Android 如何在计时器内显示吐司?
我想在计时器内显示toast消息,我使用了以下代码:Android 如何在计时器内显示吐司?,android,toast,Android,Toast,我想在计时器内显示toast消息,我使用了以下代码: timer.scheduleAtFixedRate( new TimerTask() { public void run() { try { fun1(); } catch (Exception e) {e.printStackTrace(); } } }, 0,60000); public void fun1() { //wan
timer.scheduleAtFixedRate( new TimerTask()
{
public void run()
{
try {
fun1();
} catch (Exception e) {e.printStackTrace(); }
}
}, 0,60000);
public void fun1()
{
//want to display toast
}
我得到了以下错误:
WARN/System.err(593):java.lang.RuntimeException:无法在未调用Looper.prepare()的线程内创建处理程序
WARN/System.err(593):位于android.os.Handler.(Handler.java:121)
WARN/System.err(593):位于android.widget.Toast。(Toast.java:68)
WARN/System.err(593):位于android.widget.Toast.makeText(Toast.java:231)
谢谢。您必须调用UIThread来显示Toast。不是从计时器线程 否则从该计时器线程调用UI线程 这个链接会帮助你 还有这个
谢谢。创建一个
处理程序
,并在此文件中显示toast
private Handler handler = new Handler() {
public void handleMessage(android.os.Message msg) {
// Toast here
}
};
您需要访问应用程序的上下文才能做到这一点。尝试创建自己的类,该类将上下文作为输入参数:
private class MyTimerTask extends TimerTask {
private Context context;
public MyTimerTask(Context context) {
this.context = context;
}
@Override
public void run() {
Toast.makeText(context, "Toast text", Toast.LENGTH_SHORT).show();
}
}
然后在计时器中:
timer.scheduleAtFixedRate( new MyTimerTask(this), 0,60000);
您不能在单独的线程内进行UI更新,如计时器。您应该使用Handler对象进行UI更新:
timer.scheduleAtFixedRate( new TimerTask() {
private Handler updateUI = new Handler(){
@Override
public void dispatchMessage(Message msg) {
super.dispatchMessage(msg);
fun1();
}
};
public void run() {
try {
updateUI.sendEmptyMessage(0);
} catch (Exception e) {e.printStackTrace(); }
}
}, 0,60000);
我想用我自己的观点来做我自己的祝酒词 我成功地结合了你的方法。下面的代码允许我在不崩溃的情况下显示祝酒词和更改/删除视图,只需将
MyTimerTask
构造函数的参数更改为您需要处理的任何参数即可
public void yourFunction(){
Timer timer = new Timer();
MyTimerTask mtc = new MyTimerTask(this.getContext(), tvNotice);
timer.schedule(mtc, 1000);
}
private class MyTimerTask extends TimerTask {
private TextView tv;
private Context context;
public MyTimerTask(Context pContext, TextView pTv) {
this.tv = pTv;
this.context = pContext;
}
@Override
public void run() {
updateUI.sendEmptyMessage(0);
}
private Handler updateUI = new Handler(){
@Override
public void dispatchMessage(Message msg) {
super.dispatchMessage(msg);
tv.setText("TextView Message");
Toast.makeText(context, "Toast Message", 0).show();
}
};
}
我想做一个简单的项目,可以在计时器中显示祝酒词。 计时器将使用服务启动。然后,计时器在服务启动时启动,在服务停止时停止 第一类
package com.example.connect;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
Button button1,button2;
private Handler mHandler = new Handler();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1=(Button)findViewById(R.id.button1);
button2=(Button)findViewById(R.id.button2);
}
public void Start(View v)
{
startService(new Intent(MainActivity.this , Connect_service.class));
}
public void Stop(View v)
{
stopService(new Intent(MainActivity.this , Connect_service.class));
}
}
第二类
package com.example.connect;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.widget.Toast;
public class Connect_service extends Service{
Timer timer = new Timer();
TimerTask updateProfile = new CustomTimerTask(Connect_service.this);
public void onCreate() {
super.onCreate();
Toast.makeText(this, "Service Started", Toast.LENGTH_SHORT).show();
timer.scheduleAtFixedRate(updateProfile, 0, 5000);
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Toast.makeText(this, "Service Stopped", Toast.LENGTH_SHORT).show();
timer.cancel();
}
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
}
第三类
package com.example.connect;
import java.util.TimerTask;
import android.content.Context;
import android.os.Handler;
import android.widget.Toast;
public class CustomTimerTask extends TimerTask {
private Context context;
private Handler mHandler = new Handler();
public CustomTimerTask(Context con) {
this.context = con;
}
@Override
public void run() {
new Thread(new Runnable() {
public void run() {
mHandler.post(new Runnable() {
public void run() {
Toast.makeText(context, "In Timer", Toast.LENGTH_SHORT).show();
}
});
}
}).start();
}
}
最简单的方法(IMO)是:
关键是MyActivity.this.runOnUiThread(Runnable)。我已经将所有这些信息整合到一个完整的工作代码中,请看,这对我不起作用!它仍然给出了相同的错误:java.lang.RuntimeException:无法在未调用Looper.prepare()的线程内创建处理程序
new Timer().scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
final String message = "Hi";
MyActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MyActivity.this, message, Toast.LENGTH_SHORT).show();
}
});
}
});