??? ?掌握布局與控件的使用方法
??? ?掌握有序廣播機(jī)制，根據(jù)廣播接收者的優(yōu)先級(jí)順序接收廣播
??? ?掌握廣播攔截機(jī)制

通過合理布局來搭建界面，界面效果如下圖所示。采用有序廣播方式，將下方小鴨子優(yōu)先級(jí)分別設(shè)置1000、800、600。
1、當(dāng)點(diǎn)擊大喇叭后彈出“有序報(bào)數(shù)”，下方小鴨子從左到右依次報(bào)數(shù)“1”、“2”、“3”；
2、將第二個(gè)小鴨子優(yōu)先級(jí)設(shè)置為1000，注冊(cè)位置調(diào)整到左邊第一個(gè)小鴨子前邊，當(dāng)點(diǎn)擊大喇叭后彈出“有序報(bào)數(shù)”，下方中間小鴨子首先報(bào)數(shù)“1”，之后左邊小鴨子報(bào)數(shù)“2”，最后右邊小鴨子報(bào)數(shù)“3”；
3、設(shè)計(jì)攔截機(jī)制，當(dāng)點(diǎn)擊大喇叭后彈出“有序報(bào)數(shù)”，下方中間小鴨子首先報(bào)數(shù)“1”，之后其余小鴨子不再報(bào)數(shù)。
鼓勵(lì)使用有序廣播機(jī)制和廣播攔截機(jī)制，自主設(shè)計(jì)類似功能的實(shí)驗(yàn)案例。

activity_main.xml?

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

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="30dp"
        android:layout_marginTop="60dp">

        <ImageButton
            android:id="@+id/horn"
            android:layout_width="180dp"
            android:layout_height="150dp"
            android:layout_centerHorizontal="true"
            android:background="@drawable/horn" />

        <TextView
            android:id="@+id/content_left"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toLeftOf="@+id/horn"
            android:background="@drawable/content_left_bg"
            android:gravity="center"
            android:text="有序報(bào)數(shù)"
            android:textColor="@color/white"
            android:visibility="gone" />
    </RelativeLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="150dp"
        android:orientation="horizontal">

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="40dp"
            android:layout_marginRight="20dp"
            android:orientation="vertical">
            <TextView
                style="@style/tittle_style"
                android:id="@+id/duck_1"
                />

            <ImageView
                android:layout_width="100dp"
                android:layout_height="100dp"
                android:background="@drawable/duck" />
        </LinearLayout>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="20dp"
            android:orientation="vertical">

            <TextView
                style="@style/tittle_style"
                android:id="@+id/duck_2"
                />
            <ImageView
                android:layout_width="100dp"
                android:layout_height="100dp"
                android:background="@drawable/duck" />
        </LinearLayout>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="20dp"
            android:orientation="vertical">

            <TextView
                style="@style/tittle_style"
                android:id="@+id/duck_3"
                />
            <ImageView
                android:layout_width="100dp"
                android:layout_height="100dp"
                android:background="@drawable/duck" />
        </LinearLayout>
    </LinearLayout>

</LinearLayout>

style.xml?

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="tittle_style">
        <item name="android:background">@drawable/tittle</item>
        <item name="android:layout_width">20dp</item>
        <item name="android:layout_height">20dp</item>
        <item name="android:visibility">gone</item>
        <item name="android:gravity">center</item>
        <item name="android:layout_marginLeft">15dp</item>
        <item name="android:textColor">@color/white</item>
    </style>
</resources>

這是設(shè)置鴨子報(bào)數(shù)的TextView的格式。

tittle.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<!--    設(shè)置漸變顏色-->
    <gradient
        android:endColor="#fe451d"
        android:startColor="#fe957f"
        android:type="linear"/>
<!--    設(shè)置圓角-->
    <corners android:radius="180dp"/>
</shape>

這是style調(diào)用的背景格式。文章來源地址http://www.zghlxwxcb.cn/news/detail-485915.html

MainActivity.java

package com.example.shiyan7;

import androidx.appcompat.app.AppCompatActivity;

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.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    TextView duck1, duck2, duck3;
    ImageButton horn;
    TextView content_left;
    MyBroadCastReceiver1 myBroadCastReceiver1;
    MyBroadCastReceiver2 myBroadCastReceiver2;
    MyBroadCastReceiver3 myBroadCastReceiver3;
    private int num = 0;

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

    private void init() {
        duck1 = findViewById(R.id.duck_1);
        duck2 = findViewById(R.id.duck_2);
        duck3 = findViewById(R.id.duck_3);
        horn = findViewById(R.id.horn);
        content_left = findViewById(R.id.content_left);
        horn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                content_left.setVisibility(View.VISIBLE);
                horn.setClickable(false);
                Intent intent = new Intent();
                intent.setAction("Count_Duck");
                sendOrderedBroadcast(intent,null);
            }
        });
    }

    private void register_Receiver() {
        IntentFilter intentFilter1=new IntentFilter();
        intentFilter1.addAction("Count_Duck");
        intentFilter1.setPriority(1000);
//        intentFilter1.setPriority(800);
        myBroadCastReceiver1=new MyBroadCastReceiver1();
        registerReceiver(myBroadCastReceiver1,intentFilter1);
        IntentFilter intentFilter2=new IntentFilter();
        intentFilter2.addAction("Count_Duck");
        intentFilter2.setPriority(800);
//        intentFilter2.setPriority(1000);
        myBroadCastReceiver2=new MyBroadCastReceiver2();
        registerReceiver(myBroadCastReceiver2,intentFilter2);
        IntentFilter intentFilter3=new IntentFilter();
        intentFilter3.addAction("Count_Duck");
        intentFilter3.setPriority(600);
        myBroadCastReceiver3=new MyBroadCastReceiver3();
        registerReceiver(myBroadCastReceiver3,intentFilter3);


    }

    class MyBroadCastReceiver1 extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            num=num+1;
            duck1.setVisibility(View.VISIBLE);
            duck1.setText(num+"");
            Log.i("duck1","我收到了廣播。");
            stop();
        }
    }

    class MyBroadCastReceiver2 extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            num=num+1;
            duck2.setVisibility(View.VISIBLE);
            duck2.setText(num+"");
            Log.i("duck2","我收到了廣播。");
//            abortBroadcast();
//            Log.i("duck2","我攔截了廣播。");
            stop();
        }
    }

    class MyBroadCastReceiver3 extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            num=num+1;
            duck3.setVisibility(View.VISIBLE);
            duck3.setText(String.valueOf(num));
            Log.i("duck3","我收到了廣播。");
            stop();
        }
    }

    private void stop() {
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(myBroadCastReceiver1);
        unregisterReceiver(myBroadCastReceiver2);
        unregisterReceiver(myBroadCastReceiver3);
    }
}

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