Android Handler Message 里面的message.what, message.arg1,message.obj,obtainMessage, message.setData的使用

Android Handler Message 里面的message.what, message.arg1,message.arg2,message.obj,obtainMessage, message.setData 的使用

1 message.what: 用户定义的消息代码，以便收件人可以识别
2 message.arg1 定义传递的int 类型的值1
3 message.arg2 定义传递的int 类型的值2
4 message.obj 定义传递的值由于类型是object(对象) 所以比较常用,可以传递各种值
5 handler.obtainMessage() 带参数形式发送消息,主要的却别代价可以通过下面的demo 区分,
6 message.setData() 使用bundle 的实行传参

 

下面写了一个demo具体的说下使用

 

主要代码如下

public class MainActivity extends AppCompatActivity implements Handler.Callback {

    private Handler handler;
    private TextView textView;

    private MesBean mesBean = new MesBean("张三丰", "男", 108);

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

        textView = findViewById(R.id.text_content);

        handler = new Handler(this);

        findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 开启一个线程
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        Message message = Message.obtain();
                        //用户定义的消息代码，以便收件人可以识别
                        message.what = 1;
                        // 定义传递的int 类型的值
                        message.arg1 = 119;
                        message.arg2 = 120;
                        // 定义传递的值由于类型是object(对象) 所以比较常用,可以传递各种值
                        message.obj = "传送的内容:哇咔咔";
                        handler.sendMessage(message);

                    }
                });
            }
        });

        findViewById(R.id.btn1).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        Message message = Message.obtain();
                        //用户定义的消息代码，以便收件人可以识别
                        message.what = 2;
                        // 定义传递的值定义类型为bean
                        message.obj = mesBean;
                        handler.sendMessage(message);
                    }
                });
            }
        });

        findViewById(R.id.btn2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        Message message = Message.obtain();
                        //用户定义的消息代码，以便收件人可以识别
                        message.what = 3;
                        // setData 传值
                        Bundle bundle = new Bundle();
                        bundle.putString("Name", "张三丰");
                        bundle.putString("Sex", "男");
                        bundle.putInt("Age", 108);
                        message.setData(bundle);
                        handler.sendMessage(message);
                    }
                });
            }
        });

        findViewById(R.id.btn3).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        handler.obtainMessage(4, mesBean).sendToTarget();
                    }
                });
            }
        });

    }

    @Override
    public boolean handleMessage(@NonNull Message msg) {
        switch (msg.what) {
            case 1:
                String info = (String) msg.obj;
                int mes1 = msg.arg1;
                int mes2 = msg.arg2;
                textView.setText(info + "arg1=" + mes1 + "arg2=" + mes2);
                break;
            case 2:
            case 4:
                MesBean mesBean1 = (MesBean) msg.obj;
                textView.setText(
                        mesBean1.getName() + "," + mesBean1.getSex() + "," + mesBean1.getAge());
                break;
            case 3:
                String name = msg.getData().getString("Name");
                String sex = msg.getData().getString("Sex");
                int age = msg.getData().getInt("Age");
                textView.setText(name + sex + age);
                break;

        }
        return false;
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (handler !=null){
            handler.removeCallbacksAndMessages(null);
            handler = null;
        }
    }
}

bean 文件

public class MesBean {
    private String Name;
    private String Sex;
    private int Age;

    public MesBean(String Name, String Sex, int Age) {
        this.Name = Name;
        this.Sex = Sex;
        this.Age = Age;
    }

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getSex() {
        return Sex;
    }

    public void setSex(String sex) {
        Sex = sex;
    }

    public int getAge() {
        return Age;
    }

    public void setAge(int age) {
        Age = age;
    }
}

xml 代码如下

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">


    <Button
            android:id="@+id/btn"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="点击发送消息" />


    <Button
            android:id="@+id/btn1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="传参的形式" />

    <Button
            android:id="@+id/btn2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="setData点击发送Bean消息" />

    <Button
            android:id="@+id/btn3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="obtainMessage点击发送Bean消息" />


    <TextView
            android:id="@+id/text_content"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="接受消息"
            android:textColor="#FF4444"
            android:textSize="20sp" />

</LinearLayout>

demo 地址,如果有需要的请点击查看

本文地址：https://blog.csdn.net/qq_33210042/article/details/112521010