实例化广播接收者异常

最新推荐文章于 2023-10-30 16:49:33 发布

转载最新推荐文章于 2023-10-30 16:49:33 发布 · 484 阅读

文章标签：

#广播 #exception #进度条 #同步

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最近在做一个内部类的广播接收者来实现音乐播放的进度条同步，然后一直出现如下错误

02-15 08:38:28.958: W/dalvikvm(8767): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
02-15 08:38:29.009: E/AndroidRuntime(8767): FATAL EXCEPTION: main
02-15 08:38:29.009: E/AndroidRuntime(8767): java.lang.RuntimeException: Unable to instantiate receiver com.choco.music.MainActivity$PlayerReceiver: java.lang.InstantiationException: can't instantiate class com.choco.music.MainActivity$PlayerReceiver; no empty constructor

应该就是广播接收者无法实例化，百度N天后终于找到原因。。
因为receiver是在清单文件中注册的，属于静态注册的方式，静态注册就必须加上public static，这有带来许多不便，所以只能在代码中进行动态注册

package com.example.brocastdemo;

import android.app.Activity;
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.view.View.OnClickListener;
import android.widget.Button;
//采用动态方式注册一个作为内部类的广播接收者
public class MainActivity extends Activity
{
    private Button but = null;
    private MyReceiver receiver = null;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        but = (Button) findViewById(R.id.but);

        /*动态方式注册广播接收者*/
        receiver = new MyReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction("com.aaa");
        this.registerReceiver(receiver, filter);

        but.setOnClickListener(new OnClickListener()
        {

            @Override
            public void onClick(View v)
            {
                Intent intent = new Intent("com.aaa");
                MainActivity.this.sendBroadcast(intent);
            }
        });
    }

    public class MyReceiver extends BroadcastReceiver
    {
        @Override
        public void onReceive(Context context, Intent intent)
        {
            if (intent.getAction().equals("com.aaa"))
            {
                Log.i("MainActivity","成功收到广播");
            }
        }
    }
    @Override
    protected void onDestroy()
    {
        if(receiver!=null)
            this.unregisterReceiver(receiver);
    }
}