Android Studio初学者实例：广播

本章先不进行详细讲解，后续补充，如有问题请在评论区打出来~~~

共有两个实例：饭堂开饭与数鸭子

第一个实例效果：

数鸭子效果图

 饭堂实例:

首先是布局代码

 对应的逻辑java代码

import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.ImageView;import android.widget.TextView;import androidx.appcompat.app.AppCompatActivity;public class MainActivity62 extends AppCompatActivity {    private ImageView image;    private TextView tv_left_content, tv_right_content;    private MyBroadcastReceiver receiver;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main62);        init();    }    private void init() {        image = findViewById(R.id.image);        tv_left_content = findViewById(R.id.tv_left_content);        tv_right_content = findViewById(R.id.tv_right_content);        receiver = new MyBroadcastReceiver();        String action = "Open_Rice";        IntentFilter intentFilter = new IntentFilter(action);        registerReceiver(receiver, intentFilter);        image.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                tv_right_content.setText("开饭啦！");                Intent intent = new Intent();                intent.setAction("Open_Rice");                sendBroadcast(intent);            }        });    }    class MyBroadcastReceiver extends BroadcastReceiver {        @Override        public void onReceive(Context context, Intent intent) {            if (intent.getAction().equals("Open_Rice")) {                tv_left_content.setVisibility(View.VISIBLE);            }        }    }    @Override    protected void onDestroy() {        super.onDestroy();        unregisterReceiver(receiver);    }}

 数鸭子的界面代码

 对应的逻辑Java代码

import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.ImageView;import android.widget.TextView;import androidx.appcompat.app.AppCompatActivity;//相比无序广播，有序广播的广播效率较低，但此类型是有先后顺序的，并可被拦截。//同样的 继承BroadcastReceiver//动态注册MyReceiver广播//MyReceiver  one = new MyReceiver ();//IntentFilter filter = new IntentFilter();数值越大，优先级越高。如果两个广播接收者的优先级相同，则先注册的广播接收者优先级高。//filter.setPriority(1000);//filter.addAction("Intercept_Stitch");//registerReceiver(one,filter);public class MainActivity63 extends AppCompatActivity {    private MyBroadcastReceiverOne one;    private MyBroadcastReceiverTwo two;    private MyBroadcastReceiverThree three;    private ImageView iv_horn;    private TextView tv_left_content, tv_one, tv_two, tv_three;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main63);        registerReceiver();        init();    }    private void init() {        iv_horn = findViewById(R.id.iv_horn);        tv_left_content = findViewById(R.id.tv_left_content);        tv_one = findViewById(R.id.tv_one);        tv_two = findViewById(R.id.tv_two);        tv_three = findViewById(R.id.tv_three);        iv_horn.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                tv_left_content.setVisibility(View.VISIBLE);                iv_horn.setClickable(false);  //设置喇叭图片为不可点击的状态                Intent intent = new Intent();                intent.setAction("Count_Ducks");      // 定义广播的事件类型                //这里与无序广播会有不同 sendBroadcast方法为发送无序                sendOrderedBroadcast(intent, null);  // 发送有序广播//                MyBroadcastReceiverThree receiver = new MyBroadcastReceiverThree();//                sendOrderedBroadcast(intent,null,receiver, null, 0, null, null); // 发送有序广播            }        });    }    private void registerReceiver() {        // 动态注册MyBroadcastReceiverTwo广播        two = new MyBroadcastReceiverTwo();        IntentFilter filter2 = new IntentFilter();        filter2.setPriority(1000);        filter2.addAction("Count_Ducks");        registerReceiver(two, filter2);        // 动态注册MyBroadcastReceiverOne广播        one = new MyBroadcastReceiverOne();        IntentFilter filter1 = new IntentFilter();        filter1.setPriority(1000);        filter1.addAction("Count_Ducks");        registerReceiver(one, filter1);        // 动态注册MyBroadcastReceiverThree广播        three = new MyBroadcastReceiverThree();        IntentFilter filter3 = new IntentFilter();        filter3.setPriority(600);        filter3.addAction("Count_Ducks");        registerReceiver(three, filter3);    }    //同样的 继承BroadcastReceiver  重写onReceive方法 当接收时控制图片、鸭子数量等    private int num = 0; // 存放接收到广播消息时鸭子图片上方需要显示的序号    class MyBroadcastReceiverOne extends BroadcastReceiver {        @Override//        用于接收程序发送的有序广播        public void onReceive(Context context, Intent intent) {            tv_one.setVisibility(View.VISIBLE);     //将第一只鸭子图片上方的序号控件tv_one设置为显示状态            num = num + 1;            tv_one.setText(num + "");       //将变量num显示到控件tv_one上            Log.i("BroadcastReceiverOne", "广播接收者One,接收到了广播消息");            delay();        //将广播消息延迟500毫秒后传递到下一个广播接收者中        }    }    class MyBroadcastReceiverTwo extends BroadcastReceiver {        @Override        public void onReceive(Context context, Intent intent) {            tv_two.setVisibility(View.VISIBLE);            num = num + 1;            tv_two.setText(num + "");            Log.i("BroadcastReceiverTwo", "广播接收者Two,接收到了广播消息");//            abortBroadcast(); //拦截有序广播//            Log.i("BroadcastReceiverTwo","我是广播接收者Two，广播消息被我拦截了");            delay();        }    }    class MyBroadcastReceiverThree extends BroadcastReceiver {        @Override        public void onReceive(Context context, Intent intent) {            tv_three.setVisibility(View.VISIBLE);            num = num + 1;            tv_three.setText(num + "");            Log.i("BroadcastReceiverThree", "广播接收者Three,接收到了广播消息");            delay();            //终结广播，若在第一只鸭子中执行  二和三都不会接收到广播  终结后面执行的广播  根据优先级//            abortBroadcast();        }    }    /**     * 延迟500毫秒     */    private void delay() {        try {            Thread.sleep(500);        } catch (InterruptedException e) {            e.printStackTrace();        }    }    @Override    protected void onDestroy() {        super.onDestroy();        unregisterReceiver(one);        unregisterReceiver(two);        unregisterReceiver(three);    }}