【框架】EventBus

最新推荐文章于 2025-08-16 22:13:48 发布

转载最新推荐文章于 2025-08-16 22:13:48 发布 · 47 阅读

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#移动开发

本文通过两个示例展示了EventBus的基本用法，包括如何发送和订阅消息，特别关注了不同线程模式下的行为。示例一在一个活动中发送消息并后台处理，示例二通过Fragment展示如何跨组件通信。

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EventBus线程问题

DEMO1:

public class EventBusMessage {
    private int what;
    private int arg1;
    private int arg2;

    public EventBusMessage() {
    }

    public int getArg1() {
        return arg1;
    }

    public void setArg1(int arg1) {
        this.arg1 = arg1;
    }

    public int getArg2() {
        return arg2;
    }

    public void setArg2(int arg2) {
        this.arg2 = arg2;
    }

    public int getWhat() {
        return what;
    }

    public void setWhat(int what) {
        this.what = what;
    }

    public EventBusMessage(int arg1, int arg2, int what) {
        this.arg1 = arg1;
        this.arg2 = arg2;
        this.what = what;
    }
}

/**
 * 1.加载依赖库
 * 2.发送消息
 * 3.订阅消息
 */
public class MainActivity extends AppCompatActivity {

    private TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        EventBus.getDefault().register(this);
        tv = ((TextView) findViewById(R.id.tv));
    }

    public void btnClick(View view) {
        //使用EventBus发送一条消息
//        new Thread(new Runnable() {
//            @Override
//            public void run() {
        EventBusMessage event = new EventBusMessage();
        event.setWhat(10);
        EventBus.getDefault().post(event);
        Log.d("google_lenve_fb", "btnClick: " + Thread.currentThread().getName());

//            }
//        }).start();
    }

    //订阅消息
    @Subscribe(threadMode = ThreadMode.BACKGROUND)
    public void changeTextViewText(EventBusMessage msg) {
        Log.d("google_lenve_fb", "changeTextViewText: " + Thread.currentThread().getName());
//        tv.setText(str);
        Toast.makeText(MainActivity.this, "123456:" + msg.getWhat(), Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        EventBus.getDefault().unregister(this);
    }
}

DEMO2:

效果图：

public class LeftFragment extends Fragment {

    private List<String> list;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.left_fg_layout, null);
        ListView listView = (ListView) view.findViewById(R.id.lv);
        initData();
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, list);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                EventBus.getDefault().post(list.get(position));
            }
        });
        return view;
    }

    private void initData() {
        list = new ArrayList<>();
        list.add("day1.txt");
        list.add("day2.txt");
        list.add("day3.txt");
        list.add("day4.txt");
    }
}

public class RightFragment extends Fragment {
    private TextView tv;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.right_fg_layout, null);
        tv = ((TextView) view.findViewById(R.id.content));
        EventBus.getDefault().register(this);
        return view;
    }

    @Subscribe
    public void changeText(String fileName) {
        InputStream is = null;
        StringBuffer result = new StringBuffer();
        try {
            is = getActivity().getAssets().open(fileName);
            int len = 0;
            byte[] buf = new byte[1024];
            while ((len = is.read(buf)) != -1) {
                result.append(new String(buf, 0, len));
            }
            tv.setText(result.toString());
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        EventBus.getDefault().unregister(this);
    }
}