Question

我有一个扩展BroadcastReceiver的课程。收到短信后，我想将信息传递给我的主要活动类，以便在一个方框中显示文字（如果已有文字，则附加）。

public class SmsReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent)
    {
        Intent i = new Intent(context, MainActivity.class);
            i.putExtra("updatedString","Hello");
            context.startActivity(i);
    }
}

MainActivity.java

public class MainActivity extends Activity{

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

        Bundle extras = getIntent().getExtras();
        if(extras!=null){
            results = (TextView) findViewById(R.id.results);
            results.setVisibility(View.VISIBLE);
            results.append(extras.getString("updatedString"));
        }

}

我只有一个活动类（MainActivity.java）。但是，当我这样做时，我得到一个异常无法暂停活动。

Answer 1

你有三种方式：
1）您可以在MainActivity内定义广播，如下所示：
在onCreate()

registerReceiver(smsReceiver, new IntentFilter(SMS_RECIEVED));

并在MainActivity

中定义smsReciver

private BroadcastReceiver smsReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        //you can update textBox here
        handler.postDelayed(sendUpdatesToUI, 10);  
    }
};

定义可运行以更新UI

private Runnable sendUpdatesToUI = new Runnable() {
    public void run() {
        update();
    }
};

和更新方法

private void update(String text) {
    textView.setText(textView.getText().toString() + text);
}

2）在Activity和BroadCastReceiver

之间注册一个接收者

3）使用新Intent启动Activity以更新当前打开的Activity

Intent intent = new Intent(context, MainActivity.class);
intent.putExtra("Key", "text");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);

更新：
解释方法2
MainActivity.class

onResume()

中的

registerReceiver(broadcastReceiver, new IntentFilter(SmsReceiver.BROADCAST_ACTION));

onDestroy()

中的

unregisterReceiver(broadcastReceiver);

local broadCast（broadcastReceiver，在MainActivity.class中）

private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        updateUI(intent);
    }
};
private void updateUI(Intent intent) {
    String text = intent.getStringExtra("key");
    textView.setText(textView.getText().toString() + text);
}

SmsReceiver.class
全局属性

public static final String BROADCAST_ACTION = "your.package.name.displayevent";
private final Handler handler = new Handler();
Intent intent;
Context context;

onReceive()

中的

handler.removeCallbacks(sendUpdatesToUI);
handler.postDelayed(sendUpdatesToUI, 10);

this.context = context;//you can retrieve context from onReceive argument

this.intent = new Intent(BROADCAST_ACTION);

定义两个方法

private Runnable sendUpdatesToUI = new Runnable() {
    public void run() {
        display();
    }
};

private void display() {
    intent.putExtra("key", text);
    context.sendBroadcast(intent);
}

Answer 2

修改您的代码，如下所示。

let test = fun x y u ->
(for i = 0 to (w-1) do
    for j = 0 to (h-1) do
        if i > x then
            if j > y then
                tab.(i).(j) = (if u = "DR" then tab.(i).(j) else 0)
            else
                if j = y then
                    tab.(i).(j) = (if u = "R" then tab.(i).(j) else 0)
                else
                    tab.(i).(j) = (if u = "UR" then tab.(i).(j) else 0)
        else
            if i = x then
                if j > y then 
                    tab.(i).(j) = (if u = "D" then tab.(i).(j) else 0)
                else
                    tab.(i).(j) = (if u = "U" then tab.(i).(j) else 0)
            else
                if j > y then
                    tab.(i).(j) = (if u = "DL" then tab.(i).(j) else 0)
                else
                    if j = y then
                        tab.(i).(j) = (if u = "L" then tab.(i).(j) else 0)
                    else
                        tab.(i).(j) = (if u = "UL" then tab.(i).(j) else 0)
    done
done)

从BroadcastReceiver类发送Intent到当前正在运行的活动

2 个答案: