EventBus学习笔记

最新推荐文章于 2019-09-02 12:00:41 发布

原创最新推荐文章于 2019-09-02 12:00:41 发布 · 167 阅读

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#布局

EventBus是一个非常实用的工具，个人感觉在某种程度上是可以替代广播的，之前没有用过EventBus，今天看了下，做了个小的demo，了解下功能的实现。

这边做了三个Activity，在三个Activity中做界面操作。

具体看代码：

第一步：gradle中添加依赖

compile 'org.greenrobot:eventbus:3.0.0'

第二步，代码中使用

MainActivity:

public class MainActivity extends AppCompatActivity {

    private Button btn_login;
    private TextView tv_status;

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

//注册EventBus
        EventBus.getDefault().register(this);
        btn_login = (Button) findViewById(R.id.btn_login);
        tv_status= (TextView) findViewById(R.id.tv_login_result);
        btn_login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this,RegistActivity.class);
                startActivity(intent);
            }
        });
    }

   @Subscribe          //订阅事件FirstEvent
public  void onEventMainThread(MessageEvent event){
    String msg=event.getMessage();
    tv_status.setText(""+msg);//获取事件中传递的参数
}
    @Override    protected void onDestroy() {        super.onDestroy();

//解除注册
        EventBus.getDefault().unregister(this);
    }
}

xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="opcv.test.com.eventtest.MainActivity">

    <Button
        android:id="@+id/btn_login"
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:layout_marginBottom="455dp"
        android:layout_marginTop="5dp"
        android:text="登录"
        android:textSize="12sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>

    <TextView
        android:id="@+id/tv_login_result"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        android:text="登录结果显示"
        app:layout_constraintTop_toBottomOf="@+id/btn_login"/>
</android.support.constraint.ConstraintLayout>

MessageEvent：

public class MessageEvent {
    private String message;
    public  MessageEvent(String message ){
        this.message=message;
    }


    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }
}

RegistActivity代码：
public class RegistActivity extends AppCompatActivity {

    private TextView name;
    private TextView pwd;
    private Button submit;
    private TextView register;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.regist_activity);
        EventBus.getDefault().register(this);
        register = (TextView) findViewById(R.id.btn_register);
        submit = (Button) findViewById(R.id.btn_ok);

        register.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(RegistActivity.this,LoginActivity.class);
                startActivity(intent);
            }
        });
    }

    @Subscribe          //订阅事件FirstEvent
    public  void onEventMainThread(MessageEvent event){
        String msg = event.getMessage();
        if (msg.equals("成功！")){
            Log.d("RegistActivity", "onEventMainThread: "+msg);
            RegistActivity.this.finish();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        EventBus.getDefault().unregister(this);
    }
}
xml：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="0px"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:orientation="vertical"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintVertical_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent">


        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="10dp"
            android:orientation="horizontal">

            <Button
                android:id="@+id/btn_register"
                android:layout_width="wrap_content"
                android:layout_height="30dp"
                android:layout_gravity="center_horizontal"
                android:layout_marginTop="10dp"
                android:background="@drawable/btn_bg"
                android:text="注册"
                android:textColor="#ffffff"
                android:textSize="12sp"/>

            <Button
                android:id="@+id/btn_ok"
                android:layout_width="wrap_content"
                android:layout_height="30dp"
                android:layout_gravity="center_horizontal"
                android:layout_marginLeft="10dp"
                android:layout_marginTop="10dp"
                android:background="@drawable/btn_bg"
                android:text="确定"
                android:textColor="#ffffff"
                android:textSize="12sp"/>
        </LinearLayout>


    </LinearLayout>
</android.support.constraint.ConstraintLayout>

LoginActivity:

public class LoginActivity extends AppCompatActivity {

    private TextView name;
    private TextView pwd;
    private Button submit;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login_activity);
        name = (TextView) findViewById(R.id.et_name);
        pwd = (TextView) findViewById(R.id.et_pwd);
        submit = (Button) findViewById(R.id.btn_ok);

        submit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (name.getText().toString().trim().equals("")) {
                    EventBus.getDefault().post(new MessageEvent("用户名为空"));
                    finish();
                } else if (pwd.getText().toString().trim().equals("")) {
                    EventBus.getDefault().post(new MessageEvent("密码为空"));
                    finish();
                } else {
                    EventBus.getDefault().post(new MessageEvent("成功！"));
                    finish();
                }
            }
        });
    }

}

xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="0px"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:layout_marginTop="244dp"
        android:orientation="vertical"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <EditText
            android:id="@+id/et_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/edit_shap"
            />
        <EditText
            android:id="@+id/et_pwd"
            android:layout_marginTop="5dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/edit_shap"
            />
        <Button
            android:id="@+id/btn_ok"
            android:layout_width="wrap_content"
            android:layout_marginTop="10dp"
            android:layout_height="30dp"
            android:text="确定"
            android:textSize="12sp"
            android:textColor="#ffffff"
            android:background="@drawable/btn_bg"
            android:layout_gravity="center_horizontal"/>

    </LinearLayout>

</android.support.constraint.ConstraintLayout>

其他的资源文件就不上传了，不想写用默认的吧