在我的 android 项目中，有一个活动和服务。在主布局中，我有三个控件：2 个按钮（开始和停止按钮）和一个 TextView（用于结果）。当我单击开始按钮时，服务将启动并通过 localbroadcastmanager 向主要活动发送一条短信，活动必须显示TextView 中的消息，但这没有发生。我还应该补充一点，我已将 Android 支持库 v4 添加到我的项目中，并且在运行应用程序时我没有收到任何错误和崩溃。我已经在真实设备和 genymotion 上测试了这些代码，但我没有得到想要的结果。如果您告诉我的代码有什么问题，我会：这是我的活动代码：
package ir.sanatnegar.lbcm;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class LBCMActivity extends Activity {
Button btnStart;
Button btnStop;
TextView tvMessage;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver, new IntentFilter("SAED"));
btnStart = (Button) findViewById(R.id.btnStart);
btnStart.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
startService(new Intent(LBCMActivity.this, MyService.class));
}
});
btnStop = (Button) findViewById(R.id.btnStop);
btnStop.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
stopService(new Intent(LBCMActivity.this, MyService.class));
}
});
}
@Override
protected void onPause() {
LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
super.onPause();
}
@Override
protected void onResume() {
LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver, new IntentFilter("SAED"));
super.onResume();
}
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
Log.i("LOG", "Message Received ... ");
String message = intent.getStringExtra("message");
tvMessage.setText(message);
}
};
}
// 服务代码：
package ir.sanatnegar.lbcm;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
public class MyService extends Service {
@Override
public IBinder onBind(Intent arg0) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i("LOG", "onStartCommand occured");
sendMessage();
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
Log.i("LOG", "onDestroty occured");
super.onDestroy();
}
private void sendMessage()
{
Log.i("LOG", "Broadcasting Message ...");
Intent intent = new Intent("SAED");
intent.putExtra("message", "This is a message from MyService!!!");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}
}