你好，我试了很多次，当我点击按钮时，它不显示烤面包和广播接收器。

下面附上的代码，请纠正我的错误，它运行成功，但当点击按钮时，什么也没有发生，我试图在activity_main.xml中编辑，但什么也没有发生。

MainActivity.java

package com.example.myapplication;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    // broadcast a custom intent.
    public void broadcastIntent(View view){
        Intent intent = new Intent();
        intent.setAction("com.myapplication.BOOT_COMPLETED"); sendBroadcast(intent);
MyReceiver.java
package com.example.myapplication;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
public class MyReceiver extends BroadcastReceiver{
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context, "Intent Detected.", Toast.LENGTH_LONG).show();
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapplication">
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true">
        <activity android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name="MyReceiver"
            android:exported="false">
            <intent-filter>
                <action android:name="com.myapplication.BOOT_COMPLETED">
                </action>
            </intent-filter>
        </receiver>
    </application>
</manifest>
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    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"
    tools:context=".MainActivity">
    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Example of Broadcast"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:textSize="30dp" />
    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Tutorials point "
        android:textColor="#ff87ff09"
        android:textSize="30dp"
        android:layout_above="@+id/imageButton"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="40dp" />
    <ImageButton
        android:id="@+id/imageButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:minWidth="48dp"
        android:minHeight="48dp"
        tools:ignore="SpeakableTextPresentCheck" />
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/imageButton"
        android:layout_centerHorizontal="true"
        android:onClick="broadcastIntent"
        android:text="broadcast_intent" />
</RelativeLayout>
    
android
android-studio
android-layout
broadcastreceiver
android-toast
Alice
发布于 2021-10-28
2 个回答
Aly Abdelaal
发布于 2021-10-28
0 人赞同

I hope this could help
import androidx.appcompat.app.AppCompatActivity;
import android.content.BroadcastReceiver;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity {
    BroadcastReceiver br;
    IntentFilter filter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        br = new MyReceiver();
        filter= new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
        filter.addAction(Intent.ACTION_AIRPLANE_MODE_CHANGED);
    public void broadcastIntent(View view){
        Intent intent = new Intent();
        intent.setAction("com.myapplication.BOOT_COMPLETED");
        sendBroadcast(intent);
        this.registerReceiver(br, filter);
也见此链接
https://developer.android.com/guide/components/broadcasts
    
akhil nair
发布于 2021-10-28
0 人赞同

你正在使用一个宣称的接收者.这个接收器会被其他应用程序或一些系统事件在外部调用。
然后，接收器成为你的应用程序的一个单独的入口点，这意味着，如果应用程序当前没有运行，系统可以启动应用程序并提供广播。
如果你想在应用程序中触发这个接收器，你应该注册这个接收器。在你的案例中，在MainActivity内的onCreate或onResume如下所示
broadcastReceiver = new MyReceiver ()
Intent filter = new IntentFilter("com.myapplication.BOOT")
registerReceiver(broadcastReceiver, filter)