTitle("Please logout after ");
// set dialog message
alertDialogBuilder.setMessage("Click Ok to return to the menu").setCancelable(false);
alertDialogBuilder.setPositiveButton("Ok",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// write to DB
// send msg
communication_handler.sendMessage(Message.obtain(null,MSG_SEND_INFO_TO_SERVER,0));
}
});
alertDialogBuilder.setNegativeButton("Cancel",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.cancel();
communication_handler.sendMessage(Message.obtain(null,MSG_INFO_NOT_SEND_TO_SERVER,0));
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
}
}
Android中没有阻塞UI模型，一切都是异步的。你必须改变这种行为。您可以在线程或asyncast或looperThread中调用alertDialog如果数据库中的信息必须发送到web服务器，则发送一个消息到主线程(使用Handler)，并在handleMessage(Message msg)中发送信息。