Question

我尝试创建我的第一个服务，当然没有成功。但这个应用程序成功编译，并没有在AndroidMonitor中给出任何错误。简而言之，按钮没有反应按压。我添加到Android Manifest所需的行：

+----+-----------+-------+
| id | timestamp | count |
+----+-----------+-------+
|  1 |      1970 |     3 |
|  2 |      1971 |     2 |
+----+-----------+-------+

ClientActivity

<service android:name=".MyService"></service>

为MyService

package com.example.servicetest;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class ClientActivity extends Activity {
    private Button btnStartService;
    private Button btnStopService;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnStartService = (Button) findViewById(R.id.btnStartService);
        btnStopService = (Button) findViewById(R.id.btnStopService);
        initButtonsOnClick();
    }

    private void initButtonsOnClick() {
        OnClickListener listener = new OnClickListener() {
            public void onClick(View v) {
                switch (v.getId()) {
                    case R.id.btnStartService:
                        startMyService();
                        break;
                    case R.id.btnStopService:
                        stopMyService();
                        break;
                    default:
                        break;
                }
            }
        };
        btnStartService.setOnClickListener(listener);
        btnStopService.setOnClickListener(listener);
    }

    private void startMyService() {
        Intent serviceIntent = new Intent(this, MyService.class);
        startService(serviceIntent);
    }

    private void stopMyService() {
        Intent serviceIntent = new Intent(this, MyService.class);
        stopService(serviceIntent);
    }
}

Answer 1

服务是一个可以在后台执行长时间运行的应用程序组件，而它不提供用户界面。 - 来自官方Android文档。

现在，由于服务没有ui，因此在使用服务时无法显示吐司。

Answer 2

Toast 始终与Application的主线程一起使用。所以你必须确保在主线程中使用线程。

如果你想在服务中使用Toast，那么你必须使用Handler。

请查看以下关于Handler in Thread的示例：

private Context mContext;

@Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        mContext=getApplicationContext();//Get the context here
    }

    //Use this method to show toast
    void showToast(){
        if(mContext != null){
        Handler handler = new Handler(Looper.getMainLooper());
        handler.post(new Runnable() {
            @Override
            public void run() 
            {
                    Toast.makeText(mContext, "Display your message here", Toast.LENGTH_SHORT)show();
            }
        });

    }
}

Answer 3

public class ClientActivity extends Activity {

    private Button btnStartService;
    private Button btnStopService;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btnStartService = (Button) findViewById(R.id.btnStartService);
        btnStopService = (Button) findViewById(R.id.btnStopService);

        btnStartService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent serviceIntent = new Intent(this, MyService.class);
                startService(serviceIntent);
            }
        });

        btnStopService.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent serviceIntent = new Intent(this, MyService.class);
                stopService(serviceIntent);
            }
        });
    }

}

使用此按钮单击

DisplayOrientations currentOrientation = 
Windows.Graphics.Display.DisplayProperties.CurrentOrientation;

Answer 4

Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable() {

    @Override
    public void run() {
         Toast.makeText(getApplicationContext(), 
                       "helllo", 
                       Toast.LENGTH_SHORT).show();              
    }
});

Answer 5

在您的服务中添加以下代码

  if (getActivity()!=null){
                        getActivity().runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                Toast.makeText(getActivity(), "Your Text", Toast.LENGTH_SHORT).show();

                            }
                        });
                    }

吐司不在服务中工作

5 个答案: